Texture and composition of scheelite, tourmaline and rutile in orogenic gold deposits

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Texture and Composition of Scheelite, Tourmaline and

Rutile in Orogenic Gold Deposits

Thèse

Marjorie Sciuba

Doctorat interuniversitaire en sciences de la Terre

Philosophiæ doctor (Ph. D.)

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Résumé

La scheelite, la tourmaline et le rutile des gisements d’or orogénique, encaissés dans des roches de composition et de faciès métamorphique variés ont été étudiés pour établir des paramètres discriminants pour contraindre les campagnes utilisant les minéraux indicateurs pour l’exploration aurifère. La texture et les associations minérales ont été investiguées par microscopie optique et microscopie électronique à balayage (MEB). La scheelite, la tourmaline et le rutile présentent une grande variabilité de taille, de texture et d’association minérale, qui ne sont pas informatives pour les campagnes de minéraux indicateurs. La composition minérale a été déterminée par microsonde électronique (EPMA) et ablation laser et spectroscopie de masse avec plasma couplée par induction (LA-ICP-MS). Les résultats ont été investigués par des diagrammes élémentaires et des analyses multivariées incluant des analyses en composantes principales (PCA) et des analyses de réduction des moindres carrées (PLS-DA). La composition et le faciès métamorphique des roches encaissantes régionales exercent un fort contrôle sur la composition en éléments traces de la scheelite, de la tourmaline et du rutile. Dans la scheelite, Sr, Pb, U, Th, Na, Éléments des Terres Rares (ETR) et Y; dans la tourmaline Ga et Sn; et dans le rutile Nb, Ta, V et Cr varient avec la composition de la roche encaissante. Dans la scheelite, ETR, Y, Sr, Mn, Nb, Ta et V; dans la tourmaline, Ga, Sn, Ti, ETR, Zr, Hf, Nb, Ta, Th et U; et dans le rutile Nb, Ta, V et Cr varient avec le faciès métamorphique des roches encaissantes. La composition en éléments traces de la scheelite varie avec l’âge de la roche encaissante alors que la tourmaline et le rutile ne montrent pas de variation compositionnelle avec l’âge de l’encaissant. La variation compositionnelle résulte des échanges fluide-roche lors de la circulation du fluide hydrothermal jusqu’au site de dépôt de l’or. Les résultats pour les minéraux des gisements d’or orogénique sont comparés avec ceux d’autres types de gîtes et de paramètres géologiques variées de la littérature. La scheelite et la tourmaline des gisements d’or orogénique présentent clairement une variation compositionnelle distincte comparée à celle d’autres types de gîtes et paramètres géologiques. La scheelite des gisements d’or orogénique a une signature distincte en Sr, Mo, Eu, As et Sr/Mo mais similaire en ETR par rapport à la scheelite provenant d’autres types de gîtes. Les diagrammes binaires tels que Sr/Li vs V/Sn, Sr/Sn vs V/Nb, Sr/Sn vs Ni/Nb et Sr/Sn vs V/Be discriminent la tourmaline des gisements d’or orogénique de celle provenant d’autres sources. Les diagrammes élémentaires mettent en avant une variation transitionnelle de la composition en éléments traces de la tourmaline provenant d’environnement métamorphique, à hydrothermal-magmatique, à magmatique. Le rutile des gisements d’or orogénique a une composition distincte en Mn, V, Sn, Sb et W comparée aux rutiles provenant d’autres types de gîtes et paramètres géologiques. Les diagrammes binaires incluant V vs Sb et Nb/V vs. Sn/V discriminent le rutile des gisements d’or orogénique et celui provenant des environnements magmatique-hydrothermaux et magmatiques. D’autres diagrammes binaires tel que Nb/V vs W permettent de distinguer partiellement le rutile

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des gisements d’or orogénique et celui provenant d’environnement hydrothermaux et métamorphique-hydrothermaux.

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Abstract

Scheelite, tourmaline and rutile from orogenic gold deposits and districts, hosted in varied country rocks and metamorphic facies of various ages were investigated to establish discriminant features to constrain indicator mineral surveys for gold exploration. Texture and mineral associations were investigated by optical microscopy and Scanning Electron Microscopy (SEM). Scheelite, tourmaline and rutile present a wide range of size, texture, and mineral association that are not informative for indicator mineral surveys. Mineral composition was determined using Electron Probe Micro-Analyzer (EPMA) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Results were investigated with elemental plots and multivariate statistics including Principal Component Analysis (PCA) and Partial Least Square-Discriminant Analysis (PLS-DA). The composition of the metamorphic facies of the local country rocks as well as the regional country rocks exert a strong control on scheelite, tourmaline and rutile trace element composition. In scheelite Sr, Pb, U, Th, Na, REE and Y; in tourmaline Ga and Sn; and in rutile Nb, Ta, V and Cr vary with the country rock composition. In scheelite, REE, Y, Sr, Mn, Nb, Ta and V; in tourmaline, Ga, Sn, Ti, REE, Zr, Hf, Nb, Ta, Th and U; and in rutile Nb, Ta, V and Cr vary with the metamorphic facies of the country rocks. Scheelite trace element composition vary with the country rock age whereas tourmaline and rutile do not show any compositional variation with the country rock age. Compositional variation results of fluid-rock exchange during fluid flow to gold deposition site. Results for minerals from orogenic gold deposits are compared with those from various deposit types and geological settings from literature. Scheelite and tourmaline from orogenic gold deposits present clearly a distinct compositional variation, compared to scheelite and tourmaline from other deposit types and geological settings. Scheelite from orogenic gold deposits have distinct Sr, Mo, Eu, As and Sr/Mo, but indistinguishable REE signatures, compared to scheelite from other deposit types. Binary plots such as Sr/Li vs V/Sn, Sr/Sn vs V/Nb, Sr/Sn vs Ni/Nb and Sr/Sn vs V/Be discriminate orogenic gold deposit tourmaline from that from other sources. Elemental plots highlight a transitional variation in the trace element composition of tourmaline from metamorphic, to hydrothermal-magmatic to, magmatic environments. Rutile from orogenic gold deposits has a distinctive Mn, V, Sn, Sb and W composition compared to those from various deposits types and geological settings. Binary diagrams, including V vs Sb and Nb/V vs Sn/V, discriminate rutile from orogenic gold deposits from those from hydrothermal-magmatic and magmatic deposit types. Other binary diagrams, such as Nb/V vs W, discriminate partially orogenic gold deposit rutile from hydrothermal and metamorphic-hydrothermal environments.

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Table of content

Résumé ... ii

Abstract ... iv

Table of content ... v

List of figures ... viii

List of tables ... xiii

List of appendices ... xiv

Acknowledgements ... xix

Foreword ... xx

Introduction ... 1

Chapter 1. Trace element composition of scheelite in orogenic gold deposits ... 4

1.1. Résumé ... 4

1.2. Abstract ... 4

1.3. Introduction ... 5

1.4. Geological settings of the selected orogenic gold deposits ... 6

1.5. Scheelite texture and mineral assemblages ... 7

1.6. Analytical methods ... 9

1.6.1. Sample preparation ... 9

1.6.2. Electron Probe Micro-Analysis (EPMA) ... 9

1.6.3. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) ... 9

1.6.4. Statistical analysis ... 10

1.7. Results ... 11

1.7.1. Cathodoluminescence and trace elements variation ... 11

1.7.2. Trace element composition ... 11

1.7.3. Multivariate statistics of scheelite trace element composition ... 22

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1.8.1. Trace element substitution ... 25

1.8.2. REE patterns ... 27

1.8.3. Comparison to scheelite from other types of deposits ... 29

1.9. Conclusions ... 32

Chapter 2. Chemical composition of tourmaline in orogenic gold deposits ... 34

2.1. Résumé ... 34

2.2. Abstract ... 34

2.4. Geological setting of the selected orogenic gold deposits ... 36

2.5. Analytical methods ... 37

2.5.1. Sample selection and preparation ... 37

2.5.4. Multivariate statistical analysis ... 38

2.6. Results ... 38

2.6.1. Tourmaline textures and mineral assemblages ... 38

2.6.2. Major element composition ... 41

2.6.3. Minor and trace element composition ... 42

2.6.4. Chemical zoning ... 46

2.6.5. Multi-variate analysis of tourmaline composition in relation to the geological environment ... 46

2.7. Discussion ... 49

2.7.1. Influence of geological settings ... 49

2.7.2. Rare Earth Elements patterns ... 50

2.7.3. Comparison to tourmaline from various deposit types and geological environments ... 51

Chapter 3. Texture and trace element composition of rutile in orogenic gold deposits ... 56

3.1. Résumé ... 56

3.2. Abstract ... 56

3.4. Physical and chemical properties of rutile ... 58

3.4.1. Trace element composition of TiO2 polymorphs ... 59

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3.6. Analytical method ... 59

