Major and trace element geochemistry of tourmalines from Archean orogenic gold deposits: Proxies for the origin of gold mineralizing fluids?

Accepted Manuscript Major and trace element geochemistry of tourmalines from Archean orogenic gold deposits: proxies for the origin of gold mineralizing fluids? Henrik Kalliomäki, Thomas Wagner, Tobias Fusswinkel, Grigorios Sakellaris PII: DOI: Reference:

S0169-1368(17)30059-8 http://dx.doi.org/10.1016/j.oregeorev.2017.08.014 OREGEO 2311

To appear in:

Ore Geology Reviews

Received Date: Revised Date: Accepted Date:

24 January 2017 28 July 2017 9 August 2017

Please cite this article as: H. Kalliomäki, T. Wagner, T. Fusswinkel, G. Sakellaris, Major and trace element geochemistry of tourmalines from Archean orogenic gold deposits: proxies for the origin of gold mineralizing fluids?, Ore Geology Reviews (2017), doi: http://dx.doi.org/10.1016/j.oregeorev.2017.08.014

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Major and trace element geochemistry of tourmalines from Archean orogenic gold deposits: proxies for the origin of gold mineralizing fluids?

Henrik Kalliomäki1,*, Thomas Wagner1,2, Tobias Fusswinkel1, Grigorios Sakellaris3

1

University of Helsinki, Department of Geosciences and Geography, PO Box 64, University of

Helsinki, Helsinki FI-00014, Finland 2

Institute of Applied Mineralogy and Economic Geology, RWTH Aachen University, Wüllnerstr. 2,

D-52062 Aachen, Germany 3

Malmi Geoconsulting, Pohjoisranta 14 A 30, FI-00170 Helsinki, Finland

*

Corresponding author (E-mail: [email protected])

Submitted to: Ore Geology Reviews Date: 28 July 2017 1

ABSTRACT Orogenic style gold mineralizations in the Archean Hattu Schist belt (E Finland) are present in all major host rock lithologies including epiclastic sedimentary and volcanogenic rocks, as well as felsic intrusives. The gold mineralizations occur as dissemination in altered wall rocks and within hydrothermal quartz veins. Hydrothermal tourmalines are often associated with the gold mineralizations occurring in the quartz veins, as alteration minerals in contacts of the metasedimentary host rocks and quartz veins, but also within mineral assemblages of the metasedimentary and magmatic rocks. We characterize and compare the major, trace and rare earth element chemistry of these tourmalines in order to evaluate their suitability as a petrogenetic tool for tracing the fluid sources of the hydrothermal system. By comparing the chemistry of tourmalines from gold mineralization with those from metamorphic and magmatic host rocks, we test whether tourmaline composition can be used to identify the source rocks of the gold transporting hydrothermal fluids. All analyzed tourmalines belong to the alkali super group and plot along the schorl-dravite join. The hydrothermal tourmalines have Li, Sr and V concentrations comparable to metamorphic tourmalines and clearly distinct from magmatic tourmalines. Because the concentrations of Ni, Pb, Cr, Mn, Ga, Zn and Sn show a wide overlap between magmatic, metamorphic and hydrothermal tourmalines, these elements do not permit to discriminate between different source rocks. The co-variations of many elements in hydrothermal tourmalines, when plotted against Li, show more similarity to metamorphic tourmalines and the whole-rock compositions of metasedimentary and metavolcanic host rocks than to their magmatic counterparts. This indicates that the major and trace element composition of hydrothermal tourmalines in the Hattu Schist Belt is predominantly controlled by the host rocks and local fluid-rock interactions, and does not reflect the distal fluid sources. The effect of local fluid-rock interaction is also manifested by the REE patterns of tourmalines. The magmatic tourmalines have distinct LREE enriched patterns resembling the whole-rock REE patterns of granitic intrusives, while the 2

metamorphic and hydrothermal tourmalines have flat or weakly fractionated patterns similar to metavolcanic and metasedimentary host rocks. Taken together, the tourmaline data suggest that hydrothermal tourmalines associated to gold mineralizing fluids are most likely genetically related to metamorphic rock sources without important contributions of magmatic fluids, and that local fluid-rock interaction exerted a major control on tourmaline chemistry.

Key words: Orogenic gold deposit, tourmaline, metamorphic fluids, magmatic fluids, tourmaline, trace elements

1. Introduction Tourmaline has the general chemical formula XY3Z6(T6O18)(BO3)3V3W and can incorporate considerable amounts of different major and trace elements including Na, Ca, K, Al, Mg, Fe, Si, B, F, Mn, Ti, Li, Cr, V, Zn, Ni, Co, Cu and Cl (Hawthorne and Henry, 1999; Henry et al., 2011). Tourmaline is the most abundant borosilicate mineral in the Earth’s crust and exhibits a wide range of compositions, reflecting its broad pressure-temperature stability field and occurrence in diverse igneous, metamorphic and hydrothermal environments. Because of its exceptional compositional variability and resistance to alteration and weathering, tourmaline has been considered as a robust petrogenetic indicator for the environment in which it has formed (e.g. Henry and Guidotti, 1985; van Hinsberg et al., 2011a, 2011b). Tourmaline is a characteristic hydrothermal mineral in veins and altered wall rocks of important types of hydrothermal metal ore deposits, including volcanic hosted massive Cu-Zn sulfide deposits formed on the sea floor (e.g. Slack and Coad, 1988; Plimer and Lees, 1998), granite-hosted Sn-(W)-Cu deposits (e.g. Mlynarczyk and Williams-Jones, 2006; Wagner et al., 2009; Duchoslav et al. 2017), and quartz vein hosted orogenic Au deposits (e.g. Krienitz et al., 2008; Hazarika et al. 2015).

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Tourmalines in Archean and Phanerozoic orogenic gold deposits are commonly present in gold bearing hydrothermal quartz veins, but they are also found as disseminations in hydrothermally altered sedimentary and igneous host rocks. Tourmaline can reach high modal abundance in hydrothermal quartz veins of orogenic Au deposits, and economic Au mineralization may be hosted by quartz-tourmaline vein systems (e.g. Kojonen et al., 1993; Olivo et al., 2007; Krienitz et al., 2008), demonstrating that the ore-forming fluids must have carried substantial concentrations of boron. This is supported by recent LA-ICPMS data from ore stage fluid inclusions of the Neoarchean Pampalo orogenic gold deposit in E Finland (Fusswinkel et al., 2017). The origin of orogenic gold mineralizing fluids is controversial, and current models propose either a single fluid source derived from metamorphic devolatilization (e.g. Phillips and Powell, 2010; Goldfarb and Groves, 2015; Fusswinkel et al., 2017) or a mixed source with contributions from metamorphic fluids and fluids released from felsic intrusions (e.g. Rogers et al., 2013; Gupta et al., 2014; Molnár et al., 2016a). Because tourmaline is a refractory mineral that is not easily affected by post-mineralization processes, it has been suggested that the major and trace element and isotopic composition of tourmalines from gold deposits could be used to discriminate among metamorphic and magmatic fluid sources (Pirajno and Smith, 1992; Henry and Dutrow, 1996; Slack, 1996; Jiang, 1998; Jiang et al., 1998). Based on tourmaline geochemistry, a metamorphic fluid source has been inferred in orogenic gold deposits in the Okote district in the Adola belt in eastern Africa (Deksissa and Koebler, 2002), in the Yunglon deposit in the Sanjiang Tethys belt in southern China (Jiang et al., 2004) and in the Hutti deposit in the Hutti-Maski greenstone belt in India (Hazarika et al., 2015, 2016). Conversely, contributions from both metamorphic and magmatic fluids have been suggested for the Archean G.R Halli deposit in the Chitradurga greenstone belt in India (Gupta et al., 2014) and the Archean gold deposits in the Hattu schist belt in eastern Finland (Molnár et al., 2016a). Utilizing the potential of tourmaline for tracing fluid sources

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requires to single out major and trace element characteristics that are mainly dependent on the fluid sources from those that depend on the lithochemistry of the local host rocks. Many studies that used tourmaline geochemistry as a potential proxy for the origin of gold mineralizing fluids have focused on stable isotope (O, H and especially B) and major element composition (e.g. Krienitz et al., 2008; Talikka and Vuori, 2010; Xavier et al., 2008; Molnár et al., 2016a), whereas the trace element chemistry of tourmaline from orogenic gold deposits has not been systematically investigated. In this paper, we report the results of a combined major and trace element study of tourmaline from Archean orogenic gold deposits of the Hattu schist belt in eastern Finland. The Hattu schist belt (HSB), located in the Karelian province, hosts different structurally controlled orogenic gold mineralizations, including the actively mined Pampalo deposit and several smaller prospects. The gold deposits are associated with lithologically variable metasediments and metavolcanics and apparently coeval felsic intrusions (Sorjonen-Ward, 1993; Vaasjoki et al., 1993). We characterize the major and trace element and REE compositions of tourmalines from gold mineralization and compare them to those of tourmaline from different host rock lithologies. The data are then used to investigate the effect of host rock buffering and fluid-rock reactions on tourmaline compositions. This makes it possible to evaluate whether tourmaline chemistry is a suitable proxy for resolving metamorphic and magmatic contributions to the gold mineralizing hydrothermal system.

2. Geological setting

2.1. Ilomantsi greenstone belt in the Archean Karelian province The Karelian province comprises the southwestern part of the Fennoscandian Archean craton and is bounded to the southwest by the Paleoproterozoic Svecofennian domain and to the northeast by the 5

Archean Kola domain (Fig. 1b). The Karelian province is mainly composed of granitoid rocks (with ages up to 3.24 Ga; Sergeev et al., 2007), temporally and lithologically variable greenstone belts (2.94–2.75 Ga in age; Huhma et al., 2012a, and references therein) and supracrustal sequences made up of metasedimentary rocks in between the greenstone belts. The Ilomantsi greenstone belt in eastern Finland (Fig. 1a) represents the youngest (ca. 2.75 Ga; Huhma et al., 2012a, and references therein) greenstone belt in the Karelian province. It is characterized by roughly N-S trending schist belts composed of supracrustal sequences of metasedimentary and metavolcanic rocks, which are intruded by granitoids of approximately the same age. In recent years, the Ilomantsi greenstone belt, and particularly the Hattu schist belt in the eastern part of the greenstone belt (Fig. 1a), have been the focus of increased research and exploration activity, reflecting the abundance of structurally controlled orogenic gold mineralizations.

2.2. The Hattu schist belt The N-S striking HSB is the easternmost supracrustal sequence in the Ilomantsi greenstone belt and is located adjacent to, and continues across, the national border between Finland and Russia (Fig. 1b). It is mainly composed of feldspathic epiclastic sediments and felsic pyroclastics with smaller volumes of ultramafic and mafic volcanic units and banded iron formations (BIF). The volcanosedimentary rocks have been intruded by tonalitic and leucogranitic felsic plutons (Fig. 1b; Nurmi et al., 1993; Sorjonen-Ward, 1993). Sorjonen-Ward (1993) has defined five formations (Fig. 1a) in the northern part of the HSB, which are 1) Sivakkojoki Formation (pelites, conglomerates and intermediate volcanic rocks), 2) Hosko Formation (greywackes and mafic to intermediate volcanic rocks), 3) Tiittalanvaara Formation (pelites, greywackes and BIF), 4) Kuljunki Formation (pelites; this formation has been correlated to the Hosko and Tiittalanvaara Formations) and 5) Pampalo Formation (mafic to intermediate volcanic rocks). In the southern part of the HSB, he has defined 3 formations, which are 1) Korvilansuo Formation (greywackes and mafic to intermediate volcanic 6

rocks), 2) Ukkolanvaara Formation and (pelites and greywackes) 3) Naukulampi Formation (mica schists). The Sivakkojoki Formation at the base of the HSB yields a U-Pb zircon age of 2.754 ± 0.006 Ga (Vaasjoki et al., 1993; Huhma et al., 2012a), while the Tiittalanvaara Formation higher up in the stratigraphy yields a U-Pb age of 2.726 ± 0.015 Ga (Vaasjoki et al., 1993). This rather short time span for deposition of the thick stratigraphic package has been interpreted as transition from the early distal resedimentation of volcanics and felsic crust to more proximal turbidite style deposition in shallow waters. The proximal environment produced a brief but diverse period of volcanism, which was coeval with deposition of the Pampalo Formation in a transgressive, or subsiding, submarine setting (Sorjonen-Ward, 1993). The volcanic rocks of the HSB show arc affinities (OʼBrien et al., 1993), and Hölttä et al. (2012) have therefore suggested that the volcanic suite in the entire Ilomantsi greenstone belt may represent arc magmatism within an attenuated continental margin. Based on the age determinations of the surrounding granitoids (2.757 ± 0.004 to 2.725 ± 0.006 Ga; Vaasjoki et al., 1993; Käpyaho et al. 2017) and robust field evidence (Sorjonen-Ward, 1993), the granitoids intruded during, or shortly after, the deposition of supracrustal sequences. Hence they do not represent their depositional basement, but rather a period of rapid generation of crust. The depositional basement of the HSB has remained unknown, but both supracrustal and plutonic rocks contain inherited zircon populations that represent crustal material which has an age of 3.0 Ga or even older (Sorjonen-Ward and Claoé-Long, 1993; Vaasjoki, 1993; Heilimo et al., 2011; Huhma et al., 2012a). The large scale geometry of the HSB is defined by upward-facing, generally steeply dipping structures (Sorjonen-Ward, 1993). Based on kinematic indicators, overprinting fabrics and close temporal relationships between volcanism, deformation and intrusion of granitoids, Sorjonen-Ward, (1993) has suggested that the deformation in the HSB was progressive instead of polyphasic. Progressive deformation has led to the present-day architecture of the HSB, which is characterized 7

by a transpressional N-NE trending dextral shear system where granitoid plutons have been emplaced to dilatant sites, and where several individual shear zones are distinguishable (SorjonenWard and Luukkonen, 2005). Peak Archean metamorphic temperature-pressure conditions are consistent throughout the study area and are in the range of 480–590 °C and 3.4–6.0 kbar (OʼBrien et al., 1993; Hölttä et al., 2012; 2016). However, based on pseudosection modeling and monazite geochronology of tourmaline bearing metasedimentary rocks from the NE part of the HSB, Hölttä et al. (2016) infer a metamorphic event at 2.66-2.64 Ga which may has reached peak conditions as high as 670 ° C and 7 kbar. The Archean metamorphism was later overprinted by the Paleoproterozoic Svecofennian orogeny at ca. 1.84 Ga (Hölttä et al., 2016), as indicated by K-Ar and Rb-Sr ages of micas and the resetting of oxygen isotope systems (Kontinen et al., 1992; Karhu et al., 1993; O’Brien et al., 1993). The Paleoproterozoic thermal event is manifested in places by greenschist facies mineral assemblages (Sorjonen-Ward, 1993).

