Late Cretaceous climate in the Canadian Arctic: Multi-proxy constraints from Devon Island

Accepted Manuscript Late Cretaceous climate in the Canadian Arctic: multi-proxy constraints from Devon Island

James R. Super, Karen Chin, Mark Pagani, Hui Li, Clay Tabor, David Harwood, Pincelli M. Hull PII: DOI: Reference:

S0031-0182(17)30766-6 doi:10.1016/j.palaeo.2018.03.004 PALAEO 8692

To appear in:

Palaeogeography, Palaeoclimatology, Palaeoecology

Received date: Revised date: Accepted date:

21 July 2017 6 March 2018 8 March 2018

Please cite this article as: James R. Super, Karen Chin, Mark Pagani, Hui Li, Clay Tabor, David Harwood, Pincelli M. Hull , Late Cretaceous climate in the Canadian Arctic: multi-proxy constraints from Devon Island. The address for the corresponding author was captured as affiliation for all authors. Please check if appropriate. Palaeo(2017), doi:10.1016/j.palaeo.2018.03.004

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ACCEPTED MANUSCRIPT

Late Cretaceous climate in the Canadian Arctic: multi-proxy

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constraints from Devon Island

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James R. Supera*, Karen Chinb, Mark Pagania, Hui Lia, Clay Tabor c, David Harwoodd, Pincelli M. Hulla a

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Department of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven CT 06511, USA b Department of Geological Sciences and Museum of Natural History, University of Colorado, Boulder, UCB 265, CO 80309, USA c Center for Integrative Geosciences, Beach Hall Room 207, 354 Mansfield Road - Unit 1045, Storrs, CT 06269 d Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0340, USA

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*correspondence to: [email protected] (J R Super) [email protected] (K Chin) [email protected] (H Li) [email protected] (C R Tabor) [email protected] (D Harwood) [email protected] (P M Hull)

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ACCEPTED MANUSCRIPT Abstract Arctic climate in the Late Cretaceous has long been recognized to have been warm and wet relative to the present, but quantitative assessments of paleoclimate have been challenging due, in part, to disagreements between proxies in marine and terrestrial environments. This study

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provides a first multiproxy evaluation of Late Cretaceous (~93-90 Ma to 73-72 Ma) paleoclimate

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and paleohydrology from Devon Island in the Canadian High Arctic (modern location: 76°17’ N,

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91°12’W; Late Cretaceous location: ~71°30’ N, ~24°30’W). Surface temperatures are reconstructed at ~12.6 to 20.6°C for the ocean and 11.7 to 16.9°C over land, using glycerol

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dialkyl glycerol tetraether (GDGT) based proxies measured from marine (TEX86) and terrestrial

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samples (MBT’5ME). These proxies are likely skewed towards warm month temperatures, based on novel analysis and interpretation of biomarkers in sediment and co-occurring marine

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vertebrate coprolites. The hydrogen isotopic composition (2H) of precipitation is constrained to

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have varied from –123 ‰ to –82 ‰ (VSMOW) using evidence from n-alkanes likely derived from higher plants. 18O of shelfal marine surface water is constrained to have been between –

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10.5 ‰ to –3.4 ‰, using phosphate oxygen isotopes of marine vertebrate teeth and coprolites.

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From these, marine salinity is modeled to have varied from 10 PSU and 30 PSU, indicative of

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periodic freshwater influx. These estimates indicate that large marine vertebrates lived and fed, at least intermittently, in near-shore brackish waters. Finally, the Arctic was similarly warm in both the Late Cretaceous and Paleocene/Eocene, but the Late Cretaceous isotopic composition of precipitation at Devon Island was enriched in the heavy isotope of hydrogen by up to +60 to +70 ‰ relative to Arctic Eocene sites. The combination of techniques used here reduces uncertainties related to the application of proxies to an environment without a modern analogue, providing novel paleoclimatic constraints on the Late Cretaceous Arctic region.

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Keywords: Coniacian, Campanian, TEX86, Coprolites, GDGTs, Seasonality

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ACCEPTED MANUSCRIPT 1. Introduction The climate of the Late Cretaceous was characterized by globally high temperatures relative to the modern (Barron et al., 1983, Huber 2002; Hay, 2012; Linnert et al., 2014), with temperate forests extending to the margins of the Arctic Ocean (Chin et al., 2008; Davies et al.,

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2009; Spicer and Herman, 2010; Witkowski et al., 2011; Davies et al., 2016). A lack of evidence

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for permanent sea ice in the Arctic and proxy evidence for elevated polar temperatures indicate

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greatly reduced equator-to-pole temperature gradients relative to the present, which have yet to be fully explained by global climate models (Upchurch et al., 2015; Tabor et al., 2016).

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However, the extent to which equator-to-pole temperature gradients were reduced is still in

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question, because the limited number of high latitude proxy temperature estimates vary widely (Garland et al., 2015; O’Brien et al., 2017). Proxy reconstructions of mean annual temperature

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(MAT) during the Campanian-Maastrichtian in marine and terrestrial settings in the Arctic vary

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from 18 ± 2.5°C close to the North Pole (TEX86H proxy; data from Jenkyns et al., 2004; updated to the calibration of Kim et al., 2010), to 6.3 ± 2.2 °C on the North Slope of Alaska (using the

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leaf physiogamy-based CLAMP proxy; Spicer and Herman, 2010), to 3 ± 3 °C (18Ophosphate of

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dinosaurian tooth enamel; Amiot et al., 2004). Reducing uncertainties in Arctic temperature estimates is thus key for understanding the Late Cretaceous and the role of the region in

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greenhouse climates.

The Late Cretaceous, primarily Campanian, sequences of Devon Island in the Canadian High Arctic provide a unique opportunity to address the question of Late Cretaceous Arctic temperatures. Mesozoic exposures on Devon Island occur within a regressive sequence, grading conformably from marine shales to coaly terrestrial mudstones formed along a coastal plain

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ACCEPTED MANUSCRIPT (Chin et al., 2008). Here, we generate multi-proxy and multi-environment records of high Arctic temperatures from the surface ocean (TEX86 and the 18Ophosphate of marine vertebrate teeth) and land (soil surface temperature from branched GDGT-based proxies). Additionally, we evaluate the potential utility of marine vertebrate coprolites (fossilized fecal matter) as sources of paleo-

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environmental information using biomarker and 18Ophosphate proxies.

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The Devon Island samples also allow for an assessment of the hydrological cycle of the

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Late Cretaceous Arctic. At the time, the Arctic Ocean was smaller than present and connections to the global ocean were through shallow, epicontinental seaways (Schröder-Adams et al., 2014).

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The largest of the seaways, the Western Interior Seaway (WIS), was located to the west of Devon Island and has been shown to be the location of large scale mixing of lower latitude water

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with normal marine salinity with low salinity, cooler and isotopically depleted water from the

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Arctic Ocean (Dennis et al., 2013). There is also tentative evidence for a smaller seaway

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connecting to the emerging Labrador Sea that may have connected to the Arctic Ocean close to the location of the Devon Island (Schröder-Adams et al., 2014). In addition, modeling and

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theoretical studies argue for enhanced moisture transport to high latitudes due to an invigorated

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hydrological cycle during warm climates (Pierrehumbert et al., 2002; Pagani et al., 2006; Waddel et al., 2008; Zhou et al., 2008; Krishnan et al., 2014). The combination of tectonically restricted circulation with ocean water of typical marine salinity and higher precipitation rates leads to the hypothesis of a relatively fresh Arctic Ocean during periods of global warmth (Brinkhuis et al., 2006; Zhou et al., 2008; Tabor et al., 2016). The presence of enhanced precipitation can be tested using the oxygen and hydrogen isotopes of water, with enriched isotope values attributed to decreased rainout of heavy isotopes at lower latitudes and/or increased recycling of water with

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ACCEPTED MANUSCRIPT relatively light isotopic composition back into the atmosphere from evaporation and transpiration (Jahren et al., 2009; Fricke et al., 2010; Krishnan et al., 2014). Data from Paleocene and Eocene Arctic sediments, when exchange between the Arctic and global oceans was similarly limited, supports this hypothesis showing meteoric water with enriched values of 18O and D relative to

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the modern (Pagani et al., 2006; Speelman et al., 2010). Furthermore, proxy salinity estimates of

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the Eocene Arctic Ocean using a variety of methods indicate brackish surface waters, including

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episodes of distinctly low salinity when the freshwater fern Azolla spread across the Arctic in the

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early Eocene (Brinkhuis et al., 2006; Waddel et al., 2008; Zacke et al., 2009; Speelman et al., 2010; Barke et al., 2012; Kim et al., 2014). Comparable proxy constraints on Cretaceous Arctic

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hydrology are limited, raising the question of whether early Eocene Arctic hydrology reflects general greenhouse climate dynamics. We thus present new constraints on the hydrological cycle

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of the Late Cretaceous greenhouse environment through proxy estimates of the isotopic

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composition of meteoric and marine surface waters. Altogether, our measurements provide new

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Cretaceous Arctic.

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perspectives on the poorly understood hydrology, marine salinity, and temperatures of the Late

2. Site and sample description

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2.1. Location and depositional setting Samples were collected from exposures of the Kanguk and Expedition Ford formations on northwestern Devon Island, Nunavut, Canada, at Eidsbotn graben (76°17’ N, 91°12’W) and Viks Fiord graben (76°20’ N, 91°32’ W) along the northern edge of the Canadian Arctic Platform, and located south of the Sverdrup Basin (Embry et al., 1991) (Fig. 1). The two sites were situated further south and east during the Late Cretaceous at approximately 71°30’ N,

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ACCEPTED MANUSCRIPT 24°30’W (Mathews et al., 2016). The sediments represent a regressive sequence, with distal mudstone grading into more proximal glauconitic sandstone (greensand) conformably overlain by coastal terrestrial sediment. Bentonite layers are intercalated through both terrestrial and marine sequences. Exposures at Eidsbotn graben likely represent a deeper setting than those at

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Viks Fiord graben, where interbedded coal beds were intermittently exposed subaerialy (Chin et

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al., 2008). The marine sequences represent low-sedimentation, near-shore environments

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characterized by high biological activity (Chin et al., 2008). There is evidence of terrestrial input into the marine sections, including rare woody debris, fossil pollen and spores, and silty deposits

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(Chin et al., 2008). Biostratigraphic age constraints are based on assemblages of fossil

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angiosperm pollen, marine diatoms and silicoflagellates (Chin et al., 2008; Witkowski et al., 2011; McCartney et al., 2011a,b). The base of the Eidsbotn graben section is updated here from

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Chin et al. (2008) (originally Late Santonian/Early Campanian) to an older age of approximately

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93 to 90 Ma (Late Turonian/Early Coniacian) based on new radiometric and biostratigraphic ages from stratigraphically equivalent sections of the Kanguk Formation (Davis et al., 2016). The

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top of the Eidsbotn graben section is assigned to the latest Campanian (73-72 Ma) (Fig. 1) (Chin

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et al., 2008; Witkowski et al., 2011; McCartney et al., 2011a). Witkowski et al. (2011) place the Santonian/Campanian boundary between samples EF 402 and EF 102, placing the majority of

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marine sediment samples (with the exception of EF 402, VF 303 and VF 305), all coprolites and all terrestrial sediments in the Campanian (Fig. 1). A full description of the age constraints is included in the Text S1.

2.2. Microfossils, vertebrate fossils and coprolites

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ACCEPTED MANUSCRIPT Abundant and diverse siliceous microfossils were recovered from mudstone samples, indicating high productivity that was likely seasonal due to the polar light regime (Chin et al. 2008; Witkowski et al., 2010, 2011). Body fossils and coprolites produced by large marine organisms occur within glauconitic sandstones at both Eidsbotn and Viks Fiord grabens (Chin et

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al., 2008). The body fossil record at Devon Island includes bones and teeth and provides

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evidence for productive ecosystems and a diverse community of fish and marine reptiles in

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which apex predators fed directly on plankton and benthic invertebrates (Ainley and DeMaster, 1990; Chin et al., 2008). The four marine vertebrate teeth analyzed for this study were collected

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from the same greensand interval as the coprolites from the Eidsbotn graben section. They

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represent three types of organisms, including an elasmosaurid plesiosaur, a lamniform shark and a ray-finned fish (Enchodus) (Table 1). The combined Devon Island sediments, coprolites and

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fossil teeth provide the opportunity to trace marine conditions on a variety of time scales

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(snapshots of feeding activities to multi-year sedimentary deposits) and environments (onshore

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to offshore).

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Coprolites are distinguished from sediments by morphology, micropaleontology and phosphate content. Although the coprolite producers are unknown, the size (up to 12 cm in

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length) and recognizable dietary inclusions suggest they were produced by large marine vertebrates. Further evidence for the fecal origin of the specimens is outlined in the supplementary text (Text S1). The coprolites fall into three general categories:

(1) Greensand coprolites: Characterized by 17.8 to 21.5 wt % P2O5 and an abundance of green glauconitic sand (25-63% of clasts; Chin et al., 2008). The specimens contain fragments of

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ACCEPTED MANUSCRIPT crustacean exoskeletons, pieces of mollusk shells, siliceous sponge material, and glauconitic sand. Siliceous microfossils, including radiolarians, marine diatoms and silicoflagellates are also present. These coprolites are hypothesized to have been produced by large-bodied bottom-

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feeding animals that ingested sediment along with benthic invertebrates (Chin et al., 2008).

