Are sackungen diagnostic features of (de)glaciated mountains?

    Are sackungen diagnostic features of (de)glaciated mountains? Tom´asˇ P´anek, Pavel Mentl´ık, Bob Ditchburn, Albert Zondervan, Kevin Norton, Jan Hradeck´y PII: DOI: Reference:

S0169-555X(15)30087-8 doi: 10.1016/j.geomorph.2015.07.022 GEOMOR 5315

To appear in:

Geomorphology

Received date: Revised date: Accepted date:

13 March 2015 9 July 2015 11 July 2015

Please cite this article as: P´ anek, Tom´ aˇs, Mentl´ık, Pavel, Ditchburn, Bob, Zondervan, Albert, Norton, Kevin, Hradeck´ y, Jan, Are sackungen diagnostic features of (de)glaciated mountains?, Geomorphology (2015), doi: 10.1016/j.geomorph.2015.07.022

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ACCEPTED MANUSCRIPT Are sackungen diagnostic features of (de)glaciated mountains?

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Tomáš Páneka,*, Pavel Mentlíkb, Bob Ditchburnc, Albert Zondervanc, Kevin Nortond, Jan

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Hradeckýa

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Department of Physical Geography and Geoecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic

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Centre of Biology, Geoscience and Environmental Education, University of West Bohemia, Klatovská 51, 306 19 Plzeň, Czech Republic

Environment and Materials division, GNS Science, Lower Hutt, New Zealand

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School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand

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Corresponding author. Tel.: +420 597 092 306; fax: +420 597 092 323.

Email address: [email protected] (T. Pánek).

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ACCEPTED MANUSCRIPT Abstract Deep-seated gravitational slope deformations (DSGSDs) with characteristic sackung

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landforms (e.g., double crests, trenches, uphill-facing scarps, and toe bulging) are considered

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by some researchers to be diagnostic features indicating past mountain glaciations. However,

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an extensive literature review on sackung features throughout the world reveals that in some regions, paraglacial processes are not the causes of such phenomena. Sackungen occur across

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a diverse spectrum of mountain types, with different morphoclimatic histories, including regions that have never experienced glaciation. To reinforce that sackungen may originate

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independently of glaciation, we include also two case studies from the Western Carpathians (Czech Republic and Slovakia) which are supported by detailed geomorphic mapping, 14

C and OSL). On the Ondřejník ridge (Outer Western

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trenching and absolute dating (10Be,

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Carpathians, Czech Republic), sackungen occur in the mid-Holocene in the medium-high mountains which are beyond the Pleistocene glacial limits. On the Salatín Mt. (Tatra Mts.,

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Slovakia), the sackungen, which occur in formerly glaciated terrain, date between ~7.5 and 4.2 ka BP, representing a > 4 ka time lag after the disappearance of glaciers. This suggests that

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the direct link between the ice retreat and the onset of sackung formation is not obvious, even in the case of the once glaciated mountain range. Although paraglacial stress release is undoubtedly one of the crucial causes of sackung genesis, in many mountain regions, it is not the only important mechanism. Therefore, despite occurring in numerous (de)glaciated mountains, sackung features cannot be considered as proof of past mountain glaciations, e.g., during analysis of extra-terrestrial settings. Key words: Sackung; Paraglacial processes; Dating; Western Carpathians.

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ACCEPTED MANUSCRIPT 1. Introduction Sackung features are characterized by double or multiple crests, trenches, uphill-facing

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scarps, tension cracks, toe bulging and buckling folds. They affect elevated mountain ridges

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and are considered to be characteristic paraglacial phenomena (e.g. Brückl and Parotidis,

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2005; Cossart et al., 2008; Kellerer-Pirklbauer et al., 2010, Mège et al., 2013; Zorzi et al., 2014, Coquin et al., 2015). Sackung landforms have been even used as diagnostic features to

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identify the existence of past glaciations in extra-terrestrial settings (e.g., Mars; Mège and Bourgeois, 2011).

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In paraglacial geomorphology, the origin of deep-seated gravitational slope deformations (DSGSDs) is suggested to be caused by the steepening of glacially conditioned rock slopes

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and stress release induced by valley glacier withdrawals (Ballantyne, 2002; Jarman and

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Ballantyne, 2002). Although geochronological data and numerical modelling provide

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unequivocal evidence that sackungen resulted from stress release following deglaciation in numerous mountain regions (Bovis, 1982; Bigot-Cormier et al., 2005; Cossart et al., 2008; Agliardi et al., 2009a,b; Hippolyte et al., 2009, 2012), most regions composed of typical

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sackung landforms have no chronological data relating to the onset and termination of sackung-related gravitational spreading available (e.g. Augustinus, 1995, Jarman, 2006; Kellerer-Pirklbauer et al., 2010; Crosta et al., 2013; Zorzi et al., 2014). Furthermore, the growing dataset of sackung features throughout the world reveals that these landforms also occur in regions that have never experienced Pleistocene glaciation (e.g., Němčok, 1972, 1982; Sorriso-Valvo et al., 1999; Pellegrino and Prestininzi, 2007; Pánek et al., 2009; 2011; Moro et al., 2012; Zerathe and Lebourg, 2012; Gori et al., 2014; Di Maggio et al., 2014) or where glaciers were of only limited size and would have had minimal debuttressing effects (McCalpin and Hart, 2003; Di Luzio et al., 2004; Bertolini et al., 2005).

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ACCEPTED MANUSCRIPT The main motivation of this review paper is to reinforce the independence of sackungen on mountain glaciations. Although many authors do not directly connect sackungen with

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paraglaciation, there is still a tendency to strictly attribute sackung features to deglaciated

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landscapes (e.g. Mège and Bourgeois, 2011; Mège et al., 2013) or at least attribute them

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unequivocally to paraglacial stress release, despite a lack of chronological constraints (e.g. Kellerer-Pirklbauer et al., 2010; Zorzi et al., 2014; Coquin et al., 2015). Therefore main goals

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of this paper are as follows:

i) present a review of localities where sackung-type DSGSDs have occurred,

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ii) compare the occurrence of sackungen in glaciated, previously glaciated (paraglacial) and non-glaciated environments and define conditions controlling the occurrence of sackung-type

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DSGSDs, particularly in non-glaciated environments, and iii) evaluate the time span between glacier withdrawal, sackung setting and extreme external

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factors such as earthquake and hydroclimatic extremes, respectively, in previously glaciated and non-glaciated areas.

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To do so, we performed an extensive review of published papers related to the occurrence of sackungen in different parts of the world, and provided a geomorphic/chronological investigation of two contrasting sackung-bearing mountain ridges in the Western Carpathians (Beskydy Mts. and Tatra Mts.). In this article, we describe the current state of knowledge for sackungen and present original results of sackungen numerical dating, for which we applied a new method that combines AMS radiocarbon and terrestrial cosmogenic nuclide (TCN) exposure dating (10Be).