2.3. Orogenic gold deposits in the HSB The Hattu schist belt shows many similarities to other Archean orogenic gold provinces worldwide, including host rock lithologies, structural setting, mineralization style and hydrothermal alteration. The gold mineralization is structurally controlled and is present in second- and third-order structures of major shear zones (Kojonen et al., 1993; Nurmi et al., 1993). Gold mineralization has been found in essentially all major lithologies of the HSB, including epiclastic sedimentary and volcanogenic rocks and intrusive rocks (Nurmi et al., 1993). Differences in rock competence and chemical contrasts between adjacent lithological units have played a major role in controlling the location of ore mineralization (Sorjonen-Ward et al., 2015). Most of the economic gold mineralization is hosted by mica schists, feldspathic sediments and tonalitic intrusions, and especially the contact zones with competent felsic volcanics, tonalite stocks and porphyry dikes have acted as preferential fluid pathways. 8

The HSB contains numerous orogenic gold mineralizations which are present as disseminations in altered wall rocks, whereas fewer gold mineralizations are hosted by large hydrothermal quartz vein systems. Most of the hydrothermal veins do also contain tourmaline, and quartz-tourmaline veins are rather common (Sorjonen-Ward, 1993). The absolute timing of gold introduction is not fully established and data supporting both single- and multiple-stage gold mineralization have been presented. Based on geological and isotope data, Nurmi et al. (1993) concluded that all gold mineralization was introduced in a single hydrothermal event, whereas later fluid inclusion and sulfur isotope studies suggested that at least two gold mineralization stages must have occurred (Poutiainen and Partamies, 2003; Molnár et al., 2016a). Recent U-Pb dating of hydrothermal zircon from the Pampalo gold deposit yielded an age of 2.71 Ga, which would correlate the timing of gold mineralization with the metamorphic peak in the area (Käpyaho et al., 2017). These time relationships are in agreement with the relative timing of gold introduction derived from the Kuittila deposit by Vaasjoki et al. (1993), who, however, also note that metamorphic fabrics overprint the gold mineralization. A comprehensive description of the structure, mineralogy and hydrothermal alteration of gold mineralization in the HSB is given by Nurmi et al. (1993). The main features of gold mineralization of the Kuittila, Hosko, Korvilansuo, Rämepuro, Pampalo and Pampalo East deposits (Fig. 1a) which were included in this study are briefly summarized below. Gold mineralization in the Kuittila tonalite is present in NW trending auriferous shear zones. The older WNW oriented subvertical likely magmatic-hydrothermal quartz veins which host abundant molybdenite and scheelite have been overprinted by the NW trending shear zones and are also weakly Au mineralized. The Au bearing shear zones contain abundant quartz veins and the surrounding tonalite has been affected by hydrothermal alteration which resulted in silicification and sericitization. The auriferous shear zones are crosscut by late NE trending barren milky quartz

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veins. Tourmaline is present as an accessory mineral in the host tonalite, but also in the quartz veins related to gold mineralization and within later barren quartz and tourmalinite veins. The Hosko, Korvilansuo and Rämepuro gold deposits are located in N-S to NE-SW oriented shear zones, which are hosted by metasedimentary rocks (mainly greywackes, interpreted as turbidites) and intermediate to mafic metavolcanics. The tourmaline bearing metasedimentary host rocks show widespread chlorite±sericite alteration in all these deposits. At Rämepuro and Korvilansuo, gold mineralization is also present in tonalite dikes. These are at least partly tourmalinized at Korvilansuo, while the tourmaline in Rämepuro is associated with strongly sheared and recrystallized quartz veins within the tonalite dike. Gold is typically concentrated in the quartztourmaline veins, but at Korvilansuo and Hosko in particular, it is also present as dissemination in the altered mica-schist host rocks. The Pampalo deposit is also located within a major shear zone system, but is different from most of the other gold mineralizations in the HSB. The host rocks of the Pampalo deposit are mafic and ultramafic volcanics with minor amounts of felsic and intermediate volcanoclastics. The intermediate volcanoclastics have been intruded by porphyritic dikes, which are strongly deformed and boudinaged (e.g. Nurmi et al., 1993). Gold mineralization is found as small veinlets and disseminations in the intermediate and mafic volcanics and as vein infills in fractures and boudin necks of the porphyritic dikes. Hydrothermal alteration is widespread and manifested by the typical albite+K-feldspar+biotite+sericite+carbonate mineral assemblage. The Pampalo East gold mineralization is associated with strongly albitized felsic porphyries with abundant quartztourmaline veins. Later tonalitic dikes which intruded into the talc-chlorite schists (metakomatiites) are only weakly mineralized (Nurmi et al., 1993).

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3. Samples and methods

3.1. Sampling strategy Sampling focused on gold mineralized veins, altered wall rocks and host rocks of the Pampalo, Pampalo East, Hosko and Rämepuro deposits, where representative vein and rock samples were collected from the Pampalo underground mine, open pits, exploration trenches and surface outcrops. In addition, samples were taken from selected representative drill cores of the Korvilansuo, Rämepuro and Pampalo deposits. The sampling targeted tourmaline bearing rocks and a representative suite of the main host rocks and gold mineralization styles of each deposit. In addition, several granitoid intrusions were sampled in surface outcrops, including the Tasanvaara, Korpivaara and Kuittila tonalites, the Naarva leucogranite and Viluvaara granodiorite (Fig. 1a). Approximately 70 thin sections were studied by transmitted- and reflected-light optical microscopy, and 28 tourmaline-bearing samples were selected for major and trace element analysis of the tourmaline. This final sample set covers ore zone tourmalines and barren tourmalines from all major host rock lithologies of the HSB. They were grouped in the following way: 1) metamorphic tourmalines in the metasedimentary and metavolcanoclastic host rocks, 2) magmatic tourmalines in the granitoid rocks and 3) hydrothermal tourmalines appearing within quartz veins, in tourmaline veinlets, as disseminated tourmalines within felsic dykes, and as tourmalinites related to alteration of metasedimentary and volcanoclastic rocks (Table 1).

3.2. Electron probe microanalysis (EPMA) The major element composition of tourmalines was determined by wavelength-dispersive electronprobe microanalysis in two different laboratories. One subset of samples was analyzed with the JEOL

JXA-8600

Superprobe

instrument,

upgraded

with

SAMx

hardware

and

the

XMAs/IDFix/Diss5 analytical and imaging software package, at the Department of Geosciences 11

and Geography, University of Helsinki. The second subset of samples was analyzed with the JEOL JXA-8900 Superprobe instrument at the Fachbereich Geowissenschaften, University of Tübingen in Germany. The quantitative wavelength-dispersive spectrometry (WDS) measurements were performed with 15 kV acceleration voltage and 15 nA beam current in the Helsinki laboratory, while 15 kV and 20 nA were used in the Tübingen laboratory. Details about both analytical routines used, including standards, X-ray radiations and counting times on peak and background, are summarized in Table 2. The analytical routine used in the Tübingen laboratory included measurement of B, which was used for improving the accuracy of the ZAF matrix correction procedure. However, the measured B concentrations were not used for mineral formula calculations, because the analytical uncertainty of 10-30% is obviously too large. This may reflect the lack of suitable matrix-matched reference materials for B analysis in tourmaline (synthetic boron nitride was used for EPMA). Matrix effects (chemical composition, absorption and fluorescence) that need to be corrected for do strongly affect the quantification of chemical elements with low atomic numbers such as boron (Reed, 2005). Tourmaline structural formulae were calculated on the basis of (O+OH+F) = 31 atoms per formula unit (apfu), assuming stoichiometric water and boron content and no ferric iron.

3.3. Laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) Trace element concentrations (including the REE) in tourmaline have been analyzed with the LAICP-MS system at the Department of Geosciences and Geography at the University of Helsinki, featuring a Coherent GeoLas MV 193 nm laser ablation system coupled to an Agilent 7900s ICP mass spectrometer. Spot sizes from 32 to 120 µm were used, depending on the grain size of the tourmaline. The laser repetition rate was set to 10 Hz. The flow rates of Ar plasma gas, He carrier gas and Ar auxiliary gas were set to 15 L/min, 1.0 L/min and 0.85 L/min, respectively. Two different element menus were used for 1) analysis of common trace elements and 2) analysis of the 12

REE. A laser energy of 6 J/cm² was used for analysis of common trace elements, whereas a higher energy 8 J/cm² was used for analysis of the REE, in order to extract more ablated material and to obtain higher count rates for low-concentrations elements. Element menu 1) included the following masses: 7Li, 9Be, 11B, 23Na, 24Mg, 27Al, 29Si, 39K, 42Ca, 47Ti, 51V, 52Cr, 55Mn, 57Fe, 59Co, 60Ni, 63Cu, 66

Zn,

71

Ga,

85

Rb,

88

Sr,

90

Zr,

93

Nb,

118

Sn,

137

Ba,

178

Hf,

181

Ta,

208

Pb,

232

Th,

238

U. Element menu 2)

included the following masses: 11B, 23Na, 24Mg, 27Al, 29Si, 31P, 35Cl, 42Ca, 45Sc, 79Br, 81Br, 89Y, 90Zr, 127

I,

139

232

Th,

La,

238

140

Ce,

141

Pr,

146

Nd,

147

Sm,

151

Eu,

157

Gd,

159

Tb,

163

Dy,

165

Ho,

167

Er,

169

Tm,

173

Yb,

175

Lu,

U. The reference material NIST SRM 610 was used to bracket sample analysis and as

external standard. The Si concentrations measured with EPMA were used as internal standard. The accuracy of the measured elemental concentrations was monitored by replicate analysis of NIST SRM 612 as an unknown sample, and the long-term accuracy was better than 5 % for most elements. Data reduction was done with the SILLS software package (Guillong et al., 2008) following procedures outlined in Heinrich et al. (2003). Data analysis with SILLS makes it possible to detect inclusions of other minerals in tourmaline in the time-resolved LA-ICP-MS signals. The inclusions are detectable in the laser ablation signals by a sharp increase in the count rate of the elements present in such mineral inclusions. The presence of micro-inclusions, especially of zircon, was quite commonly observed in the tourmaline signals, but such parts of the full tourmaline signals were excluded when defining the integration window for quantification of element concentrations in tourmaline, or alternatively the elements affected by these micro-inclusions were excluded from the dataset (Fig. 2).

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4. Results

4.1. Tourmaline occurrences in the HSB

4.1.1. Metamorphic tourmalines The metamorphic tourmalines (Fig. 3a) occur as disseminated and often as minor phases in the sampled metagraywacke and metaandesite host rocks. The maximum grain sizes of the metamorphic tourmalines are about 250 μm and they are somewhat more abundant within the metagraywackes than in the metaandesites. In both host rock lithologies, the tourmalines have euhedral prismatic and/or acicular crystal shapes and they are often aligned with their crystallographic c-axis parallel to the main foliation of their host rock. They are commonly intergrown with quartz and muscovite and also with biotite and/or chlorite. Tourmalines in metagreywackes from the Korvilansuo gold prospect occur also as inclusions within larger chlorite crystals. The metagreywacke has a second foliation which appears to post-date the coeval growth of tourmaline and chlorite. Well-preserved crystal morphology, sparse occurrence in their host rocks (compared to tourmalinites) and the intergrowth with metamorphic minerals suggest that they formed during metamorphism of the host rocks.

4.1.2. Magmatic tourmalines Disseminated magmatic tourmalines are characteristic of the Naarva leucogranite and associated pegmatites, whereas the sampled tonalitic intrusives only contain tourmaline in hydrothermal quartz and tourmaline veins. The tourmalines in the Naarva leucogranite are mostly subhedral and up to 800 μm in size and they are weakly altered along small fractures which contain epidote. Tourmaline is more abundant in the associated pegmatites (Figs. 3b and c), where they form crystals up to several cm in size which typically have quartz and muscovite inclusions. The pegmatite hosted 14

tourmalines show well-developed growth zoning with a color sequence from brown to green and/or blue from core to rim (Fig. 3b). They show less evidence of fracture-controlled alteration than the tourmaline in the leucogranite. Tourmaline is typically associated with coarse-grained Kfeldspar+quartz+plagioclase+muscovite in the leucogranite and the pegmatites.