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(2) Phosphatic coprolites: Specimens are black or tan and composed primarily of a

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microcrystalline calcium phosphate groundmass (29.0 to 37.8 wt % P2O5) and include abundant siliceous microfossils (Chin et al., 2008). The rarity of fish bone inclusions suggests that the

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producing animals were primarily planktivorous or fed upon soft-bodied invertebrates in the

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upper water column, in contrast to the benthic-feeding producers of the greensand coprolites.

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Most phosphatic coprolites are extensively burrowed (Chin et al., 2008).

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(3) Mixed coprolites: Specimens have an intermediate composition, with higher phosphate content than the greensand coprolites but with more included greensand than the phosphatic

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coprolites (Chin et al., 2008). Burrows are also common, but specimens are not as thoroughly

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bioturbated as the phosphatic coprolites.

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Precise stratigraphic placement of the coprolites and teeth was not possible because the specimens were collected from unconsolidated sediments on unstable slopes (Chin et al., 2008). At both localities, coprolites and fossil teeth were associated with thick glauconitic sandstones near the top of the Kanguk Formation, which are thought to represent a sandy, near-shore environment within the photic zone (Rigby et al., 2007). The likely stratigraphic interval of the

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ACCEPTED MANUSCRIPT coprolites and teeth is indicated in Fig. 1 and the closest marine sediment samples are EF 106 at Eidsbotn and VF 102 at Viks Fiord graben.

3. Marine vertebrate teeth and coprolites as paleoclimatic indicators

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Marine vertebrate teeth have been widely used for paleoclimate reconstructions,

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including Late Cretaceous temperature records from the Western Interior Seaway and Tethys Sea

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using carbonate clumped isotope paleothermometry (47) (Dennis et al., 2013; Petersen et al.,

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2016), and the 18Ophosphate of bioapatite (Amiot et al., 2004; Bernard et al., 2010; Pucéat et al., 2007, 2010; Kocsis et al., 2009; Kocsis et al., 2014). These authors highlight two important

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ecological considerations for the interpretation of tooth-based paleoclimate proxies. First, large marine reptiles (including plesiosaurs) likely elevated their body temperatures relative to ambient

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waters. As a result, their teeth, unlike those of apparently poikilothermic fish like Enchodus, may

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not have recorded environmental temperatures (Bernard et al., 2010; Harrel et al., 2016). Second,

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not all teeth record the same spatial and/or temporal snap-shot of the environment. The rate of replacement of teeth varies between sharks (Kim et al., 2014) and plesiosaurs (Amiot et al.,

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2010). Both types of animals were likely able to live, at least intermittently, in brackish waters

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(Zacke et al., 2009; Vandermark et al., 2014). The limited number of teeth analyzed for this study does not allow for an exploration of the variability within and between species, though the data provide an approximate marine vertebrate 18Ophosphate end-member for comparison with the coprolites.

Coprolites provide a perspective on the diet and environment of marine vertebrates distinct from that based on their teeth (Qvarnstrom et al., 2016). Coprolites were likely buried

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ACCEPTED MANUSCRIPT rapidly and lithified (Jain, 1983; Eriksson et al., 2011). High phosphorus content in coprolites is indicative of a predatory fecal producer that consumed phosphorus-rich tissues. Phosphatization of fecal matter appears to be driven by microbially mediated transformations of fecal organic phosphorus into orthophosphate in anoxic microenvironments (Briggs et al., 1993; Chin et al.,

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2003; Hollocher et al., 2010). Rapid phosphatization of feces would have helped preserve

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biomarkers that might have otherwise degraded in marine sediment (Eriksson et al., 2011).

To date, most studies of coprolite geochemistry have focused on testing the identification

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of fossil fecal material, constraining diet, and identifying the fecal-matter producer. For instance,

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Zatoń et al. (2015) used organic and inorganic geochemical methods to constrain the producers of a diverse Upper Triassic assemblage of terrestrial and marine coprolites in Poland. However,

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lipid and phosphate oxygen isotopes have been applied infrequently due to the relative rarity of

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coprolites in most settings and concerns over destructive sampling (Bull et al., 2012).

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Furthermore, the use of coprolites to reconstruct environmental factors such as temperature and the isotopic composition of water has been limited (although see Kocsis et al., 2014 for an

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exception).

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4. Materials and methods 4.1 Samples

All samples were collected in 1998 and 2003 and have been used in studies of the trophic structure of the ancient Arctic ecosystem (Chin et al., 2008), diatom assemblages (Witkowski et al., 2011), silicoflagellate assemblages (McCartney et al., 2011b), hexactinellid sponges (Rigby et al. 2007) and hesperornithiform birds (Wilson et al., 2010, 2016). Biomarkers were extracted

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ACCEPTED MANUSCRIPT and analyzed from each of 15 sediment (30 to 50 grams dry weight) and 11 coprolite samples (5 to 20 grams dry weight). Phosphate oxygen isotopes were measured on four marine vertebrate teeth and seven coprolites (Table 1). Three coprolites (VR-1, UL-52 and UL-59) were analyzed

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for both biomarkers and phosphate oxygen isotopes.

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4.2 Bulk sediment and coprolite analysis

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The organic carbon of the sediments and coprolites, as well as phosphate composition, was previously characterized for most samples (Chin et al., 2008). Additional information from

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the RockEval 6 analyses, principally Tmax, is presented here (Table S1).

4.3.1 Lipid extraction and separation

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4.3 Biomarker and phosphate oxygen isotope sample preparation and analysis

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Sediments and coprolites were freeze-dried, homogenized with mortar and pestle, and lipids were extracted with a Dionex 300 Accelerated Solvent Extractor with a solvent mixture of

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dichloromethane/methanol (2:1, v/v). Total lipid extracts were passed through silica gel columns

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using 4 ml of hexane, 4 ml of dichloromethane and 4 ml of methanol to separate aliphatic, aromatic and polar fractions for subsequent biomarker analyses. The aliphatic fraction was

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desulfurized using activated copper and n-alkanes were separated from cyclic and branched alkanes using urea adduction (Dirghangi et al., 2013). The polar fraction was passed through activated basic Al2O3 gel columns using dichloromethane/methanol (1:1; v/v) (Schouten et al., 2007). The polar fraction was then dried under a nitrogen stream at 40°C, dissolved in hexane/2propanol (99:1; v/v), and passed through a 0.45 µm PTFE filter.

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ACCEPTED MANUSCRIPT 4.3.2 n-Alkane abundance and compound-specific 13C and 2H analysis The distribution of n-alkanes was analyzed using an Agilent 7890B Gas Chromatograph (GC) fitted with a flame ionization detector (FID), a Restek Rxi-1ms capillary column (60 m x 0.25 mm i.e., 0.25 μm film thickness), helium as the carrier gas (constant flow rate of 2.0

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mL/min), and a temperature program ramping at 15°C/min from 90°C to 320°C, then held at

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320°C for 15 minutes (Krishnan et al., 2014). n-Alkanes and the isoprenoids pristane and

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phytane were identified and quantified relative to external standards (A6 and B4 from Prof.

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Schimmelman, University of Indiana) using Agilent’s Chemstation software (Table S4).

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Compound specific carbon (13C) and hydrogen (2H) were analyzed using a Thermo Trace Gas Chromatograph (GC) connected to Thermo GC-C III (for CO2) and GC-TC III (for

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H2), and measured using Thermo MAT 253 isotope ratio mass spectrometer (with the same

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column, temperature program, and external standard as described above). 13C and 2H values

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are expressed relative to Vienna Pee Dee Belemnite (VPDB) and Vienna Standard Mean Ocean

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Water (VSMOW), respectively.

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Analyses were done in duplicate and external reproducibility was ± 0.2 13C and ± 8 ‰ for 2H. In 2H analyses, H3+ can be produced during ionization, reducing the sensitivity of the instrument. The H3+ factor quantifies this effect and was measured daily using the same H2 reference gas at an elevated but stable value of 25 ppm/mV (Hren et al., 2009).

4.3.3 Glycerol dialkyl glycerol tetraether (GDGT) analysis

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ACCEPTED MANUSCRIPT Isoprenoidal and branched glycerol dialkyl glycerol tetraethers (GDGTs) were analyzed from the filtered polar fraction using an Agilent 1200 high performance liquid chromatograph (HPLC) system coupled to a 6130 quadropole mass selective detector (MSD). Compounds were separated using two UHPLC silica columns (BEH HILIC columns, 2.1 × 150 mm, 1.7 μm;

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Waters) in series (fitted with a Waters 2.1 × 5 mm silica pre-column of the same material) in a

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column compartment maintained at 30°C (Hopmans et al., 2016). Samples were eluted

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isocratically for 25 min with hexane/2-propanol (98.2:1.8; v/v), followed by a linear gradient to hexane/2-propanol (96.5:3.5; v/v) for 25 min, and then a linear gradient to hexane/2-propanol

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(90:10; v/v) over 30 min that was then maintained for 10 minutes. Flow rate was 0.2 ml/min and

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back pressure ranged from 195 to 210 bars. Total run time was 110 minutes, including 20 minutes for re-equilibration. GDGTs were detected using selective ion monitoring of the

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protonated molecules [M+H]+, with Atmospheric Pressure Chemical Ionization (APCI) source

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conditions as in Schouten et al. (2007). Samples were measured against an internal standard and quantified using a co-injected synthetic C46 standard of known concentration (Huguet et al.,

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2006a).

4.3.4 Phosphate oxygen isotopes

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A subset of teeth and coprolite samples (Table 1) was analyzed for phosphate oxygen isotopes from silver phosphate crystals prepared by John Bloch (University of New Mexico) according to the protocol from (Stephan et al. 2000). Ag3PO4 samples were degassed on a vacuum line at 400C for 2 minutes, weighed into 3.5 mm silver capsules and pyrolyzed at 1400°C in a thermal conversion elemental analyzer (TCEA) at Yale University (Blake et al., 2010). The evolved CO gas was transported via a Conflo III device to a Thermo DeltaPlus XP

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ACCEPTED MANUSCRIPT isotope ratio mass spectrometer. Samples were run in triplicate with an average external reproducibility of ± 0.18 ‰, determined by repeated measurements of the NIST Standard Reference Material 120c (+ 10.2 ‰) and in-house lab standards.

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4.4 Biomarker indices and calibrations

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Indices and proxy calibrations used in this study are outlined in Table 2.

4.4.1 n-Alkane indices

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n-Alkane profiles were characterized using the average chain length (ACL) and the odd-

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over-even chain length ratio (carbon preference index, CPI) (Bray et al., 1967; Marzi et al., 1993; Krishnan et al., 2014). Two ranges were used to calculate ACL and CPI: the first (n-C24 to n-

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C31) focuses on long-chain length n-alkanes that are produced predominately by higher plants,

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whereas the second (n-C17 to n-C35) includes shorter chain length n-alkanes, that are more representative of bacterial and algal production; these dominate the coprolites. Thermal

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degradation of organic matter also causes the ACL and CPI to be lower, necessitating an

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independent control on thermal maturity to assess biological n-alkane contributions. The nalkane contribution of aquatic plants relative to terrestrial plants was also measured using Paq, a

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qualitative measure of the ratio of mid-chain length n-alkanes (n-C23 to n-C25) that are thought to come predominantly from aquatic plants compared to higher chain lengths (Ficken et al. 2000). This interpretation is supported by pollen analyses from Chin et al. (2008), which show that the terrestrial sediments had high abundances of stereisporites produced from bryophytes like sphagnum (Table S2). Furthermore, seed-producing plant pollen in terrestrial samples is dominated by gymnosperms with the exception of sample EF 501, which has a high abundance

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ACCEPTED MANUSCRIPT of angiosperm palynomorphs. Marine samples are characterized by high abundances of dinoflagellate palynomorphs and, when measurable, other palynomorphs derive primarily from gymnosperms (Table S2). Finally, pristane/phytane (acyclic isoprenoids) ratio was used as a qualitative indicator of the redox conditions of the depositional environment, with the

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assumption that both compounds are degradation products of the phytol side-chain of chlorophyll

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(Evenick et al., 2016). Interpretation can be ambiguous, however, due to factors like the

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anaerobic bacterial degradation of other biological precursors such as tocopherols resulting in pristane and the presence of phytane in some methanogenic Archaea (ten Haven et al., 1987;

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Hughes et al., 1997; Rontani et al., 2013).

4.4.2 GDGT indices

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Glycerol dialkyl glycerol tetraethers are used to reconstruct sea surface temperature

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(SST) using the TEX86 proxy as well as proxies related to GDGT source (BIT, MI, RI, [2]/[3]) (Table 2). The relationship between the TEX86 index and sea surface temperature depends on the

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choice of calibration. Two calibrations (BAYSPAR (Tierney et al., 2015) and TEX86H (Kim et

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al., 2010)) are used, the former using a Bayesian approach that accounts for regional variations in the TEX86/SST relationship and the latter being a global, logarithmic relationship widely applied

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in paleoclimate studies. BAYSPAR was calculated using the ‘analog’ approach, which builds linear calibrations based on areas with similar TEX86 values in the modern ocean, which results in a calibration built from mainly modern mid-latitude sites given the relatively high TEX86 measured at Devon Island.