2. Sackung – terminology, origin and regional occurrence 4

ACCEPTED MANUSCRIPT 2.1. Terminological constraints The term sackung (the plural form is sackungen) was first used by Zischinsky (1966, 1969) to

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describe multiply linear morphological features (e.g., ridge troughs, uphill- and downhill-

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facing scarps and enclosed depressions) related to the deep-seated gravitational spreading of

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mountain ridges. In the context of paraglacial geomorphology, Zischinsky (1966) described an association between glacial debuttressing and the initiation of rock mass creep (Ballantyne,

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2002). Since then, this theory has been cited in numerous studies (e.g. Beck, 1968; Němčok, 1972; Mahr and Němčok, 1977; Radbruch-Hall, 1978; Bovis, 1982; McCalpin and Irvine,

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1995; Agliardi et al., 2001; Crosta et al., 2013). It has been noted that these processes have often coincided with DSGSDs (Agliardi et al., 2001; note that the acronym “DGSD” is

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sometimes used for the same features; e.g. Soldati, 2004, 2013). Although there is substantial

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intersection between sackungen and DSGSDs, the later cover a wider spectrum of slope deformations (Soldati, 2004, 2013). As suggested by Agliardi et al. (2012), sackungen are

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formed as a result of rock mass sagging, i.e., sagging of mountain ridges or rockflow (Cruden and Varnes, 1996; Bisci et al., 1996), and involve predominantly layered metamorphic,

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igneous and sedimentary rocks in alpine areas. In addition to this process, DSGSDs may originate via lateral spreading, a process typical for nearly horizontal sedimentary rocks overlying ductile formations such as limestones above clays or clayey shells (Pasuto and Soldati, 1996, 2013). This study focuses on the sackung-related DSGSDs in mountains, which are connected with typical linear landform assemblages involving primarily expressive uphillfacing scarps and double-crested ridges (Fig. 1).

2.2. Origin

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ACCEPTED MANUSCRIPT Sackungen form as a result of the deep-seated gravitational deformation of mountain ridges (Radbruch-Hall, 1978). Although the majority of studies suggest that the most common mode

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of formation is a long-term (>103–104 years) creep (Radbruch-Hall, 1978; McCalpin and

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Irvine, 1995; Agliardi et al., 2001; Hippolyte et al., 2009, 2012; Pere, 2009), some

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observations including paleoseismic trenching and monitoring reveal possible episodic reactivations of accelerated movements (McCalpin and Hart, 2003; El Bedoui et al., 2009; Agliardi et al., 2012; Gutiérrez et al., 2012; Crosta et al., 2014), and even catastrophic failure

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in the form of large rockslides and rock avalanches (Hewitt et al., 2008; Chigira et al., 2010,

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2013; Bianchi Fasani et al., 2014). The kinematics of sackung-type DSGSDs have been presented by Agliardi et al. (2001; 2012; Fig. 1). The most typical process includes ridge-top sagging and spreading, i.e., normal faulting on single or multiple, steep, inclined

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discontinuities (e.g. Agliardi et al., 2001, 2009a,b; Gutiérrez-Santolalla et al., 2005; Audemard et al., 2010; Li et al., 2010; McCalpin et al., 2011; Hippolyte et al., 2012). However, incipient

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sliding/slumping and toppling may also occur and contribute to the kinematics (Němčok, 1972; Bovis, 1982; McCalpin and Irvine, 1995; Hippolyte et al., 2009; Pánek et al., 2011;

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Agliardi et al., 2012). The most common prerequisite is a very low ratio between the transport and volume of the rock mass, combined with a deep-seated (often >200–300 m), fairly discontinuous (sometimes ductile) shear plane with a thickness of up to several tens of meters (Němčok 1972; Mahr and Němčok, 1977 Dramis and Sorriso-Valvo, 1994; Agliardi et al., 2012). Sackungen are generally related to structural features, such as faults, fold axes, bedding, foliation and other elements (Agliardi et al., 2001; Pánek et al., 2011; Di Maggio et al., 2014; Zorzi et al., 2014); however, influencing factors and triggers are often difficult to recognize (McColl, 2012). The most widely proposed trigger processes include stress relief, debuttressing, the loss of lateral support and elevated cleft water pressures. These processes 6

ACCEPTED MANUSCRIPT are common in mountainous areas undergoing deglaciation processes, rapid river incision, tectonic or glacioisostatic uplift and/or episodic seismic events driven by tectonics or

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postglacial rebound (Agliardi et al., 2001; McColl, 2012; Crosta et al., 2013; Ballantyne et al.,

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2014). In some specific circumstances, sackungen are caused by terrain subsidence due to the

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dissolution of underlying evaporite rocks (Gutiérrez et al., 2012; Carbonel et al., 2013) or

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karstification (Pánek et al., 2009).

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2.3. Worldwide distribution Fig. 2 displays the global distribution of sackung-type DSGSDs, especially those reported in

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peer-reviewed journals since the 1990s. The most significant studies of sackungen in various

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types of mountain settings are summarized in Table 1. Only the most important papers, e.g. those where term “sackung” was defined, or first dating or monitoring studies, are included

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for the older pre-1990 period. A comprehensive list of pre-1990 studies related to sackungen is included within the bibliographic paper of Pasuto and Soldati (1990). The majority of

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sackung-type DSGSDs were reported in formerly glaciated high mountains, which experienced glacier advances during the LGM (Hughes et al., 2013). These areas include the Pacific Coast Ranges of British Columbia (Bovis, 1982; Thompson et al., 1997), the Rocky Mountains of the USA (McCalpin and Irvine, 1995), the Mérida Andes of Venezuela (Audemard et al., 2010), Norway (Blikra et al., 2006), Iceland (Coquin et al., 2015), Scotland (Jarman, 2006), the European Alps (Hippolyte et al., 2009, 2012; Agliardi et al., 2012, 2013; Crosta et al., 2013), the Pyrenees (Gutiérrez-Santolalla et al., 2005; Gutiérrez et al., 2008), the Himalayas (Hewitt, 2006; Schroder et al., 2011), the Japanese Alps (Kobayashi, 1956; Nishii and Ikeda, 2013) and the Southern Alps of New Zealand (Beck, 1968; Korup, 2005; Pere, 2009; Barth, 2014) (Fig. 2). However, chronological studies supporting the paraglacial origins

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ACCEPTED MANUSCRIPT of sackungen in these regions are surprisingly scarce. Rare examples, in which sackung origins dated to just after deglaciation (101 to first 103 years), exist from the Pacific Coast

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Ranges (Bovis, 1982) and locations in the European Alps (Bigot-Cormier et al., 2005;

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Agliardi et al., 2009a; Hippolyte et al., 2012). More frequently, high-resolution dating of