4.1.3. Hydrothermal tourmalines Tourmalinites (Figs. 3d, e and f) represent the products of pervasive hydrothermal alteration of metasedimentary and metavolcanic lithologies. The tourmalinites contain a network of hydrothermal quartz veins and veinlets and they have a modal abundance of more than 30 vol.% of tourmaline. Zones of hydrothermal alteration in the HSB are typically on the centimeter- to meterscale, and the amount of tourmaline gradually decreases away from the margins of the quartz veins into the weakly altered host rock. It is sometimes difficult to distinguish between tourmalinites formed by hydrothermal alteration and closely-spaced tourmaline-rich quartz vein networks. The appearance of tourmaline as massive aggregates within the quartz veins could represent either brecciated tourmalinized host rock or local accumulations of tourmaline within the quartz veins. In such cases, we have classified the samples as tourmalinites, whereas we have classified clearly distinguishable individual quartz veins with abundant tourmaline as quartz-tourmaline veins. The tourmaline crystals in the tourmalinites are mostly 50-500 μm in size and the tourmaline accumulations are composed of euhedral prismatic to needle-shaped crystals which are often aligned along the main foliation. Sometimes, large fine-grained and closely packed aggregates of acicular tourmaline crystals are found (Fig. 3f). The average grain size of the tourmaline appears to increase with the abundance of quartz, and sometimes tourmaline is present as inclusions within hydrothermal quartz and sulfide minerals. The tourmaline crystals in the tourmalinites rarely show growth zoning or the growth zoning is only weakly developed, with light-green to bluish cores and green to brownish rims. Tourmalines in some metabasalt (PAM-67.7) and metakomatiite (PAE-6) 15

samples from the Pampalo deposit show well-developed growth and sectoral zoning. The tourmalinites also show sericite alteration. The main sulfide minerals within tourmalinites are pyrite, chalcopyrite and pyrrhotite, but arsenopyrite is also abundant in the tourmalinites in the Hosko deposit. Two different types of tourmaline-bearing hydrothermal veins can be distinguished, which are 1) tourmaline-dominated veins and 2) quartz+tourmaline±calcite veins. They may be present as successive vein generations, e.g. in samples KUI-3 and PAM-5 (Figs. 3g and h). The tourmalinedominated veins were observed only in the tonalitic intrusions and in the felsic porphyry dike in the Pampalo deposit. The quartz+tourmaline±calcite veins crosscut both the felsic intrusions and the supracrustal host rock sequence. The tourmalines in both vein types have variable grain sizes (up to 750 μm along the direction of elongation) and commonly prismatic to acicular crystal shapes. In some quartz+tourmaline veins where calcite is abundant, the tourmalines differ from the other tourmaline types by their characteristic blue (Figs. 3k and l) or very dark green to brown color. Some of the quartz+tourmaline±calcite veins in metabasalts from the Pampalo deposit and from tourmaline veinlets in the Tasanvaara tonalite contain altered tourmalines which show poikiloblastic textures with inclusions of quartz and some epidote (Fig. 3l). In these samples, epidote is more abundant than in other samples. The tourmalines in most tourmaline veins lack zoning and only the tourmalines in some quartz±calcite veins display well-developed growth zoning. Pyrite and chalcopyrite are the dominant sulfides in the tourmaline bearing vein samples from the Pampalo deposit, whereas in the Rämepuro deposit pyrrhotite is also present. The tourmaline-bearing veins from the tonalite intrusions and one quartz+tourmaline vein sample (PAM-13) from the Pampalo metabasalts do not contain sulfides. Disseminated hydrothermal tourmalines in the altered felsic dike from the Pampalo deposit (PAM-4) are up to 1.2 mm in size (along the direction of elongation) and they have acicular crystal shapes. They show weakly developed and irregular zoning, and contain many quartz and few 16

muscovite inclusions. Some of the tourmaline crystals are less altered and they have better developed euhedral crystal shape and show growth zoning. The tourmalines in the felsic dike are intergrown with porphyric K-feldspar and interstitial quartz and minor biotite, calcite, epidote and muscovite. The K-feldspar shows pervasive sericitization. Disseminated fine-grained sulfides are associated with the tourmaline, indicating that gold mineralization has post-dated the intrusion of the felsic dikes.

4.2. Major element composition of tourmalines The average compositions of the different tourmaline types are summarized in Table 3 (the complete data set is provided in the Electronic Supplementary Material). Based on the classification scheme of Henry et al. (2011), almost all tourmalines from the HSB have a clear predominance of (Na+K) on the X-site and belong to the alkali group (Fig. 4a). Only a few data points from tourmalinites of the Hosko deposit plot in the field of the X-vacancy group, and some tourmalines from a quartz+tourmaline+calcite vein hosted in metabasalts from the Pampalo deposit plot in the field of the calcic group (Fig. 4a). The great majority of metamorphic, magmatic and hydrothermal tourmalines have compositions that lie along the schorl-dravite binary (Fig. 4b). The only exception are few data points from tourmalinites of the Hosko deposit, which lie along a compositional trend that extends from compositions along the schorl-dravite join into the foitite field (Fig. 4b). Most of the data from tourmalinites from Hosko as well as the majority of magmatic tourmalines are Fedominated and plot into the schorl field, whereas the metamorphic tourmalines and most of the hydrothermal tourmalines plot into the dravite field (Fig. 4b). The F concentrations in the different tourmaline types are quite variable, ranging from below the limit of detection (0.3–0.4 wt.%) to a maximum of about 1 wt.% (Table 3). Elevated F concentrations were detected in some magmatic tourmalines and disseminated hydrothermal tourmalines in the felsic porphyry dike from the Pampalo deposit (PAM-4) as well as in a few grains from tourmalinites of the Hosko deposit 17

(samples HOS-6, HOS-4 and HOS-3). The highest F concentrations translate into slightly more than 0.5 apfu on the W site, and classify these tourmalines as the fluor-endmembers (see complete data in the Electronic Supplementary Material). The compositional variations between different analyzed growth zones in the tourmalines are smaller than variations between the different tourmaline types, and between different samples of the same tourmaline type. Some tourmalines show variations in Mg, Fe and Al between core and rim on the order of about 1-3 wt.%. Typically, Fe increases and Mg decreases from core to rim (e.g. samples NAR-1.1 and HOS-7; Table 3). Some samples (e.g. PAM-3, KVS-40.6 and HOS-4) show considerable variations in their Fe and Mg concentrations of several wt.%, which reflect compositionally distinct tourmaline populations but not texturally clear growth zoning. It is not possible to discriminate the different texturally recognizable tourmaline types by their major element compositions, but the tourmaline types show some broad variations in terms of their Al, Fe and Mg concentrations. The magmatic tourmalines have lower Mg concentrations (0.73-1.02 apfu) than the metamorphic tourmalines (1.56-2.25 apfu). By comparison, the Mg concentrations of the hydrothermal vein hosted tourmalines (1.22-1.92 apfu) are more similar to the metamorphic tourmalines. The only exception are tourmalines from the tourmaline-dominated vein from the Pampalo felsic dike (PAM-5) which have Mg concentrations (0.66 apfu) that are close to the magmatic tourmalines. By contrast, the disseminated hydrothermal tourmalines (PAM-4) in the same felsic dike and tourmalines in the quartz+tourmaline+calcite vein (PAM-5) that crosscuts the tourmalinite vein have Mg concentrations (1.76 and 1.69 apfu, respectively) that are otherwise characteristic for the metamorphic tourmalines. The hydrothermal tourmalinites, on the other hand, show more variable Mg concentrations than the other tourmaline types. The tourmalinites from the Hosko deposit have mostly Mg concentrations (0.64-0.91 apfu) that resemble those of the magmatic tourmalines. However, a smaller population of tourmalines with higher Mg concentrations, similar to those of the metamorphic tourmalines, was detected as individual grains (HOS-4) and as 18

compositionally distinct cores (HOS-7). The tourmalinites from the other localities have Mg concentrations (1.59-2.13 apfu) which are close to the metamorphic tourmalines. The Fe concentrations show more variation and considerable overlap between different types of tourmalines. The magmatic tourmalines and the hydrothermal tourmalinites from the Hosko deposit are enriched in Fe (1.42–1.76 apfu) compared to the metamorphic tourmalines and hydrothermal tourmalinites from the other deposits (0.88-1.22 apfu). However, more Fe-rich tourmalines are also present as small populations among the metamorphic tourmalines from the Pampalo metaandesite (PAM-3) and the hydrothermal tourmalinites from the Korvilansuo deposit (KVS-40.6) which otherwise have much lower Fe concentrations. Similarly, tourmalines with lower Fe concentrations are present as a small population (HOS-4) and compositionally distinct cores (HOS-7) among the generally more Fe-rich hydrothermal tourmalines of the Hosko deposit. The hydrothermal vein hosted tourmalines have highly variable Fe concentrations (0.97-2.54 apfu), which show no obvious correlation with the different host lithologies or distinct tourmaline generations. The Al content of all tourmalines analyzed is commonly higher than 6 apfu, indicating some Al substitution on the Y-site. The highest amount of Al substituting on the Y-site is observed for magmatic tourmalines and the tourmalinites from the Hosko deposit, as shown by 6.38-6.4 apfu and 6.40-6.72 apfu of Al, respectively. Only the tourmalines from the Hosko tourmalinites show a positive correlation of Al with the Fe concentration (Fig. 5b), while tourmaline from the other tourmalinites shows a negative correlation between both elements. Commonly, analyzed tourmalines show a positive correlation between Mg and Si, while the correlations between Fe and Si are less obvious (Figs. 5a and 5c). The magmatic tourmalines and the tourmalinites from the Hosko deposit are generally more Fe-rich, Mg-poor and Al-rich compared to all other tourmaline types. However, compositional overlap between different tourmaline types is a common feature in the tourmaline bearing samples of the HSB. 19

4.3. Trace element characteristics of tourmalines The average trace element compositions (including the REE) of the different tourmaline types are summarized in Table 4 and the complete dataset is reported in the Electronic Supplementary Material. Due to the small grain size, it was not possible to analyze different growth zones and cores and rims in most samples. In cases where core and rim compositions could be successfully analyzed, the differences were small (see Electronic Supplementary Material). Hence, the averages presented in Table 4, unless marked separately (e.g. samples NAR-1.1 and PAM67.7), represent the average values of the analyzed tourmaline grains. In addition, the standard deviations within analyzed samples, and even within discrete growth zones, are commonly of the same magnitude as the compositional variations between different samples of the same tourmaline type. The concentrations of most trace elements analyzed are low and typically below 10 μg/g, including Nb, Ba, Ta, Th, U, Rb, Hf, Be and Cu, and in most cases Zr as well. The concentrations of Nb, Hf, Ta, Th and U are often below the limit of detection or just slightly higher than 1 μg/g. On the other hand, the concentrations of Li, Co, Ni and Ga can reach up to about 200 μg/g, and V, Cr, Mn, Zn and Sr can be as high as about 0.3 wt.% (Table 4). The variations in trace element concentration between the different tourmaline types and even within a given sample are quite high, up to one order of magnitude. In the distinctly zoned magmatic tourmalines from the Naarva pegmatites (NAR-1.0), the composition of Mn increases systematically from core to rim, from 630 μg/g in the cores to 990 μg/g in the first rim and then to 1230 μg/g in the second outer rim. Zn shows a similar trend of increase with 620 μg/g in the core and 840 μg/g in the first rim, but the second rim has approximately the same Zn concentrations as the first rim. For other trace elements, some differences between core and rim are detectable, but they are of lower magnitude than for Mn and Zn. It is commonly observed that the compositions of tourmaline rims in the pegmatite are similar to the compositions of the magmatic tourmalines in the granitic host rock which are not 20

growth zoned. In the hydrothermal tourmalinite from the Pampalo metabasalt (PAM-67.7), the largest differences in trace element concentrations are observed for V and Sr, which have concentrations of 210 and 410 μg/g and 170 and 320 μg/g in the core and rim, respectively. The concentrations of Li, V and Sr in the hydrothermal and the metamorphic tourmalines vary widely (Li: 8-72 μg/g; V: 210-1000 μg/g; Sr: 160-3300 μg/g), which makes it impossible to discriminate among the two tourmaline types based on these trace elements (Figs. 6a, b and c). By contrast, the magmatic tourmalines have distinctly higher Li concentrations (150-190 μg/g) and lower V (10-35 μg/g) and Sr (7-15 μg/g) concentrations, and the concentrations of all three elements lie in a much narrower range (Figs. 6a, b and c). The metamorphic tourmalines show differences in the concentrations of Ga, Sn, Zn and Cr, which reflect their different host rock lithologies. The concentrations of Ga, Sn and Zn are lower and those of Cr are higher in metasediment hosted tourmalines compared to metavolcanic hosted tourmalines (Figs. 6e, h, d and f). The concentrations of these elements in the metavolcanic hosted tourmalines show considerable overlap with those in the magmatic tourmalines and the hydrothermal tourmalinites in the felsic dike of the Pampalo gold deposit. Irrespective of their host rock lithologies, the metamorphic tourmalines have Ni (23-150 μg/g) and Pb (5-22 μg/g) concentrations which lie in a rather narrow range. The higher Ni and Pb concentrations set the metamorphic tourmalines apart from the magmatic tourmalines, which have typically lower Ni (413 μg/g) and Pb (2.4-3.2 μg/g) (Figs. 6g and i). The hydrothermal tourmalinites have Ga and Sn concentrations which are comparable to those of the metamorphic tourmalines hosted by metagreywackes (including the tourmalinites from the Pampalo metavolcanics which host the metamorphic tourmalines that have Ga and Sn concentrations similar to magmatic tourmalines) (Fig. 6e and h). The Zn and Cr concentrations of tourmalinites shows distribution patterns analogous to the Ga and Sn concentrations, except in the Pampalo and Hosko deposits (Figs. 6d and f). The tourmalinites in the Hosko deposit have Zn and 21

the tourmalinites in Pampalo have Cr concentrations lying in the same range as those of the metavolcanic hosted metamorphic and magmatic tourmalines. The Ni and Pb values of the vein tourmalines from the Pampalo deposit overlap with both the data of the magmatic tourmalines and those of the metamorphic tourmalines (Figs. 6g and i). The Ga (Fig. 6e), Sn (Fig. 6h), Zn (Fig. 6d), and Cr (Fig. 6f) values overlap with those of the magmatic (and metavolcanic hosted metamorphic tourmalines) and of the metagraywacke hosted metamorphic tourmalines. The vein tourmalines from the Tasanvaara tonalite have Sn (Fig. 6h), Zn (Fig. 6d) and Cr (Fig. 6f) concentrations which lie on the same trend that is shown by the metamorphic and magmatic tourmalines. Remarkably, the Pb and Ni concentrations in some of the hydrothermal tourmalinites and vein tourmalines differ more significantly from both the magmatic and the metamorphic tourmalines than is the case for most other elements (Figs. 6g and i). The Ni concentrations show the largest variations in the hydrothermal tourmalinites and vein tourmaline samples (Fig. 6g). The disseminated hydrothermal tourmalines from the felsic dike of the Pampalo deposit have Pb and Ni concentrations more similar to all analyzed metamorphic tourmalines, while the Ga, Sn, Zn and Cr values are closer to those of the magmatic and metamorphic tourmalines from the metavolcanic host rocks (Fig. 6).