3.6.1. Sample preparation ... 59

3.6.2. Scanning Electron Microscopy (SEM) ... 60

3.6.5. Statistical analysis ... 61

3.7. Rutile texture and mineral assemblages ... 61

3.8. Results ... 63

3.8.1. Chemical zoning ... 63

3.8.2. TiO2 polymorphs ... 64

3.8.3. Compositional variations in relation to the geological settings ... 66

3.8.4. Multivariate statistical analysis of rutile trace element composition ... 69

3.9. Discussion ... 74

3.9.1. Rutile grain size ... 74

3.9.2. Assimilation of the country rock signature ... 75

3.9.3. Comparison to rutile from various deposit types and geological environments ... 77

Conclusions ... 80

Bibliography ... 82

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List of figures

Figure 0-1. Distribution of the selected orogenic gold deposits in this study, (a) in the world Map is adapted from the Canada Geological Survey database; (b) in the Abitibi subprovince, Canada; map modified from Poulsen et al. (2000) and (c) in the Yilgarn craton, Australia. Map is adapted from Robert et al. (2005). ... 4 Figure 1-1. Scheelite texture and mineral associations in orogenic gold deposits (a) aggregate of anhedral scheelite grains (Cuiaba, Brazil), (b) subhedral scheelite grains (Canadian Malartic, Abitibi), (c) dynamic recrystallization of scheelite at Hutti (India), (d) fine grains disseminated scheelite (Kochkar, Russia), (e) scheelite veins (Kumtor, Kyrgyzstan), (f) scheelite associated with hydrothermal and metamorphic minerals such as clinopyroxene (Navachab, Namibia), (g) scheelite in association with tourmaline (Essakane, Burkina Faso), (h) scheelite is associated with pyrite with gold inclusion at Tarmoola, Eastern Goldfields, (i) scheelite with native gold, magnetite and hematite (Crusader, Australia). ... 8 Figure 1-2. Cathodoluminescence (CL) images of scheelite show (a) homogeneous CL (Dome, Abitibi; the halo effect is an artefact due to camera resolution), (b) sub-grains within larger scheelite (Essakane, Burkina Faso), (c) homogeneous fine grains (Hutti, India), (d) homogenous scheelite cut by thin veinlets (Tarmoola, Yilgarn), (e) brecciated (Mount Pleasant, Southern Cross), (f) brecciated structure at the edge of the grain (Crusader, Australia), (g) oscillatory zoning (Kochkar, Russia), (h) homogeneous CL (Rosebel, Suriname), (i) oscillatory zoning (Crusader, Agnew district). ... 12 Figure 1-3. Variation of the trace elements composition with the CL zonation in scheelite from the Macraes deposit, New Zealand. (a) The CL shows two generations: the first generation labelled “1” is brecciated by the second generation labelled “2”. (b) LA-ICP-MS profile shows the trace element variation within the different scheelite generations. The first generation is characterized by high Sr, Na, Mg, Mn, Th and U, and low Y and ∑REE content, whereas, the second generation is characterized by low Sr, Na, Mg, Mn, Th and U, and high Y and ∑REE content. Zones 2a and 1b are too small to be quantified. (c) The first generation is characterized by a flat REE pattern and the second generation is characterized by a bell-shaped REE pattern, both with positive Eu anomalies. ... 13 Figure 1-4. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) Sr, (d) Mo, (e) Na, (f) Y, (g) Nb, (h) As, (i) Eu, (j) Gd and (k) Pb, show homogeneous composition typical for scheelite from orogenic gold deposits (Dome, Abitibi)... 14 Figure 1-5. Rare earth element patterns in scheelite from orogenic gold deposits. (a) bell-shaped pattern with positive Eu anomaly, (b) flat pattern with positive Eu anomaly, (c) bell-shaped with negative Eu anomaly, (d) LREE-enriched pattern, (e) HREE-enriched pattern, (f) flat pattern without Eu anomaly. Data are normalized to chondrite from McDonough and Sun (1995). The North American Shale Composite (NASC) values are from Gromet et al. (1984). ... 15 Figure 1-6. Binary plots for REE contents in scheelite (a) (Gd/Yb)CN vs (La/Sm)CN and (b) ∑REE vs Eu* from

orogenic gold deposits, (c) (Gd/Yb)CN vs (La/Sm)CN and (d) ∑REE vs Eu* from various deposit types.

Data for orogenic gold deposits from literature include Ghaderi et al. (1999); Brugger et al. (2000b); Roberts et al. (2006); Xiong et al. (2006); Liu Yan et al. (2007); Dostal et al. (2009); Song et al. (2014); Cave et al. (2016); Hazarika et al. (2016); Poulin (2016). Abbreviations: Bell + : bell-shaped pattern with positive Eu anomaly; Bell -: bell-shaped pattern with negative Eu anomaly; Bell Ho + : bell-shaped

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pattern centered in Ho with positive Eu anomaly as described in Dostal et al. (2009); Bell Ho - : bell-shaped pattern centered in Ho with negative Eu anomaly as described in Dostal et al. (2009). ... 17 Figure 1-7. LA-ICP-MS trace element binary plots for scheelite from orogenic gold deposits (a) ∑REE+Y vs Na; (b) Eu anomaly (Eu*) vs Na; (c) Nb vs Ta; (d) ∑REE+Y vs Sr; (e) Na vs Sr, data for Rosebel are from EPMA; (f) Pb vs Sr; (g) ∑REE+Y vs Nb+Ta+V; (h) ∑REE vs Y; (i) U vs Th. Data from the literature include Ghaderi et al. (1999) and Dostal et al. (2009). ... 19 Figure 1-8. Scheelite composition from orogenic gold and other deposit types for (a) Sr, (b) Mo, (c) Y and (d) Na. Literature data for orogenic gold deposits are from Anglin et al. (1996); Ghaderi et al. (1999); Brugger et al. (2000b); Dostal et al. (2009); Graupner et al. (2010); Hazarika et al. (2016); Poulin 2016; Poulin et al. (2016). Data for skarn deposits are from Eichhorn et al. (1997); Zhigang et al. (1998); Liu Yan et al. (2007); Peng et al. (2010); Song et al. (2014); Poulin (2016); Poulin et al. (2016). Data for Greisen and VMS are from Poulin (2016). Abbreviation: Can. Malartic: Canadian Malartic. ... 20 Figure 1-9. LA-ICP-MS trace element diagrams for scheelite in orogenic gold deposits (a)

(Sr+Na)/(Sr+Na+10x(Nb+Ta+V+As)) vs (REE+Y+10x(Nb+Ta+V+As))/

(Sr+REE+Y+10x(Nb+Ta+V+As)); (b) Fe-Mn-Mg scheelite composition measured by LA-ICP-MS; (c) Fe-Mn-Mg carbonate composition. ... 21 Figure 1-10. Partial Least Square-Discriminant Analysis of LA-ICP-MS data for scheelite in orogenic gold deposits. (a) qw*1-qw*2 and (b) t1-t2 scores for mineralization age; (c) qw1*-qw2* and (d) t1-t2 scores for

host rock compositions; (e) qw*1-qw*2 and (f) t1-t2 scores for metamorphic facies of the host rocks. The

qw*1-qw*2 plots show the correlation between elements and the element contribution to each group.

The t1-t2 plots show the distribution of scheelite sample according to each preselected grouping. ... 24 Figure 1-11. LA-ICP-MS trace element binary plots for scheelite from orogenic gold deposits and other deposits types (a) Sr vs Eu anomaly (Eu*), (b) Sr/Mo vs Eu*, (c) Mo vs As, and (d) Sr/Mo vs As. Data for orogenic gold deposits: Ghaderi et al. (1999); Dostal et al. (2009); Cave et al. (2016); Hazarika et al. (2016); Poulin (2016). Data for skarn deposits: Xiong et al. (2006); Ren et al. (2010); Song et al. (2014); Guo et al. (2016); Poulin (2016); Fu et al. (2017), and for porphyry-related deposits: Poulin (2016) and Sun and Chen (2017). ... 30 Figure 1-12. Partial Least Square-Discriminant Analysis of LA-ICP-MS data for scheelite from different deposit types. (a) The qw*1-qw*2 loadings plot shows correlations among elemental variables and deposit types.