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ACCEPTED MANUSCRIPT TEX86 interpretations can be complicated by isoprenoidal GDGT input from Archaea apart from marine Thaumarchaeota, which are thought to be the principal pelagic source in the modern ocean (Schouten et al., 2013). Archaea in soils produce isoprenoidal GDGTs that can overprint the marine signal if there is significant soil organic matter input. The BIT index

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evaluates the proportion of branched GDGTs in a sample that are thought to be produced by

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primarily soil bacteria. BIT values >0.3 may indicate terrestrial influence in marine samples

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(Hopmans et al., 2004). Evidence of in situ production of branched GDGTs in marine environments and the preferential preservation of branched GDGTs relative to isoprenoidal

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GDGTs during oxic degradation, however, make interpretation of BIT site dependent (Huguet et

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al., 2009; Smith et al., 2012; Weijers et al., 2014; Xiao et al., 2016). The Methane Index detects isoprenoidal GDGT input from methanotrophic Archaea, with values >0.3 indicating potentially

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compromised TEX86 results. The [GDGT-2]/[GDGT-3] ratio is correlated with depth and

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subsurface production of isoprenoidal GDGTs and is used to verify the shallow water depth interpretation at Devon Island and to test whether the coprolites have values similar to the

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sediments (Taylor et al., 2013).

4.4.3 Soil pH and temperature indices from brGDGTs

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The degree of cyclization and methylation of bacterially-produced branched GDGTs (CBT and MBT, respectively) correlate with both pH and mean annual air temperature (MAAT) in soils (Weijers et al., 2007a; Peterse et al., 2012; De Jonge et al., 2014a; Naafs et al., 2017a). Recent advances chromatographic methodology, applied in this study, allow for better separation of the 5- and 6-methyl isomers of GDGT-II and GDGT-III and the formulation of improved pH and temperature calibrations using only the 5-methyl (5ME) isomers (Hopmans et al., 2016). The

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ACCEPTED MANUSCRIPT proportion of the 6-methyl isomer is indicated by the IR6ME. Both the original and updated pH (CBT and CBT5ME) and MAAT (MBT’CBT and MBT’5ME) calibrations are shown to facilitate comparisons with published data (Table 2). A recently developed pH and MAAT calibration for peat is also included due to the presence of coal beds that likely started as peat

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prior to lithification (Naafs et al., 2017b).

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5. Results 5.1 Bulk sediment and coprolites

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Total organic carbon (TOC) ranges from 0.9 % to 3% (average 2.4%) in marine

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sediments, and from 32.8 % to 35.3 % in the coaly terrestrial sediments at Eidsbotn graben, whereas a bentonite layer (sample EF 502) had a TOC of 0.2 % (Table 3, Fig. 2). This bentonite

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layer is excluded from subsequent biomarker discussion due to its distinct lithology and low

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TOC. Tmax from the marine sediments ranged from 408-425C (average 415C). Tmax for

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coprolites (n = 4) had a higher average of 438C and a range from 422C to 448C (Table S1).

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5.2 n-Alkanes

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5.2.1 n-Alkane abundance

Long chain n-alkanes are abundant in these sediment samples and show an odd-over-even preference. n-C23 and n-C25 dominate in most terrestrial samples, but n-C27 and n-C29 dominate in most marine sediments (Table 3, Figs. 2-3). Paq suggests that organic matter in terrestrial sediments, with the exception of VF 111, was dominated by aquatic plants. Coprolites have abundant medium chain length alkanes and few to no n-alkanes longer than n-C25, with prominent peaks including n-C18, n-C19 and n-C22 (Fig. S3). ACL and CPI were distinctly

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ACCEPTED MANUSCRIPT lower in the coprolites than in the sediments. Pristane and phytane were minor components in the sediments, but highly abundant in the coprolites, sometimes with higher relative abundance than the n-alkanes (Table S3). Two chromatograms of the aliphatic fraction prior to urea adduction are shown in Fig. 4, including a terrestrial coal (EF 505) and a greensand coprolite (UL-97). UL-

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97, typical of the coprolites, has a relatively high background and several abundant peaks that are

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likely a mix of sterols and hopanoids, and reflect the diet and microbial activity within the

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coprolite, though these compounds are not characterized in this study (Zatoń et al., 2015).

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(Relative abundances in Table S2).

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5.2.2 n-Alkane 13C

Stable carbon isotopes (13C, VPDB) of individual n-alkanes have a large range across

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marine and terrestrial sediments, varying from –43 ‰ to –28.1 ‰ for n-C23, n-C25, n-C27 and

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n-C29 (Table 4). Marine and terrestrial sediments generally have similar values at each site

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suggesting a common source of n-alkanes. At Eidsbotn graben, the 13C of n-C23, n-C25 and nC27 is consistently offset between the n-alkanes in the same sample, with the exception of the

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terrestrial bentonite sample EF 502 (Fig. 2).

Analysis of the 13C (VPDB) of individual alkanes in coprolites is limited due to low abundance, but n-C17, n-C18, n-C21 and n-C23 were measured in most samples (Table 4). The difference among 13C values for n-C17, n-C18 and n-C21 is small (< +0.6 ‰) and 13C for the three n-alkanes averaged –30.1 ‰ for these three n-alkanes in all three coprolite types (excluding UL-59 from the n-C21 average due to a distinctly depleted value of –37 ‰ for n-C21). n-C23 has an average value of –31 ‰ for the mixed and phosphatic coprolites, but there are insufficient

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ACCEPTED MANUSCRIPT alkanes to measure 13C in the greensand coprolites. Samples with a peak amplitude greater than 3 Vs are included in the table and had a reproducibility of ± 0.2 ‰.

5.2.3 n-Alkane 2H

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When measurable, hydrogen isotopes (2H) of individual n-alkanes differed between

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marine and terrestrial sediments (Table 5). Higher chain length n-alkanes (n-C23, n-C25, n-C27

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and n-C29) are more depleted in terrestrial sediments at both localities relative to marine

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sediments (with averages of the individual n-alkanes ranging from –189 ‰ to –170 ‰ in terrestrial sediments and –154 ‰ –141 ‰ in marine sediments) (Table 5). In terrestrial samples,

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2HC23 and 2HC25 are similar and generally had the most depleted values, whereas n-C27 and n-

2H (<3 Vs peak amplitude) (Table 5).

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C29 are generally more enriched. n-C17 and n-C18 were not abundant enough to measure for

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Quantification of 2H in coprolite n-alkanes was challenging due to the low abundance

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and high background, though 2HC18, 2HC21 and 2HC23 were measured in a subset of the coprolites (Fig. S4). 2HC18 has a mean of -90‰ across all coprolite categories and varies from –

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65 ‰ to –122 ‰ (Table 5). n-C23 is the only n-alkane present in measurable abundance in both

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the coprolites and sediments. 2HC23 in the coprolites (range: –77 ‰ to –107 ‰) is more enriched than the terrestrial sediments (–192 ‰ to –207 ‰) and marine sediments (–117 ‰ to –189 ‰).

5.3 Isoprenoidal GDGTs

5.3.1 isoGDGT indices

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ACCEPTED MANUSCRIPT The TEX86 Index measured in marine sediments at both sites ranges from 0.46 to 0.56 with an average value of 0.51 (Table 6, Figs. 2-3). BIT measured in marine sediments is between 0.07 and 0.16, with the exception of sample EF 207 (BIT = 0.66). Most marine sediment samples from both sites were lower than the 0.3 threshold used to evaluate the influence of soil organic

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matter (Weijers et al., 2007a), while sample EF 207 is excluded from the TEX86 temperature

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discussion due to high BIT value. Terrestrial sediments are clearly distinguished with BIT values

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 0.99. The Methane Index in marine sediments ranged from 0.09 to 0.18, excluding sample EF

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207 with a value of 0.21. All marine sediment samples are below the threshold of 0.3 proposed to detect the influence of methanogenic Archaea (Zhang et al., 2011). The Ring Index in marine

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sediments varies from 1.97 to 2.47 and the  Ring Index between 0.06 to 0.43. Some values are greater than the ~0.3 threshold proposed to indicate potential influence by non-thermal factors

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such as archeal growth rate but are included in the discussion of SST due to the uncertain

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meaning of the proxy in this setting (Zhang et al., 2016). (Table S3).

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TEX86 values in the coprolites samples are similar to those of marine sediments, though with a larger range (0.44 to 0.63) (Table 6, Figs. 2-3). TEX86 is lowest in the greensand

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coprolites (0.44 to 0.55; n = 4) and similar in the mixed (0.53 to 0.57; n = 3) and the phosphatic

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coprolites (0.54 to 0.63; n = 4). BIT values range between 0.11 and 0.28 in all coprolite types, while Methane Index has a range from 0.14 to 0.26 The Ring Index varied from 1.61 to 2.40 across all coprolite types and  Ring Index ranged from 0.03 and 0.51.

5.3.2 TEX86 – temperature calibration SST estimates from marine sediments at the Eidsbotn graben section depend on the calibration, with the 50th percentile estimate from BAYSPAR resulting in cooler values (range =

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ACCEPTED MANUSCRIPT 12.6°C to 19.4°C) relative to warmer estimates from TEX86H calibration (range = 15.5°C to 20.6°C) (Table 6). SST reconstructions are similar at the Eidsbotn and Viks Fiord sections.

TEX86 based temperature estimates from the coprolites were somewhat warmer than the

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marine sediments and varied between coprolite type (Table 6, Fig. 5). Combining coprolites

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from both sites, and presenting only the BAYSPAR calibration for simplicity, the greensand

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coprolites have an average of 15.5°C (range = 11.1°C to 19.4°C). The mixed coprolites have a smaller range and higher temperatures of 19.2°C (range = 17.9°C to 20.9°C). The phosphatic

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coprolites also give a higher average temperatures of 22.2°C (range = 18.7°C to 25.4°C). The

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one standard deviation BAYSPAR calibration error of individual samples is variable but has an

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average of ~4°C (Table 6) .

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5.4 Branched GDGTs

At Eidsbotn graben, MBT’5ME values are relatively constant between terrestrial and

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marine sediment samples, while MBT’ values (Table 2; includes both the 5- and 6-methyl

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isomers of GDGT-II and GDGT-III) decreases from the base to the top of the marine sediment section before increasing in the overlying terrestrial sediments. CBT and CBT5ME show a

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marked decline from the base of the Eidsbotn graben section up to sample EF 106 (0.66 to 0.28 for CBT and 0.67 to 0.33 for CBT5ME), and then an increase in sample EF 207 (the sample with high BIT) and the terrestrial sediments (Table 6, Fig. 2). Caution should be taken when interpreting trends, however, given the small number of samples. The Viks Fiord graben samples had similar values.

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ACCEPTED MANUSCRIPT The average MAAT (mean annual air temperature) estimate from terrestrial samples is 15.5°C (range = 11.7°C to 16.9°C) using the MBT’5MEsoil calibration and 19.0°C (range = 16.2°C to 20.7°C) using the MBT’/CBT calibration. MAAT estimates from marine samples is 14.1°C (range = 11.9°C to 16.4°C) using the MBT’5MEsoil calibration and 17.5°C (range =

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16.0°C to 19.4°C) using the MBT’/CBT calibration (Table 6, Fig. S6). MAAT reconstructed

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from MBT’/CBT is 3°C warmer than MBT’5ME, and the MBT’5MEpeat calibration resulted in

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temperatures intermediate to the MBT’/CBT and MBT’5ME estimates. Average MAAT estimates from branched GDGTs in the coprolites indicate similar to slightly cooler temperatures

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than the sediments (Fig. 5): greensand coprolites are 11.3°C (range = 10.3 to 12.3°C,

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MBT’5ME) and 12.3°C (range = 11.5 to 13.1°C, MBT’CBT); mixed coprolites are 13.5°C (range 12.3 to 15.6°C, MBT’5ME) and 14.0°C (range = 13.1 to 15.7°C, MBT’CBT);; and

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to 15.5°C, MBT’CBT) (Table 6).

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phosphatic coprolites are 12.8°C (range = 8.5 to 15.4°C, MBT’5ME) and 13.5°C (range = 10.1

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Average soil pH estimates indicate that terrestrial sediments were more acidic (CBT: 6.1

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(range = 5.7 to 6.3); CBT5ME 6.3 (range = 5.9 to 6.5)) than the terrestrial source of branched GDGTs in the marine sediments (CBT: 7.0 (range = 6.4 to 7.4); CBT5ME: 7.0 (range = 6.5 to

(Table 6).

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7.3)). Soil pH estimates from the coprolites were similar to those from the marine sediments

5.4 Phosphate oxygen isotopes Phosphate oxygen isotopes from marine vertebrate teeth (n = 4) and coprolites (n = 7) had a range of δ18OPO4 from +13.2 ‰ to +19.5 ‰ with an analytical precision of ± 0.2 ‰ (Table

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ACCEPTED MANUSCRIPT 8). Teeth from the ray-finned fish Enchodus had the most depleted values (+17 ‰ and +17.5 ‰), whereas the lamniform shark tooth had a value of 17.9 ‰, and the plesiosaur tooth had a value of +18.4 ‰. The coprolites had a wide range of values, where greensand coprolites ranged from +13.2 ‰ to +14.6 ‰, phosphatic coprolites ranged from +13.5 ‰ to +19.3 ‰ (3 samples were >

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+17.5 ‰), and the one mixed coprolite had a value of +18.4 ‰.

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6.1 Organic matter source and thermal maturity

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6. Discussion

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Several types of sedimentological and geochemical data suggest that the organic matter in the sections is immature, so biomarkers recovered in the analyses are not significantly affected

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by thermal degradation (Pedenchouk et al., 2006). Thermal immaturity of the sediments is

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supported by relatively high carbon preference index (CPI) and average chain length (ACL) values (Table 3), which point to the consistent odd-over-even preference and high ACL of

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undegraded higher plant sources (Sachse et al., 2012). Additionally, Tmax in all sediment samples

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was lower than 435°C threshold indicative of thermally immature organic matter (Table S1) (Baudin et al., 2015).