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sackungen reveal substantial delays (>4–5 ka) with respect to ice retreat (McCalpin and Irvine, 1995; Gutiérrez-Santolalla et al., 2005, Le Roux et al., 2009; Sanchez et al., 2010). This suggests that glacial erosion in a manner similar to river incision, and the subsequent

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debuttressing of the oversteepened valley walls may produce slopes predisposed to sackung

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development but does not necessarily initiate the movement. Furthermore, there are examples of well-developed sackungen in mid-mountain ranges, which never experienced glaciations (Figs. 2 and 3). In California, USA, sackungen in sandstone and

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siltstone beds in the Anaheim Hills (Johnson and Cotton, 2005) occur at low elevation (~400 m a.s.l.), and several late Holocene sackungen in the San Gabriel Mountains have been

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attributed to seismic events on the adjacent San Andreas Fault (McCalpin and Hart, 2003). Other Holocene sackung-type DSGSDs with no link to mountain glaciation were recently

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reported in the Iberian Chain, Spain (Gutiérrez et al., 2012; Carbonel et al., 2013). Further sackung-type DSGSDs have been documented in some of the formerly non-glaciated regions in the Apennines (Sorriso-Valvo et al., 1999; Bertolini et al., 2005; Di Luzio et al., 2004; Esposito et al., 2013; Bianchi Fasani et al., 2014), Sicily (Saroli et al., 2005; Di Maggio et al., 2014), the Carpathians (Němčok, 1972; Alexandrowicz and Alexandrowicz,1988; Pánek et al., 2011; Lenart and Pánek, 2014) and Japan (Chigira 2005; Chigira et al., 2013). The majority of these were caused by highly anisotropic bedrock formed by sedimentary or metamorphic rocks (Sorriso-Valvo et al., 1999) and were controlled by the occurrence of geological structures, particularly faults, joints and bedding planes.

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ACCEPTED MANUSCRIPT 3. Methods To investigate the complex, and sometimes ambiguous, relations of sackungen to mountain

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glaciation, we performed detailed geomorphological and geochronological studies on two

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contrasting mountain ridges in the Western Carpathians. Some of the pioneering studies of

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sackung-type DSGSDs were performed in this region (Němčok, 1972; Mahr and Němčok, 1977). First, we focus on the Ondřejník ridge, which is situated in the Outer Western

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Carpathians (Beskydy Mts., Czech Republic) and formed from flysch sedimentary rocks. This DSGSD was previously described by Pánek et al. (2011), and has been reevaluated here based

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on new LIDAR-based topography which has enabled further analysis and better identification of sackung features in this densely forested locality. The second DSGSD at the Salatín Mt. is

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located in the Tatra Mts. (Slovakia), i.e. the highest mountains of the Carpathians formed by

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the crystalline granite core, and was first described by Němčok (1982). In this study, we

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deformation.

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define the spatial attributes and context of the sackungen in detail and date the slope

3.1. Geomorphic mapping

To recognize principal landform assemblages and their genesis, we conducted geomorphic mapping based on field campaigns supported by high-resolution aerial photographs, a LIDAR-based digital elevation model (launched in 2014 by Czech Office for Surveying, Mapping and Cadastre; for the Ondřejník ridge, Beskydy Mts.) and a photogrametrically derived digital elevation model (5-m grid DEM; for the Salatín Mt., Tatra Mts.), which was launched by the EUROSENSE-group between 1998–2009 and last updated in 2012. Field GPS mapping focused on linear features related to DSGSDs, including synthetic/downhillfacing scarps, antithetic/uphill-facing scarps, tension cracks and landslide lobes. At the Salatín 9

ACCEPTED MANUSCRIPT ridge, both glacial (e.g., cirques, moraines, and glacier trimlines) and periglacial (e.g., rock glaciers) landforms were examined in order to determine potential relationships between

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sackungen and deglaciation patterns. The field survey also focused on the selection of the

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most suitable sites for TCN dating and trenching. Geophysical sounding (see Pánek et al.,

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2011) and structural measurements (dip and dip directions) of discontinuities were performed to better understand the relationships between the bedrock structure and sackung landforms

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throughout the study areas.

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3.2. Dating

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Be TCN dating. A combination of both methods was only possible for the Salatín

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and (ii)

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The dating strategy relied on (i) trenching associated with OSL and AMS radiocarbon dating

Mt. (Tatra Mts) study. A lack of suitable bedrock outcrops on predominantly soil-covered

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sackung scarps in the Onřejník Mt. area (Beskydy Mts.) excluded it from TCN dating. Recently, trenching has been established as an effective tool for determining the chronology

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of sackung scarps (McCalpin and Irvine, 1995; Gutiérrez-Santolalla et al., 2005; Agliardi et al., 2009a; McCalpin et al., 2011; Gutiérrez et al., 2012; Gori et al., 2014). At the Ondřejník ridge, three trenches were dug using an excavator across distinctive sackung scarps, with a maximum length of 19 m and a depth of 4 m (for location, see Fig. 4). Due to the remoteness and strict regulations of the Tatra Mts. National Park, only two manually excavated trenches were dug across the uphill-facing scarp Sc6 at the Salatín ridge, with a length of 4 m and a depth of 1 m (for location, see Fig. 5). All walls of trenches were structurally described, and crucial depositional facies were analysed using standard sedimentological methods. Datable material was examined and sampled for OSL at the Ondřejník ridge and AMS radiocarbon dating in both studied sites (Table 2). OSL dating was performed for one sample (O1) from 10

ACCEPTED MANUSCRIPT Trench 1 at the Ondřejník ridge in the Gliwice Luminescence Dating Laboratory of the Institute of Physics, Silesian University of Technology (Poland) (for details see Pánek et al.,

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2011). In total, three bulk samples of organic soils were taken from excavated trenches in both

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sackung localities. AMS radiocarbon dating was carried out at the Center for Applied Isotope

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Studies, University of Georgia (USA) and the Gliwice Radiocarbon Laboratory of the Institute of Physics, Silesian University of Technology (Poland; Table 2). Radiocarbon dates were converted into calendar ages using the IntCal 13 calibration curve (Reimer et al., 2013)

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included in the OxCal v 4.2 software package (Bronk Ramsey and Lee, 2013).