(b) The t1-t2 scores plot shows the distribution of scheelite samples in the qw*1-qw*2 space. (c) Variable

importance of the projection (VIP) per deposit types shows the detailed element contribution per deposit. Data for orogenic gold deposits: Ghaderi et al. (1999); Dostal et al. (2009); Hazarika et al. (2016) and Poulin (2016), for skarn deposits: Song et al. (2014) and Poulin (2016) and for porphyry-related deposits: Poulin (2016) and Sun and Chen (2017). ... 32 Figure 2-1. Tourmaline textures and mineral associations in orogenic gold deposits (a) disseminated euhedral greenish tourmaline (Royal Hill, Rosebel, Suriname), (b) disseminated euhedral tourmaline with light blue core and subtle orange rim (Hoyle Pond, Canada), (c) aggregate of subhedral orange tourmaline (Roberto, Canada), (d) aggregate of subhedral tourmaline with bluish grey core and greenish brown rim (Canadian Malartic, Canada), (e) disseminated subhedral tourmaline with greyish core and brownish rim associated with sulfides (New Consort, South Africa), (f) aggregate of subhedral orange to brown tourmaline associated with gold (Essakane, Burkina Faso). ... 40

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Figure 2-2. Back-scattered electron images of tourmaline zoning in orogenic gold deposits, (a) Complex sector zoning (Essakane, Burkina Faso), (b) oscillatory zoning coupled with sector zoning (Salsigne, France), (c) oscillatory zoning (TR98-111, James Bay, Canada), (d) irregular zoning (Big Bell, Australia), (e) narrow rim with large core (New Consort, South Africa), (f) thick rim with small core (Orezone, James Bay, Canada). ... 40 Figure 2-3. (a) Major, minor and (b) trace elements concentrations sorted by median tourmaline composition for orogenic gold deposits, measured by EPMA and LA-ICP-MS. See Appendices C-5 and C-6 for EPMA and LA-ICP-MS data. ... 41 Figure 2-4. (a) Back-scattered electron images of zoned tourmaline and EPMA maps, (b) Ti, (c) Fe, (d) Ca, (e) Mg, (f) V (TR98-111 showing, James Bay, Canada). ... 42 Figure 2-5. Classification of tourmaline from orogenic gold deposits and other deposit types and settings (a)

X-Vacant-Ca-(Na+K) ternary diagram (b) Mg/(Fe+Mg) vs Vac/(Na+K+Vac) diagram and (c) Mg/(Fe+Mg) vs Ca/(Ca+Na) diagram. Diagrams are adapted from Henry et al. (2011). ... 42 Figure 2-6. LA-ICP-MS trace element binary plots for tourmaline from orogenic gold deposits (a) La vs Zr, (b) Yb vs Zr, (c) ∑REE vs Zr, (d) Zr vs Hf, (e) Fe vs Sn, (f) ∑REE vs Ti, (g) Eu anomaly vs Y, (h) Ni vs Co and, (i) ∑REE vs Ga. Data from literature: Lottermoser and Plimer 1987; Slack and Coad 1989; Gallagher and Kennan 1992; Jiang et al. (2002); Deksissa and Koeberl (2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017); Kalliomäki et al. (2017); Manéglia (2017). ... 44 Figure 2-7. Rare earth element patterns in tourmaline from orogenic gold deposits. Data are normalized to chondrite from McDonough and Sun (1995). Deposit patterns in Appendix C-15 ... 45 Figure 2-8. LA-ICP-MS binary plots of Eu anomaly vs (La/Sm)CN for tourmaline from (a) various deposit types

and (b) orogenic gold deposits only. Data from literature: Lottermoser and Plimer 1987; Slack and Coad 1989; Gallagher and Kennan 1992; Jiang et al. (2002); Deksissa and Koeberl (2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017); Kalliomäki et al. (2017); Manéglia (2017). ... 45 Figure 2-9. Partial Least Square Discriminant Analysis of LA-ICP-MS data for tourmaline in orogenic gold deposits hosted in country rock with various compositions. (a) qw*1-qw*2 loadings show correlations

among elemental variables and country rock classes, (b) t1-t2 scores shows the distribution of

tourmaline from in the space defined by qw*1-qw*2, and, (c) VIP shows the importance of compositional

variables in classification of different country rock classes. Data for orogenic gold deposits include Grzela (2017) and Manéglia (2017). ... 47 Figure 2-10. Partial Least Square Discriminant Analysis of LA-ICP-MS data for tourmaline from orogenic gold deposits hosted in country rocks with various compositions and metamorphosed to various facies. (a) qw*1-qw*2 loadings show correlations among elemental variables and classes defined by composition

and metamorphic facies of the country rocks, (b) t1-t2 scores shows the distribution of tourmaline from

in the space defined by qw*1-qw*2, and (c) VIP shows the importance of compositional variables in

classification of classes defined by composition and metamorphic facies of the country rocks. Data for orogenic gold deposits include Grzela (2017) and Manéglia (2017). ... 48 Figure 2-11. Trace element binary plots for tourmaline from various deposit types and rocks (a) Sr vs V, (b) Nb vs V, (c) Li vs Sn, (d) Ta vs Be, (e) Sr/Li vs V/Sn, (f) Sr/Sn vs V/Nb, (g) Ta vs Ni, (h) Nb vs Ga and, (i)

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Sr/Sn vs Ba. Data for orogenic gold deposits: Jiang et al. (2002); Deksissa and Koeberl (2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017); Kalliomäki et al. (2017); Manéglia (2017). ... 52 Figure 2-12. PLS-DA of LA-ICP-MS data for tourmaline from various deposit types and rocks using Li, Sc, V, Co, Zn, Sr, Sn, and Pb (a) qw*1-qw*2 loadings loadings show correlations among elemental variables

and classes defined by deposit types and geological environments, (b) t1-t2 scores scores shows the

distribution of tourmaline from in the space defined by qw*1-qw*2,and (c) VIP shows the importance of

compositional variables in classification of classes defined by deposit types and geological environments. ... 54 Figure 3-1. BSE image of textures and zoning of rutile from orogenic gold deposits. (a) complex rutile with lamellar zones with different shades of grey in contact with porous dark rutile (Hoyle Pond); (b) dark grey rutile is replaced by light grey rutile or possibly sector zoning (Dome); (c) homogeneous, coarse anhedral rutile with pyrite and quartz as possible late infilling in pyrite (Goldex); (d) anhedral rutile cut by quartz-pyrite-carbonate vein (Obuasi); (e) homogeneous platy rutile in quartz vein, (Beaufor); (f) rutile replaced by rim of titanite (Roberto); (g) anhedral rutile with complex zoning with possibly two generations of rutile (Hoyle Pond); (h) rutile in inclusions in pyrite, dark grey rutile light grey rutile as replacement texture or sector zoning (Muruntau) and (i) coarse grained rutile with thin lighter rutile veinlets, cut by irregular veins of chlorite-quartz (Canadian Malartic). ... 62 Figure 3-2. BSE images of textures and zoning of rutile from orogenic gold deposits. (a) anhedral rutile along foliation around arsenopyrite possibly reflecting dissolution-precipitatioin textures (Juneau); (b) anhedral rutile with pyrrhotite inclusions (New Consort); (c) pseudomorphic replacement of rutile grain with cleavage (Tiriganiaq, Meliadine); (d) rutile inclusions in ilmenite (Rosebel); (e) and (f) anhedral rutile with acicular inclusions of light grey rutile (Goldex); (g) rutile replacing ilmenite (St. Ives); (h) fine grained acicular rutile replacing compositional bands of earlier ilmenite exsolutions (Hira Buddini) and (i) rutile with treilli texture replacing ilmenite (Giant). ... 63 Figure 3-3. Sector zoning in rutile (Muruntau) (a) under BSE, and trace elements EPMA maps in (b) Si, (c) Mg, (d) Fe, (e) Mn, (f) Sn, (g) W, (h) Cr and, (i) Nb... 64 Figure 3-4. Irregular patchy zoning in rutile (Canadian Malartic) (a) transmitted light, and trace elements

LA-ICP-MS maps in (b) V, (c) Fe, (d) Sc, (e) Sb, (f) Sn, (g) W, (h) Nb, and (i) Ta. ... 65 Figure 3-5. Ternary diagrams showing the trace element composition of TiO2 polymorphs: (a) Ti vs.

100(Fe+Cr+V) vs. 1000xW, adapted from Clark and Williams-Jones (2004). (b) Al+Ti/V vs. Fe+Cr+Sb+Mo+Sn vs. 10x(W+Zr) adapted from Plavsa et al. (2018). (c) 100xCr vs. Al vs. Fe adapted from Plavsa et al. (2018). (a) EPMA, (b) and (c) LA-ICP-MS data. ... 65 Figure 3-6. Trace element concentrations sorted by median for rutile from orogenic gold deposits, measured by EPMA and LA-ICP-MS. See Appendix E-4 and Appendix E-6 for EPMA and LA-ICP-MS data, respectively. ... 66 Figure 3-7. Binary plots for rutile from orogenic gold deposits of (a) V vs. Nb, (b) Ta vs. Nb, (c) La vs. Ba, (d) U vs. Th, (e) Y vs. Th, (f) La vs. Ca, (g) U/La vs. Zr/Th and (h) Zr/Ba vs. Sc/Y. (a) and (b) are with EPMA data and (c) to (h) are with LA-ICP-MS data. Data from literature: Clark and Williams-Jones (2004); Scott and Radford (2007); Dostal et al. (2009); Scott et al. (2011); Martin (2012); Auger (2016); Pochon et al. (2017); Agangi et al. (2019). ... 67