4.3.1. REE patterns The average REE concentrations of the different tourmalines are presented in Table 4; the complete dataset including chondrite normalized (Boynton, 1984) values is given in the Electronic Supplementary Material. The concentrations of some of the REE, mostly those of the heavier REE above Sm, were frequently below the limit of detection, resulting in incomplete REE patterns. Nevertheless, the REE patterns show some differences between tourmaline types. The magmatic tourmalines and the disseminated hydrothermal tourmalines from the Pampalo felsic dike (sample PAM-4) show a distinct enrichment in LREE and considerable decrease of the chondrite normalized patterns towards the HREE (Fig. 7b). By contrast, the REE patterns of the metamorphic tourmalines 22

are flat or show only a moderate enrichment in the LREE (Fig. 7a). The hydrothermal tourmalines have patterns which are either flat, show a weak enrichment in LREE or a weak enrichment in both LREE and HREE relative to the MREE (Figs. 7c, d and e). Characteristic (La/Yb)N values for the magmatic tourmalines and for those from sample PAM-4 are 45-112, whereas they are 14 and 0.04-5.05 for metamorphic and hydrothermal tourmalines. Few hydrothermal tourmalines show weak enrichment in the HREE, reflected by (Gd/Yb)N values as low as 0.09. The average total REE concentrations (∑REE including La to Lu, but excluding Y) are highest in the metamorphic tourmalines compared to magmatic and hydrothermal tourmalines (Table 4). The REE patterns of almost all tourmalines analyzed show a positive Eu anomaly, except the tourmaline dominated veins (TAS-1) and quartz-calcite-tourmaline (KUI-1) veins from tonalites that show also negative Eu anomalies. The Eu anomalies are higher in the hydrothermal tourmalinites and vein tourmalines compared to the magmatic and metamorphic tourmalines (Table 4). The vein hosted tourmalines and hydrothermal tourmalinites do also have Ce anomalies.

5. Discussion The major and trace element chemistry of hydrothermal tourmalines is controlled by three main factors, which are 1) the mineralogy and bulk composition of the host rocks, 2) the pressuretemperature conditions of tourmaline crystallization, and 3) the chemistry of the external hydrothermal fluids (e.g. Henry and Guidotti, 1985). Especially the Mg, Fe and Al concentrations in tourmaline are known to vary in a systematic way from low- to high-grade metamorphic conditions (Henry and Dutrow, 1996; van Hinsberg and Schumacher, 2009). The peak metamorphic P-T conditions in the Hattu Schist Belt are rather well established as lower to mid amphibolite facies (480–590 °C and 3.4–6.0 kbar), with variations of the estimated peak P-T conditions across the 23

study area amounting to a maximum of 110 °C and 2.6 kbar (OʼBrien et al., 1993; Hölttä et al. 2012; 2016). This suggests that the first-order factors which have controlled the tourmaline chemistry in the HSB are the bulk composition of the lithologically variable host rocks and fluidrock interactions involving the external gold mineralizing hydrothermal fluids. The major and trace element compositions of the different tourmaline types (magmatic, metamorphic and hydrothermal) show rather wide variations and considerable overlap. Therefore, it is not straightforward to discriminate the tourmaline types based on their compositional features. Multiple stages of tourmaline formation are demonstrated by growth zoning and the presence of different sets of tourmaline bearing veins that crosscut each other. The growth zoned tourmalines do not necessarily show distinct compositional differences between successive zones, and the major and trace element variations between growth zones are at least on the same order as variations between samples or different grains in individual samples. Despite the considerable chemical variations observed for the different tourmaline types, some element characteristics nevertheless make it possible to distinguish for example the magmatic and the metamorphic tourmalines.

5.1. Tourmaline major element compositions The tourmaline data show that the bulk composition of their host rocks exerts a major control on the tourmaline major element characteristics. Tourmalines in granitoidic rocks have generally lower Mg/(Mg+Fe) ratios (0-0.4) than the tourmalines hosted by metapelitic rocks (0.4-1.0 (e.g. Henry and Dutrow, 1996). This effect is clearly visible in the dataset from the HSB, where magmatic tourmalines have average Mg/(Mg+Fe) ratios of 0.19-0.29, whereas metamorphic tourmalines have Mg/(Mg+Fe) ratios of 0.38-0.59 (Fig. 4b; Table 3). The hydrothermal tourmalines have Mg/(Mg+Fe) ratios that are overlapping with those of the magmatic and metamorphic tourmalines, but the majority of the data lie in the compositional field of metamorphic tourmalines. The only hydrothermal tourmalinites which have Mg/(Mg+Fe) ratios similar to the clearly magmatic 24

tourmalines are those from the Hosko deposit (Fig. 4b). The Hosko deposit differs from the other gold deposits of the HSB by the abundant sericitic alteration of the host rocks that predates the regional foliation and by the abundance of arsenopyrite compared to other sulfides in the ore assemblages (Sorjonen-Ward et al., 2015). These peculiarities may be reflected in the Mg/(Mg+Fe) ratios of hydrothermal tourmaline from the Hosko deposit. The Hosko deposit is associated with several felsic dikes, but these are unlikely the source of these apparently magmatic affinities because similar compositional features are not found in the tourmalines from other deposit where felsic dikes are present as well. Hydrothermal tourmalines with low Mg/(Mg+Fe) ratios have already been described from the Hosko deposit by Molnár et al. (2016a). Compared to the data from the hydrothermal tourmalinites, the Mg/(Mg+Fe) ratios of the vein hosted hydrothermal tourmalines do not permit to interpret them in terms of metamorphic or magmatic signatures. While the metasediment hosted hydrothermal vein tourmalines have Mg/(Mg+Fe) ratios which would place them within the metamorphic compositional field, the vein hosted hydrothermal tourmalines from the Pampalo deposit and tonalites have Mg/(Mg+Fe) ratios which overlap with those of the magmatic and metamorphic tourmalines (Fig. 4; Table 3). In addition, even tourmaline types with rather well defined Mg/(Mg+Fe) ratios that would place them into either the magmatic or metamorphic group show grain populations (samples HOS-4 and KVS40.6) or distinct growth zones (sample HOS-7) which are compositionally distinct.

5.2. Tourmaline trace element and REE compositions There are only a few studies that have addressed the trace element composition of hydrothermal tourmalines from orogenic gold deposits. Therefore, there is a lack of background data that would permit to firmly establish trace element criteria for magmatic and metamorphic fluid sources. Most of the published tourmaline trace element studies have focused on the genetic link between hydrothermal veins, granitic pegmatites and potential source granites (e.g. Marks et al., 2013; Yang 25

et al., 2015). Other studies compared the trace element compositions of hydrothermal tourmalines of ore deposits with the bulk rock concentrations of inferred magmatic and metamorphic host rock lithologies (e.g. Taylor and Slack, 1984; Griffin et al., 1996). Tourmalines genetically related to granitic rocks typically have higher Li and lower V and Sr contents than those related to metavolcanic or metapelitic rocks (Taylor and Slack, 1984; Jiang et al., 2004; Galbraith et al., 2009; Hezel et al., 2011). These results are in accordance with our findings for the magmatic and metamorphic tourmalines of the HSB. The hydrothermal and metamorphic tourmalines of the HSB have similar Li, V and Sr concentrations, which are clearly distinct from those of the magmatic tourmalines. Even the Li, V and Sr compositions of hydrothermal vein tourmalines hosted by tonalities and felsic porphyry dikes are distinct from the magmatic tourmalines and closely resemble those from metamorphic host rocks. This group of elements is therefore suitable as a proxy for the fluid sources for hydrothermal tourmalines associated with the orogenic gold mineralization in the HSB, indicating predominantly metamorphic fluids. In addition, highly variable but similarly high Sr concentrations have been reported for tourmalines from the Hutti-Maski greenstone belt (Dharwar craton, India), where the mafic lithologies have been inferred as a potential source for the high Sr content (Hazarika et al., 2015). High Ni, Cr and Mn concentrations of hydrothermal tourmalines have been related to input of these elements from metasedimentary-volcanic country rocks rather than magmatic sources (Taylor and Slack, 1984; Jiang et al., 2004; Galbraith et al., 2009). By contrast, the Pb concentration data in hydrothermal tourmaline give more mixed messages. Elevated Pb concentrations of tourmalines from the greenstone hosted emerald deposits of the Yukon Territory in Canada have been related to granitic sources (Galbraith et al., 2009), whereas hydrothermal tourmalines from the alteration zones of volcanogenic massive sulfide deposits have been reported to contain substantially higher Pb compared to tourmalines from granites or granitic pegmatites (Taylor and 26

Slack, 1984; Griffin et al., 1996). Furthermore, the hydrothermal tourmalines with high Pb concentrations from these massive sulfide deposits usually have low Zn concentrations (and low Zn/Fe ratios) which would discriminate them from granite related tourmalines that typically have higher Zn concentrations (Griffin et al., 1996). Such compositional discrimination of tourmalines cannot be straightforwardly done for the data of the HSB due to the considerable compositional overlap between magmatic and metamorphic tourmalines for many trace elements (e.g. Cr, Ga, Zn, Mn, Ni and Pb) and the large variation of these elements in hydrothermal tourmalines. In addition, the concentrations of certain trace elements appear to reflect more local host rock buffering than the fluid source. For example, enrichment in Ga and Sn is not only observed in the clearly magmatic tourmalines, but also in hydrothermal tourmalines hosted by felsic dikes and intermediate metavolcaniclastics of the Pampalo gold deposit. Similarly, the average Cr concentrations in most tourmalines from different host rock lithologies of the Pampalo deposit are lower than in tourmalines from other localities. Although the REE dataset is small and incomplete, it nevertheless provides some insight into likely fluid sources for orogenic gold mineralization. The chondrite normalized REE patterns of metamorphic tourmalines are distinct from those of the magmatic tourmalines, and are more similar to those of the hydrothermal vein hosted tourmalines and tourmalinites. Moreover, they show a good match with the whole-rock REE patterns of the supracrustal rocks (OʼBrien et al., 1993). The chondrite normalized REE patterns of the magmatic tourmalines are characterized by considerable REE fractionation, relative enrichment of the LREE over the HREE and more pronounced positive Eu anomalies. By contrast, the REE patterns of the metamorphic tourmalines are relatively flat or show only weak fractionation and weaker Eu anomalies. It was suggested in previous studies that the REE patterns of hydrothermal tourmalines may truly reflect the REE signature of the hydrothermal fluid from which they precipitated and could therefore be used as a proxy for the fluid sources (e.g. Plimer et al., 1991; Jiang et al., 2004; Marks 27

et al., 2013). Because almost all hydrothermal tourmalinites and vein hosted tourmalines have REE patterns which resemble those of the metamorphic tourmalines (Fig. 7), the tourmaline REE data of the HSB support an essentially metamorphic source for the hydrothermal tourmalines and associated orogenic gold mineralization. The only exception is shown by a few hydrothermal tourmalines hosted by tonalitic dikes and intrusives (samples PAM-4, PAM-5 and TAS-1), which have more fractionated and LREE-enriched REE patterns more similar to those of the magmatic tourmalines. This highlights that the major and trace element composition of hydrothermal tourmaline may be strongly affected by interaction with local host rocks. Therefore, interpretation of tourmaline composition data in terms of fluid sources is possible, but requires detailed characterization of the variations due to different host rock lithologies.

5.3. Controls on tourmaline composition in orogenic gold environments The classification scheme of Henry and Guidotti (1985) identifies tourmaline compositional fields in different host rock lithologies based on the Fe-Al-Mg system. The magmatic tourmaline data from the HSB would plot within the field that defines Li-poor granitoids and related granitic pegmatites and aplites (Fig. 8). The metamorphic tourmalines would fall into the field of metapelites+metapsammites (Fig. 8). Interestingly, the hydrothermal vein tourmalines (except the tourmaline dominated vein sample PAM-5 and few single data points in sample PAM-51.5), plot within the field of metapelites+metapsammites along with the data of the metamorphic tourmalines (Fig. 8). Similarly, the hydrothermal tourmalinites plot in the metapelite+metapsammite field, except for the tourmalinites from the Hosko deposit (Fig. 8). The hydrothermal tourmalinite samples from the Hosko deposit, which have Mg/(Mg+Fe) ratios that overlap with those of the magmatic tourmalines, lie on a trend in the Fe-Al-Mg diagram that extends from the field of Lipoor granitoids to the metapelite+metapsammite field (Fig. 8). This demonstrates that the