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Five sackung scarps (represented by six dated samples; Table 3) in the Salatín Mt. ridge area were selected for TCN dating (see Fig. 5 for location). We selected scarp surfaces with

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minimal evidence of rockfalls, and without scree deposits at their base. The TCN ages were

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verified at one location (the scarp/antithetic scarp set Sc5 and Sc6) using AMS radiocarbon dating (for localization see Fig. 5). This strategy is novel for the timing of DSGSDs and

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provides significant confidence in the dating. All samples for TCN dating were collected by chiselling the upper surfaces (≤5 cm) of quartz-rich granodiorites from outcrops in exposed

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scarps. The sample thickness, topographic shielding and overall geometry (dip, height and length etc.) of sampling surfaces were recorded. The scarcity and limited exposure of bedrock scarps prevented the collection of vertical sequences. Thus, we were not able to determine slip rates on particular sackung faults (e.g. Hippolyte et al., 2009, 2012). Topographic and shielding information for the six samples SAL1–6 is given in Table 3. The shielding correction factors were calculated using the method of Tikhomirov et al. (2014). The granodiorite samples were crushed and sieved to 125–250 micron. Quartz was leached with dilute HF/HNO3 (Kohl and Nishiizumi, 1992) and hot phosphoric acid using a recently improved technique (Ditchburn et al., 2014). Quartz purity was checked by ICP-MS. After adding a Be carrier (Table 4), the quartz was dissolved and Be leached from the fluoride salt 11

ACCEPTED MANUSCRIPT with water (Stone, 1998). Be separation followed von Blanckenburg et al. (2004) and Norton et al. (2008). Residual boron was minimized by dissolving the Be(OH)2 gel in H2SO4, and

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then transferring to a Pt dish, and adding a few drops of 50% HF. The mixture was evaporated

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dry to remove boron as BF3 gas and then combusted at red heat (900–1000°C) to convert the

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BeSO4 to BeO. Sample preparation was completed by mixing the BeO with Ag powder and pressing into a Cu cathode holder (Ditchburn et al., 2014). 10Be AMS measurement was done with the XCAMS system (Zondervan et al., in press). Several blanks were prepared to 10

Be contributions from the Be carrier, the preparation process, and the AMS

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quantify the

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system, and to apply the machine and processing blank subtractions (Table 4). The exposure ages given in Table 5 were derived under the assumption that the exposed surfaces have not been eroded. Assuming probable values for the erosion rates, typically 1–10 mm ka-1(Midriak,

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1983), only marginally increases the ages by 4–7%.

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4. Geomorphology and age constraints of the Ondřejník ridge sackung

4.1. Landform assemblages

The Ondřejník ridge (max. elev. 964 m a.s.l.; Fig. 4) is situated at the NW margin of the Outer Western Carpathians. It was formed via thrusting of an accretionary wedge of CretaceousPaleogene flysch onto the Carpathian foredeep during the Miocene (Menčík et at., 1983). It occupies the front portion of the Godulla nappe and has a brachysynclinal structure (Pánek et al., 2011). The prevailing lithology includes medium- to thick-bedded flysch of the Godula Member (Late Cretaceous), which consists of thick glaukonitic sandstones overlying weaker siltstones, claystones and shales (Menčík et at., 1983). From a morphological point of view, the Ondřejník ridge forms an isolated, ~7.5-km-long elevation, which strikes in the N–S 12

ACCEPTED MANUSCRIPT direction and rises a maximum of 550 m above the surrounding piedmont (Fig. 4). As in other parts of the Outer Western Carpathians, no glacial landforms or sediments have been proven

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in the areas surrounding the Ondřejník ridge. Continental ice sheets terminated at least 5 km

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northward during the Elsterian and Saalian glaciations, while during the Weichselian,

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glaciation did not reach the broader surrounding areas (Nývlt et al., 2011). Therefore we can exclude a glaciation in the area since at least before the Last Glacial Maximum (LGM). The wider surrounding area of the study site is prone to mass movements involving numerous

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DSGSDs, landslides and earthflows (Baroň et al., 2004; Pánek et al., 2011, 2013).

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As depicted by the high-resolution LIDAR imagery, sackung features occur along the entire stretch of the ridge (Fig. 4b). The most conspicuous uphill-facing scarp occurs on the west-

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facing slope. It is nearly 2 km long and a maximum of 4 m high and strikes in the N–S

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direction through the central and southern parts of the ridge (Fig. 3f). Its southern termination is characterized by a swarm of multiple scarps (both uphill- and downhill-facing), which

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affect the entire slope and range in altitude from 725–900 m. To the north, scarp crosses the ridge axis and continues as a prominent synthetic scarp on the east-facing slope of the ridge

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(Fig. 4b). Assemblages of sackung landforms also developed on the east-facing slope of the ridge. The dominant feature of its central and southern segment is a >1 km long dowhillfacing scarp, with several associated uphill-facing features, which give rise to typical symmetric sackungen, per Beck (1968; Fig. 4c). The northernmost spur of the Ondřejník ridge is a double-crested ridge (Fig. 4b). Lower flanks of the Ondřejník ridge are occupied by a nearly continuous sequence of landslides and earthflows (Fig. 4b). Structural data and geophysical Electric Resistivity Tomography measurements reveal that the majority of sackungen in the Ondřejník ridge are significantly influenced by the system of steep, N–S to NNE–SSW trending joints and faults (Pánek et al., 2011; Fig. 4b,c).

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ACCEPTED MANUSCRIPT 4.2. Time constraints Three trenches dug across uphill-facing scarps revealed the geometry of sackung faults,

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associated secondary grabens and post-emplacement sedimentary infill, including colluvial

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wedges, fine grained slope deposits and reworked loess (Pánek et al., 2011; Fig. 4b). A

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detailed description of all three trenches is provided by Pánek et al. (2011). The positions of excavated trenches are shown in Fig. 4b.

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Datable material was obtained from two trenches (#1 and 2; Fig. 4b). An OSL-dated basal sequence of reworked loess, which was overlain by faulted bedrock in Trench 1 from the

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double-crested ridge in the northern part of the study area, exhibited a minimum age of 5.94±0.34 ka (sample O1) (Table 2, Fig. 4b). The AMS radiocarbon analysis of the basal

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sequence of organic soils from Trench 2 yielded a calibrated age of 1470±50 BP (O2 sample).

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However, this horizon is situated at the top of the sedimentary infill. Thus, it provides only the

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upper limit for the genesis of these sackung-related half-grabens. Both trenches reveal that the movements responsible for the sackung genesis were rather episodic, and because the sedimentary infill of grabens is not affected by younger faulting, they are no longer active.

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Although our chronological dataset is poor, we found that some portions of the Ondřejník ridge sackung (double-crested ridge in the N part) originated in the Holocene, specifically in the late Atlantic chronozone (~6 ka BP).