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Figure 3-8. Rare earth element patterns for rutile from orogenic gold deposits. Data are normalized to chondrite from McDonough and Sun (1995). Deposit patterns in Appendix E-10. ... 69 Figure 3-9. Partial Least Square-Discriminant Analysis of EPMA data for rutile from orogenic gold deposits hosted in various country rocks. (a) qw*1-qw*2 loadings, (b) t1-t2 scores, (c) VIP-cumulative and scores

contributions for each group including rutile from deposits hosted in (d) felsic rocks, (e) intermediate rocks, (f) mafic, (g) mafic-ultramafic and (h) sedimentary rocks VIP. Oblique lines in d and g show the extend of the score contributions. Data from this study and Auger (2016). ... 71 Figure 3-10. Partial Least Square-Discriminant Analysis of EPMA data for rutile from orogenic gold deposits classified by country rocks metamorphosed to various facies. (a) qw*2-qw*3 loadings, (b) t2-t3 scores,

(c) VIP-cumulative and scores contributions for each group including rutile from deposits hosted in rocks metamorphosed (d) from lower to middle greenschist facies, (e) in upper greenschist facies and (f) from lower to middle amphibolite facies. Oblique lines in D and G show the extend of the score contributions. Data from this study and Auger (2016). ... 73 Figure 3-11. Partial Least Square-Discriminant Analysis of LA-ICP-MS data for rutile from orogenic gold deposits hosted in country rocks with various compositions and metamorphosed to various facies. (a) qw*1-qw*3

loadings and (b) t1-t3 scores and (c) VIP-cumulative. ... 74

Figure 3-12. Trace element binary plots for rutile from various deposit types and rocks (a) V vs Mn, (b) V vs Sn, (c) Fe vs n, (d) V vs Nb, (e) Nb vs U, (f) Fe vs Mn, (g) V vs Sb, (h) Nb/V vs W and (i) Nb/Sb vs Sn/V. Plots (a), (e) and (f) refer to the LA-ICP-MS data and (b), (c), (d), (g) and (h) refers to the EPMA data. ... 78

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List of tables

Table 2-1. Median trace element compositions in tourmaline from orogenic gold deposits with the metamorphic facies of the country rock. ... 46 Table 3-1. Median composition in rutile from deposits hosted in various metamorphic facies country rocks ... 68

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List of appendices

Appendix A-1. Geological settings of the gold deposits studied for scheelite. ... 108

Appendix A-2. Scheelite characteristics in the studied orogenic gold deposits ... 112

Appendix A-3. Analytical conditions for trace element analyses in scheelite by EPMA. ... 115

Appendix A-4. EPMA elements composition in scheelite from orogenic gold deposits ... 116

Appendix A-5. Analytical conditions for trace element analyses in scheelite by LA-ICP-MS ... 120

Appendix A-6. LA-ICP-MS trace elements composition in scheelite from orogenic gold deposits ... 121

Appendix A-7. Comparison between LA-ICP-MS and EPMA analyses for (a) Sr, (b) Mo, (c) Y and (d) Na. Red line – 1:1 ratio; abbreviation: DL: Detection limit of the electron microprobe. ... 145

Appendix A-8. Trace elements concentrations sorted by median scheelite composition for orogenic gold deposits, measured by LA-ICP-MS. ... 146

Appendix A-9. Carbonate coloration of samples with scheelite for deposits hosted in (a) low grade metamorphic facies rocks (b) moderate grade metamorphic facies rocks (c) high grade metamorphic facies rocks. ... 147

Appendix A-10. Variation of the trace elements composition with a the oscillatory zoning shown by CL in scheelite from the Crusader deposit, Agnew district (Australia). Zone 1 is characterized by (a) darker CL and high content in Na, V, As, Nb, Ta, Y and REE, and low Mo in (b). Zone 2 is brighter CL and low content in Na, V, As, Nb, Ta, Y and REE, and higher Mo. (c) Both zones have a similar positive-slope REE pattern. ... 148

Appendix A-11. Rare earth elements patterns from LA-ICP-MS data in scheelite from (a) Dome and Hollinger (Timmins, Canada); (b) Young Davidson (Matachewan, Canada); (c) Malartic (Canada), (d) Val-d’Or camp (Canada); (e) Meliadine (Canada); (f) Cuiaba (Brazil); (g) Buzwagi (Tanzania) and Essakane (Burkina Faso), (h) Hutti (India); (i) Kochkar (Russia); (j) Kumtor (Kyrgyzstan). ... 149

Appendix A-12. Rare earth elements patterns from LA-ICP-MS data in scheelite from (a) Marvel Loch (Australia); (b) Nevoria (Australia); (c) Edward’s Find (Australia); (d) Crusader (Australia); (e) Tarmoola (Australia); (f) Paddington (Australia); (g) Mt Pleasant (Australia); (h) Norseman camp (Australia); (i) Mt. Charlotte (Australia); (j) Macraes (New Zealand). ... 150

Appendix A-13. Principal Component Analysis of LA-ICP-MS data for scheelite in orogenic gold deposits. Rare Earth Elements are reduced to ∑REE and Eu anomaly (Eu*). (a) PC1-PC2, (b) PC1-PC3 and (c) PC2-PC3 with emphasis on the mineralization age, (d) PC1-PC2, (e) PC1-PC2-PC3 and (f) PC2-PC2-PC3 with emphasis on the host rock composition, (g) PC1-PC2, (h) PC1-PC3 and (i) PC2-PC3 with emphasis on the metamorphic facies of the host rock. ... 151

Appendix A-14. Principal Component Analysis of LA-ICP-MS data for scheelite from different deposit types. Data from the literature for orogenic gold deposits: Dostal et al. (2009); Hazarika et al. (2016) and Poulin (2016), for skarn deposits: Song et al. (2014) and Poulin (2016), and for porphyry related deposits: Poulin (2016) and Sun and Chen (2017). ... 152

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Appendix B-1. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) As, (d) Sr, (e) Mo, (f) Nb, (g) Sr, (h) V, (i) La, (j) Y and (k) Eu (thin section MALA-10, Canadian Malartic, Canada). ... 153 Appendix B-2. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) As, (d) Sr, (e) Mo, (f) Nb, (g) Sr, (h) V, (i) La, (j) Y and (k) Eu (thin section CUIA-03, Cuiaba, Brazil). ... 154 Appendix B-3. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) As, (d) Sr, (e) Mo, (f) Nb, (g) Sr, (h) V, (i) La, (j) Y and (k) Eu (thin section HUTT-02, Hutti, India). ... 155 Appendix B-4. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) As, (d) Sr, (e) Mo, (f) Nb, (g) Sr, (h) V, (i) La, (j) Y and (k) Eu (thin section KOCH-06A, Kochkar, Russia). ... 156 Appendix B-5. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) As, (d) Sr, (e) Mo, (f) Nb, (g) Sr, (h) V, (i) La, (j) Y and (k) Eu (mineral concentrate NORS-01, Norseman, Australia). ... 157 Appendix B-6. Images of scheelite (a) reflected light, (b) cathodoluminescence and trace elements LA-ICP-MS maps in (c) As, (d) Sr, (e) Mo, (f) Nb, (g) Sr, (h) V, (i) La, (j) Y and (k) Eu (thin section MACR-01D, Macraes, New Zealand). ... 158 Appendix C-1. Geological settings of the gold deposits selected for tourmaline. ... 159 Appendix C-2. Tourmaline characteristics ... 161 Appendix C-3. EPMA elements composition in tourmaline from orogenic gold deposits and other localities. 163 Appendix C-4. Analytical conditions for trace element analyses in tourmaline by LA-ICP-MS. ... 187 Appendix C-5. LA-ICP-MS trace elements composition in tourmaline from orogenic gold deposits and other localities. ... 188 Appendix C-6. Correlation matrix among HFSE, LILE and compatible elements for tourmaline from orogenic gold deposits. Coefficients greater than 0.60 are in bold, coefficients between 0.40 and 0.60 are in italics. ... 248 Appendix C-7. Comparison between LA-ICP-MS and EPMA analyses for (a) Na, (b) Ca, (c) K, (d) Fe, (e) Al, (f) Mg, (g) Mn, (h) Ni, (i) Zn, (j) Ti, (k) V and (l) Sc. Red line – 1:1 slope. ... 249 Appendix C-8. Partial Least Square Discriminant Analysis with EPMA major elements for tourmaline in orogenic gold deposits hosted in various country rock compositions. (a) qw*1-qw*2 loadings, (b) t1-t2 scores, (c)

VIP. Data from the literature: Grzela (2017) and Manéglia (2017). ... 250 Appendix C-9. Binary plot of Mn vs Ti with color variation under non polarized light of EPMA data in tourmaline from orogenic gold deposits. ... 251 Appendix C-10. LA-ICP-MS trace element binary plots for tourmaline from orogenic gold deposits (a) ∑REE vs Sn, (b) ∑REE vs Hf, (c) ∑REE vs Zr, (d) ∑REE vs Nb, (e) ∑REE vs Th, (f) ∑REE vs U and, (g) ∑REE vs Y. Data from the literature: !!! INVALID CITATION !!! Jiang et al. (2002); Deksissa and Koeberl