28

Mg/(Mg+Fe) ratios are not necessarily a suitable proxy for the fluid source of hydrothermal tourmalines. Similarities in the major and trace element signatures of metamorphic tourmalines and their precursor least-altered clastic sedimentary host rocks suggest that tourmaline composition is largely controlled by host rock composition (Raith, 1988; Slack et al., 1993b). As shown in Figure 5b, the hydrothermal tourmalinites, the vein-hosted hydrothermal tourmalines and the metamorphic tourmalines show a good correlation between Fe (apfu) and Al (apfu) and the compositional fields of these tourmaline types do largely overlap. They are clearly distinct from the majority of data from the magmatic tourmalines. This strongly supports the genetic link between the hydrothermal tourmalines and metamorphic rocks. The tourmaline data from the Hosko deposit extend from the metamorphic to the magmatic compositional field, but significant input of magmatic fluid into the hydrothermal system at such a local scale appears rather unlikely. Moreover, none of the tourmalinites from the other gold deposits in the HSB plot in the magmatic compositional field, although some of them are also located in the vicinity of granitoid bodies. In addition, variable Mg/(Mg+Fe) ratios in tourmalinites can also be the product of growth competition and partitioning of Mg and Fe between tourmaline and other ferromagnesian silicates such as chlorite (e.g. Slack, 1996). Large compositional overlap and elemental co-variations between hydrothermal and metamorphic tourmalines leads to some important interpretations. Only a small group of elements, namely Li, V and Sr are suitable indicators for discriminating between magmatic and metamorphic tourmalines, and may therefore be used as proxies for the origin and source of hydrothermal tourmalines in the HSB. Out of this group, we use Li, which preferentially fractionates into fluids and can serve as an indicator of potential distant fluid sources (Duke, 1995; Ridley and Diamond, 2000), as a reference element to compare the behavior of other trace elements in hydrothermal tourmalines. As can be seen in Figure 9, plots of Mn, Ni and Cr against Li show the greatest 29

compositional overlap between magmatic and hydrothermal tourmalines, while plots for Pb, Ga, Zn and Sn show only modest overlap and those for Sr and V show a good separation between both groups. Despite the considerable compositional variations, the metamorphic tourmalines and the hydrothermal tourmalines show the largest overlap and covariations for a number of elements, while the overlaps of both tourmaline types with clearly magmatic tourmalines are much smaller. This finding is in best agreement with the interpretation that the hydrothermal tourmalines were formed from fluids which had interacted with, or were alternatively produced locally by compositionally variable metavolcanic and metasedimentary host rock lithologies. This is supported by the correlation between the Li, Sr, Ni, Cr and Pb compositions of tourmaline and the metavolcanic and metasedimentary host rocks (Fig. 9). The chondrite normalized whole-rock REE patterns of the metasedimentary and metavolcanic lithologies vary from nearly flat without significant fractionation to patterns which show a moderate enrichment in LREE and a systematic decrease towards the HREE (O’Brien et al., 1993). The chondrite normalized patterns of the granitic intrusions (Kuittila and Tasanvaara tonalites) have more fractionated patterns with clear enrichment in LREE (O’Brien et al., 1993). These differences in the whole-rock REE patterns are reflected by the data of the metamorphic and magmatic tourmalines. The metamorphic tourmalines have flat or only weakly fractionated patterns which resemble those of the metasedimentary and metavolcanic host rocks, whereas the magmatic tourmalines have distinctly LREE enriched patterns which are very similar to those of the granitoid intrusives. This good agreement demonstrates that the REE patterns of tourmalines are a suitable proxy for their host rock environment. Taking the REE data for the metamorphic and magmatic tourmalines in the HSB as a basis, the hydrothermal tourmalines which exclusively have rather flat and unfractionated REE patterns would be best interpreted in terms of metamorphic fluid sources. Published REE datasets for hydrothermal vein tourmalines or tourmalinites are not extensive, but REE patterns comparable to hydrothermal tourmalines from the orogenic gold 30

deposit in the HSB have been reported from the supracrustal rock hosted Houxianyu borate deposit in China (Jiang et al., 1997), the Yunglong tin deposit in China (Jiang et al., 2004), tourmaline-rich metasedimentary rocks in the Martinamor antiform in Spain (Pesquera et al., 2005) and orogenic gold deposits of the Hutti-Maski greenstone belt in India (Hazarika et al., 2015). Comparable tourmaline REE patterns have also been found in a number of granite hosted environments, including the granitic hosted Asarcik vein type Pb-Zn-Cu±U deposit in Turkey (Yavuz et al., 2011), granitic pegmatites and migmatitic gneisses in SW Germany (Marks et al., 2013) and granites of the Qitiang batholith in China (Yang et al., 2015). The results of these studies as well as our data from the HSB show that the REE systematics of hydrothermal tourmalines strongly depends on the REE composition of the host rock lithologies, which can lead to similarities between metamorphic and magmatic rock sourced hydrothermal tourmalines. This highlights the critical importance of analyzing and characterizing the trace element and REE composition of tourmalines of all potential source lithologies (including magmatic, metavolcanic and metasedimentary rocks) in addition to those of the hydrothermal tourmalines related to ore mineralization. Without a sufficiently complete dataset that includes these source rock lithologies, conclusions drawn based solely on the trace element and REE data for hydrothermal tourmalines may be incorrect. Europium and cerium anomalies in hydrothermal tourmalines have been used for interpreting the ore-forming environments. Europium occurs mostly in the divalent state (Eu2+) in hydrothermal and metamorphic fluids at temperatures above 250 ºC (e.g. Sverjensky et al., 1984), which facilitates incorporation into the tourmaline structure (van Hinsberg, 2011). The metamorphic fluids forming tourmalines may therefore have different Eu2+/Eu3+ ratios compared to their source rocks (Jiang et al., 2004; Marks et al., 2013), as evident for the data from the HSB. The whole-rock REE patterns of the metavolcanic and metasedimentary rocks have generally very weak negative Eu anomalies, if at all (OʼBrien et al., 1993), whereas all of the metamorphic, magmatic and hydrothermal tourmalines have distinctly positive Eu anomalies. The Ce4+ ion, on the other 31

hand, is more stable than Ce3+ in metamorphic hydrothermal fluids under high ƒO2 and its abundancy is manifested by anomalies in the normalized REE patterns (Bau, 1991; Jiang et al. 2004). The REE patterns of hydrothermal vein tourmalines hosted by the Kuittila and Tasanvaara tonalitic intrusives show (both negative and positive) Ce anomalies, whereas the host rocks in the HSB do not show Ce anomalies, with the single exception of some tholeiitic metavolcanics (OʼBrien et al., 1993). Similar differences between the Ce anomalies in REE patterns of hydrothermal tourmalines and those of their host rocks have been described for the Yunglon tin deposit China (Jiang et al., 2004). Thus, we suggest that the Eu or Ce anomalies in REE patterns of hydrothermal tourmalines are not suitable as proxies for the distal fluid sources, but the magnitude of these anomalies rather reflects the redox state of the fluid and crystallochemical controls on Eu and Ce incorporation into tourmaline.

5.4. Metamorphic or magmatic fluid sources in HSB gold deposits Based on new U-Pb geochronological data of hydrothermal zircons, Käpyaho et al. (2017) concluded that the gold mineralization which occurred at 2.71 Ga post-dates most of the granitoids in the HSB, which have ages around 2.75 Ga. Therefore, only the younger 2.695±0.005 Ga Naarva leucogranite could have played a role in the formation of the orogenic gold deposits. The hydrothermal tourmalines from the Hosko deposit (the deposit located closest to the Naarva leucogranite) do have some elemental characteristics (e.g. Mg, Fe, Al and Zn) which resemble those of the magmatic tourmalines of the Naarva leucogranite. This could potentially be interpreted in terms of a contribution of magmatic fluids released from leucogranites to the gold mineralizing hydrothermal system. However, the major and trace element data of tourmalines from the other orogenic gold deposits (e.g. Korvilansuo, Rämepuro and Pampalo) do not show any characteristics that would support a significant magmatic contribution to the hydrothermal fluids. In addition, the B isotope compositions of the tourmalinites, specifically those from the Hosko and Korvilansuo 32

deposits, have been interpreted to be inherited from the fluids derived from their metasedimentary host rocks (Molnár et al., 2016a). Only the hydrothermal tourmalines which are hosted by felsic intrusives have B isotope compositions which would support formation from magmatic fluids (Molnár et al., 2016a). Strong arguments against contributions of magmatic fluids released from the leucogranites to gold mineralization in the HSB come from fluid chemistry data and mass balance considerations. The exceptionally low Pb and Zn concentrations and low Cl/Br ratios of gold ore stage fluids of the Pampalo deposit argue strongly against input of magmatic fluids into the gold mineralizing hydrothermal system and in fact support a pure metamorphic devolatilization model (Fusswinkel et al., 2017). Moreover, the Naarva type leucogranites make up only a very small volume fraction of the HSB, compared to the volumetrically dominant supracrustal sequences and the older tonalitic granitoids. Therefore, the fluid volumes that could have been produced by volatile release from the leucogranites could not have contributed more than few percent of the fluid volume that would have been produced from devolatilization of the supracrustal rocks including metasediments and metavolcanics. This rules out any significant contribution of magmatic fluids to gold deposit formation in the HSB, which is in line with the tourmaline trace element data from this study that support the dominant influence of metamorphic sources for gold mineralization and highlight the effects of local-fluid rock-interaction.

6. Conclusions 1) Tourmalines from the HSB, including hydrothermal tourmalines related to gold mineralization, granite-hosted magmatic tourmalines and metamorphic tourmalines hosted by metasedimentary and metavolcanic rocks, have major element compositions that plot mainly along the dravite-schorl binary. They show rather large within- and between-sample variations in their major, trace and rare earth element compositions. 33

2) Comparison of hydrothermal tourmalines associated with gold mineralizing quartz veins to metamorphic and magmatic tourmalines demonstrates that only selected trace elements (i.e. Li, V and Sr) are suitable for discriminating between magmatic and metamorphic sources. Most other trace elements show considerable overlap between magmatic and metamorphic tourmalines, and the compositionally variable hydrothermal tourmalines. 3) The co-variations of some trace elements (e.g. Mn, Ni, Cr, Zn, Ga, Pb and especially Li, V, and Sr) in hydrothermal tourmalines are similar to those of the metamorphic tourmalines and they differ from the magmatic tourmalines. The compositional trends for the trace elements in tourmalines reflect the different trends shown by the metasedimentary and metavolcanic host rocks, compared to the granitoid intrusives. This shows that fluid-rock interaction with local compositionally diverse host rocks exerted major control on the composition of hydrothermal tourmalines. 4) The effect of fluid-rock interaction is also shown by the chondrite-normalized REE patterns of tourmalines that closely reflect those of their host rocks. REE patterns of magmatic tourmalines resemble those of the host granites, whereas REE patterns of metamorphic and hydrothermal tourmalines are comparable to those of metasedimentary and metavolcanic host rocks. The REE patterns of hydrothermal tourmalines are potentially suitable as proxies for the fluid sources, provided that background data for the REE composition of magmatic and metamorphic host rocks and tourmalines are available.

Acknowledgements This project was made possible by funding from the Academy of Finland, grant number 266180. We would like to thank Endomines Oy for their outstanding and generous support during field work campaigns and sampling, particularly Janne Vehmas, Ida Eriksson, Jani Rautio and Markus Ekberg. We thank Helena Korkka for the preparation of thin sections. The support of Thomas Wenzel

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during EPMA analysis at the Fachbereich Geowissenschaften, University of Tübingen (Germany) is greatly appreciated.

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44

Figure captions:

Fig. 1. (a) Simplified geological map of the Hattu schist belt (HSB), illustrating the main supracrustal units and granitoid intrusives, the major shear zones and the location of gold deposits and sampling sites. Modified from Sorjonen-Ward and Luukkonen (2005). The inset (b) gives an overview of the large-scale geology of the Fennoscandian Shield, modified from Sorjonen-Ward (1993). Fig. 2. Typical example of time-resolved LA-ICP-MS signals of tourmaline. The integration window that was used for quantification of elemental concentration data in tourmaline is highlighted by a purple box, whereas the gas blank signal is highlighted by a gray box. (a) Representative analysis of a relatively short signal of a small tourmaline grain. The abrupt decrease in the B count rate after the first plateau indicates that the laser ablation has penetrated through the tourmaline grain and that the ablated material is now coming from a different mineral underneath the tourmaline. (b) Representative analysis of a large tourmaline grain with a stable signal along the entire ablation time. (c) Representative analysis of a tourmaline grain which contains many microinclusions of zircon. The micro-inclusions are manifested by the sudden increase in the count rates of Zr, Th and U that cause distinct peaks in the time-resolved signal. The elements affected by these micro-inclusions were excluded from the dataset. The inset in (d) shows a zoom-in of the count rates of Zr, Th and U. (e) Representative analysis of a tourmaline grain which contained inclusions other than zircon. This caused simultaneous increase of several elements above the level measured in inclusion-free parts of the tourmaline. In such cases, the parts of the time-resolved signals that were affected by the inclusions were excluded from the integration window used for quantification of the tourmaline.

45

Fig. 3. Hand specimen and thin section photographs illustrating the textural appearance of the different tourmaline types of the Hattu schist belt, eastern Finland. (a) Thin section photograph of metamorphic tourmaline in metagraywacke host rock; Korvilansuo deposit (KVS-35.5). (b) Thin section photograph of magmatic tourmaline in K-feldspar rich pegmatite; Naarva leucogranite (NAR-1.0). The magmatic tourmalines show a well-developed growth zoning. (c) Hand specimen photograph of coarse-grained magmatic tourmalines in pegmatite matrix; Naarva leucogranite (NAR-1.0). (d) Hand specimen photograph of laminated tourmalinite; Hosko deposit (HOS-4). (e) Thin section photograph showing laminated tourmalinite with lamination-parallel quartz and crosscutting set of younger quartz veinlets; Korvilansuo deposit (KVS-40.1). (f) Contact between tourmalinite and quartz vein, Korvilansuo deposit (KVS-40.6). (g) Thin section overview photograph of mineralized felsic dike crosscut by tourmaline-dominated veins and later quartz+tourmaline+calcite vein; Pampalo deposit (PAM-5). (h) Thin section photograph highlighting crosscutting relations between the two tourmaline bearing vein generations; Pampalo deposit (PAM-5). (i) Thin section overview photograph of tourmaline bearing hydrothermal quartz vein; Pampalo deposit (PAM-13). (j) Detail of euhedral to subhedral tourmaline crystals in hydrothermal quartz vein; Pampalo deposit (PAM-13). (k) Thin section photograph of quartz+tourmaline+calcite vein in metabasalt host rock; Pampalo deposit (PAM-51.0). (l) Thin section photograph of poikiloblastic crystals of blue tourmaline; Pampalo deposit (PAM-51.0). Mineral abbreviations: Tur: tourmaline; Ms: muscovite; Qz: quartz; Kfs: K-feldspar; Cal: calcite.