5. Geomorphology and age constraints of the Salatín ridge sackung

5.1. Landform assemblages

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ACCEPTED MANUSCRIPT Wide and flat portions of the Salatín ridge (highest top at 2048 m a.s.l.; Fig. 5) are situated in the westernmost part of the Tatra Mts. The ridge is formed by a lithologically homogenous

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rock sequence consisting of a Tatric crystalline basement of Variscan/Carboniferous biotitic

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granodiorite (Němčok et al., 1994). Due to the occurrence of several stages of Alpine

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tectonics between the middle-Cretaceous and Quaternary periods (Králiková et al., 2014), the granodiorite is densely fractured and involves numerous shear zones striking in NE–SW, NW–SE and E–W directions (Fig. 5b). Repeated, heavy glaciations during the Pleistocene

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greatly impacted the current landscape. According to Zasadni and Kłapyta (2014), the Tatra

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Mts. hosted 55 glacier systems, which occupied a total of 280 km2 during the Last Glacial Maximum (LGM; herein dated to ~26–18 ka BP). The largest glaciers attained thicknesses of up to 400 m (Zasadni and Kłapyta, 2014). New

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Cl ages of moraines and glacially polished

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surfaces throughout the mountains reveal that the last cirque glaciers disappeared at ~11 ka BP (Makos et al., 2013, 2014).

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Linear features involving downhill- and uphill-facing scarps affect a section of the Salatín ridge that is more than 1.5 km long (Fig. 5b). Most of them were predisposed by

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discontinuities of highly fractured granodiorite. The longest system (approximately 500 m long) of echelon sackung scarps is situated between the top of Mount Salatín and the Skriniarky saddle (Fig. 6a). Overall collapse in the Salatínská dolina valley (Fig. 5c) is toward the northeast, with two different modes (Beck, 1968) of sackung, including; asymmetric sackung, which occurred on downhill-facing scarps in the SE termination (facing to the NE; Fig. 6b), and symmetric sackung, with opposing uphill- and downhill-facing scarps, which affected only the top of Salatín Mt. (Fig. 6c). The largest vertical throws are found on Salatín Mt., reaching 11 m in height. Somewhat different features of DSGSDs affect the NW portion of the study ridge (in the section NW of the Salatín Mt.; Fig. 6e). These scarps are situated on the gently inclined SW slope of the broad ridge and involve both downhill-facing scarps with 15

ACCEPTED MANUSCRIPT height up to 15–20 m, oriented to the S and SW in accordance with the general slope inclination, and uphill-facing scarps scarps, which attain a maximum height of 2 m. Both

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types of scarps delimit systems of several wide-bottom grabens, characteristic of this part of

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the Salatín ridge (Fig. 6e,f). Some portions of the hanging walls of the grabens are occupied

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by undrained depressions, with small ponds and swamps. High downhill-facing scarps represent outcrops of the main shear surface of the DSGSD, revealing the collapse of the ridge to the S and SW. (Fig. 5c). Valley floors to the NE and SW of the disturbed ridge are

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sequences of glacial moraines (Fig. 5b).

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filled by extensive relict rock glaciers, and only lower portions of the glacial troughs contain

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5.2. Time constraints

The internal structure of the trench across the uphill-facing scarp (Sc6) in the NW part of the

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ridge reveals highly fractured granodiorite bedrock, with dense jointing in the area of the inferred sackung plane (Fig. 7). Including the recent soil, there are five stratigraphic units that

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postdate displacement events and overlie granodiorite bedrock (units 1–5 in Fig. 7). None of these units was deformed by subsequent activation of the sackung plane. Massive coarse colluvium (unit 5 in Fig. 7), especially in the proximity of the scarp, is likely the colluvial wedge and is related to the displacement event. Just above this unit, there is a distinct organicrich soil with scattered granodiorite clasts (unit 4). It most likely represents deposits in a small pond, which originated below the sackung scarp. AMS radiocarbon dating of bulk samples (from both walls of the trench) from this unit yielded calibrated ages of 4310±60 (SALB) and 4230±60 BP (SALA), respectively, with a pooled age of 4270±40 BP, representing the minimum age of the sackung scarp (Table 2). The absence of deformation since ~4.2 ka BP within stratigraphic units 1–5, together with the presence of coarse colluvium just below the

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ACCEPTED MANUSCRIPT sackung scarp which we interpret as a colluvial wedge, reveals the episodic nature of movements along this scarp. 10

Be exposure dating dataset is limited (n = 6), the obtained

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Although our sackung scarp

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spectrum of ages is reasonably coherent across the studied ridge (Table 5, Fig. 8). The oldest

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scarp (Sc 2) is aged 7.5±0.7 ka, while the youngest (Sc4) was exposed at 4.2±0.5 ka BP. Four of the sampled scarps (Sc1, 3, 4, and 5) yielded statistically similar ages (at a 95% confidence

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level), which centred around ~4.8 ka BP. The absence of dated vertical sequences does not allow for accurate constraint of the onset and termination of sackung activity or inference of

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slip rates on individual sackung scarps. However, because some samples come from the upper portions of scarps (e.g., Sal3 – 5.2±0.5 ka BP – taken 93 cm below the edge of Sc1 scarp), it is

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likely that the beginning of the sackung movements is mid-Holocene. Furthermore, the upper

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limit of the sackung activity is verified by the 4.3±0.04 ka age for scarp Sc6 which is situated opposite to Sc5 and is characterized by two

Be exposure ages of 4.6±0.4 ka (Sal5) and

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6.4±0.6 ka (Sal6).

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6. Discussion

6.1. The origin of sackungen in the Western Carpathians Taking into account that the Ondřejník ridge has not been glaciated and the sackungen on the Salatín ridge originated at least 3–4 ka after the final retreat of glaciers from adjacent cirques (Makos et al., 2013, 2014; Fig. 8), it is highly unlikely that deglaciation triggered both sackungen. Even on the Salatín ridge, which is situated in terrain that was significantly reshaped by late Pleistocene glacier movements, deglaciation cannot be definitively identified

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ACCEPTED MANUSCRIPT as the cause of initial activity. A possible earthquake trigger cannot be completely ruled out, but seismicity in both areas is rather marginal, with historical earthquakes reaching maximum

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moment magnitudes (Mw) of ~4.5–5.5 (Pagaczewski, 1972). This seismicity level is

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considered to be the lower bound for the generation of major rock slope failures (Keefer,

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1984; Jibson, 2009).

The most likely direct causes at both sites are Holocene climatic changes and extreme

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hydroclimatic events such as intense and prolonged rainfalls. Portions of both analysed sackung-related DSGSDs from the Western Carpathians originated during the final stage of

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the humid Holocene climatic optimum (Davis et al., 2003; Mayewski et al., 2004). The double-crested ridge in the northern part of the Ondřejník locality (Outer Western

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Carpathians) formed in the late Atlantic chronozone, a humid period characterized by

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pronounced floods (Starkel et al., 2006) and enhanced mass movement activity (Margielewski, 2006; Pánek et al., 2013). The sackung scarps on the Salatín ridge are also

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roughly contemporaneous with the exceptionally humid phases in the Altlantic and Subboreal chronozones (~8.5–8, 5–4.5 and 3.6–3 ka BP), which were reconstructed for the Tatra Mts.