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Organic matter in the coprolites is distinct from the sediments. The ACL and CPI of coprolites are more representative of algal and/or bacterial inputs relative to the sediments. We also note that the Tmax of the coprolites had a large range, with some values above 435°C (Table S1). It is unlikely, however, that the coprolites and their enclosing sediment experienced different thermal histories. High Tmax in the coprolites of herbivorous dinosaurs has previously been attributed to bacterial inputs, which can lead to high Hydrogen Index (HI) values, and does

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ACCEPTED MANUSCRIPT not indicate thermal maturity (Hollocher et al., 2010) (Table S1). Pristane/phytane values suggest anoxic pore waters in the depositional environment, though the ratios may also be indicative of high microbial input (Chin et al., 2008; Hughes, 1997; Evenick, 2016). Furthermore, there is no evidence of a contribution of isoprenoidal GDGTs from sources besides marine Thaumarchaeota

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in the marine sediment and coprolites based on low (<0.3) values for the Methane Index and BIT

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Index (Hopmans et al., 2004; Zhang et al., 2011). Values for RI (the difference between the

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average number of isoprenoidal GDGT rings, i.e. the ring index or RI, and a modern correlation

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of ring index and TEX86) are above 0.3 for some samples, though the exact threshold for this proxy is not fully understood, particularly in the unique Devon Island samples and depositional

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setting. Uncertainty remains regarding the interpretation of these proxies in the coprolites and is

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discussed in section 6.2

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6.2 Marine and terrestrial temperature constraints from Devon Island

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SST estimates from TEX86 in marine sediments from both sections at Devon Island sediments indicate average Late Cretaceous temperatures of 16.4°C (using the BAYSPAR

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calibration) or 18.5°C (using the TEX86H calibration) (Table 6, Figs. 2-3). The environment of the Late Cretaceous Arctic has no modern analogue, making the choice of calibration difficult,

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though the Devon Island results are consistent with, and somewhat warmer than, the one other Arctic TEX86 record from the Campanian (from the CESAR 6 core on Alpha Ridge) with an average estimated SST of ~18°C (converted to the TEX86H calibration) at ~85°N (Jenkyns et al., 2004) (Fig. 1). TEX86 is calibrated to mean annual temperature based on modern sediment coretops, but samples from Devon Island may be more reflective of warm months in the Arctic due to the

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ACCEPTED MANUSCRIPT influence of seasonality on biological production (Sluijs et al., 2006; Sluijs et al., 2009; Eberle et al., 2010). The inferred coupling between deposition of the microfossil-rich phosphatic and mixed coprolites and seasonal Arctic plankton blooms provides a way to test this hypothesis. If TEX86 measurements of the coprolites are assumed to reflect environmental GDGT signals and,

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thus, environmental temperatures, these temperatures represent extremely short periods of time.

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The exact duration is uncertain, though it is likely to be on the order of days to weeks,

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considering that ingested food usually passes through a vertebrate within days. The high concentration of microfossils in the phosphatic and mixed coprolites suggests

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that the fecal producers sampled the water column during seasonal plankton blooms and may

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have consumed the GDGT-producing planktonic Archaea during feeding. This assumption is supported by a study of GDGTs measured from the intestines and stomachs of marine decapods,

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which demonstrated that gut GDGTs reflected environmental temperatures and were likely

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consumed incidentally during feeding (Huguet et al., 2006b). Further support comes from the similarity of indices related to GDGT source (BIT, Methane Index, and Δ Ring Index) in the

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coprolites and sediments (Figs. 2-3), indicating that the isoprenoidal GDGTs were likely

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produced by marine Thaumarchaeota. The [GDGT-2]/[GDGT-3] ratio in the sediments and coprolites was relatively low (<5), consistent with shallow water conditions and/or minimal

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subsurface GDGT production (Table 6). [GDGT-2]/[GDGT-3], as well as the other source proxies, might also be affected by archaeal activity within the feces, both during transit through the digestive tract of the producing organism or after deposition. Low ACL and CPI in the coprolites indicate either algal or microbial n-alkane sources, supported by the presence of compounds such as pristane and phytane and abundant diatom microfossils (Fig. 4). It is possible that GDGT producers may have colonized the coprolites after production and may not represent

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ACCEPTED MANUSCRIPT a dietary signal, though evidence that the GDGTs were produced by marine Thaumarchaeota would suggest that GDGTs would represent surface or near surface conditions given the inferred shallow (<100 m) marine depositional setting (Chin et al., 2008).

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Temperature estimates from the coprolites overlap the sedimentary estimates, with

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coprolite BAYSPAR values ranging from 11.1°C to 25.4°C, relative to a marine sediment range

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of 12.6°C to 19.4°C. The temporally constrained nature of these fossils provide novel perspectives on the variation of temperature in near-shore surface waters in the spring through

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the fall, the inferred timing of the plankton blooms being fed upon directly by the coprolite

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producers or their prey. It is also possible that warm TEX86 temperature estimates represent mixing with soil organic matter, though the low BIT, CPI and ACL of the coprolites suggest that

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such mixing was limited. These values support the inference that higher TEX86 temperature

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estimates from the phosphatic and mixed coprolites are skewed toward warm summer months,

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and do not reflect an annual average.

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MBT’5MEsoil estimates of MAAT (averaging terrestrial sediments at both sites) indicate that temperatures were somewhat hotter at Eidsbotn graben (16.3°C) relative to Viks Fiord

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graben (14.2°C (Table 6). The peat specific calibration (MBT’5MEpeat) also indicates slightly hotter temperatures (Eidsbotn avg.: 18.1°C). The difference between marine and terrestrial sediments was small compared to the calibration error (root mean square error of  4.8°C) of either MBT’5MEsoil or MBT’CBT, though estimates of terrestrial temperatures from branched GDGTs analyzed in marine sediments are usually somewhat cooler than the terrestrial average by up to 4-5°C. Terrestrial estimates likely represent local temperature estimates, as n-alkanes

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ACCEPTED MANUSCRIPT and GDGTs at both locations are inferred to be derived incidentally, and produced in a coastal swamps, given high sedimentary TOC% (>30%), low soil pH, and the prevalence of stereisporite (sphagnum) pollen (Chin et al., 2008). Conversely, the cooler terrestrial temperature estimates from marine sediments likely reflect soil derived organic matter derived from a large, potentially

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elevated catchment, based on n-alkane data indicative of plant communities living in drier soils.

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It is also possible that the difference could reflect some amount of in-situ production of branched

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GDGTs in rivers, though in modern Arctic draining rivers the inferred MAATs are similar to the surrounding drainage (De Jonge et al., 2014b). Our branched GDGT-based estimates provide an

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independent constraint on terrestrial Arctic temperature proxies such as Climate Leaf Analysis

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Multivariate Program (CLAMP). A CLAMP data compilation from the north slope of Alaska (78°N) provides the geographically closest estimate of terrestrial climate in the Campanian,

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suggesting a MAT of 6.3 ± 2.2°C, a warm month mean (WMM) of 14.5 ± 3.1°C and a cold

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month mean of -2 ± 3.9°C (Spicer and Herman, 2010). Our terrestrial GDGT temperature estimates overlap with this estimated warm month mean temperature, suggesting that the

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brGDGT estimate may reflect warm season temperatures, though the data should be compared

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with caution given the use of different temperature proxies from different locations (Fig. 6). Studies of MBT’/CBT in modern soils at high latitudes provide mixed evidence as to whether

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this proxy captures mean annual temperatures (Weijers et al. 2011), or a warm season mean (Eberle et al., 2010; Shanahan et al., 2013;).

Branched GDGT temperature estimates from the coprolites also provide insights on seasonal shifts in soil temperatures. MBT’5MEsoil MAAT estimates were similar to or colder (8.5°C to 15.6°C) than the average soil temperature estimates derived from the terrestrial

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ACCEPTED MANUSCRIPT sediment samples (~15.1°C) (Table 6). The spread of values in the coprolite data may again reflect environmental snapshots over the intervals when the feces were produced. In particular, the apparent cold bias may indicate soil organic matter input during the colder part of the year. Alternatively, it might also represent an influx of terrestrial organic matter from cooler, higher

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elevations during seasonal riverine input, which carried nutrients that stimulated phytoplankton

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blooms that, directly or indirectly, provided food for the coprolite producers (Chin et al., 2008).

Temperature outputs from an Earth system model simulation (Community Climate

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System Model; CCSM4) using Campanian boundary conditions and 4x preindustrial pCO2 (1120

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ppm) support the seasonal interpretation. Modeled August sea surface temperatures are similar to Devon Island MBT’5ME and BAYSPAR estimates as well as CLAMP Warm Month Mean

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(WMM) estimates from the North Slope of Alaska (Spicer and Herman et al., 2010; Petersen et

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al., 2016, Tabor et al., 2016) (Fig. 6; model description in Text S1). Seasonal interpretation of biomarker temperatures begin to reconcile the disagreement between model outputs and proxy

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data, particularly at high latitudes, noted in previous studies of the Late Cretaceous (Upchurch et

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al., 2015; Tabor et al., 2016). Model uncertainties regarding paleogeography (including epicontinental seaway connections in the Arctic) (Schröder-Adams et al., 2014), atmospheric

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pCO2 levels (e.g. Wang et al. 2014), cloud-aerosol interactions (Kump and Pollard, 2008) and atmospheric composition (Poulsen et al., 2015) complicate interpretation of absolute values from model outputs, though comparisons with proxy data provides at least a qualitative test of the validity of different model assumptions (Bice et al., 2006; Hunter et al., 2013).

6.3 Paleohydrology

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ACCEPTED MANUSCRIPT Precipitation isotope composition is inferred from sediments using the 2H of n-alkanes, which are presumed to have derived from a combination of higher plants (n-C27 and n-C29) and aquatic plants and bryophytes (n-C25 and n-C23) (Nichol et al., 2010; Sachse et al., 2012). Late Cretaceous precipitation at Devon Island was substantially enriched in 2H relative to the modern

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Arctic, with the 2Hprecipitation recorded in plant waxes ranging from –83 ‰ to –146 ‰ compared

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to a modern average from nearby Baffin Island of –191 ‰ (modern annual range from -280 ‰ in

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January to –140 ‰ in July/August; IAEA/WMO (2017)) (Table 7). This difference is likely due

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to a combination of differences in water transport to high latitudes, local evaporative balance and plant species composition (Speelman et al., 2010; Krishnan et al., 2014). Hydrogen isotope data

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and proxy estimates of surface ocean isotopic composition from teeth and coprolites (– 78 ‰ to –17 ‰) suggest that the ancient salinity at the Devon Island localities may have varied from 10

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PSU to 30 PSU, which is in contrast to modern Arctic Ocean surface water salinities of 32.5 PSU

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(Table 8). The lower range of most proxy estimates overlap with the Campanian CCSM4 model

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annual average salinity of ~14 PSU at 5 m depth near the locality, though some of the teeth suggest higher salinities. The modeled seasonal salinity range was ~11 PSU to ~16 PSU, with the

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lowest salinity during the summer and the highest during the winter. The isotopic and inferred

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salinity estimates reflect a fresh Late Cretaceous Arctic Ocean, likely the result of a higher rates of precipitation (supported by more enriched precipitation isotopes indicative of greater moisture transport to high latitudes) and a more restricted ocean basin with limited mixing with the more saline global ocean.

The 2H preserved in terrestrial sediments was consistently more depleted than that in marine sediments (average 2H23/25/27/29 = –182 to –191 ‰ versus and average 2H23/25/27/29 = –

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ACCEPTED MANUSCRIPT 137 to –150 ‰). This could be caused by non-terrestrial sources for the long-chain alkanes in marine sediments (n-C27 and n-C29) (Zegouagh et al., 1998), but this is unlikely because the 13C of individual n-alkanes in the marine and terrestrial records are similar (Pagani et al., 2006). Thermal (Pedentchouk et al., 2006) and microbial (Brittingham et al., 2017) alteration could

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have lowered 13C and raised 2H values, though the sediment immaturity suggest these isotopic

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signals are primary.

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Estimating the 2H of precipitation from plant wax n-alkanes requires assumptions regarding the fractionation of hydrogen isotopes during lipid biosynthesis, but the systematics of

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plant wax hydrogen isotopes under the seasonally continuous light conditions of the Arctic summers is incomplete (Yang et al., 2009, 2011; Sachse et al., 2012). Hence, a range of possible

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fractionations from –100 ‰ (‘low’) to –60 ‰ (‘high’) between precipitation and n-alkane (alkaneis presented (Table 7; Feakins et al., 2014). The ‘low’ fractionation represents an average of

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water)

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modern C3 angiosperms and conifers (Sachse et al., 2012). The ‘high’ fractionation reflects 2H enrichment in n-C27 and n-C29 from Metasequoia and Taxodium, taxa closely related to taxa

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abundant in the Late Cretaceous Arctic, grown in continuous light (Yang et a., 2009, 2011;

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Spicer and Herman et al., 2010). Two features are evident: (1) n-C27 and n-C29 are enriched in terrestrial sediments by +26 ‰ to +35 ‰ relative to the same compounds measured in marine sediments and (2) marine sediments were more enriched in 2H than terrestrial sediments by an average of –50 ‰ for n-C23 and n-C25, –25 ‰ for n-C27 and - n-C29.