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(2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017), Kalliomäki et al. (2017) and Manéglia (2017). ... 252 Appendix C-11. LA-ICP-MS trace element binary plots for tourmaline from orogenic gold deposits (a) Y vs Zr, (b) Ta vs Nb, (c) Th vs U, (d) Ga vs Sn, (e) Sc vs V and and, (f) Cr vs Mg. Data from the literature: Jiang et al. (2002); Deksissa and Koeberl (2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017), Kalliomäki et al. (2017) and Manéglia (2017). ... 253 Appendix C-12. REE binary plots for tourmaline in orogenic gold deposits (a) (La/Yb)CN vs ∑REE, (b) (La/Sm)CN

vs SmCN, (c) (Gd/Yb)CN vs YbCN, (d) (La/Sm)CN vs ∑LREE and and, (e) (Gd/Yb)CN vs ∑HREE. Data

from the literature: King et al. (1988), Jiang et al. (2002), Deksissa and Koeberl (2004), Roberts et al. (2006), Hazarika et al. (2015), Hazarika et al. (2016), Grzela (2017), Manéglia (2017) and Kalliomäki et al. (2017). ... 254 Appendix C-13. Major and minor element variation with zoning in tourmaline from orogenic gold deposits from LA-ICP-MS maps; (a) microphotograph in plane polarized light of tourmaline from Rosebel (Suriname); (b) Fe; (c) Mg; (d) Ca; (e) V; (f) Ti; (g) microphotograph in plane polarized light of tourmaline from Excelsior (USA); (h) Fe; (i) Mg; (j) Ca; (k) V; (l) Ti; (m) microphotograph in plane polarized light of tourmaline from Hoyle Pond (Canada); (n) Fe; (o) Mg; (p) Ca; (q) V and (r) Ti. Abbreviations: Carb: carbonate, Chl: chlorite, Qz: quartz, Tur: tourmaline. ... 255 Appendix C-14. Partial Least Square Discriminant Analysis of LA-ICP-MS data for tourmaline from orogenic gold deposits hosted in various country rock compositions and formed at various ages. (a) qw*1-qw*2

loadings, (b) t1-t2 scores and (c) VIP. Data from the literature : Grzela (2017) and Manéglia (2017).256

Appendix C-15. Rare earth elements patterns from LA-ICP-MS data in tourmaline core from orogenic gold deposits; (a) Hollinger (Canada); (b) Hoyle Pond (Canada); (c) Young Davidson (Canada); (d) Canadian Malartic (Canada); (e) Roberto (Canada); (f) James Bay (Canada); (g) Excelsior (USA); (h) Rosebel (Suriname); (i) Essakane (Burkina Faso); (j) New Consort (South Africa); (k) Hira Buddini (India); (l) Uti (India); (m) Big Bell (Australia) and (n) St. Ives (Australia). ... 257 Appendix C-16. Rare earth elements variations with zoning in tourmaline from orogenic gold deposits from

LA-ICP-MS data; (a) St. Ives (Australia); (b) Royal Hill (Rosebel, Suriname); (c) Young Davidson (Canada); (d) Hollinger (Canada); (e) Hoyle Pond (Canada) and (f) Hira Buddini (India). ... 258 Appendix C-17. Rare earth element patterns in tourmaline from (a) the Lincoln Hill gold deposit (USA), (c) hydrothermal veins cutting the VMS mineralization at LaRonde (Canada) and (c) Roberto pegmatite (Canada). ... 259 Appendix C-18. Variation of the REE patterns with the optical zoning in Roberto pegmatite. ... 260 Appendix C-19. Trace element binary plots for tourmaline from various deposit types and rocks (a) Y vs Zr, (b) Ta vs Nb, (c) Th vs U, (d) Ga vs Sn, (e) Sc vs V, (f) Ta vs Zr, (g) Li vs Be, (h) Sr/Sn vs Ba/Ga, and (i) Ta vs U. Data from the literature: Jiang et al. (2002); Deksissa and Koeberl (2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017); Kalliomäki et al. (2017) and Manéglia (2017). ... 261 Appendix C-20. Trace element binary plots for tourmaline from various deposit types and rocks (a) V vs Sr, (b) Sn vs Zn/Nb, (c) Sn vs Co/Nb, (d) V vs Ni, (e) Sn vs Sr/Ta, (f) Sn vs Co/La, (g) V vs Cr, (h) Sr/Sn vs Ni/Nb, and (i) Sr/Sn vs V/Be. Data for orogenic gold deposits: Jiang et al. (2002); Deksissa and Koeberl

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(2004); Roberts et al. (2006); Hazarika et al. (2015); Hazarika et al. (2016); Grzela (2017); Kalliomäki

et al. (2017) and Manéglia (2017). ... 262

Appendix D-1. Images of zoned tourmaline (a) under polarized light and LA-ICP-MS maps (b) Ca (c) Ti, (d) Sr, (e) V, (f) Ga, (g) Ni, (h) Sn, (i) Sc and (j) Cr (thin section EXCE-01, Excelsior, USA). ... 263

Appendix D-2. Images of zoned tourmaline (a) under polarized light and LA-ICP-MS maps (b) Fe (c) Cr, (d) Li, (e) Mn, (f) Ti, (g) Sr, (h) V, (i) Sc and (j) Ni (thin section POND-09B, Hoyle Pond, Canada). ... 264

Appendix D-3. Images of zoned tourmaline (a) under polarized light and LA-ICP-MS maps (b) Co (c) Cr, (d) Ga, (e) Ti, (f) V, (g) Sr, (h) Ni, (i) Sn and (j) Sc (thin section RHD-380-29B, Royal Hill, Rosebel, Suriname). ... 265

Appendix E-1. Geological settings of the selected gold deposits studied for rutile ... 266

Appendix E-2. Rutile characteristics in the studied orogenic gold deposits ... 272

Appendix E-3. Analytical conditions for trace element analyses in rutile by EPMA ... 276

Appendix E-4. EPMA elements composition in rutile from orogenic gold deposits ... 277

Appendix E-5. Median detection limits for trace element analyses in rutile by LA-ICP-MS ... 307

Appendix E-6. LA-ICP-MS trace elements composition in tourmaline from orogenic gold deposits ... 308

Appendix E-7. Comparison between LA-ICP-MS and EPMA analyses for (a) Ti, (b) Si, (c) Al, (d) Mn, (e) Mg, (f) As, (g) Fe, (h) V, (i) Cr, (j) Nb, (k) Zr and (l) Sn, (m) Sb, (n) Ta and (o) W... 333

Appendix E-8. Ternary plots for rutile from orogenic gold deposits (a) Ti vs 100x(Fe+Cr+V) vs 1000xSn, (b) Ti vs 100x(Fe+Cr+V) vs 1000xW and (c) Ti vs 100x(Fe+Cr+V) vs 1000x(Sn+W), (d) Ti vs 100x(Fe+Cr+V) vs 1000xSb and (e) Ti vs 100x(Fe+Cr+V) vs 1000x(Sb+W), adapted from Clark and Williams-Jones (2004). Data from this study and literature: Clark and Williams-Jones (2004); Martin (2012); Agangi et al. (2019). ... 334

Appendix E-9. Binary plots for rutile from orogenic gold deposits of (a) V vs Fe, (b) V vs W, (c) W+Nb+Sb+Ta vs Fe+V+Cr, (d) Hf vs Zr, (e) Sc vs Zr, (f) Ta vs Zr, (g) Th vs La, (h) Sc vs La, (i) Y vs Yb, (j) Fe vs W, (k) Ba vs Sn and (l) Ca vs Sr. (a) to (c) are with EPMA data and (d) to (l) are with LA-ICP-MS data. Data from this study and literature: Clark and Williams-Jones (2004); Scott and Radford (2007); Dostal et al. (2009); Scott et al. (2011); Martin (2012); Auger (2016); Pochon et al. (2017); Agangi et al. (2019).335 Appendix E-10. Rare earth elements patterns from LA-ICP-MS data in rutile from orogenic gold deposits; (a) Red Lake; (b) Hollinger; (c) Hoyle Pond; (d) Canadian Malartic; (e) Goldex; (f) Lac Herbin; (g) Beaufor; (h) Roberto; (i) Sixteen-to-One; (j) Royal Hill, Rosebel; (k) Obuasi; (l) Essakane; (m) Muruntau; (n) Uti, (o) Big Bell; (p) Tindals and (q) Raleigh. ... 336

Appendix E-11. Partial Least Square-Discriminant Analysis of EPMA data for rutile from orogenic gold deposits from country rocks metamorphosed to various facies including Si, Fe, Mg, Cr, V, Nb, Ta, W, Sn and Sb. (a) qw*1-qw*2 loadings and (b) t1-t2 scores, (a) qw*1-qw*3 loadings and (b) t1-t3 scores. Data from this study and literature: Auger (2016). ... 337 Appendix E-12. Partial Least Square-Discriminant Analysis of LA-ICP-MS data for rutile from orogenic gold deposits hosted in country rocks with various compositions and metamorphosed to various facies,

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including Nb, Ta, W, Zr, Hf, U, La, Ce, Yb, Y, Sc, Sn, Sb, Cr, Fe, V, Pb, Ba, Na, Al, As and Au. (a) qw*1