Fig. 4. Overview of the major element composition of magmatic, metamorphic and hydrothermal tourmalines from the HSB, with fields for main tourmaline types from Henry et al. (2011). (a) Classification based on X-site occupancy distinguishing tourmalines of the calcic group, vacancy group and alkali group. Most tourmalines from the HSB fall into the alkali group. (b) Classification based on Mg/(Mg+Fe) and X-vacancy/(X-vacancy+Na+K) ratios, distinguishing tourmaline fields 46

of foitite, Mg-foitite, schorl and dravite end-members. The majority of tourmaline data from the HSB plot along the schorl-dravite binary, while the data from the hydrothermal tourmalinites extend towards foitite.

Fig. 5. Variation diagrams illustrating the composition of magmatic, metamorphic and hydrothermal tourmalines from the HSB. (a) Mg (apfu) as function of Si (apfu). (B) Al (apfu) as function of Fe (apfu). (C) Fe (apfu) as function of Si (apfu).

Fig. 6. Summary of the range in (a) Li, (b) V, (c) Sr, (d) Zn, (e) Ga, (f) Cr, (g) Ni, (h) Sn, and (i) Pb concentrations of magmatic, metamorphic and hydrothermal tourmalines from the HSB. Hydrothermal tourmalines have Li, V and Sr concentrations which are comparable to those of the metamorphic tourmalines. These elements distinguish the two groups clearly from the magmatic tourmalines, while most other elements show considerable overlaps between all three groups.

Fig. 7. Chondrite normalized (Boynton, 1984) REE patterns of (a) metamorphic tourmalines showing flat or moderately LREE enriched patterns, (b) magmatic tourmalines and disseminated hydrothermal tourmalines with LREE enriched patterns, (c) hydrothermal vein tourmalines with weak REE fractionation, (d) hydrothermal vein tourmalines and (e) tourmalinites with flat or concave upward patterns.

Fig. 8. Major element composition of magmatic, metamorphic and hydrothermal tourmalines from the HSB plotted into the ternary Al-Fe(tot)-Mg tourmaline provenance diagram (Henry and Guidotti, 1985). The diagram distinguishes tourmalines from eight different geological environments, which are 1) Li-rich granitoid pegmatites and aplites, 2) Li-poor granitoids and their associated pegmatites and aplites, 3) Fe3+-rich quartz-tourmaline rocks (hydrothermally altered 47

granites), 4) metapelites and metapsammites with a coexisting Al-saturating phase, 5) metapelites and metapsammites without a coexisting Al-saturating phase, 6) Fe3+-rich quartz-tourmaline rocks, calc-silicate rocks, and metapelites, 7) low-Ca meta-ultramafics and Cr, V-rich metasediments, and 8) metacarbonates and metapyroxenites. Most of the tourmalines from the HSB have compositions which are comparable to tourmalines typically hosted by metapelites and metapsammites, while only some tourmalinites from the Hosko deposit plot close to granitoid hosted tourmalines.

Fig. 9. Variation diagrams of selected trace elements in magmatic, metamorphic and hydrothermal tourmalines from the HSB as function of Li concentrations. For comparison, wholerock data for the main host rock lithologies (O’Brien et al. 1993) are plotted along with the tourmaline data.

48

(a)

(b)

Kartitsa granodiorite

Kola domain

rc A

NORWAY

a he

SWEDEN

n

Hosko deposit

Pr

7000

7005

Fig. 1

e ot

Karelia domain

Na leu arva co gra nit e

ic zo ro

N

FINLAND

6990

Korpivaara tonalite Pampalo deposit

6980

Tasanvaara tonalite

HSB RUSSIA

300 km High strain zones

N

Sampled granitoids

Sampled deposits Archean

Proterozoic

Granitoids Leucogranites

Granodiorites

Unnamed granites

Tonalites

Viluvaara granodiorite Supracrustal units Rämepuro deposit

Korvilansuo Fm. (greywackes, pelites and mafic volcanics) Tiittalanvaara Fm. (pelites, greywackes, banded iron formations) Ukkolanvaara Fm. (pelites, greywackes, banded iron formations)

Silvevaara granodiorite

Naukulampi Fm. (pelites) Ruukinpohja Fm. (mafic volcanics and igneous rocks)

6970

Korvilansuo deposit

Pampalo Fm. (mafic to intermediate volcanics) Sivakkojoki Fm. (pelites, gonglomerates, intermediate volcanics)

Kuittila tonalite

5 km 4550

Hosko Fm. (greywackes and mafic to intermediate volcanics) Kuljunki Fm. (pelites)

Pogosta granodiorite

Undifferentiated mica schists 4560

4570

Fig. 2 109

(a)

108

HOS-4

108

NAR-1.0

Counts per second

B

106 105 104

Li Be

107

107

Counts per second

(b)

B Na

106

Mg Al

105

Si K

104

Ca Ti

10

3

103

V Cr

10

102

2

Mn Fe

101

0

30

60

90

101

120

0

30

Time (s)

120

zr

Ni

(e)

KVS-38.9

U

Rb Sr

Counts per second

106

106 105 104

103

Sr

Zr Nb

Ti

105

Sn

Ca

Ba

104

Hf Ta

Zr

10

3

10

2

Zn Ga

107 Th

107

Co Cu

108

(c) TAS-1

108

Counts per second

90

Time (s) (d) TAS-1

109

60

Pb Th

102

101

0

35

70

Time (s)

105

140

101

U

0

30

60

Time (s)

90

120

Fig. 3

(a)

Metamorphic tourmalines

(b)

Magmatic tourmalines

Tur

Kfs

Qz

Tur

(c)

Tur Ms

Qz

200 um

5cm

Tur

Hydrothermal tourmalinites

Tur

1mm

(e)

(d)

(f)

Tur

Tur Qz

Qz 1mm

0.5 cm

3 cm Hydrothermal vein tourmalines

Tourmaline dominated vein

(g)

Qz-Tur-vein Tur

(i)

Qz-Cal-Tur vein

(k)

Qz

Qz-Cal-Tur-vein

Tur

q Cal 1 cm

2 mm Qz-Cal-Tur-vein

(h)

Qz

0.6 mm

(j)

Qz

(l)

Tur Cal Tur

7 mm

Tur

600um

400um

Fig. 4

Ca

Calcic group

X-

va

ca

nc

yg

rou

p

Alk

p

rou

g ali

(a)

X-vacancy/(X-vacancy+Na+K)

X- site vacancy

Na+K

Foitite

Mg-foitite (b)

0.6 0.5 0.4 0.3 0.2 0.1 0.0

Schorl 0.1

Dravite 0.2

0.3

0.4

0.5

0.6

Mg/(Mg+Fetot)

Metamorphic tourmalines Magmatic tourmalines Disseminated hydrothermal tourmalines

0.7

0.8

Tourmalinites Vein tourmalines

Fig. 5

(a)

Mg (apfu)

2.0 1.5 1.0 0.5

5.5

7.0

5.6 5.7

5.8 5.9 6.0 Si (apfu)

(b)

6.1

6.2

Hosko tourmalinite trend

Al (apfu)

6.5 6.0 5.5 5.0 0.5

Fe (apfu)

2.5

1.0

1.5 Fe (apfu)

2.0

2.5

(c)

2.0 1.5 1.0 0.5 5.5

5.6 5.7

5.8 5.9 6.0 Si (apfu)

6.1

6.2

Metamorphic tourmalines Magmatic tourmalines Disseminated hydrothermal tourmalines Tourmalinites Vein tourmalines

Sn (ppm)

Ni (ppm) 1000

10

100 100

Ga (ppm)

Li (ppm)

Zn (ppm)

100

10

10

(g)

100

10

1

(h)

1

0.1

(i)

10

1 1000

(b)

(c)

Metamorphic tourmalines Magmatic tourmalines Disseminated hydrothermal tourmalines RÄM-1C RÄM-2 KUI-1 PAM-13 PAM-5 PAM-51.0 PAM-51.5 R140-56-8 TAS-1 TAS-2

1000

Cr (ppm)

V (ppm)

(a)

NAR-1.0 NAR-1.1 KVS-35.5 PAM-3 R140-56-8 RÄM-5 PAM-4 HOS-2 HOS-4 HOS-6 HOS-7 KVS-38.9 KVS-40.1 KVS-40.6 PAE-6 PAM-67.6

RÄM-1C RÄM-2 KUI-1 PAM-13 PAM-5 PAM-51.0 PAM-51.5 R140-56-8 TAS-1 TAS-2

NAR-1.0 NAR-1.1 KVS-35.5 PAM-3 R140-56-8 RÄM-5 PAM-4 HOS-2 HOS-4 HOS-6 HOS-7 KVS-38.9 KVS-40.1 KVS-40.6 PAE-6 PAM-67.6

Sr (ppm) 1000

RÄM-1C RÄM-2 KUI-1 PAM-13 PAM-5 PAM-51.0 PAM-51.5 R140-56-8 TAS-1 TAS-2

NAR-1.0 NAR-1.1 KVS-35.5 PAM-3 R140-56-8 RÄM-5 PAM-4 HOS-2 HOS-4 HOS-6 HOS-7 KVS-38.9 KVS-40.1 KVS-40.6 PAE-6 PAM-67.6

Pb (ppm)

Fig. 6

(d)

100

(e)

100

10

(f)

1000 100

10 10

1

Tourmalinites Vein tourmalines

Fig. 7

(a)

Metamorphic tourmalines

10 1 0.1 0.01

100

Sample/Chondrite

Sample/Chondrite

100

0.001

(c)

Vein tourmalines (PAM-5 (Qz-cal-tur),TAS-1)

10 1 0.1 0.01

Sample/Chondrite

10 1 0.1

0.01 0.001

1 0.1 0.01

100 10 1 0.1 0.01 0.001

0.001 100

10

Magmatic tourmalines Disseminated hydrothermal tourmalines

0.001

Sample/Chondrite

Sample/Chondrite

100

(b)

(e)

Tourmalinites

(d)

Vein tourmalines

Fig. 8

Al

Al

Elbaite

Metamorphic tourmalines Magmatic tourmalines Disseminated hydrothermal tourmalines Tourmalinites Vein tourmalines

2

Alkali-free dravite

4

7 5

Schorl Buergerite

3

Mg

Fe(tot)

1

6

Dravite

8 Uvite

Al50Fe(tot)50

Al50Mg50

Fig. 9

1000

100

10

1

1

10

(h) 100

100

10

(c)

(f)

10

1000

1000

(i)

Zn (ppm)

Pb (ppm)

100

(e)

10

Mn (ppm)

1

1

Ga (ppm)

100

(g)

0.1

1000

Sr (ppm)

Cr (ppm)

1000

10

100

10

(b)

(d) Sn (ppm)

(a)

V (ppm)

Ni (ppm)

1000

100

1

100 10

Li (ppm)

100

Host rocks (bulk) Granites Metasedimentary rocks Intermediate metavolcanics Mafic metavolcanics Ultramafic metavolcanics

10

Li (ppm)

100

Tourmalines Metamorphic tourmalines Magmatic tourmalines Disseminated hydrothermal tourmalines Tourmalinites Vein tourmalines

10

Li (ppm)

100

Table 1: Configuration of wave length dispersive (WDS) for electron microprobe analysis. 1. Batch

2. Batch

Element

Standard

Line

Crystal

Standard

Line

Crystal

B

BN

Ka

LDEB

F

Topas_Utah

Ka

LDE1

Fluorite

Ka

TAP

Na

Albite

Ka

TAP

Albite

Ka

TAP

Mg

Diopside

Ka

TAP

Ka

TAP

Al

Al2O3

Ka

TAP

Diopside Plagioclase, Almandine

Ka

TAP

Si

Diopside

Ka

TAP

Almandine

Ka

TAP

Cl

Tugtupite

Ka

PETJ

K

Sanidine

Ka

PETJ

Sanidine

Ka

PET

Ca

Diopside

Ka

PETJ

Diopside

Ka

PET

Mn

Rhodonite

Ka

PETJ

Ti

SrTiO3

Ka

PETH

Rutile

Ka

LIF

Fe

Haematite

Ka

LIFH

Haematite

Ka

LIF

Table 2: Sample list of different tourmalines types in the Hattu Schist Belt with their locality, host rock lithology and relations to main mineralizations. Sample

Locality (deposit)

Lithological unit

KVS35.3

Korvilansuo

Graywacke

Metamorphic tourmaline

Barren

KVS-38.9

Korvilansuo

Graywacke

Hydrothermal tourmalinite

Ore zone

KVS-40.1

Korvilansuo

Graywacke

Hydrothermal tourmalinite

Ore zone

KVS-40.6

Korvilansuo

Graywacke

Hydrothermal tourmalinite

Ore zone

KVS39.1

Korvilansuo

Graywacke

Hydrothermal tourmalinite

Ore zone

HOS-2

Hosko

Graywacke

Hydrothermal tourmalinite

Not determined

HOS-4

Hosko

Graywacke

Hydrothermal tourmalinite

Not determined

HOS-6

Hosko

Graywacke

Hydrothermal tourmalinite

Not determined

HOS-7

Hosko

Graywacke

Hydrothermal tourmalinite

Not determined

HOS-3

Hosko

Graywacke

Hydrothermal tourmalinite

Not determined

PAE-6

Pampalo east

Komatiites

Hydrothermal tourmalinite

Ore zone

PAM-3

Pampalo

Andesitic tuff

Metamorphic tourmaline

Ore zone

PAM-4

Pampalo

Felsic dyke (in andesitic tuff)

Disseminated hydrothermal tourmaline

Ore zone

PAM-5

Pampalo

Felsic dyke

Veinlet tourmaline

Ore zone

PAM-13

Pampalo

Metabasalt

Veinlet tourmaline

Barren

PAM51.0

Pampalo

Metabasalt

Veinlet tourmaline

Barren

PAM51.5

Pampalo

Metabasalt

Veinlet tourmaline

Barren

PAM-67.7

Tourmaline type

Relation to ore zone

Pampalo

Metabasalt

Hydrothermal tourmalinite

Barren

RÄM-1c

Rämepuro

Graywacke

Hydrothermal tourmalinite

Ore zone

RÄM-2

Rämepuro

Graywacke

Hydrothermal tourmalinite

Ore zone

RÄM-5

Rämepuro

Graywacke

Barren

R140-56-8

Rämepuro

Graywacke

Ore zone

NAR-1.1

Naarva

Leucogranite

Metamorphic tourmaline Veinlet tourmaline+Metamorphic tourmaline Magmatic tourmaline