One possible explanation for this pattern of greater marine enrichment, would be a large catchment basin that integrated more enriched, inland waters that fed into the marine realm

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ACCEPTED MANUSCRIPT recorded by the Devon Island marine sediments (Bowen et al., 2005). The relatively depleted 2Hprecipitation values captured by the terrestrial samples from the same locality may simply reflect the local freshwater entering the neritic marine system, during the time they were deposited.

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The 2Hprecipitation was converted to 18Oprecipitation using the global meteoric water line

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(ẟ2H = 8 x ẟ18O + 10) to facilitate comparison with phosphate oxygen isotope data (Bowen et al.,

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2005), and ranged from –17 to –12 ± 1.4 ‰ (n-C27 and n-C29), and –20 to –15 ± 1.4 ‰ (n-C23

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and n-C25) for terrestrial sediments (Table 7). These are considered minima, because the local meteoric water line may have had a slope of 9.5 instead of 8 as estimated for a high Arctic,

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humid Eocene forest (Jahren et al., 2009). Our lower estimates agree with the one proxy estimate of Campanian, Arctic coastal 18Oprecipitation of –22 ‰ to –20 ‰ (Suarez et al., 2013), which may

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have represented a higher elevation with isotopically depleted precipitation due to orographic

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effects, and are broadly consistent with the modeling results of Poulsen et al. (2007) and Zhou et

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al. (2008). These values are enriched by about +5 ‰ relative to the modern annual precipitation average at a station on Baffin Island (–26 ‰), while overlapping with the most enriched modern

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summer 18Oprecipitation of –19 ‰ at the same station (IAEA/WMO, 2017).

In order to estimate sea surface salinity of the coastal Late Cretaceous Arctic Ocean at Devon Island, we first estimate the 18O of seawater (δ18Osw). Using the calibration of Pucéat et al. (2010), the δ18Osw experienced by each sample is calculated as:

δ18Osw-sample = δ18Ophosphate – (Growth Temperature – 118.7) / –4.22

(1)

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ACCEPTED MANUSCRIPT with 18Ophosphate representing the δ18O of phosphate from either teeth or coprolites and growth temperature derived from the average BAYSPAR estimate. This assumes that the BAYSPAR estimate represents the temperature at which the phosphate formed, which may not be the case if the animal was warm blooded, if the tooth formed over an extended period of time, or if the

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animal migrated after the tooth was formed at a lower latitude. There may have been a seaway

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connecting the area around Devon Island to the proto-Labrador Sea during the Campanian,

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presenting a possible migration route. Using temperature range derived from the average sediment BAYSPAR SSTs, δ18Osw varies from –10.5 ‰ to –3.4 ‰. δ18Osw values derived from

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the teeth ranged from –7.5 ‰ to –3.4 ‰, using the same temperature constraints except for an

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assumed body temperature of 35°C for the plesiosaur tooth (Bernard et al., 2010) (Table 8).

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The isotopic composition of seawater is also independently calculated using, presumably,

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algae-derived n-alkanes found in the coprolites. While n-alkanes are not diagnostic biomarkers

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of specific organisms, the assumption can be made that most medium-chain length n-alkanes were produced by algae and that hydrogen isotopes were incorporated into the n-alkane from

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seawater with a constant fractionation (Pagani et al., 2006; Sachse et al., 2012). 2HC18 could be evaluated in 5 coprolites, and ranged from –123 ‰ to –66 ‰. Applying a fractionation of C18= –75 ‰ for marine algae (Sachse et al., 2012), we infer that 2Hseawater varied from –48 ‰

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water

to +9 ‰. To facilitate comparison with the phosphate δ18O data, the data are converted to 18Osw using the global meteoric water line, resulting in a δ18O range from –5.4‰ to 0 ‰ (Pagani et al., 2006). The heavier hydrogen isotope values in the coprolites may be the result of bacterially derived n-alkanes with unconstrained fractionations (Li et al., 2009).

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ACCEPTED MANUSCRIPT The isotopic data are used to estimate salinity using a simple mixing model of precipitation and ocean water of normal marine salinity using the following equation (Pagani et al., 2006; Waddel et al., 2008):

(2)

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Salinity = 35 – (δ18Osw-sample – (δ18Osw-ice free))/( δ18Oprecip – δ18Osw-ice free) x (34-0.69)

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assuming linear mixing between precipitation (salinity of 0 PSU) and sea water with average marine salinity (35 PSU), and an ice free global δ18Osw-ice free (–1.3 ‰). Arctic salinity in

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marginal, shallow seas is constrained from 10 PSU to 30 PSU (Table 8). The large range is

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partially due to the uncertainties with the calculation, while it may also be the result of feeding behaviors that caused the coprolite producers to encounter water of variable salinity.

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Overlapping salinity estimates from the teeth and coprolites suggest that the teeth may have

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come from the same animals that produced the coprolites, though further work is needed to

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explore both biological and paleoenvironmental information in coprolites.

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6.4 The Arctic greenhouse in the Late Cretaceous and early Eocene The Late Cretaceous paleoclimatic data from Devon Island can be compared with early

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Eocene greenhouse climates. Our averaged TEX86H estimates of Late Cretaceous Devon Island SSTs (18.5°C) are similar to those of the late Paleocene and early Eocene from the ACEX core of ~18°C (Sluijs et al., 2006; Frieling et al., 2017). The MBT’/CBT estimates of soil temperatures from the ACEX core also indicate average terrestrial temperatures from 14 to 16°C, and ~20°C during the PETM (Weijers et al., 2007b; recalibrated to MBT’CBT in Peterse et al., 2012), similar to the range of MBT’/CBT estimates from the Late Cretaceous at Devon Island of

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ACCEPTED MANUSCRIPT 15.6°C to 20.7. Estimates of salinity were also similar during the early Eocene, with a range of marine salinities from 20-25 PSU, which overlap the predicted 10-30 PSU predicted for the Late Cretaceous (Waddell et al., 2008; Kim et al., 2014). These data suggest that a warm, relatively

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fresh Arctic Ocean persisted from the Late Cretaceous in the early Paleogene.

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7. Conclusions

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This study presents the first paired terrestrial-marine record of Arctic climate in the Late Turonian/Early Coniacian through Campanian, using a suite of GDGT-based and n-alkane

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proxies. Late Cretaceous sea surface temperature is estimated to have been ~18.5°C using

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TEX86H calibration or ~16.4°C using BAYSPAR calibration and terrestrial surface temperatures are estimated to have been 17.4°C using MBT’5MEsoil, with both estimates likely skewed

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towards warm, summer months. We tested and used a new approach to discern the effect of

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seasonality on the TEX86 and MBT’CBT proxies with the first GDGT records from marine vertebrate coprolites. Uncertainties remain about the source of GDGTs in coprolites, but their

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presence in coprolites reflects temporally-constrained periods of time. Thus the range of

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estimates (upwards of 25.4°C) likely represent snapshots of the spring through fall during periods of food availability. We also developed new estimates of high latitude precipitation

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isotopes and Arctic salinity from leaf-wax n-alkanes, the 18Ophosphate of marine vertebrates and phosphate-rich coprolites. Campanian Arctic coastal salinity ranged from 10 PSU to 30 PSU. The hydrogen isotopic composition of precipitation was enriched upward of +60 ‰ to +70 ‰ relative to background levels in the early Eocene Arctic. These data suggest that the climatic processes that delivered moisture to the high latitudes in the Late Cretaceous may have been

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ACCEPTED MANUSCRIPT distinct from those of the early Eocene, while warm, greenhouse temperatures were maintained during each interval.

Acknowledgments: We thank J. Eberle, John Bloch, John Storer and S. Cumbaa for their work

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in the field at Devon Island, and the Government of Nunavut, the Canadian Museum of Nature,

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D. Stenton, and K. Shepherd for allowing us to study the fossils. We thank Prof. John Bloch of

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the University of New Mexico for providing the silver phosphate used for the phosphate oxygen isotope analysis. We thank Prof. John Bloch of the University of New Mexico for providing the

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silver phosphate used for the phosphate oxygen isotope analysis. We also thank Prof. Ruth

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Blake, Dr. Yvette Eley, Dr. Charlotte O’Brien and Dr. Srinath Krishnan for providing guidance on the interpretation of data in a unique environment. Prof. Jay Ague and Prof. Noah Planavsky

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provided helpful discussion on the structure of the study and, finally, we’d like to thank Prof.

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Ellen Thomas for providing detailed feedback that greatly improved this manuscript. For the model experiment, CRT acknowledges high performance computing support from the

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Yellowstone supercomputer provided by the National Center for Atmospheric Research

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Computational and Information Systems Laboratory, sponsored by the National Science Foundation (NSF). DH acknowledges the generosity of Claudia Schröder-Adams and Jens Herrle

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in supplying samples from localities on the Canadian Arctic margin that allowed for the diatom and silicoflagellate age assessment of sample EF-402. DH also acknowledges productive discussions with Kevin McCartney and Jakub Witkowski regarding Cretaceous Arctic diatom and silicoflagellate biostratigraphy.

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ACCEPTED MANUSCRIPT Funding: Portions of this research were funded by NSF Polar Programs Award no. 0241002 to

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K.Chin, J. Eberle, and J. Bloch.

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Tabor, C.R., Poulsen, C.J., Lunt, D.J., Rosenbloom, N.A., Otto-Bliesner, B.L., Markwick, P.J., Brady, E.C., Farnsworth, A. and Feng, R., 2016. The cause of Late Cretaceous cooling: A multimodel-proxy comparison. Geology, 44(11), pp. 963-966.

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Tierney, J.E. and Tingley, M.P., 2015. A TEX86 surface sediment database and extended Bayesian calibration. Scientific Data, 2, pp. 150029.

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Upchurch, G.R., Kiehl, J., Shields, C., Scherer, J. & Scotese, C., 2015. Latitudinal temperature gradients and high-latitude temperatures during the latest Cretaceous: Congruence of geologic data and climate models. Geology, 43(8), pp. 683-686.

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Waddell, L.M. and Moore, T.C., 2008. Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate. Paleoceanography, 23(1).

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ACCEPTED MANUSCRIPT Weijers, J.W., Schefuß, E., Kim, J.H., Damsté, J.S.S. and Schouten, S., 2014. Constraints on the sources of branched tetraether membrane lipids in distal marine sediments. Organic Geochemistry, 72, pp. 14-22. Wilson, L.E., Chin, K., Cumbaa, S., and Dyke, G. 2011. A high latitude hesperornithiform (Aves) from Devon Island: palaeobiogeography and size distribution of North American hesperornithiforms. Journal of Systematic Palaeontology 9, pp. 9-23.

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Wilson, L.E., Chin, K., & Cumbaa, S.L. 2016. A new hesperornithiform (Aves) specimen from the Late Cretaceous Canadian High Arctic with comments on high latitude hesperornithiform diet. Canadian Journal of Earth Sciences. 53(12), pp. 1476-1483.

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Witkowski, J. & Harwood, D.M., 2010. Observations on two Late Cretaceous species of Lepidodiscus Witt (Bacillariophyta) from Devon Island, Canadian High Arctic. Micropaleontology, 56(6), pp. 587-597.

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Witkowski, J., Harwood, D.M. & Chin, K., 2011. Taxonomic composition, paleoecology and biostratigraphy of Late Cretaceous diatoms from Devon Island, Nunavut, Canadian High Arctic. Cretaceous Research, 32(3), pp. 277–300.

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ACCEPTED MANUSCRIPT Zhang, Y.G. et al., 2011. Methane Index: A tetraether archaeal lipid biomarker indicator for detecting the instability of marine gas hydrates. Earth and Planetary Science Letters, 307(34), pp. 525–534. Zhang, Y.G., Pagani, M. & Wang, Z., 2016. Ring Index: A new strategy to evaluate the integrity of TEX86 paleothermometry. Paleoceanography, 31(2), pp. 220–232.

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Zhou, J., Poulsen, C.J., Pollard, D. & White, T.S., 2008. Simulation of modern and middle Cretaceous marine δ18O with an ocean‐atmosphere general circulation model. Paleoceanography, 23(3), pp. 10-26.

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Figure 1 – Site Location and Stratigraphy: Modern location of Devon Island, Nunavut, Canada and the location of Eidsbotn graben and Viks Fiord graben. Stratigraphic column of the Upper Cretaceous Kanguk and Expedition Fiord formations of Devon Island indicates the stratigraphic level of the sediment samples and the approximate sampling interval of the coprolites. Correlation between sections is based on diatom assemblages (Witkowski et al., 2011). Sections adapted from Chin et al. (2008) and Witkowski et al. (2011).

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Figure 2 – Eidsbotn graben section, total organic carbon, n-alkane distribution indices (carbon preference index, average chain length, and pAquatic plant), GDGT-based organic temperature proxies, GDGT source indices, and compound specific isotopes ( 13C and 2H): Coprolites are plotted with the likely source interval indicated by a vertical error bar and a horizontal bar representing range of coprolite values. Indices and calibrations are described in Table 2.

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Figure 3 – Viks Fiord graben section, total organic carbon, n-alkane distribution indices (carbon preference index, average chain length, and pAquatic plant), GDGT-based organic temperature proxies and GDGT source indices. Coprolites are plotted with the likely source interval indicated by a vertical error bar and a horizontal bar representing range of coprolite values. Indices and calibrations are described in Table 2.

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Figure 4 – Example aliphatic hydrocarbon gas chromatograph-FID profile for a coal and a greensand coprolite. Numbers identify n-alkanes chain lengths. UCM = unresolved complex mass.