-qw*2 loadings and (b) t1-t2 scores, (c) qw*2-qw*3 loadings and (d) t2-t3 scores. ... 338

Appendix E-13. Partial Least Square-Discriminant Analysis of EPMA data for rutile in orogenic gold deposits of various ages. (a) qw*1-qw*2 loadings and (b) t1-t2 scores and scores contributions for each group

including rutile from deposits formed at (c) Archean, (d) Proterozoic, and (e) Phanerozoic. Data from this study and Auger (2016). ... 339 Appendix E-14. Trace element binary plots for rutile from various deposit types and rocks (a) V vs Al, (b) V vs Cr, (c) Ta vs Nb, (d) V vs Fe, (e) V vs Zr and (f) Fe vs U. Plot (a) and (f) refers to the LA-ICP-MS data and (b), (c), (d), (g) and (h) refers to the EPMA data. ... 340 Appendix F-1. (a) Back scattered images of zoned rutile and EPMA maps (b) Cr (c) V, (d) Ta, (e) W, (f) Nb (g) Sb, (h) Mo, (i) Zr and (j) Al (thin section HOLL-07A, Hollinger, Canada). ... 341 Appendix F-2. (a) Back scattered images of zoned rutile and EPMA maps (b) W (c) Fe, (d) Sb, (e) V, (f) Nb (g) Zr, (h) Cr, and (i) Al (mineral concentrate BIGB-01, Big Bell, Australia). ... 342

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Acknowledgements

Tout d’abord, je tiens à remercier mon directeur de recherche, Georges Beaudoin, qui m’aura guidé à travers ce projet de recherche. Merci de m’avoir encouragée et de m’avoir aidé à mener à bien de nombreuses discussions.

Je remercie les membres du jury d’avoir évaluer mon manuscript : Matthieu Harlaux, Bertrand Rottier, ainsi que Crystal Laflamme.

Je voudrais ensuite remercier toutes les personnes qui ont contribuées de loin ou de prêt à compléter ma collection d’échantillons. Certaines auront manifestées un grand intérêt et donnés leur set complet de lames minces alors que d’autres m’auront clairement mentionnées une cause perdue… La liste est longue et les personnes se reconnaitront.

Je voudrais ensuite remercier toutes les personnes qui m’ont assisté lors des techniques analytiques telles que Marc Choquette, André Ferland, Dany Savard, Marko Kudrna Prasek et Philippe Pagé. Je tiens à remercier tout particulièrement Sheida Makvandi, pour avoir été ma collègue et amie, mais aussi pour avoir bâti le socle de l’édifice de la chaire de recherche dans laquelle nous avions travaillé ensemble, c’est-à-dire les analyses multivariées, le travail en amont des analyses et les scripts qui vont avec ! Un grand merci à Émilie Bédard pour son amitié et son efficacité au travail ! Merci à Anne-Aurélie Sappin pour ses petits coups de pouce de senior et son entrain infini. Je remercie ensuite toutes les personnes du département de Géologie et Génie Géologique de l’Université Laval : François Huot, Guylaine et sa bonne humeur, Edmond, Julia, Marcel, Josée…

J’ai une pensée toute particulière pour mes amis et collègues de travail, de prêt et de loin : Donald, mon fidèle ami de bureau avec son accent franc-ontarien que j’ai fait répéter de nombreuses fois et qui a été mon double en canot de rivière, Clovis, Tom, FX, Victor, Renato et son éternel sourire, Nathan qui manque de sourire, Débora, Nicolas, sans oublier Stéphanie : on aura mis du temps à s’adresser la parole mais c’est pour une amitié infinie.

Je remercie également mes parents qui m’ont permis d’arriver où j’en suis aujourd’hui et tout particulièrement ma sœur qui m’aura inculqué cette foi de battante et cette capacité de croire en moi-même.

Finalement, ma plus grande gratitude va à Roman. Si une thèse n’est définitivement pas le travail d’une seule personne, Roman serait deuxième auteur. Je te remercie pour ton soutien quotidien, tes idées, tes connaissances, ton investissement, ton temps, ta foi envers mon projet... La liste est tellement longue que les mots me manquent. Merci de m’avoir donné les ressources morales et matérielles pour mener à bien ce projet et clore ce chapitre de nos vies.

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Foreword

All chapters in this thesis were written by the author. The first and second chapters entitled “Trace element composition of scheelite in orogenic gold deposits” and “Chemical composition of tourmaline in orogenic gold deposits” has been published and submitted, respectively, to Mineralium Deposita. The third chapter entitled “Texture and trace elements composition of rutile in orogenic gold deposits” is in preparation for submission to a scientific journal. The first author of the articles, Marjorie Sciuba, completed the sample collection, prepared the samples, carried out the analytical work and interpreted the data. Co-authors to the articles include Georges Beaudoin (Université Laval), research director of the Ph.D. project, Sheida Makvandi, (Université Laval), post-doctoral fellow (Université Laval), and Donald Grzela, M.Sc. student at Université Laval.

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Introduction

Indicator mineral method

The indicator mineral technique has been developed significantly since the 1980s and it has been successfully used in geochemical exploration, especially for exploration in glaciated terrains. A broad set of indicator minerals are now available for many deposit types such as diamond-bearing kimberlite (e.g. McClenaghan and Kjarsgaard 2007), metamorphosed volcanogenic massive sulfides (VMS; e.g. Heimann et al. 2005), porphyry Cu deposits (e.g. Averill 2011; Kelley et al. 2011), magmatic Cu-Ni-PGE deposits (e.g. Averill 2001, 2011; McClenaghan 2011), Mississipi Valley Type (MVT) Pb-Zn (e.g. Paulen et al. 2011; Oviatt et al. 2013) and some other deposit types. Indicator minerals are commonly recovered from quaternary formations such as soil, glacial, stream or aeolian sediments. Indicator mineral dispersion in the surficial environment may potentiall lead to discovery of mineral deposits. This technique was successfully used to discover several deposits, for example Casa Berardi (Québec, Canada; Sauerbrei et al. 1987). McClenaghan (2005) defines indicator minerals “as mineral species that, when appearing as transported grains in clastic sediments, indicate the presence in bedrock of a specific type of mineralization, hydrothermal alteration or lithology”. An indicator mineral may be the mineral of interest itself, such as gold or mineral associated with the mineralization. Indicator minerals are recovered from surface samples such as till, stream sediment or soil. After mineral separation, they are counted and investigated for different features such as shape, texture or roundness that inform on the transport distance and the potential source. Indicator minerals are particularly useful for reconnaissance exploration in glaciated terrains where physical disaggregation is important (McClenaghan 2005). The indicator mineral method has many benefits for geochemical exploration including (1) large targeted areas are favorable for blind discoveries, (2) several deposit-types can be targeted in a single survey, (3) mineral dispersion can provide evidence of the distance from the source (Averill 2001), (4) indicator mineral dispersal trains are potentially larger than dispersion patterns using stream sediment samples such that this increases the potential for discovery (Kelley et al. 2011). The indicator mineral method is used not only for mineral deposit exploration but also for rock types and geological terranes (Friedrich 1992; Stendal and Theobald 1994). The indicator mineral method has mostly been developped by case studies around known mineral deposits and syntheses have reviewed the state-of-the-art knowledge on the method (Thorleifson and McClenaghan 2003; McClenaghan 2005; Paulen and McMartin 2010). Mineral deposit types explored using indicator mineral method include gold, diamond, VMS, MVT, porphyry Cu, magmatic Ni-Cu-PGE, W-Mo, Cu skarn and greisen deposits. Indicator minerals have physical and chemical properties that make them chemically stable and resistant to mechanical abrasion. Most of them are easy to identify and have specific properties (i.e. density, magnetic susceptibility, colour under UV light, etc.) for the mineral separation.

Physical properties

Indicator minerals have high specific gravity (S.G > 3.2; Averill 2001) favoring their concentration in hydrodynamic traps during transport. Differences in density between indicator mineral species are used for mineral separation. According to their relative hardness, indicator minerals may be reshaped during transport. Soft minerals such as gold (hardness: 2.5) are more malleable and deformable than harder minerals such as tourmaline (7.0-7.5) and rutile (6-6.5). Others such as galena are sectile. As a consequence, soft minerals are reshaped during transport (Averill 2001). The initial size of indicator minerals is controlled by processes during

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crystallization. They may be fractured by hydration during volcanism or pre-glacial weathering and abraded during transport (McClenaghan 1994; McClenaghan and Kjarsgaard 2001). Cleavage planes in minerals facilitate fracturing and mineral comminution. Fracturing is part of the factor controlling grain size and the relative abundance of indicator minerals in glacial drift (McClenaghan 1994; McClenaghan and Kjarsgaard 2001). Fracture-resistant minerals such as Mg-ilmenite are generally coarse-grained (0.5-1.0 mm) compared to fracture-prone minerals such as Cr-pyrope that easily breaks into smaller grains (0.25-0.5 mm; Averill 2001). High magnetic susceptibility (e.g. magnetite) and fluorescence properties under UV light (e.g. scheelite) are additional physical properties facilitating mineral separation and selection (Averill 2001). Colourful indicator minerals are visually more distinctive and, thus, easier to recognize and select.