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from the pollen record of Obidowicz (1996) (Fig. 8). The idea that these sackungen did initiate at the termination of prolonged humid period is in accordance with Crozier’s (2010) idea, that deep-seated slope failures are generated by long-term climate cycles. Similar climatic controls on Holocene rock slope failures in the European Alps have been recently reported by Prager et al. (2008) and Zerathe et al. (2014). Thus, we hypothesize that prolonged elevated water tables, increased pore-water pressures and long-term gradual reductions in rock mass strength created favourable conditions for the progression of DSGSD during the Holocene at both studied ridges, even where glacial pre-conditioning is not present. Although a climatically-driven origin of sackungen is rarely reported, some recent studies

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ACCEPTED MANUSCRIPT suggest that monitored features experienced pronounced accelerations during heavy rainfall

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periods (e.g. Ambrosi and Crosta, 2006).

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6.2. Sackung – high diversity of possible settings

Our two case studies of sackung-bearing ridges in the Western Carpathians show that similar sackung landforms may originate in settings with very different geological structures, local

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relief and Quaternary history. Moreover, there are numerous sackung-related DSGSDs that

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have no spatial relations to past glacial patterns in the Western Carpathians situated in diverse lithological settings of medium-high mountains (e.g., flysch, carbonates, metamorphic and

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igneous rocks) (Fig. 2; Němčok, 1982; Alexandrowicz and Alexndrowicz, 1988; Briestenský

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et al., 2011; Pánek et al., 2011), and in mountain ranges throughout the world (Fig. 1, Table 1). A review of world sackung by Mège and Bourgeois (2011) contains only a limited number

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of published sackung cases (44 studies) and focuses on formerly glaciated alpine landscapes. This has led to the conclusion that sackungen are almost exclusively observed in mountainous

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regions that were glaciated during the Quaternary period (Mège and Bourgeois, 2011). Our extended sackung dataset (86 studies) shows that a substantial number of examples (at least 34 studies, >64 sackung sites) come from landscapes that have not experienced paraglacial readjustment (Table 1). Therefore, the incidence of sackungen outside paraglacial domains is not unusual, as stated by Mège et al. (2013), but rather common. As such, the use of sackung as terrestrial analogues for extraterrestrial paraglacial landform assemblages (e.g., Mège and Bourgeois, 2011) could be misleading. In summary, it appears that sackung originate if at least one of the following factors is strongly accentuated in the given landscape: (i) local topography with a sufficiently steep gradient, irrespective of relationships with glacial oversteepening (e.g., Crosta et al., 2013), 19

ACCEPTED MANUSCRIPT fluvial incision (e.g., Pánek et al., 2011) or tectonic uplift (e.g., Barth, 2014); (ii) unstable anisotropic bedrock (e.g., Pere, 2009), with the presence of first-order tectonic structures (e.g.,

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Agliardi et al., 2009b) and/or underlying strata prone to ductile flow or dissolution (e.g.,

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Carbonel et al., 2013); (iii) paraglacial behaviour, including debuttressing, hydroclimatic

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changes, permafrost degradation, and postglacial rebound (e.g., Coquin et al., 2015); and (iv) the incidence of high magnitude events such as earthquakes (Dramis and Sorriso-Valvo, 1983)

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or heavy rainfalls (Chigira et al., 2013).

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6.3. Sackung in paraglacial landscapes

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Paraglacial processes still represent important mechanisms that cause formation of sackung-

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related DSGSDs (Benn and Evans, 1998; Ballantyne 2002, 2005). Indeed, a large number of sackungen occur in settings that experienced deglaciation after the LGM (Fig. 1, Table 1).

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Recently performed orogen-scale inventories in the European Alps reveal a clustering of DSGSDs around areas with exceptionally large LGM ice thicknesses (Crosta et al., 2013).

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However, available dated sackung-type DSGSDs in mountains with well-known deglaciation chronology reveal a complex time-response of the sackung onset following the ice retreat (Table 6). Other than studies by Bovis (1982) and Hippolyte et al. (2012), all chronologically constrained sackungen show a significant (>4–5 ka) time lag with respect to ice retreat, which is potentially related to the long-term nature of stress relaxation, subcritical crack growth and progressive failure of intact rock bridges within the rock mass (Kemeny, 2003; McColl, 2012; Ballantyne et al., 2014). Such examples, as well as our case study from the Tatra Mts., reveal that factors involved in paraglacial rock slope stability such as glacial erosion, debuttressing, sheet jointing, and static fatigue (McColl, 2012) are significant precursors to sackung formation but rarely act as direct triggers. They mainly include extreme external factors, such

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ACCEPTED MANUSCRIPT as earthquakes and hydroclimatic extremes. This is documented by the observation of the sudden origin of ca. 10-m high new sackung scarps in the epicentral area of the 2002 Mw 7.9

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Denali fault earthquake in Alaska, USA (Jibson et al., 2004). Although this area is within the

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paraglacial framework, it was only due to seismicity, which caused dynamic loading of the

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slopes, and the resulting origin of sackung scarps. This case highlights the fact that even in the paraglacial landscapes, additional forces are usually necessary to generate sackung

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deformations.

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7. Conclusions

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The literature review and two case studies presented here highlight that, on a broader time

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scale, the onset of sackungen may be controlled, not only by glacial debuttressing, but also by general patterns of Holocene climatic changes leading to variations in pore pressures, where

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large topographic gradients and bedrock weaknesses exist. Although formerly glaciated mountains are especially susceptible to the origin of sackung-type DSGSDs, there are

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numerous cases of this phenomenon outside these regions. More than 64 examples have been described in mid-mountain areas that have never been glaciated, and well developed examples of Holocene sackungen from the Western Carpathians support this finding. Typical sackungtype DSGSD landforms might originate in landscapes that were never glaciated (e.g., Beskydy Mts. in Flysch Carpathians), especially on ridges formed by highly anisotropic bedrock dissected by fluvial erosion and/or underlying strata prone to ductile flow, dissolution or karstification. Results from the Tatra Mts. and examples from other mountainous areas imply a substantial time lag (>4–5 ka) in the onset of sackungen in respect to ice retreat in many paraglacial environments. In such settings, DSGSDs and related sackung landforms

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ACCEPTED MANUSCRIPT might not be directly driven by deglaciation. In particular, extreme external factors, such as

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Acknowledgements

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earthquakes or hydroclimatic events, may trigger DSGSDs and related sackung landforms.

This study was conducted within the framework of the Czech Science Foundation, project 13-

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15123S. Special thanks are extended to Zbyněk Engel, Jan Lenart, David Pěcha and Václav Škarpich for their help during the field work and to reviewers Alexander Strom and Mauro

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Soldati for valuable comments that substantially improved the manuscript. The authors would

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Captions

Tables

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Table 1. Classification of studies dealing with sackung-related DSGSDs.

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Table 2. OSL and AMS radiocarbon data used in the study.