NAR-1.0

Naarva

Leucogranite

Magmatic tourmaline

Barren

KUI-1

Kuittila

Tonalite

Veinlet tourmaline

Barren

TAS-1

Tasanvaara

Tonalite

Veinlet tourmaline

Barren

TAS-2

Tasanvaara

Tonalite

Veinlet tourmaline

Barren

Barren

Table 3: Representative average major elemental compositions of tourmalines from the Hattu schist Belt. Abbreviations: MET: metamorphic tourmalines; MT: Magmatic tourmalines; DHT: Disseminated hydrothermal tourmalines; VT: Vein tourmalines; n.m.: not measured; u.d.l.: under the limit of detection. Sample

KVS-35.3

RÄM-5

R140-56-8 NAR-1.1

MET

PAM-3 (Fe>9) (Fe<9) MET MET

PAM-4 rim (2) MT DHT

KVS-38.9

HOS-2

MT

NAR-1.0 core rim (1) MT MT

Type n

HOS-7 core rim TUR TUR

HOS-3

KVS-39.1

KVS-40.1

TUR

HOS-4 HOS-6 (Fe<9) (Fe>9) TUR TUR TUR

MET

MET

20

4

5

17

11

TUR

20

13

8

18

32

TUR

TUR

TUR

36

6

18

24

18

18

22

32

SiO₂

35.90

35.50

35.92

35.64

36.27

35.02

35.38 35.01

34.88

34.92

13

34.57

34.86

35.90

34.46

34.75

35.47

34.29

36.07

35.75

35.55

TiO₂

0.56

0.53

0.42

Al₂ O₃

31.23

26.82

29.07

0.59

0.61

0.32

0.37

0.40

30.67

31.42

32.13

33.10 32.71

32.69

0.48

0.43

0.74

0.35

0.64

0.77

0.42

0.69

0.65

0.53

0.68

30.32

34.26

33.35

32.79

33.20

33.65

33.35

33.90

32.81

30.52

29.52

FeO

7.22

11.49

MgO

6.74

6.94

6.29

7.23

8.69

11.64

10.25 11.98

8.98

6.94

6.35

3.63

4.09

3.05

12.45

9.47

7.11

11.10

6.40

11.80

10.49

7.50

10.07

10.83

7.44

8.26

2.90

7.03

6.60

3.26

6.46

2.52

3.39

5.76

3.61

3.11

7.26

CaO

0.89

0.25

1.01

0.80

0.33

0.31

0.29

7.24

0.24

0.25

0.79

1.02

0.38

0.16

0.32

0.32

0.48

0.57

0.32

1.32

1.50

MnO Na₂ O

0.03

0.04

0.06

n.m.

n.m.

n.m.

1.76

2.77

2.36

2.11

2.57

2.25

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

n.m.

0.06

n.m.

2.16

2.15

2.15

2.76

1.84

1.63

2.49

1.65

1.70

1.78

1.67

1.77

1.74

K₂ O

0.02

0.07

0.04

0.04

0.04

1.83

0.05

0.04

0.05

0.05

0.06

0.04

0.04

0.03

0.03

0.07

0.03

0.04

0.05

0.04

0.04

F

0.01

0.67

13 0.35

0.60

0.83

u.d.l.

u.d.l.

0.91

0.79

0.68

0.99

0.75

0.76

1.37

0.75

0.96

0.68

0.66

0.80

0.02

0.64

Cl 0.01 Sum. 84.37 MgO/(MgO 0.48 +FeO)

0.02 85.02

0.01 84.99

n.m. 84.03

n.m. 86.29

n.m. 86.26

n.m. n.m. 86.46 86.20

n.m. 86.45

n.m. 86.82

n.m. 86.60

n.m. 86.12

n.m. 85.95

n.m. 85.38

n.m. 86.10

n.m. 85.47

n.m. 85.51

n.m. 86.41

0.01 84.68

n.m. 85.25

0.38

0.59

0.49

0.42

0.24

0.29

0.20

0.19

0.43

0.48

0.23

0.50

0.18

0.24

0.43

0.26

0.22

0.49

0.47

Si(T)

6.00

6.12

6.03

5.99

5.98

5.92

5.90

5.90

5.88

5.86

5.68

5.85

5.95

5.86

5.83

5.89

5.77

6.01

5.98

5.99

Al(T)

0.00

0.00

0.00

0.01

0.02

0.08

0.10

0.10

0.12

0.14

0.32

0.15

0.05

0.14

0.17

0.11

0.23

0.00

0.02

0.01

B(T)

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

Al(Z)

6.00

5.45

5.75

6.00

6.00

6.00

6.00

6.00

6.00

5.85

6.00

6.00

6.00

6.00

6.00

6.00

6.00

6.00

6.00

5.85

Mg(Z)

0.00

0.55

0.25

0.00

0.00

0.00

0.00

0.00

0.00

0.15

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.15

Al(Y)

0.15

0.00

0.00

0.07

0.08

0.31

0.40

0.40

0.38

0.00

0.32

0.45

0.35

0.51

0.49

0.41

0.49

0.45

0.00

0.00

Ti(Y)

0.07

0.07

0.05

0.08

0.08

0.04

0.05

0.04

0.05

0.06

0.05

0.09

0.04

0.08

0.10

0.05

0.09

0.08

0.07

0.09

Mg(Y)

1.68

1.23

2.00

1.74

1.56

0.92

1.02

0.77

0.73

1.60

1.62

0.82

1.60

0.64

0.85

1.42

0.91

0.77

1.81

1.67

Fet(Y)

1.01

1.66

0.88

1.02

1.20

1.64

1.43

1.69

1.76

1.33

0.98

1.56

0.89

1.68

1.47

1.04

1.42

1.51

1.04

1.16

∑Y

2.91

2.96

2.94

2.90

2.92

2.91

2.90

2.90

2.92

2.99

2.97

2.92

2.88

2.90

2.90

2.93

2.90

2.82

2.92

2.92

Ca(X)

0.16

0.05

0.18

0.14

0.06

0.06

0.05

0.04

0.05

0.14

0.18

0.07

0.03

0.06

0.06

0.09

0.10

0.06

0.24

0.27

Na(X)

0.57

0.93

0.77

0.69

0.82

0.74

0.70

0.70

0.70

0.90

0.59

0.53

0.80

0.54

0.55

0.57

0.55

0.57

0.56

0.60

K(X)

0.00

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.01

0.02

0.01

0.01

0.01

0.01

0.01

X□

0.27

0.01

0.04

0.16

0.11

0.20

0.24

0.24

0.24

0.00

0.23

0.39

0.16

0.39

0.37

0.34

0.34

0.36

0.19

0.12

F

0.00

0.33

0.44

0.00

0.00

0.48

0.41

0.36

0.36

0.52

0.39

0.40

0.72

0.40

0.51

0.36

0.35

0.42

0.01

0.34

Cl

0.00

0.01

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

Table 3: continues Sample Type

KVS-40.6 (Fe<9) TUR

(Fe>9) TUR

PAE-6

PAM-67.6

RÄM-1c RÄM-2 TUR

KUI-1 Tur Qz-tur VT VT

PAM-5 Tur VT

Qz-cal-tur VT

TUR

TUR

TUR

n

19

4

22

30

SiO₂

36.16

34.48

36.10

36.02

TiO₂

0.62

0.64

0.63

Al₂ O₃

31.96

31.72

28.44

FeO

7.59

11.14

MgO

7.42

CaO

1.18

MnO Na₂ O

PAM-13 PAM51.0

R140-56-8 TAS-1

TAS-2

VT

PAM51.5 all core VT VT

rim VT

VT

VT

VT

VT

24

28

21

7

5

14

35.29

36.38

35.37

36.03

35.24

35.83

18

11

16

2

2

25

16

21

36.63

35.98

35.92

34.78

36.44

36.37

35.25

35.69

0.53

0.68

0.60

0.41

0.39

0.37

30.13

33.08

32.65

27.95

29.71

27.65

0.55

0.59

0.09

0.03

0.02

0.01

0.32

0.53

0.56

29.15

31.07

29.36

30.33

30.11

31.57

31.23

27.98

7.85

8.73

7.95

7.72

11.19

10.05

28.01

17.44

10.17

7.13

10.87

11.46

12.95

8.43

8.12

11.00

11.13

4.88

8.52

6.92

6.48

6.60

7.00

1.33

0.77

1.15

0.59

0.46

0.95

6.97

2.54

6.76

7.90

5.69

4.84

4.29

6.44

6.75

6.52

6.74

0.60

0.16

0.95

1.15

1.35

1.18

1.81

0.72

0.26

1.89

0.89

n.m.

n.m.

n.m.

0.04

n.m.

n.m.

1.93

1.70

2.57

1.92

2.27

2.35

n.m.

n.m.

0.03

0.11

0.03

0.07

0.13

0.25

0.06

n.m.

0.17

0.06

2.21

2.29

2.45

2.32

1.97

1.89

1.80

1.44

2.05

2.63

1.72

K₂ O

0.05

0.05

0.03

0.02

0.04

2.37

0.05

0.06

0.09

0.06

0.05

0.02

0.03

0.02

0.01

0.02

0.04

0.20

0.06

F

0.54

0.00

0.62

u.d.l.

Cl Sum. MgO/(MgO +FeO)

n.m. 87.45

n.m. 85.95

n.m. 85.53

0.02 85.47

0.63

0.54

u.d.l.

u.d.l.

0.06

0.47

u.d.l.

u.d.l.

u.d.l.

u.d.l.

u.d.l.

0.79

0.18

u.d.l.

n.m. 87.01

n.m. 87.34

n.m. 85.13

n.m. 86.11

0.01 86.03

0.01 86.38

0.01 86.51

0.02 85.34

0.01 85.73

0.01 85.65

0.01 85.75

n.m. 86.51

0.03 85.48

0.01 85.53

0.49

0.30

0.52

0.44

0.45

0.46

0.38

0.41

0.13

0.40

0.53

0.34

0.30

0.25

0.43

0.45

0.37

0.38

Si(T)

5.89

5.80

Al(T)

0.11

0.20

6.06

6.01

5.79

5.92

6.03

6.01

6.13

6.01

5.98

6.08

6.05

5.94

6.03

6.01

6.01

6.05

0.00

0.00

0.21

0.08

0.00

0.00

0.00

0.00

0.02

0.00

0.00

0.06

0.00

0.00

0.00

B(T)

3.00

0.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

3.00

Al(Z) Mg(Z)

6.00

6.00

5.62

5.92

6.00

6.00

5.61

5.84

5.67

5.76

5.96

5.85

6.00

5.99

6.00

6.00

5.62

5.60

0.00

0.00

0.38

0.08

0.00

0.00

0.39

0.16

0.33

0.24

0.04

0.15

0.00

0.01

0.00

0.00

0.38

0.40

Al(Y)

0.03

0.08

0.00

0.00

0.19

0.19

0.00

0.00

0.00

0.00

0.00

0.00

0.02

0.00

0.15

0.09

0.00

0.00

Ti(Y)

0.08

0.08

0.08

0.07

0.08

0.07

0.05

0.05

0.05

0.07

0.07

0.01

0.00

0.00

0.00

0.04

0.07

0.07

Mg(Y)

1.80

1.22

1.75

1.64

1.59

1.60

1.39

1.57

0.33

1.46

1.89

1.28

1.22

1.08

1.59

1.66

1.28

1.30

Fet(Y)

1.03

1.57

1.10

1.22

1.09

1.05

1.59

1.40

2.54

1.43

0.97

1.54

1.61

1.85

1.17

1.12

1.57

1.58

∑Y

2.94

2.95

2.93

2.93

2.95

2.92

3.04

3.02

2.91

2.97

2.94

2.84

2.87

2.97

2.91

2.91

2.95

2.96

Ca(X)

0.21

0.24

0.14

0.21

0.10

0.08

0.17

0.11

0.03

0.17

0.20

0.24

0.21

0.33

0.13

0.05

0.35

0.16

Na(X)

0.61

0.56

0.84

0.62

0.72

0.74

0.73

0.74

0.83

0.75

0.62

0.62

0.59

0.47

0.66

0.84

0.57

0.78

K(X)

0.01

0.01

0.01

0.00

0.01

0.01

0.01

0.02

0.01

0.01

0.00

0.01

0.01

0.00

0.00

0.01

0.04

0.01

X□

0.17

0.19

0.02

0.17

0.17

0.17

0.08

0.14

0.13

0.06

0.17

0.13

0.19

0.19

0.21

0.10

0.04

0.05

F

0.28

0.00

0.33

0.00

0.33

0.28

0.00

0.00

0.04

0.25

0.00

0.00

0.00

0.00

0.00

0.41

0.10

0.00

Cl

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.01

0.00

0.00

0.00

0.00

0.01

0.00

Table 4: Representative average trace and rare earth elemental compositions of tourmalines from the Hattu schist belt. Abbreviations: MET: metamorphic tourmalines; MT: Magmatic tourmalines; DHT: Disseminated hydrothermal tourmalines; VT: Vein tourmalines; Qz: quartz; Tur; tourmaline; Cal: Calcite; n.m.:not measured; u.d.l.: under the limit of detection. Type Li Be V Cr Mn Co Ni Cu Zn Ga Rb Sr Zr Nb Sn Ba Hf Ta Pb Th U Y P Sc La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ∑REE La/Yb Gd/Yb Eu/Eu* Ce/Ce*

KVS-35.3 MET

PAM-3 MET

RÄM-5 MET

R140-56-8 MET

NAR-1.1 MT

20.78 2.72 445.05 894.96 120.79 20.05 87.82 0.84 189.45 40.36 u.d.l 517.08 22.78 0.31 1.03 1.13 0.33 0.07 16.57 0.14 0.18