Chemical properties

Useful indicator minerals should be chemically stable in the surficial environment and resistant to weathering. Sulfides may be used as indicator minerals in some conditions. Most sulfides with the possible exception of chalcopyrite and sphalerite, are unstable under oxidizing conditions whereas arsenides such as loellingite (FeAs2) are relatively stable (Averill 2001). Processes such as pre-glacial supergene alteration of the mineral

orebody or in-situ weathering and oxidation of transported grains may affect indicator minerals and especially sulfides. Such processes may partially to completely destroy sulfides and lower the indicator minerals abundance in till (Averill 2001).

During the last decades, research on indicator minerals focused on characterizing indicator mineral composition to constrain mineral provenance (e.g. Stendal and Theobald 1994; McClenaghan and Kjarsgaard 2007; Makvandi et al. 2012; McClenaghan et al. 2012a; McClenaghan et al. 2012b; Nadoll et al. 2012; Boutroy et al. 2014; Nadoll et al. 2014; Makvandi et al. 2015; McClenaghan et al. 2015; Auger 2016; Makvandi et al. 2016a; Makvandi et al. 2016b; Manéglia et al. 2018; Grzela et al. 2019). Advances on analytical techniques, and especially LA-ICP-MS, enable to quantify more precisely the mineral trace element composition, on smaller and smaller volumes.

For instance, the composition of Fe-oxides including magnetite and hematite are documented for Volcanogenic Massive Sulfide (VMS), Iron Oxyde Copper Gold (IOCG), Iron Oxyde Apatite (IOA), Banded Iron Formation (BIF), porphyry, skarn, Fe-Ti, V, Cr, Ni-Cu, clastic Pb-Zn and other deposit types (e.g. Dupuis and Beaudoin 2011; Dare et al. 2012; Makvandi et al. 2012; Nadoll et al. 2012; Boutroy et al. 2014; Dare et al. 2014; Nadoll et al. 2014; Makvandi et al. 2015; Makvandi et al. 2016a; Makvandi et al. 2016b). Apatite is another example of commonly used indicator mineral that has a well characterized mineral composition (e.g. Bouzari et al. 2016; Hazarika et al. 2016; Mao et al. 2016; Adlakha et al. 2017; Wilkinson et al. 2017). The trace element composition of minerals such as magnetite, hematite and apatite can now be used with confidence to determine their provenance in indicator mineral surveys and to trace various deposit types.

Developing indicator mineral methodology for orogenic gold

exploration

Orogenic gold deposits represent one of the major gold source worldwide (Phillips and Powell 2014) for the mineral industry and represent about 45 % of gold deposits containing more than 1 Moz Au (production + reserves), compared to other gold deposit types including intrusion-related deposits (28% for porphyry, skarn, manto, Carlin and breccia-pipe), epitermal (25 %) and paleoplacers (3 %; Goldfarb et al. 2005). Orogenic gold

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deposits are defined by Groves et al. (1998) as gold deposits that formed at temperatures of 180-700°C and pressures of <1-5 kbar (Groves 1993; Hagemann et al. 1996; Ridley et al. 1996) associated with metamorphic terranes, under compressional to transpressional deformation in an accretion prism. Orogenic gold deposits are now explored with classical techniques such as bedrock and structural mapping geophysics for lithologies that have a geophysical signatures, and geochemistry including lithogeochemistry, and surficial sampling (overburden, till, stream etc.) for gold. For example, Rio Tinto use indicator mineral technique at broad scale for diamond exploration and has developed a laboratory which is able to process and analyze about 10 000 grains per day (Agnew 2014). Gold grains are commonly used to track gold deposits in combination with other minerals such as sulfides (i.e. pyrite, arsenopyrite, galena), tellurides, scheelite and rutile (McClenaghan and Cabri 2011; Moles and Chapman 2011). Tourmaline is considered as indicator for orogenic gold deposits (this study). However, indicator mineral technique needs to be constrained for orogenic gold exploration to determine precisely the indicator mineral source and to orient the exploration program.

Scheelite, tourmaline and rutile are formed by hydrothermal processes with the orogenic gold mineralization (e.g. McCuaig and Kerrich 1998; Eilu et al. 1999; Goldfarb et al. 2005) and they were proposed to be studied for their mineral composition. Scheelite, tourmaline and rutile have specific gravity of 5.9-6.1, 2.9-3.1 and 4.2, respectively and hardness of 4.5-5.0, 7.0-7.5 and 6.0-6.5, respectively (Nesse 2012). Additionally, scheelite is fluorescent under UV light, which make it easy to pick in heavy mineral concentrate. Thus, these three minerals appear as ideal indicators. According to previous studies, tourmaline and rutile have good potential to respond to the country rock composition and mineralization type (e.g. Lottermoser and Plimer 1987; Slack and Coad 1989; Gallagher and Kennan 1992; Jiang et al. 1999; Keller et al. 1999; Selway et al. 1999; Selway et al. 2000; Williamson et al. 2000; Clark and Williams-Jones 2004; Poulin 2016; Poulin et al. 2016; Hong et al. 2017; Poulin et al. 2018).

Research objectives

This study aimed at defining mineralogical and geochemical features of scheelite, tourmaline and rutile in orogenic gold deposits for indicator mineral methodologies. To reach this goal, the following objectives were defined:

 Study indicator minerals from a representative set of orogenic gold deposits

 Determine texture, shape, grain size and mineral association by optical microscopy and SEM.

 Measure in-situ the chemical composition in major and trace elements of scheelite, tourmaline and rutile by EPMA and LA-ICP-MS.

 Define discriminant criteria for scheelite, tourmaline and rutile in orogenic gold deposits

Methodology

 Review literature for scheelite, tourmaline and rutile and establish mineral composition database for comparison.

 Select orogenic gold deposits (Figure 0-1) by taking into account the variety of geological settings including country rock composition, metamorphic facies of the country rock, country rock age and mineralization age. Collect samples from the mineralization that contains scheelite, tourmaline or rutile from those deposits from various sources including researchers, museums and mines.

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 Characterize the mineral composition by statistical analysis including elemental binary and ternary plots as well as multivariate statistics including PCA and PLS-DA, according to the selected geological settings of orogenic gold deposits.

 Compare the composition of scheelite, tourmaline and rutile from orogenic gold deposits with those from other deposit types and environments available in literature.

Figure 0-1. Distribution of the selected orogenic gold deposits in this study, (a) in the world Map is adapted from the Canada Geological Survey database; (b) in the Abitibi subprovince, Canada; map modified from Poulsen et al. (2000) and (c) in the Yilgarn craton, Australia. Map is adapted from Robert et al. (2005).

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Table 0-1. List of the selected deposits for the study

Location Scheelite Tourmaline Rutile

North American Shield

Meliadine district x x Giant x Red Lake x Roberto x x James Bay x x Dome x x x Hollinger x x x Hoyle Pond x x Young Davidson x x x Canadian Malartic x x x Beaufor x x Goldex x Lac Herbin x Sigma-Lamaque x x

North American cordillera

Alaska-Juneau x

Excelsior x

Alleghany x

Amazon craton

Rosebel x x x

Sao Francisco craton

Cuiaba x

Massif Central

Salsigne x

West African craton

Essakane x x x

Damara orogen

Navachab

x

Location Scheelite Tourmaline Rutile

Tanzanian craton Buzwagi x Bulyanhulu x North Mara x Navachab x Kaapvaal craton New Consort x x Dharwar craton Hutti x x Uti x Hira Buddini x Uralide Kochkar x Tien Shan Kumtor x x Muruntau x Yilgarn craton Marvel Loch x Nevoria Edward’s Find x Tarmoola x Transvaal x Paddington x Mt Pleasant x Big Bell x x Waroonga x Harbour Lights x Kanowna Belle x Tindals x Raleigh x St. Ives x x Wallaby x Porphyry x

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Sunrise Dam x Norseman x Mt Charlotte x Tasman orogen Fosterville x Otago schist Macraes

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Thesis outline

The PhD thesis presents the outcome of the study as a succession of three chapters as following:

The general introduction about indicator mineral method, the problematic, the research objectives and the followed methodology and the thesis outlines are presented at the beginning of the manuscript.

Chapter 1 examines the case of scheelite, as indicator mineral for orogenic gold deposits. This chapter is part

of a publication released in Mineralium Deposita: Sciuba, M., Beaudoin, G., Grzela, D., and Makvandi, S. (2019) Trace element composition of scheelite in orogenic gold deposits, Mineralium Deposita. Co-authors include Georges Beaudoin, the thesis supervisor, Donald Grzela, M.Sc. student and Sheida Makvandi, post-doctoral fellow. DOI: 10.1007/s00126-019-00913-4

Chapter 2 examines the case of tourmaline, as indicator mineral for orogenic gold deposits. This chapter is

part of a publication under review at Mineralium Deposita: Sciuba, M., Beaudoin, G., and Makvandi, S. (submitted) Chemical composition of tourmaline in orogenic gold deposits. Co-authors include Georges Beaudoin, the thesis supervisor and Sheida Makvandi, post-doctoral fellow.