Table 4. Analytical data of samples used for

10

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Table 3. Topographic and shielding data of samples used for 10Be exposure age dating. Be exposure age dating. The 10

Be/9Be values

Be/9Be = 2.709×10-11 (Nishiizumi et al.,

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have been calibrated to standard KN_01-5-1 with

10

2007). Four cathodes Be #3114, with 10Be/9Be ratio = 2×10-16 determined independently, were 10

Be/9Be ratio and to subtract that from samples

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used to derive an average machine blank

SAL1–6 and the other two blanks. Cathode Be #3594 was a process blank and was subtracted 10

Be concentrations of samples SAL1–6. Their resulting

Be concentrations are

Be concentrations and zero-erosion exposure ages calculated with version

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10

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given in Table 5. Table 5. Sample

10

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from the

2.2 of the CRONUS calculator, using the time-dependent Lal-Stone model (Balco et al., 2008). The uncertainty associated with that model, given in column ‘ext. unc.’, is dominant

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over the analytical error by approximately a factor two. Table 6. Time-response between previously dated sackung onsets and glacial ice withdrawal for previously glaciated regions. The location and dating methods of each study are included.

Figures Fig. 1. Main modes of sackung-bearing ridges (adopted from Agliardi et al., 2001)

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ACCEPTED MANUSCRIPT Fig. 2. Distribution of published sackung-related DSGSDs since ~1990. a) Worldwide context. b) Detailed view of Europe. In the European Alps (hatched area), which has a

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relatively complete inventory of features (n = 1033; Crosta et al., 2013), only the most

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significant studies with dating and typical sackung forms are included (for references, see

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Table 1).

Fig. 3. Selected examples of sackungen described from non-glaciated mountains. Arrows

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show position of sackung scarps. a) Conspicuous uphill-facing scarp crossing the ridge of the

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Malý Kriváň Mt. (1671 m a.s.l.; Malá Fatra Mts, Slovakia) consisting of Mesozoic sandstones, dolomites and Paleozoic granites (photo: T. Pánek). b) Uphill-facing scarp and graben in the limestone terrain of the coastal strip of the Crimean Mts., Ukraine (ca. 600 m

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a.s.l.; photo: T. Pánek). c) Uphill-facing scarps along the limestone ridge of Vânturariţa-Buila Massif (Southern Carpathians, Romania) (photo courtesy: J. Lenart). d) Nearly 3-km-long

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crestal graben on the Mt. Barigazzo (Northern Apennines - Italy, flysch substratum) (photo courtesy: G. Bertolini). e) Grabens and uphill-facing scarps affecting limestone terrain of the

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NW coastal range of the Sicily (Mt. Speziale; photo courtesy: C. Di Maggio). f) Uphill-facing scarp in the flysch Ondřejník ridge, Outer Western Carpathians (photo: T. Pánek).

Fig. 4. Location and settings of the Ondřejník ridge sackung, Outer Western Carpathians. a). Position of the study site in the Carpathians. b) Main geomorphic features of the Ondřejník ridge displayed on the LIDAR-based shaded relief. Locations of trenches for OSL/AMS dating are marked. Inserted rose diagram and stereonet (equal area projection on the lower hemisphere) reveal main discontinuities (joints and faults) within the flysch bedrock. Inserted trenches (for localization see the map) display main structural features of uphill-facing scarps and grabens. For more information, see Pánek et al. (2011). c) Geological cross-section of the 43

ACCEPTED MANUSCRIPT ridge (according to Rybář et al. 2006) in the vicinity of Trench 3. Electrical resistivity tomography profile revealing strongly anisotropic bedrock in the ridge section of the part of

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the cross-section is included.

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Fig. 5. Localization and settings of the Salatín ridge sackung, Tatra Mts. a) Position of the study site in the Carpathians. b) Main geomorphic features of the Salatín ridge and adjacent valleys. Sampling sites for

10

Be exposure dating (SAL1-6) and the location of a trench for

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AMS radiocarbon dating are marked. Inserted rose diagram and stereonet (equal area

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projection on the lower hemisphere) display main discontinuities within the granodiorite. c) Examples of cross-sections in different parts of the ridge (see b for localization.)

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Fig. 6. Sackung features in the Salatín ridge, Tatra Mts. Sampling sites and some major landforms related to ridge collapse are depicted. a) Double ridge/graben at the top of the

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Salatín Mt. (in the foreground), and a system of en echelon scarps continuing SE. b) Asymmetric sackung (ridge collapse to the left) affecting the SE part of the Salatín ridge. c)

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Symmetric sackung with graben between two opposing scarps at the Salatín Mt. d) Tension crack at the Salatín Mt. e) Wide grabens in the NE section of the Salatín ridge, originated within extensive DSGSD, moving to the SE (to the left). f) Synthetic (master) scarp in the foreground, with adjacent wide-bottom graben and uphill-facing scarp in the background. NE part of the Salatín ridge.

Fig. 7. Trench in the NE part of the Salatín ridge used for AMS radiocarbon dating. SE wall of the trench is documented in detail.

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ACCEPTED MANUSCRIPT Fig. 8. Timing of studied sackungen and their chronological context against selected regional

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ACCEPTED MANUSCRIPT Table 1 Sackungen types Dated sackungen with onset < 5 ka after deglaciation

Region North America Europe

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South America Europe

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Japan North America

Sackungen in (de)glaciated mountains2

New Zealand North America

Europe

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Sackungen in non-glaciated mountains3

Asia

Africa Asia

New Zealand 1

Main references1 Bovis (1982); McCalpin and Irvine (1995) Bigot-Cormier et al. (2005); Agliardi et al. (2009a); Hippolyte et al. (2009; 2012) Nishii et al. (2013) Tabor (1971); Radbruch-Hall et al. (1976); Beget (1985); Varnes et al. (1989; 1990); Bovis and Evans (1996); Kellogg (2001); Smith (2001); Schwab and Kirk (2002); Jibson et al. (2004); Kinakin and Stead (2005); Li et al. (2010); McCalpin et al. (2011); Sakals et al. (2012) Ego et al. (1996); Audemard et al. (2010) Němčok (1972, 1982); Soldati and Pasuto (1991); Reitner et al. (1993); Pasuto et al. (1997); Jarman (2002; 2006; 2009); Jarman and Ballantyne (2002); Hermann and Becker (2003); Tibaldi et al. (2004); Brückl and Paroditis (2005); Gutiérrez –Santolalla et al. (2005); Wilson (2005); Ambrosi and Crosta (2006); Blikra et al. (2006); Hürlimann et al. (2006); Gutiérrez et al. (2008); Tibaldi and Pasquarè (2008); Ustaszewski et al. (2008); Reitner and Linner (2009); Crosta et al. (2013); Krieger et al. (2013); Jarman et al. (2014) Kobayashi (1956); Hewitt et al. (2006); Chigira et al. (2010); Shroder et al. (2011); Nishii and Matsuoka (2012); Nishii and Ikeda (2013) Beck (1968); Korup (2005), Barth (2014) Ponti and Wells (1991); Harp and Jibson (1996); McCalpin and Hart (2003); Kellogg (2004); Johnson and Cotton (2005) Němčok (1972; 1982); Alexandrowicz and Alexandrowicz (1988)4; Sorriso-Valvo et al. (1999); Berardino et al. (2003); Di Luzio et al. (2004); Rizzo and Leggeri (2004); Bertolini et al. (2005); Griffiths et al. (2005); Saroli et al. (2005); Moro et al. (2007; 2012); Pánek et al. (2009; 2011); Briestenský et al. (2011); Coltorti et al. (2011); Gutiérrez et al. (2012); Carbonel et al. (2013); Tolomei et al. (2013); Bianchi Fasani et al. (2014); Di Maggio et al. (2014); Gori et al. (2014); Lenart and Pánek (2014) Mège et al. (2013) Chigira (2005); Chigira et al. (2013); Baroň et al. (2013); Hou et al. (2014) McLean et al. (2015)