56.01 3.75 858.28 20.19 510.99 0.90 99.31 1.28 615.05 110.04 1.61 1491.42

24.33 2.20 351.49 455.06 343.41 11.56 22.68 1.14 199.55 44.74 1.28 888.09 1.61 0.06 0.54 0.60 0.27 u.d.l 5.27 0.32 0.40

23.21 1.27 361.18 561.56 186.57 16.77 154.68 1.30 299.76 45.94 11.98 1324.94 13.17 0.64 0.44 14.65 1.72 0.05 10.18 0.27 0.77

149.41 2.36 19.01 6.71 1118.48 10.82 11.08 0.93 586.10 126.28 0.02 13.99 0.07 0.38 6.23 0.03 0.02 0.17 3.16 0.01 0.01 0.07 10.32 11.18 1.08 1.74 0.15 0.41 0.06 0.05 0.03 0.00 0.02 0.00 0.01 0.00 0.01 0.00 3.57 59.10 2.11 3.29 1.03

0.23 3.94 3.14 0.06 21.91 0.30 1.61 u.d.l 15.21 1.93 2.81 0.27 0.92 0.29 0.10 0.24 0.04 0.21 0.05 0.13 0.02 0.11 0.02 7.13 13.62 2.02 1.14 0.94

NAR-1.0 MT core 192.07 1.08 35.16 23.77 627.81 11.33 13.15 1.09 615.98 111.06 0.05 15.03 0.21 0.35 4.00 0.07 0.04 0.23 2.59 0.11 0.77 0.02 9.14 9.29 0.83 1.48 0.13 0.41 0.07 0.04 0.03 0.00 0.02 0.00 0.01 0.00 0.01 0.00 3.04 86.75 3.30 3.15 1.06

NAR-1.0 MT rim1 185.73 2.26 16.20 11.49 993.68 8.67 7.60 1.05 840.15 123.22 0.04 9.32 0.15 0.59 5.94 0.05 0.06 0.29 2.56 0.03 0.46 0.03 7.92 6.33 0.84 1.47 0.13 0.37 0.07 0.03 0.03 0.00 0.01 0.01 0.02 0.00 0.01 0.01 3.01 54.01 2.19 2.19 1.05

NAR-1.0 MT rim2 176.40 2.16 10.59 5.26 1225.93 7.52 4.40 1.00 881.73 132.69 0.03 7.44 0.07 0.63 7.01 0.05 u.d.l 0.21 2.36 u.d.l 0.01 0.02 5.95 7.31 1.01 1.66 0.15 0.40 0.07 0.03 0.04 0.00 0.02 0.00 0.01 0.00 0.01 0.00 3.42 112.08 5.47 1.76 1.04

PAM-4 DHT

HOS-2 TUR

HOS-4 TUR

HOS-6 TUR

HOS-7 TUR

KVS-38.9 TUR

KVS-40.6 TUR

45.17 5.62 681.72 20.01 856.46 1.35 20.45 1.45 576.91 156.21 2.77 608.70 0.66 0.29 8.28 8.71 0.29 0.16 27.94 0.17 0.19 0.28 u.d.l 9.13 1.64 2.06 0.16 0.39 0.06 0.08 0.05 0.01 0.05 0.01 0.04 0.01 0.03 0.00 4.57 45.61 1.76 4.23 0.97

41.21 8.74 474.20 613.50 640.40 2.68 24.66 0.71 760.45 48.72 u.d.l 364.03 0.05 0.07 0.60 0.46 0.15 0.02 11.07 0.08 0.11

41.87 6.90 595.48 257.90 714.99 7.30 80.72 0.85 1050.47 57.71 u.d.l 364.88 0.39 0.12 0.78 0.70 0.27 0.07 7.76 0.60 0.13 0.12 u.d.l 38.25 1.33 2.34 0.25 0.58 0.10 0.27 0.05 0.01 0.03 0.01 0.04 u.d.l u.d.l 0.01 5.01

43.53 4.89 487.46 63.93 832.95 1.70 36.37 0.69 1077.77 55.78 0.13 355.89 0.10 0.05 0.43 0.56 u.d.l u.d.l 9.50 0.02 u.d.l 0.12 u.d.l 42.44 0.14 0.21 0.02 0.07 0.08 0.10 0.04 0.00 0.03 0.01 0.04 0.01 0.08 0.03 0.87 1.38 0.46 5.42 0.95

34.46 6.03 243.32 207.37 207.73 5.98 11.09 0.80 469.83 36.52 4.13 375.60 41.47 0.15 0.46 3.85 1.47 0.03 7.45 0.34 0.76

21.10 1.34 294.77 321.10 388.47 14.96 26.55 2.21 196.43 48.11 0.15 522.75 0.08 0.10 1.48 1.10 0.07 0.02 14.60 0.03 0.04 0.09 u.d.l 46.35 0.09 0.13 0.02 0.05 0.06 0.06 0.02 0.00 0.01 0.01 0.02 0.01 0.05 0.01 0.53 0.43 0.41 5.43 0.87

21.69 1.06 295.99 326.46 638.00 13.27 31.60 0.92 223.00 46.32 0.12 1023.09 0.17 0.06 1.13 4.46 0.19 0.19 18.78 0.34 0.71 0.33 9.11 110.10 0.11 0.21 0.03 0.15 0.07 0.04 0.15 0.02 0.13 0.04 0.09 0.03 0.17 0.03 1.27 0.13 0.84 1.09 0.84

10.89 0.97

Table 4: continues Sample Type

PAE-6 TUR

Li Be V Cr Mn Co Ni Cu Zn Ga Rb Sr Zr Nb Sn Ba Hf Ta Pb Th U Y P Sc La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ∑REE La/Yb Gd/Yb Eu/Eu* Ce/Ce*

11.73 0.57 334.87 1247.04 109.90 32.47 527.48 0.94 111.18 61.88 u.d.l 3315.22 0.03 0.03 0.92 3.18 u.d.l 0.04 40.00 u.d.l 0.13 0.01 5.98 1.63 0.14 0.23 0.02 0.08 0.01 0.08 u.d.l 0.00 0.00 u.d.l u.d.l 0.00 u.d.l 0.00 0.57

1.07

PAM-67.6 TUR core 14.44 u.d.l 209.68 2.09 233.61 18.60 49.74 0.90 134.77 29.78 u.d.l 170.36 0.11 u.d.l 0.16 0.90 0.03 u.d.l 6.88 u.d.l u.d.l 0.03 u.d.l 25.73 0.01 0.03 0.00 0.02 0.01 0.02 0.01 u.d.l 0.01 0.00 0.01 0.00 0.02 0.00 0.14 1.12 0.27 8.42 1.09

PAM-67.6 TUR rim 13.81 0.15 405.10 3.12 276.59 28.18 49.69 1.19 150.55 36.94 u.d.l 323.11 0.07 u.d.l 0.35 2.75 u.d.l u.d.l 15.80 u.d.l u.d.l 0.04 u.d.l 19.81 0.07 0.14 0.01 0.06 u.d.l 0.06 0.08 u.d.l 0.00 0.00 0.02 0.00 0.00 0.00 0.45 5.05 18.64 1.19

RÄM-1c TUR

RÄM-2 TUR

18.66 2.15 315.28 351.39 227.70 8.80 13.20 0.92 146.62 48.40 u.d.l 1377.72 0.12 0.04 0.74 1.04 0.08 u.d.l 3.81 0.11 0.10 0.13 u.d.l 61.12 0.32 0.48 0.04 0.19 0.09 0.32 0.03 0.01 0.05 0.01 0.04 0.01 0.04 0.01 1.63 0.51 0.78 17.78 0.97

19.52 2.41 322.32 176.89 277.80 12.57 30.86 0.99 312.36 42.81 26.16 1733.00 0.74 0.14 1.05 3.48 0.28 0.04 14.12 0.10 0.18 0.20 u.d.l 23.22 0.23 0.33 0.03 0.09 u.d.l 0.21 0.01 0.01 0.04 0.01 0.04 0.01 0.11 0.02 1.12 0.20 0.11 0.97

KUI-1 VT Tur 8.67 0.32 372.71 203.66 422.32 34.41 80.04 2.59 160.08 52.41 0.04 877.87 0.74 2.99 2.64 0.98 0.19 1.41 22.43 0.22 0.35 0.16 6.57 32.60 0.15 0.22 0.03 0.13 0.04 0.04 0.05 0.01 0.03 0.01 0.02 0.00 0.03 0.01 0.78 0.63 1.36 2.56 0.78

KUI-1 VT Qz-Tur 16.31 0.40 379.54 214.92 377.58 37.21 79.22 7.00 178.09 44.37 6.32 768.08 0.99 0.25 1.05 7.12 0.09 u.d.l 16.24 0.13 0.09 1.05 4.68 18.52 0.94 0.49 0.22 0.97 0.20 0.05 0.16 0.03 0.18 0.03 0.11 0.02 0.13 0.03 3.56 0.17 1.26 0.84 0.26

PAM-5 VT Tur 71.86 7.18 395.51 2.63 170.10 8.91 28.24 1.10 382.77 86.83 u.d.l 2925.85 0.92 2.09 8.09 1.43 0.17 0.18 10.01 0.05 u.d.l 0.97 u.d.l 4.79 0.34 0.47 0.05 0.16 0.02 0.10 0.05 0.01 0.08 0.03 0.22 0.05 0.52 0.10 2.19 0.04 0.09 9.76 0.90

PAM-5 VT 53.29 1.34 1002.40 22.79 856.35 0.12 25.21 0.99 527.44 164.44 u.d.l 344.76 0.03 0.07 3.71 0.10 u.d.l u.d.l 12.57 u.d.l u.d.l 0.21 u.d.l 8.97 0.44 0.61 0.05 0.15 0.06 0.04 0.04 0.01 0.04 0.01 0.03 0.00 0.04 0.01 1.53 0.54 0.97 2.39 0.97

PAM-13 VT Qz-Cal-Tur 15.37 0.09 230.13 103.89 185.96 44.54 342.31 0.87 108.32 37.25 u.d.l 369.65 0.02 0.00 0.13 1.82 u.d.l 0.00 15.40 0.01 0.01 0.05 10.43 3.30 0.04 0.07 0.01 0.05 0.04 0.04 0.03 0.00 0.02 0.00 0.02 0.00 0.01 0.00 0.32 2.82 3.60 3.57 0.84

PAM51.0 VT

PAM51.5 VT

R140-56-8 VT

TAS-1 VT

TAS-2 VT

13.10 1.05 701.07 4.81 690.00 24.53 8.17 0.90 183.26 18.02 0.08 249.51 0.39 0.01 0.32 1.09 0.11 u.d.l 1.24 u.d.l u.d.l 0.16 u.d.l 14.32 0.02 0.02 0.01 0.03 u.d.l 0.03 0.01 0.00 0.02 0.00 0.02 0.00 0.04 0.01 0.22 0.50 0.25

17.50 1.97 517.33 3.17 934.56 13.18 4.27 1.03 256.17 10.69 u.d.l 164.46 0.19 0.02 0.30 0.83 0.05 u.d.l 1.97 u.d.l u.d.l 0.19 u.d.l 0.76 0.01 0.02 0.02 u.d.l u.d.l 0.02 0.02 0.00 0.03 0.01 0.04 0.01 0.07 0.02 0.26 0.30 0.22

0.34

0.39

20.54 1.96 310.65 176.14 237.35 7.74 5.59 1.08 321.92 63.77 u.d.l 1299.30 1.47 0.07 3.00 1.16 0.18 0.02 9.18 0.18 0.99 0.30 u.d.l 29.06 0.48 0.80 0.07 0.26 0.07 0.39 0.09 0.01 0.09 0.02 0.07 0.01 0.09 0.02 2.48 0.23 0.93 15.38 1.03

26.02 7.92 258.67 49.17 1213.89 28.89 23.94 0.92 1152.79 49.41 0.67 340.94 0.85 0.08 0.78 1.97 0.34 0.01 77.52 0.07 0.02 0.12 6.53 0.82 0.14 0.41 0.05 0.28 0.12 0.02 0.07 0.01 0.04 0.01 0.03 0.00 0.02 0.00 1.19 0.97 3.01 0.56 1.20

7.97 0.73 354.58 494.87 475.38 20.41 25.59 3.13 193.05 55.46 2.43 628.61 0.69 0.17 2.00 1.05 0.16 0.05 15.21 0.05 0.07 0.51 u.d.l 53.46 0.64 0.72 0.09 0.45 0.10 0.09 0.09 0.01 0.07 0.02 0.05 0.01 0.09 0.02 2.45 0.24 1.02 2.77 0.73

Highlights: -Differing chemistry of host rocks is reflected in the variable chemistry of tourmalines associated to orogenic gold deposit. -Tourmaline chemistry is more suitable proxy for fluid-rock interactions than tracking the distal fluid sources of gold. - Only if the bulk host rock chemistry is known, tourmaline chemistry may be reliable proxy for gold mineralizing fluids. -Li, Sr and V composition of hydrothermal tourmalines indicates metamorphic sources for gold mineralizing fluids.

55

1000

100

10

1

1

10

(h) 100

100

10

(c)

(f)

10

1000

1000

(i)

Zn (ppm)

Pb (ppm)

100

(e)

10

Mn (ppm)

1

1

Ga (ppm)

100

(g)

0.1

1000

Sr (ppm)

Cr (ppm)

1000

10

100

10

(b)

(d) Sn (ppm)

(a)

V (ppm)

Ni (ppm)

1000

100

1

100 10

Li (ppm)

100

Host rocks (bulk) Granites Metasedimentary rocks Intermediate metavolcanics Mafic metavolcanics Ultramafic metavolcanics

10

Li (ppm)

100

Tourmalines Metamorphic tourmalines Magmatic tourmalines Disseminated hydrothermal tourmalines Tourmalinites Vein tourmalines

10

Li (ppm)

100