Chapter 3 examines the case of rutile, as indicator mineral for orogenic gold deposits. This chapter will be

submitted to a scientific journal as follow: Sciuba, M. Beaudoin, G. Texture and trace element composition of rutile in orogenic gold deposits (in prep). Co-author is Georges Beaudoin, the thesis supervisor.

The general conclusion and recommendations for future work are presented at the end of the manuscript. Appendices A to F contain supplementary materials that support the articles. Appendices A and B are associated with chapter 1 (scheelite), appendices C and D with chapter 2 (tourmaline), and appendices E and F with chapter 3 (rutile).

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Chapter 1. Trace

element

composition

of

scheelite in orogenic gold deposits

1.1. Résumé

La scheelite de vingt-cinq gisements d’or orogénique représentatifs avec des contextes géologiques variés a été analysée par microsonde électronique (EPMA) et laser ablation et spectroscopie de masse avec plasma couplée par induction (LA-ICP-MS) pour établir des paramètres géochimiques discriminants pour contraindre les études de minéraux indicateurs pour l’exploration aurifère. La scheelite des gisements d’or orogénique a cinq patrons d’éléments des terres rares (ETR) incluant un patron en forme de cloche avec une anomalie (i) positive ou (ii) négative en Eu; (iii) un patron plat avec une anomalie positive en Eu et, moins communément, (iv) un patron enrichi en ETR légères, et v) un patron enrichi en ETR lourdes. Les patrons des ETR sont interprétés comme le reflet de la source des fluides hydrothermaux ou le partage des ETR avec les minéraux co-précipités. La scheelite des gisements formés dans des roches métamorphisées depuis le faciès des schistes verts supérieurs au faciès des amphibolites inférieures ont une teneur faible en ETR, Y, et Sr et une teneur élevée en Mn, Nb, Ta et V, comparé à la scheelite formée dans des roches métamorphisées sous le faciès des schistes verts moyen. La scheelite des gisements encaissés dans des roches sédimentaires a une teneur élevée en Sr, Pb, U et Th, et une teneur faible en Na, ETR et Y comparé à la scheelite des gisements encaissés dans des roches felsiques à intermédiaires. Les analyses statistiques incluant des diagrammes élémentaires et des statistiques multivariées avec la méthode d’analyse discriminante des moindres carrées (PLS-DA) montrent que le faciès métamorphique des roches encaissantes, et la composition de l’encaissant régional exercent un fort contrôle sur la composition de la scheelite. Ceci résulte des échanges fluide-roche lors de la circulation des fluides jusqu’au site de minéralisation de l’or. Les PLS-DA et les diagrammes binaires de ratios élémentaires montrent que la scheelite des gisements d’or orogénique possède une signature distincte en Sr, Mo, Eu et Sr/Mo, mais une signature en ETR indistinguable, comparée à celle de la scheelite des autres types de gîtes.

1.2. Abstract

Scheelite from twenty-five representative orogenic gold deposits from various geological settings was investigated by EPMA (Electron Probe Micro-Analyzer) and LA-ICP-MS (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometer) to establish discriminant geochemical features to constrain indicator mineral surveys for gold exploration. Scheelite from orogenic gold deposits displays five REE patterns including a bell-shaped pattern with a (i) positive or (ii) negative Eu anomaly; iii) a flat pattern with a positive Eu anomaly and, less commonly, (iv) a LREE enriched pattern, and (v) a HREE enriched pattern. The REE patterns are interpreted to reflect the source of the auriferous hydrothermal fluids and, perhaps, co-precipitating mineral phases. Scheelite from deposits formed in rocks metamorphosed at upper greenschist to lower amphibolite facies have low contents in REE, Y, and Sr, and high contents in Mn, Nb, Ta and V, compared to scheelite formed in rocks metamorphosed below the middle greenschist facies. Scheelite from deposits hosted in sedimentary rocks has high Sr, Pb, U and Th, and low Na, REE and Y, compared to that hosted in felsic to intermediate rocks. Statistical analysis including elemental plots and multivariate statistics with PLS-DA (Partial Least Square-Discriminant Analysis) reveal that the metamorphic facies of the host rocks, as well, as the regional host rock composition exert a strong control on scheelite composition. This is a result of fluid-rock exchange during fluid flow to gold deposition site. PLS-DA and elemental ratio plots show that scheelite

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from orogenic gold deposits have distinct Sr, Mo, Eu, As and Sr/Mo, but indistinguishable REE signatures, compared to scheelite from other deposit types.

1.3. Introduction

The association between gold and scheelite in orogenic gold deposits has long been recognized. Goldfarb et al. (2005) review the characteristics of orogenic gold deposits. In many deposits, scheelite predates and/or is contemporaneous with gold deposition, such as in the Val-d’Or district, Canada (Beaudoin and Pitre 2005), at Mt. Charlotte, Australia (Mueller 1991) or Charmitan, Uzbekistan (Graupner et al. 2010). Scheelite is a major mineral in greisen and skarn (Xiong et al. 2006; Ren et al. 2010; Song et al. 2014; Guo et al. 2016; Poulin 2016; Poulin et al. 2016; Poulin et al. 2018), and a minor mineral in Cu-(Mo-Au) porphyry deposits (Poulin 2016; Poulin et al. 2016; Sun and Chen 2017; Poulin et al. 2018), where it occurs in veins or disseminated in altered rocks. Scheelite is also an accessory mineral in aplite, pegmatite and metamorphosed sedimentary exhalative Fe-Mn (Brugger et al. 1998; Uspensky et al. 1998) and volcanogenic massive sulphides deposits (Poulin 2016; Poulin et al. 2016; Poulin et al. 2018).

The indicator mineral technique is used in exploration using overburden sediments for several deposit types. Discriminant geochemical features in major, minor and trace elements of indicator minerals may be used to recognize a deposit type. For instance, Cr-rich spinel and Cr-rich garnet are indicators for diamond-bearing kimberlite (Gurney 1984; Fipke et al. 1995; McClenaghan and Kjarsgaard 2007), and Ni-Cu mineralization (Aumo and Salonen 1986; Peltonen et al. 1992; Somarin 2004), whereas magnetite has been shown to be useful to fingerprint various mineral deposit types (Dupuis and Beaudoin 2011; Boutroy et al. 2014; Dare et al. 2014). Scheelite is considered an indicator mineral for orogenic gold (McClenaghan and Cabri 2011) and tungsten deposits (Lindmark 1977; Toverud 1984; Johansson et al. 1986). In indicator mineral surveys, scheelite is recovered from the heavy mineral fraction or overburden sediments, but the deposit type at the source of the scheelite grains cannot, currently, be determined.

Scheelite (CaWO4) and powellite (CaMoO4) form a partial solid solution where Mo6+ substitutes for W6+ (Tyson

et al. 1988). Pure scheelite is bluish under short wave fluorescent light, whereas Mo-rich scheelite is typically yellow in color (Van Horn 1930; Shoji and Sasaki 1978). Scheelite is luminescent under an electron beam allowing to study textural zonation and successive scheelite generations in relationship with their trace element composition. The REE, Y, As, and Sr content in scheelite have a minor effect on the cathodoluminescence (CL) response (Brugger et al. 2000a; MacRae et al. 2009; Poulin 2016; Poulin et al. 2016), whereas Mo variation is associated with CL zoning, (Poulin 2016; Poulin et al. 2016). The CL zoning may result from primary crystallization or from multi-stage evolution (Brugger et al. 2000a).

Replacement of W by Mo and Ca by Sr, Pb, Fe, Mn, Ba and REE have been reported (Cottrant 1981; Raimbault et al. 1993; Ghaderi et al. 1999) and traces of Na, V, Nb, Ta, S, As, Pb, U, Th, Mn, Fe, Au, Ba, B, Co, Cr, K, Ni, Sb Sc, Zn, Bi, Cu, Sn, Zn, Li, Ti and Rb have been measured in variable amounts in scheelite from various types of deposits (Anglin 1992; Eichhorn et al. 1997; Zhigang et al. 1998; Ghaderi et al. 1999; Brugger et al. 2000a; Brugger et al. 2000b; Brugger et al. 2002; Xiong et al. 2006; Liu Yan et al. 2007; Dostal et al. 2009; Graupner et al. 2010; Peng et al. 2010; Ren et al. 2010; Song et al. 2014; Hazarika et al. 2016; Poulin 2016; Poulin et al. 2016; Fu et al. 2017; Sun and Chen 2017).The high REE concentrations (~10-5,000 ppm; Uspensky et al. 1998) in scheelite have been used for Sm-Nd geochronology in order to date the gold mineralization (Anglin 1992; Anglin et al. 1996; Frei et al. 1998; Uspensky et al. 1998; Kempe et al. 2001; Roberts et al. 2006) whereas the Sr and Nd isotopic compositions have been used to constrain the sources