Includes only the most important sources, particularly in the European Alps. This is because some recent studies involve widespread datasets of DSGSDs (e.g., Crosta et al. 2013 analyse distribution of 1033 DSGSDs in the European Alps).

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Includes mountains still sustaining mountain glaciers and those that were completely deglaciated after the LGM. 3

Includes mountains without any evidence for the presence of glaciers during the last glacial period or with very limited glaciation.

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Some of the features described in this study originated by lateral spreading.

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4

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ACCEPTED MANUSCRIPT Table 2 Material

O1/Trench 1Ondřejník ridge

GdTL-1180

silt

O2/Trench 2Ondřejník ridge

Gd-11999

SALA/TrenchSalatín ridge

UGAMS 18598

SALB/TrenchSalatín ridge

UGAMS 18599

Conventional age (BP)

Calibrated age (cal BP)

OSL age (ka)

Reference

5.94±0.34

Pánek et al. (2011)

T

Laboratory and dating method

AMS3

1470±50

Pánek et al. (2011)

organic soil (bulk)

3830±25

4230±60

this study

organic soil (bulk)

3870±25

4310±60

this study

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1575±50

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AMS3

organic soil (bulk)

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AMS2

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OSL1

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Code and location

1

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Gliwice Luminescence Dating Laboratory of the Institute of Physics, Silesian University of Technology (Poland) Gliwice Radiocarbon Laboratory of the Institute of Physics, Silesian University of Technology (Poland

3

Center for Applied Isotope Studies, University of Georgia (USA)

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ACCEPTED MANUSCRIPT Table 3 longitude

altitude

shielding

density

thickness

[°N]

[°E]

[masl]

[]

[g cm-3]

[cm]

SAL1

49.2142

19.6862

2029

0.656

2.65

3.5

SAL2

49.2139

19.6866

2027

0.776

2.65

SAL3

49.2112

19.6886

2010

0.720

2.65

4.5

SAL4

49.2116

19.6875

2028

0.509

2.65

3.5

SAL5

49.2159

19.6821

1991

0.863

2.65

4.5

SAL6

49.2159

19.6822

1991

0.772

2.65

4.5

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latitude

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sample

4.0

ACCEPTED MANUSCRIPT Table 4 10

Be/9Be

Be carrier

(Be#)

[g]

[mg]

[10-12 at at-1]

SAL1

3587

24.3853

0.401

0.071

0.004

1.79

0.10

SAL2

3588

27.3861

0.406

0.113

0.006

2.9

0.2

SAL3

3589

36.4538

0.407

0.129

0.005

3.38

0.14

SAL4

3590

45.9755

0.410

0.166

0.006

4.4

0.2

SAL5

3591

47.7796

0.411

0.171

0.005

4.58

0.15

SAL6

3592

39.7263

0.409

0.179

0.007

4.8

0.2

processing blank

3594

-

0.393

0.011

0.002

0.17

0.06

carrier blank

3595

-

0.426

0.006

0.002

0.05

0.05

machine blank

3114

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0.0046

0.0003

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quartz

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error

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Be conc.

error

[103 at g-1]

age

error

ext. unc.

[103 yr]

66

5

4.2

0.3

0.5

SAL2

101

6

5.5

0.3

0.6

SAL3

88

4

5.2

0.2

0.5

SAL4

92

4

7.5

0.3

0.7

SAL5

92

3

4.6

0.2

0.4

SAL6

115

5

6.4

0.3

0.6

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ACCEPTED MANUSCRIPT Table 6 Onset of sackung faulting

Time lag following glacier retreat

Dating method

Reference

Affliction Creek/Coastal Range (Canada)

AD 1865– 1875

Immediate response

Lichenometry

Bovis (1982)

Aspen Highlands, Colorado (USA)

~11–11.5 ka BP

2.5–4 ka

Vallibierna and Estós Valles, Central Pyrenees (Spain)

~5.9–7.8 ka BP

>5 ka

El Ubago, Central

~16.9 ka BP

Originated probably just before deglaciation, seismic trigger?

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Trenching, radiocarbon dating

McCalpin and Irvine (1995)

Trenching, radiocarbon dating

GutiérrezSantolalla et al. (2005)

Trenching, radiocarbon dating

Gutiérrez et al. (2008)

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Pyrenees (Spain)

~10.3 ka BP

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La Clapière, European Alps (France)

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Locality

>3 ka

10

Bigot-Cormier et al. (2005)

Be exposure dating

Le Pra, European Alps (France)

~5.6 ka BP

6.4–9.4 ka

10

Sanchez et al. (2010)

Arcs, European Alps (France)

~11 ka BP

1–4 ka

10

Hippolyte et al. (2009)

Rognier, European Alps (France)

~17 ka BP

Immediate response

10

Hippolyte et al. (2012)

Bregaglia valley, European Alps (Italy/Switzerland)

~29.4 ka BP

Originated well before LGM

Trenching, OSL dating

Tibaldi and Pasquarè (2008)

Mt. Croce, European

~120–40 ka;

Survived Last Glacial;

Trenching, radiocarbon

Tibaldi et al.

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Be exposure dating

Be exposure dating

ACCEPTED MANUSCRIPT reactivation ~32.5 ka BP

secondary deformation originated well before LGM

dating

(2004)

Mt. Watles, European Alps (Italy)

~10 ka BP

<4–5 ka

Trenching, radiocarbon dating

Agliardi et al. (2009a)

Mt. Noguchigoro, Japanese Alps (Japan)

~6 ka BP

2–5 ka

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Alps (Italy)

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Be exposure dating

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Nishii et al. (2013)

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Global review of sackung-type DSGSDs First 10Be exposure dating of sackung in the Carpathians Comparison of sackungen originated in paraglacial and non-glaciated landscapes Critical reassessment of the relevancy of sackungen in the paraglacial geomorphology

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