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Figure 5 - Coprolite vs. Sediment GDGT-based temperature estimates and n-alkane distribution indices: Crossplots show the relationship between the coprolites and the sediments for marine and terrestrial temperature proxies (left) and n-alkane indices carbon preference index (CPI) and average chain length (ACL). Error bars of the coprolites reflect combined calibration and analytical error while the error bars of the sediments represent the full range of measured values.

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Figure 6 - Campanian-Maastrichtian latitudinal temperature gradient: Compilation of Campanian-Maastrichtian temperature estimates from a range of proxies. TEX86 and MBT’5ME may be skewed toward the warmer part of the year. 5-meter depth marine temperatures from a climate model with Campanian boundary conditions are also plotted; the biomarker proxies from Devon Island overlap with the August temperatures from the simulation.

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ACCEPTED MANUSCRIPT Table 1 – Sample list: Sediments, coprolites and teeth analyzed for this study. Table 2 – Biomarker indices and proxy calibrations: Description of biomarkers and proxy calibrations used in this study.

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Table 3 –Bulk sediment analysis and n-alkane indices: Dashes represent samples that were not measured or were not abundant enough for calculation. Grey shading indicates terrestrial samples or terrestrial averages.

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Table 4 - ẟ13C of individual n-alkanes: Analytical precision from duplicate measurements of the same sample was ± 0.2‰ (1). Grey shading indicates terrestrial samples or terrestrial averages.

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Table 5 - ẟ2H of individual n-alkanes: Analytical precision from duplicate measurements of the same sample was ± 8‰ (1). Grey shading indicates terrestrial samples or terrestrial averages.

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Table 6 - GDGT-based temperature, pH and source proxies measured from sediments and coprolites: Table 2 contains descriptions of the various indices and proxies. Grey shading indicates terrestrial samples or terrestrial averages.

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Table 7 - Isotopes of precipitation: Constraints on the hydrogen isotope composition of environmental water from the 2H of alkanes assuming a range of biosynthetic fractionation factors (‘high’ alkane-water = -60‰, ‘low’ alkane-water = -100‰ (Sachse et al., 2012). Note that nC23 and n-C25 have relatively depleted values relative to n-C27 and n-C29. There is also a large difference (25‰ to 50‰) between the more enriched marine and more depleted terrestrial samples. Data are converted into oxygen isotopes using the global meteoric water line of Bowen et al., (2005).

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Table 8 – Temperature and salinity estimates from the oxygen Isotope data from coprolites and vertebrate tooth enamel: δ18Ophosphate includes the phosphate oxygen isotope composition teeth and coprolites, measured in triplicate. Temperature is then estimated using the Puceat et al., (2010) calibration and a δ18OSW -1.3‰ (note the unrealistically high temperatures). The δ18OSW is then constrained using the range of temperatures from TEX86H and BAYSPAR in the sediments, while assuming the plesiosaur tooth represents a body temperature of 35℃ (Bernard et al., 2010). Data are also converted to hydrogen isotope values for comparisons with n-alkane data. Salinity estimates come from a mixing model using a range of δ18Oprecipitation from -20‰ to -15‰ with saline water with δ18OSW -1.3‰ and salinity of 35‰.

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ACCEPTED MANUSCRIPT Table 1: Sample list. Sediments Meters Above Base

Setting1

Weight (grams)

Lithology

EF 501

221

Terrestrial

43

Coaly Interval

EF 502

220

Terrestrial

55

Bentonite

EF 503

215

Terrestrial

35

Coaly Interval

EF 505

210

Terrestrial

36

Coaly Interval

EF 207

205

Marine

39

T

x

EF 106

198

Marine

51

Bentonite

x

EF 103

130

Marine

52

EF 104

122

Marine

EF 102

96

Marine

EF 402

31

Marine

VF 102

50

Marine

45

Grey Shale

VF 105

26

Terrestrial

VF 111

24

Terrestrial

22

Lignite

VF 305

19

Marine

38

Black Shale

VF 303

2

Marine

39

Black Shale

Type

Weight (grams)

Biomarker Analysis

Section 3

IP

Black Shale

Black Shale

CR

North Composite Section

Coprolite Bearing Interval

ID

47

Black Shale

39

Black Shale

33

Black Shale

30

Coaly Interval

US

Material

Sediment

Composite Section

Section

AN

Viks Fiord Graben

Eidsbotn Graben

Locality

x

Teeth Coprolites

AC North Composite Section

Viks Fiord Graben

Meters Above Base

ED

ID NC-12

170 - 206

Greensand

19

x

UL-59

170 - 206

Greensand

19

x

UL-97

170 - 206

Greensand

53

x

PT

Coprolites

Material

CO-12

170 - 206

Phosphatic

29

x

RLO-79

170 - 206

Phosphatic

22

x

CO-17

170 - 206

Phosphatic

29

CE

Section

Composite Section

Eidsbotn Graben

Locality

M

Marine Vertebrate Teeth and Coprolites ẟ18Ophosphate Analysis

x

x

UL-52

170 - 206

Phosphatic

21

DPL-1

170 - 206

Plesiosaur

-

x

x x

DLA-1

170 - 206

Lamnid Shark

-

x

DEN-1

170 - 206

Enchodus

-

x

DEN-1

170 - 206

Enchodus

-

x

IM-18

30 - 50

Greensand

22

CD-2

30 - 50

Greensand

-

x x

IM-9

30 - 50

Mixed

19

x

JM-2

30 - 50

Mixed

29

x

VR-1

30 - 50

Mixed

21

x

ME-2

30 - 50

Phosphatic

19

x

CD-3

30 - 50

Phosphatic

-

x

ME-5

30 - 50

Phosphatic

-

x

x

55

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The depositional setting previously characterized based on microfossils, sedimentology and pollen (Chin et al., 2008).

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1

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ACCEPTED MANUSCRIPT Table 2: Biomarker indices and proxy calibrations. Biomarker Indices and Proxy Calibrations

Branched GDGT Temperature Calibrations

Description

Citation

Carbon Preference Index (CPI)

= 0.5 x (∑odd n-alkanes/∑even n-alkanes)

Two ranges used: n-C17 to n-C35 and n-C24 to n-C31. Higher values indicate greater input from higher plants vs. algal or bacterial sources and/or lower maturity.

Bray and Evans, 1961; Marzi et al., 1993

Average Chain Length (ACL)

Average n-alkane chain length weighted relative abundance within defined range

Two ranges used: n-C17 to n-C35 and n-C24 to n-C31. Higher values indicate greater input from higher plants vs. algal or bacterial sources and/or lower maturity.

Krishnan et al., 2014

Fraction Aquatic Plant (pAq)

= (n-C23 + n-C25)/(n-C23 + n-C25 + nC29 + n-C31)

Qualitative indicator of input from aquatic plants, which produce relatively higher amounts of n-23 and n-25.

Ficken et al., 2000

TEX86

= (GDGT-2 + GDGT-3 + cren')/(GDGT-1 + GDGT-2 + GDGT-3 + cren')

Ratio of isoprenoidal GDGTs produced by marine Thaumarcheota

Schouten et al., 2002

BIT Index

= (GDGT-Ia + GDGT-IIa + GDGTIIIa)/(GDGT-Ia + GDGT-IIa + GDGT-IIIa + Cren)

Relative abundance of brGDGTs to crenarcheol. Values >0.3 may indicate terrestrial input of isoGDGTs and unreliable TEX86 estimates, though in-situ production/oxic degradation can also influence index. Includes 5- and 6-methyl isomers.

Hopmans et al., 2006

Methane Index (MI)

= (GDGT-1 + GDGT-2 + GDGT3)/(GDGT-2 + GDGT-3 + Cren + Cren')

Estimates contribution of isoprenoidal GDGTs by methanogenic archaea, Values >0.3 may indicate methanogenic input of isoGDGTs and unreliable TEX86 estimates.

Zhang et al., 2011

Ring Index (RI)

= 0 x GDGT-0 + 1 x GDGT-1 + 2 x GDGT-2 + 3 x GDGT-3 + 4 x Cren + 4 x Cren'

Weighted average number of isoGDGT rings. Correlated with temperature.

Zhang et al., 2016

Δ Ring Index

= |(-0.77*TEX86 + 3.32*TEX86^2 + 1.59) - Ring Index|

Difference between a modern coretop correlation between RI and TEX86. Larger values (>0.5 indicate archaeal community/ecology that may have differed from the modern.

Zhang et al., 2016

[2]/[3]

= GDGT-2/GDGT-3

Lower values suggest shallower water depth and/or subsurface production of GDGTs. H

Taylor et al., 2013

TEX86H

SST = 68.4 x log(TEX86) + 38.6

BAYSPAR

Linear relationship, regionally variable

MBT'

= (GDGT-Ia + GDGT-Ib + GDGTIc)/(GDGT-Ia + GDGT-Ib + GDGT-Ic + GDGT-IIa + GDGT-IIb + GDGT-IIc + GDGT-IIIa + GDGT-IIa' + GDGT-IIb' + GDGT-IIc' + GDGT-IIIa')

The degree of methylation of branched GDGTs, includes both 5- and 6-methyl isomers.

Peterse et al., 2012

= (GDGT-Ia + GDGT-Ib + GDGTIc)/(GDGT-Ia + GDGT-Ib + GDGT-Ic + GDGT-IIa + GDGT-IIb + GDGT-IIc + GDGT-IIIa)

The degree of methylation of branched GDGTs, includes only 5-methyl isomers.

De Jonge et al., 2014

The degree of cyclization of branched GDGTs, includes both 5- and 6-methyl isomers.

Weijers et al., 2007

The degree of cyclization of branched GDGTs, includes only 5-methyl isomers.

De Jonge et al., 2014

CBT

CBT5ME

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US

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MBT'5ME

T

Formula

AN

Proxy

AC

Branched GDGT Indices1

TEX86 Temperature Calibrations

Isoprenoidal GDGT Indices1

Alkanes Relative Abundance and Isotopes

Cateogry

= -log((GDGT-Ib + GDGT-IIb + GDGTIIb')/(GDGT-Ia + GDGT-IIa + GDGTIIa')) = -log((GDGT-Ib + GDGT-IIb)/(GDGT-Ia + GDGT-IIa))

Global mean annual SST calibration. r2 = 0.86 , RMSE ± 2.5 Regionally varying, Bayesian global mean annual SST calibration.

Kim et al., 2010 Tierney et al., 2015

IR6ME

= ∑6-methyl isomers of GDGT-II and GDGT-III/∑6- and 5-methyl isomers of GDGT-II an GDGT-III

The ratio of 6-methyl to 5-methyl branched GDGTs. Low values (<0.5) typical of mineral soils, higher values may be related to aquatic production.

Dang et al., 2016

MBT'/CBT

MAT = 0.81 - 5.67 x CBT + 31 x MBT'

Mean annual air temperature (MAAT) over soil; r2 = 0.58, RMSE ± 5.0°C

Peterse et al., 2012

MBT'5MEsoil

MAT = -15.25 + 40.01 x MBT'5ME

Mean annual air temperature (MAAT) over soil, only includes 5-methyl isomers; r2 = 0.66, RMSE ± 4.8°C

Naafs et al., 2017a

MBT'5MEpeat

MAT = 42.18 x MBT'5ME - 23.05

Mean annual air temperature (MAAT) over soil, only includes 5-methyl isomers, formulated for peats; r2 = 0.76, RMSE ± 4.7°C

Naafs et al., 2017b

57

Branched GDGT pH Calibrations

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Soil pH calibration; r2 = 0.7, RMSE ± 0.8 pH units

Peterse et al., 2012

CBT5ME

pH = 7.84 - 1.73 x CBT5ME

Soil pH calibration, only includes 5-methyl isomer; r2 = 0.85, RMSE ± 0.52 pH units

De Jonge et al., 2014

CBT5MEpeat

pH = 2.49 x (log((GDGT-Ib + GDGT-IIa' + GDGT-IIb + GDGT-IIb' + GDGTIIIa')/(GDGT-Ia + GDGT-IIa + GDGTIIIa))+8.07

Soil pH calibration, only includes 5-methyl isomer, formulated for peats; r2 = 0.58 , RMSE ± 0.8 pH units

Naafs et al., 2017

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Isoprenoidal GDGTs include GDGT-0, GDGT-1, GDGT-2, GDGT-3, and Crenarchaeol (cren) and the Crenarcheol Regioisomer (cren'). Branched GDGTs include Ia, Ib, Ic, IIa, IIb, IIc, IIIa, IIIb, IIIc. For GDGT-II and GDGTIII, the 6-methyl isomer is distinguished from the 5-methyl isomer by an apostrophe. GDGTs in formulas represent fractional abundances.

AC

1

CBT

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ACCEPTED MANUSCRIPT Table 3: Bulk sediment analysis and n-alkane indices. Sediment n-Alkanes

EF 501

221

Terrestrial

EF 502

220

Terrestrial

EF 503

215

EF 505

TOC (%)

CPIC17-

CPIC24-

ACLC17-

ACLC25-

C35

C31

C35

C31

Coaly Interval

32.8

1.7

1.5

25.7

Bentonite

0.2

2.0

3.6

24.7

Terrestrial

Coaly Interval

35.3

2.8

3.3

210

Terrestrial

Coaly Interval

34.4

1.8

EF 207

205

Marine

Black Shale

2.1

EF 106

198

Marine

Bentonite

EF 103

130

Marine

EF 104

122

EF 102

Pris/Phyt

Paq

28.5

0.8

0.77

27.6

0.3

0.61

26.4

28.0

0.7

0.73

1.6

26.0

28.0

1.0

0.66

3.0

3.8

26.6

27.7

0.1

0.51

1.0

1.7

2.8

25.3

27.5

0.57

Black Shale

2.6

2.4

3.2

26.5

27.7

0.45

Marine

Black Shale

1.5

1.3

1.3

26.6

28.6

0.43

96

Marine

Black Shale

1.8

3.1

4.9

26.7

28.0

0.42

EF 402

31

Marine

Black Shale

1.8

2.2

2.9

26.6

27.9

VF 102

50

Marine

Grey Shale

0.9

1.5

3.8

24.1

27.7

0.2

0.44

VF 105

26

Terrestrial

Coaly Interval

2.5

5.0

24.1

27.0

0.2

0.78

VF 111

24

Terrestrial

Lignite

1.0

1.1

28.3

30.1

0.5

0.18

VF 305

19

Marine

Black Shale

2.4

2.2

3.4

25.8

28.0

VF 303

2

Marine

Black Shale

3.0

1.8

2.8

24.6

27.4

2.31 ± 0.65 2.09 ± 0.51 1.84 ± 0.29 1.88 ± 0.35

3.14 ± 1.07 2.14 ± 0.85 3.30 ± 0.41 3.33 ± 0.43

26.4 ± 0.5 26.0 ± 0.3 24.9 ± 0.7 25.4 ± 1.2 25.9 ± 0.9 25.9 ± 1.3

Section 3 Marine

1.8 ± 0.5

Eidsbotn

Terrestrial

34.2 ± 1.0

AN

Eidsbotn

Viks Fiord

Marine

Viks Fiord

Terrestrial

2.1 ± 0.9

All Marine Sediments

1.9 ± 0.7

2.2 ± 0.6

3.2 ± 0.9

All Terrestrial Sediments

25.7 ± 14.7

2.0 ± 0.6

2.7 ± 1.4

TOC (%)

CPIC17-

ACLC17-

C35

C35

M

2

T

2

IP

Lithology

CR

North Composite Section

Setting

ID

US

Composite Section

Section

Averages1

Viks Fiord Graben

Eidsbotn Graben

Locality

Meters Above Base

2

27.9 ± 0.4 28.2 ± 0.2 27.7 ± 0.2 27.8 ± 0.1

0.60

0.40 0.3 0.13 0.83 ± 0.11 0.27 ± 0.05 0.22 ± 0.00

27.8 ± 0.3

0.2 ± 0.1

28.2 ± 1.0

0.6 ± 0.3

0.58 0.50 ± 0.07 0.72 ± 0.05 0.47 ± 0.07 0.52 ± 0.08 0.5 ± 0.1 0.6 ± 0.2

Coprolite n-Alkanes

North Composite Section

Type

Phosphate (wt %)

ED

ID

2

2

Pris/Phyt

170 - 206

Greensand

-3

-

0.8

19.1

0.3

UL-59

170 - 206

Greensand

21.0

0.3

0.8

19.2

0.5

UL-97

170 - 206

Greensand

16.0

0.7

0.7

19.6

0.8

CO-12

170 - 206

Phosphatic

-

-

0.8

19.5

0.2

RLO-79

170 - 206

Phosphatic

-

-

0.8

19.9

-

UL-52

170 - 206

Phosphatic

30.2

0.1

0.7

20.8

0.2

IM-18

30 - 50

Greensand

-

-

0.5

20.9

0.2

IM-9

30 - 50

Mixed

20.2

0.2

1.0

20.2

0.2

JM-2

30 - 50

Mixed

20.9

0.1

1.5

21.1

0.4

VR-1

30 - 50

Mixed

22.1

0.3

1.0

20.1

0.5

ME-2

30 - 50

Phosphatic

-

-

0.8

20.1

0.3

Greensand

19 ± 3

0.5 ± 0.2

Mixed

21 ± 1

0.2 ± 0.1

Phosphatic

30

0.1

0.71 ± 0.12 1.16 ± 0.24 0.77 ± 0.07

19.7 ± 0.7 20.5 ± 0.4 20.1 ± 0.4

0.43 ± 0.23 0.35 ± 0.12 0.24 ± 0.04

PT

NC-12

CE

Composite Section

Section

AC

Viks Fiord Graben

Eidsbotn Graben

Locality

Meters Above Base

Averages1

1

Categories with more than one sample include averages with 1σ variation. Two ranges of alkanes were used to calculate CPI and ACL in the sediments. The smaller range (n-C24 to n-C-31) includes only the higher chain length n-alkanes while the broader range (n-C17 to n-C-35) includes shorter chain lengths often associated with algae/bacteria. Only the larger range is used in the coprolites due to a lack of higher chain length n-alkanes. 3 Dashes represent samples that were not measured or where compounds were below detection limit. 2

59

ACCEPTED MANUSCRIPT Table 4: ẟ13C of individual n-alkanes. Sediment n-Alkane ẟ13C (‰) Meters Above Base

Setting

n-C17

n-C18

n-C21

n-C23

n-C25

n-C27

n-C29

n-C31

EF 501

221

Terrestrial

-32.2

-32.5

-31.1

-30.4

-31.0

-31.9

-32.3

-32.7

EF 502

220

Terrestrial (Bentonite)

-

2

-28.5

-29.2

-27.4

-35.1

-35.3

-39.5

-38.5

EF 503

215

Terrestrial

-

-

-30.5

-30.6

-30.6

-29.9

-33.2

-35.7

EF 505

210

Terrestrial

-27.4

-27.2

-31.7

-31.4

-32.1

-32.5

-33.5

-34.4

EF 207

205

Marine

-

-

-33.0

-32.5

-31.2

-31.8

-32.7

-31.9

EF 106

198

Marine

-

-

-

-

-

-

-

-

EF 103

130

Marine

-

-

-

-

-

-

-

-

EF 104

122

Marine

-

-

-33.7

-33.7

-32.7

-43.0

-35.2

EF 102

96

Marine

-

-

-

EF 402

31

Marine

-

-

-

VF 102

50

Marine

-

-29.1

-34.2

VF 105

26

Terrestrial

-

-

VF 111

24

Terrestrial

-

-

VF 305

19

Marine

-

-

VF 303

2

Marine

-

-

Marine

-

Eidsbotn

Terrestrial

-29.8 ± 2.4

Viks Fiord

Marine

-

Viks Fiord

Terrestrial

All Terrestrial Sediments

-30.2

-31.3

-37.7

-31.3

-27.0

-27.5

-26.7

-28.5

-34.8

-34.8

-31.7

-31.9

-33.6

-31.9

-35.0

-31.0

-29.7

-32.5

-33.6

-33.0

-35.5

-31.1

-29.4

-32.5

-33.6

-31.8

-32.4

-32.8

-31.2

-31.4

-34.4

-33.4

-39.2

-36.9

-31.4

-29.8

-22.8

-29.6

-33.4 ± 0.4 -31.1 ± 0.5 -35.3 ± 2.9 -35.3 ± 0.3 -34.5 ± 2.4

-31.8 ± 2.8 -30.8 ± 0.4 -34.8 ± 1.7 -31.1 ± 0.1 -33.1 ± 2.8

-30.4 ± 1.9 -31.2 ± 0.6 -31.4 ± 0.2 -29.6 ± 0.2 -30.8 ± 1.5

-30.9 ± 2.5 -31.4 ± 1.1 -31.0 ± 0.9 -32.5 ± 0.0 -30.9 ± 2.0

-35.5 ± 5.4 -33.0 ± 0.5 -30.3 ± 5.3 -33.6 ± 0.0 -33.2 ± 6.0

-33.3 ± 1.7 -34.3 ± 1.2 -31.6 ± 1.6 -32.4 ± 0.6 -32.6 ± 1.8

-

-34.4 ± 2.2

IP -34.1

-

-

-

-

-29.8 ± 2.4

-29.4 ± 2.3

-32.2 ± 2.3

-30.3 ± 1.3

-31.3 ± 1.9

-32.4 ± 1.6

-34.3 ± 2.4

M

All Marine Sediments

-

-29.9 ± 2.7

AN

Eidsbotn

-33.6

US

Section 3

T

North Composite Section

ID

CR

Composite Section

Section

Averages1

Viks Fiord Graben

Eidsbotn Graben

Locality

Coprolite n-Alkane ẟ13C (‰) Type

n-C17

n-C18

n-C21

n-C23

n-C25

Pristane

Phytane

170 - 206

Greensand

-28.9

-29.6

-29.0

-

-

-29.9

-30.3

UL-59

170 - 206

Greensand

-29.0

-31.2

-37.9

-

-

-29.0

-29.6

UL-97

170 - 206

Greensand

-

-

-

-

-

-

-

CO-12

170 - 206

Phosphatic

-28.7

-29.5

-30.3

-32.1

-

-

-

170 - 206

Phosphatic

-

-29.6

-29.5

-28.6

-

-29.5

-29.6

170 - 206

Phosphatic

-

-29.4

-37.6

-29.5

-

-

-

IM-18

30 - 50

Greensand

-

-28.7

-30.0

-

-

-

-

IM-9

30 - 50

Mixed

-

-28.8

-30.6

-31.5

-

-

-

JM-2

30 - 50

Mixed

-29.6

-30.1

-30.8

-32.7

-

-

-

VR-1

30 - 50

Mixed

-29.0

-30.0

-31.5

-30.8

-30.5

-29.6

-29.5

ME-2

30 - 50

Phosphatic

-

-29.5

-30.5

-30.8

-31.0

Greensand

-29.0 ± 0.1

-29.8 ± 1.0

-32.3 ± 4.0

-

-

-29.5 ± 0.4

-30.0 ± 0.4

Mixed

-29.3 ± 0.3

-29.6 ± 0.6

-31.0 ± 0.4

-31.7 ± 0.8

-30.5

-29.6

-29.5

-28.7

-29.5 ± 0.1

-32.0 ± 3.3

-30.3 ± 1.3

-31.0

-29.5

-29.6

RLO-79

CE

AC

Viks Fiord Graben

UL-52

North Composite Section

ED

ID NC-12

PT

Section

Composite Section

Eidsbotn Graben

Locality

Meters Above Base

Averages1

Phosphatic

-

1

Categories with more than one sample include averages with 1 variation. Dashes represent samples that were not measured or where compounds were below detection limit.

2

60

ACCEPTED MANUSCRIPT Table 5: ẟ2H of individual n-alkanes. Sediment n-Alkane ẟ2H (‰)

EF 501 EF 502

n-C17

n-C18

n-C21

n-C23

n-C25

n-C27

n-C29

n-C31

221

Terrestrial

-211

-219

-218

-207

-193

-164

-191

-

220

Terrestrial (Ben.)

-

-78

-113

-130

-164

-166

-160

-

EF 503

215

Terrestrial

-

-182

-187

-206

-204

-185

-171

-144

EF 505

210

Terrestrial

-94

-118

-184

-192

-196

-177

-166

-142

EF 207

205

Marine

-

-

-

-

-

-

-

-

EF 106

198

Marine

-

-

-

-

-144

-146

-126

-

EF 103

130

Marine

-

-

-

-133

-172

-157

-140

-

EF 104

122

Marine

-

-

-

-117

-151

-154

-130

-

EF 102

96

Marine

-

-

-

-147

-148

-137

-153

-128

-

EF 402

31

Marine

-

-

VF 102

50

Marine

-

-

VF 105

26

Terrestrial

-

-

VF 111

24

Terrestrial

-

-

VF 305

19

Marine

-

-

VF 303

2

Marine

-

Eidsbotn

Marine

-

Section 3

Averages1

Eidsbotn

Terrestrial

-153 ± 59

170 - 206

-190

-185

-163

-160

-

-100

-184

-193

-170

-171

-

-118

-189

-180

-182

-162

-

-

-113

-162

-138

-

-146

-118

-

-

-132 ± 12

-153 ± 10

-145 ± 10

-136 ± 10

-128

-173 ± 42

-196 ± 15

-202 ± 7

-198 ± 4

-175 ± 8

-176 ± 11

-143 ± 1

-150 ± 9

-118

-166 ± 17

-157 ± 18

-100

-187 ± 3

-189 ± 4

-167 ± 4

-166 ± 6

-

-

-

-115.7 ± 2.3

-149.5 ± 22.6

-154.1 ± 13.5

-151.2 ± 15.3

-141.0 ± 11.6

-123.2 ± 5.3

-152.7 ± 58.7

-149.3 ± 54.8

-160.4 ± 45.8

-184.9 ± 25.8

-189.2 ± 12.5

-170.9 ± 7.8

-169.7 ± 10.4

-142.8 ± 0.8

Type

n-18

n-21

n-23

Greensand

-84

-132

-

Greensand

-

-

-

Greensand

-81

-

-77 -107

M

ED

UL-97

-

-

-116 ± 2

PT

170 - 206

CO-12

170 - 206

Phosphatic

-

-

RLO-79

170 - 206

Phosphatic

-

-

-

UL-52

170 - 206

Phosphatic

-101

-72

-94

CE

Composite Section

IM-18

30 - 50

Greensand

-

-

-

IM-9

30 - 50

Mixed

-123

-106

-102

JM-2

30 - 50

Mixed

-66

-54

-85

VR-1

30 - 50

Mixed

-

-60

-104

30 - 50

Phosphatic

-

-

-

Greensand

-82 ± 2

-132

-77

Mixed

-94 ± 28

-73 ± 23

-97 ± 9

Phosphatic

-

-72

-

AC

Eidsbotn Graben Viks Fiord Graben

North Composite Section

170 - 206

UL-59

-

-140

-

Coprolite n-Alkane ẟ2H (‰)

NC-12

-131

-153

-

Terrestrial

Meters Above Base

-130

-151

-

Marine

Viks Fiord

ID

-149

-148

-

Viks Fiord

All Terrestrial Sediments

Section

-

-

-167 ± 15

All Marine Sediments

Locality

ME-2

Averages1

IP

Setting

T

Meters Above Base

CR

North Composite Section

ID

US

Composite Section

Section

AN

Viks Fiord Graben

Eidsbotn Graben

Locality

1

Categories with more than one sample include an average with 1 variation.

61

ACCEPTED MANUSCRIPT Table 6: GDGT-based temperature, pH and source proxies measured from sediments and coprolites

Sediments

Setting

TEX86

221

Terrestrial

0.72

220

Terrestrial (Ben.)

0.47

215

Terrestrial

0.74

210

Terrestrial

0.71

205

Marine

0.56

21.2

20.1

12.2

16.2

198

Marine

0.46

15.6

12.6

3.8

8.4

130

Marine

0.53

19.9

18

9.7

122

Marine

0.53

19.5

17.9

9.7

96

Marine

0.53

19.5

17.9

31

Marine

0.52

19.2

17.1

50

Marine

0.46

15.5

12.6

26

Terrestrial

0.71

24

Terrestrial

0.76

19

Marine

0.50

18.1

2

Marine

0.55

20.6

0.52 ± 0.03 0.72 ± 0.02 0.50 ± 0.03 0.73 ± 0.03 0.51 ± 0.03 0.68 ± 0.10

19.2 ± 1.7

17.3 ± 2.3

9.0 ± 2.6

13.2 ± 2.4

21.3 ± 2.4

26.0 ± 2.8

18.1 ± 2.1

15.9 ± 2.8

7.5 ± 3.1

11.8 ± 2.9

19.9 ± 2.9

24.3 ± 3.4

18.8 ± 1.9

16.8 ± 2.5

8.5 ± 2.8

12.8 ± 2.7

20.8 ± 2.6

25.4 ± 3.1

BAYSPAR 2.5th Percentile

BAYSPAR 16th Percentile

BAYSPAR 84th Percentile

Eidsbotn

Marine

Eidsbotn

Terrestrial

Viks Fiord Viks Fiord

Marine Terrestrial

Type

NC-12

170 - 206

Greensand

UL-59

170 - 206

Methane Index

Ring Index

Δ Ring Index

B

0.97

0.88

1.86

1

0.90

0.28

1.69

0

0.98

0.95

1.90

1

0.96

0.58

2.13

1

T

29.5

0.21

1.99

0.20

0

16.5

20.3

0.11

2.21

0.27

0

13.9

21.9

26.7

0.13

2.18

0.06

0

13.9

21.9

26.7

0.11

2.43

0.32

0

IP

24.3

9.8

13.9

22.0

26.8

0.14

2.21

0.10

0

9.0

13.2

21.1

25.8

0.18

1.97

0.12

0

3.8

8.4

16.5

20.4

0.09

2.34

0.40

0

0.97

0.83

1.87

0

0.99

1.14

1.78

0

15.6 19.4

0

7.3

11.5

19.5

23.9

0.13

2.47

0.43

11.4

15.5

23.6

28.6

0.14

2.24

0.08

0

0.14 ± 0.04 0.97 ± 0.01 0.12 ± 0.02 0.98 ± 0.01 0.14 ± 0.04 0.96 ± 0.03

2.16 ± 0.15 0.80 ± 0.16 2.35 ± 0.10 0.98 ± 0.15 2.23 ± 0.16 0.78 ± 0.28

0.18 ± 0.09 1.96 ± 0.12 0.30 ± 0.16 1.82 ± 0.05 0.22 ± 0.13 1.87 ± 0.13

0. 0 1. 0 0. 0 0. 0 0. 0 0. 0

BAYSPAR 97.5th Percentile

Methane Index

Ring Index

Δ Ring Index

B

Coprolites

TEX86

TEX86H (MAT °C)

BAYSPAR 50th Percentile

0.45

14.8

11.9

2.9

7.6

15.8

19.5

0.20

1.95

0.04

0

0.55

20.7

19.4

11.4

15.4

23.6

28.7

0.26

1.83

0.34

0

UL-97

170 - 206

Greensand

0.44

14.4

11.1

2.0

6.8

15.0

18.6

0.14

2.11

0.21

0

CO-12

170 - 206

Phosphatic

0.54

20.4

18.7

10.7

14.7

22.8

27.8

0.24

2.05

0.10

0

RLO79

170 - 206

Phosphatic

0.63

25.0

25.4

17.4

21.3

30.3

36.7

0.20

2.40

0.03

0

UL-52

170 - 206

Phosphatic

0.58

22.4

21.6

13.8

17.7

26.1

31.5

0.22

2.02

0.24

0

IM-18

30 - 50

Greensand

0.55

21.0

19.4

11.4

15.4

23.5

28.6

0.19

2.07

0.11

0

IM-9

30 - 50

Mixed

0.53

19.8

17.9

9.7

13.9

21.9

26.9

0.17

1.61

0.51

0

JM-2

30 - 50

Mixed

0.54

20.3

18.7

10.7

14.6

22.7

27.7

0.17

1.82

0.32

0

VR-1

30 - 50

Mixed

0.57

21.9

20.9

12.9

16.9

25.3

30.7

0.21

1.80

0.43

0

ME-2

30 - 50

Phosphatic

0.60 0.50 ± 0.05 0.55 ± 0.02 0.59 ± 0.03

23.3 17.7 ± 3.1 20.7 ± 0.9 22.8 ± 1.6

23.1

15.2

19.1

27.7

33.8

15.5 ± 4.0

6.9 ± 4.5

11.3 ± 4.1

19.5 ± 4.1

23.9 ± 4.8

19.2 ± 1.3

11.1 ± 1.3

15.1 ± 1.3

23.3 ± 1.5

28.4 ± 1.6

22.2 ± 2.4

14.3 ± 2.4

18.2 ± 2.4

26.7 ± 2.7

32.5 ± 3.3

0.20 0.20 ± 0.04 0.18 ± 0.02 0.22 ± 0.02

2.25 1.99 ± 0.11 1.74 ± 0.10 2.18 ± 0.15

0.06 0.17 ± 0.11 0.42 ± 0.08 0.10 ± 0.08

0 0. 0 0. 0 0. 0

Greensand Averages1

Mixed Phosphatic

1

BAYSPAR 97.5th Percentile

Greensand

CE

North Composite Section

BAYSPAR 84th Percentile

Terrestrial, SST not calculated

ED

ID

Meters Above Base

AC

Composite Section

Eidsbotn Graben Viks Fiord Graben

PT

All Terrestrial Sediments

Section

BAYSPAR 16th Percentile

Terrestrial, SST not calculated

All Marine Sediments

Locality

BAYSPAR 2.5th Percentile

CR

EF 501 EF 502 EF 503 EF 505 EF 207 EF 106 EF 103 EF 104 EF 102 EF 402 VF 102 VF 105 VF 111 VF 305 VF 303

BAYSPAR 50th Percentile

US

Section 3

TEX86H (MAT °C)

Meters Above Base

AN

North Composite Section

ID

M

Composite Section

Section

Averages1

Viks Fiord Graben

Eidsbotn Graben

Locality

Includes average with 1 variation.

62

ACCEPTED MANUSCRIPT Table 7: Precipitation isotopes calculated from leaf wax n-alkanes. ẟ2Hprecipitation Estimates from Sediments (‰)1

Section 3

n-C23 Low

n-C23 High

n-C25 Low

n-C25 High

n-C27 Low

n-C27 High

n-C29 Low

n-C29 High

221

Terrestrial

-119

-157

-103

-141

-72

-111

-101

-139

220

Terrestrial (Bentonite)

-34

-75

-71

-111

-73

-113

-66

-106

215

Terrestrial

-118

-155

-115

-153

-94

-133

-79

-118

210

Terrestrial

-102

-141

-107

-145

-86

-124

-73

-113

205

Marine

-

-

-

-

-

-

-

-

198

Marine

-

-

-49

-89

-51

130

Marine

-37

-78

-80

-119

-63

122

Marine

-19

-61

-56

-96

96

Marine

-52

-93

-53

-93

31

Marine

-

-

-54

50

Marine

-53

-94

-57

26

Terrestrial

-

-

-

24

Terrestrial

-93

-132

19

Marine

-99

-138

2

Marine

-69

-109

Terrestrial Sed. Average ẟ2Hprecipitation

-108 ± 11

Marine Sed. Average ẟ2Hprecipitation

-55 ± 25

Hydrogen isotopic composition of precipitation

Terrestrial Sed. Average ẟ18Oprecipitation

Oxygen isotope composition of precipitation2

-28

-70

-44

-85

-60

-100

-33

-74

IP

-92

-103

-42

-82

-59

-99

-95

-33

-75

-35

-76

-97

-59

-99

-45

-86

-

-

-

-

-

-104

-142

-78

-117

-

-

-89

-128

-91

-130

-69

-109

-43

-83

-

-

-51

-91

-146 ± 10

-107 ± 5

-145 ± 5

-82 ± 9

-121 ± 8

-84 ± 12

-123 ± 11

-95 ± 24

-60 ± 15

-100 ± 14

-57 ± 17

-97 ± 16

-46 ± 13

-86 ± 12

-15 ± 1.34

-20 ± 1.28

-15 ± 0.59

-19 ± 0.57

-12 ± 1.07

-16 ± 1.02

-12 ± 1.48

-17 ± 1.42

-8 ± 3.14

-13 ± 3.01

-9 ± 1.87

-14 ± 1.79

-8 ± 2.13

-13 ± 2.04

-7 ± 1.62

-12 ± 1.55

ED

Marine Sed. Average ẟ18Oprecipitation

T

Setting

CR

EF 501 EF 502 EF 503 EF 505 EF 207 EF 106 EF 103 EF 104 EF 102 EF 402 VF 102 VF 105 VF 111 VF 305 VF 303

Meters Above Base

US

North Composite Section

ID

AN

Composite Section

Section

M

Viks Fiord Graben

Eidsbotn Graben

Locality

Constraints on the hydrogen isotope composition of environmental water from the 2H of alkanes assume a range of biosynthetic fractionation factors (‘high’ alkane-water = -60‰, ‘low’ alkane-water = -100‰ (Sachse et al., 2012). 2 Data are converted into oxygen isotopes using the global meteoric water line of Bowen et al., (2005).

AC

CE

PT

1

63

ACCEPTED MANUSCRIPT Table 8: Temperature and salinity estimates from the oxygen Isotope data from coprolites and vertebrate tooth enamel Phosphate δ18O - Temperature, δ18OSW and Salinity δ18OSW using TEX86 Temp. (‰)3

δ2HSW, converted with GMWL (‰)4

Estimated Salinity (PSU)5

Greensand Mixed Phosphatic Phosphatic Greensand Phosphatic Phosphatic Enchodus Enchodus Plesiosaur

14.6 ± 0.2 18.4 ± 0.2 19.3 ± 0.3 17.5 ± 0.3 14 ± 0.1 19.5 ± 0.1 13.5 ± 0.1 17 ± 0.2 17.5 ± 0.1 18.4 ± 0.2

51.6 ± 0.8 35.6 ± 0.8 31.8 ± 1.3 39.4 ± 1.3 54.1 ± 0.4 30.9 ± 0.4 56.2 ± 0.4 41.5 ± 0.8 39.4 ± 0.4 44 ± 0.8

-10.1 to -8.5 -6.3 to -4.7 -5.4 to -3.8 -7.2 to -5.6 -10.5 to -9.1 -5 to -3.6 -11 to -9.6 -7.5 to -6.1 -7 to -5.6 -3.4

-71 to -58 -41 to -28 -33 to -21 -48 to -35 -74 to -63 -30 to -19 -78 to -67 -50 to -39 -46 to -35 -17

13 - 21 22 - 28 24 - 29 20 - 26 12 - 20 25 - 30 10 - 19 19 - 25 20 - 26 29 - 30

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Water Temperature (°C), Assumes δ18OSW = –1.3 ‰2

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Measured δ18Ophosphate (‰)1

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Viks Fiord

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Eidsbotn

Vertebrate Teeth

Coprolite

Type

Sample ID

Lamniform 17.9 ± 0.1 37.7 ± 0.4 -6.6 to -5.2 -43 to -32 21 - 27 Shark 1 18 Raw δ Ophosphate , measured in triplicate. 2 Temperature is then estimated using the Puceat et al., (2010) calibration and a δ 18OSW of -1.3 ‰. 3 18 δ OSW constrained using the range of temperatures from using the TEX86H and BAYSPAR calibrations in the sediments, while assuming the plesiosaur tooth represents a body temperature of 35℃ (Bernard et al., 2010). 4 Converted to hydrogen isotope values for comparisons with n-alkane data. 5 Salinity estimates come from a mixing model using a range of δ18Oprecipitation from -20‰ to -15‰ with saline water with δ18OSW -1.3 ‰ and salinity of 35 PSU.

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Highlights - Arctic TEX86 sea surface temperatures of ~13-21°C in Late Cretaceous - MBT’5ME terrestrial temperature estimates of ~12-17°C - Warm month bias of TEX86 suggested by biomarker analysis of marine coprolites - Neritic salinity highly variable (10-30 PSU) - Isotopic composition of precipitation highly enriched relative to modern

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Figure 1

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Figure 3

Figure 4

Figure 5

Figure 6