Eleonora Carocci
email: eleonora.carocci@univ-lorraine.fr

Christian Marignac

Michel Cathelineau

Laurent Truche

Marc Poujol

Marie-Christine Boiron

Filipe Pinto

Incipient wolframite deposition at Panasqueira (Portugal): W-rutile and tourmaline compositions as proxies for early fluid composition

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Introduction 33 upright F3 folds, with a S3 axial-plane schistosity, followed by dextral faulting (Diez Fernandez and Pereira, 2017;and references therein). 111

Crustal melting and concomitant mantle-derived heat input continued through D3 to D5, with the 112 pervasive emplacement of syn-to post-kinematic granite plutons, in three pulses roughly coincident 113 with the D3 to D5 events (e.g., [START_REF] Dias | U-Pb zircon and 921 monazite geochronology of post-collisional Hercynian granitoids from the Central Iberian 922 Zone[END_REF][START_REF] Mateus | Sistemas mineralizantes epigenéticos na Zona Centro-Ibérica; 1028 expressão da estruturação orogénica meso-a tardi-varisca (Epigenetic ore-forming systems in 1029 Central-Iberian Zone; products of an evolving orogenic framework in meso-to late-Variscan 1030 times)[END_REF]Sant'Ovaia et al., 114 2010;Fernandez-Suarez et al., 2011). Water-absent dehydration melting (incongruent biotite 115 melting) produced cordierite-bearing diatexites in the cores of D2 migmatitic domes (Pereira 116 Gomez et al., 2000). Permian mafic dikes (290-265 Ma) testify to a mantle influence until the very 117 end of the collision [START_REF] Orejana | The 1057 Variscan gabbros from the Spanish Central System: A case for crustal recycling in the sub-1058 continental lithospheric mantle?[END_REF][START_REF] Scarrow | Lamprophyre dikes 1116 as tectonic markers of late orogenic transtension timing and kinematics: A case study from the 1117 Central Iberian Zone: Tectonics[END_REF]. 118

Numerous mineralized systems were active in the CIZ in close association with Late 119

Carboniferous tectonics and granitoid emplacement giving rise to more than 150 peri-and intra-120 granitic rare metal (Nb-Ta, Li, W, Sn) and shear-zone hosted (Au-Ag-As-Sb-Pb-Zn-Cu) deposits 121 [START_REF] Tornos | 300 Million years of episodic 1132 hydrothermal activity: stable isotope evidence from hydrothermal rocks of the eastern Iberian 1133 Central System[END_REF][START_REF] Neiva | Portuguese granites associated with Sn-W and Au mineralizations[END_REF][START_REF] Mateus | Sistemas mineralizantes epigenéticos na Zona Centro-Ibérica; 1028 expressão da estruturação orogénica meso-a tardi-varisca (Epigenetic ore-forming systems in 1029 Central-Iberian Zone; products of an evolving orogenic framework in meso-to late-Variscan 1030 times)[END_REF][START_REF] Noronha | Fluids and Variscan metallogenesis in granite related systems in Portugal: 1048 Water-Rock Interaction International Symposium[END_REF]. 122 123

Geological setting and previous work 124 125

The Panasqueira W-Cu (Ag)-Sn deposit in central Portugal lies within the Central Iberian Zone 126 (CIZ) (Fig. 1), in the core of a late Carboniferous anticlinorium bordered by narrow synclines of 127 Ordovician Armorican Quartzite (Fig. 2-A). The deposit consists of a dense network of sub-128 horizontal mineralized quartz veins crosscutting the subvertical foliation of the greenschist facies 129 mica-schists of the Beira Schists (Fig. 2-B). These veins crosscut numerous pods and vein-like 130 masses of barren quartz locally named "seixo-bravo" which are probably late kinematic and cover 131 an area of over six km 2 ; their vertical extent is several hundred meters (Polya, 1989). 132

A granite body concealed beneath the deposit (Fig. 2-B) was responsible for a 6x3 km 133 metamorphic contact aureole of schists, marked by cordierite-biotite spots and cordierite-andalusite 134 assemblages. These mineral assemblages constrain the pressure to have been less than 300 MPa at 135 the time of emplacement of the Panasqueira granite [START_REF] Pattison | Instability of Al2O5 'triple point' assemblages in muscovite+biotite+quartz 1066 bearing metapelites, with implications[END_REF][START_REF] Kuhn | Al-in-Hornblende barometry of Southern New England intrusions and comparison 986 with metamorphic bathograds[END_REF]. A greisenized 136 cupola at the top of the granite is still observed in some of the galleries. This cupola was described 137 by [START_REF] Kelly | Geologic, fluid inclusion, and stable isotope studies of the tin-984 tungsten deposits of Panasqueira[END_REF] as having being overlain by a quartz cap, although this has not been 138 corroborated. The greisenized cupola sits atop a sheet-like body of evolved granites that are mainly 139 evident in a few drill holes [START_REF] Bussink | Geochemistry of the Panasqueira tungsten-tin deposit[END_REF]De Amorin, 2017), but have been encountered locally in 140 some of the deepest galleries of the mine (LB level, Barroca Grande sector: [START_REF] Lourenço | Paleofluidos e mineralizações associadas às fases tardias da Orogenia 1012 Hercínica[END_REF]. The 141 cupola sent out several sill-like apophyses, and towards its base, a matrix-supported breccia formed 142 with large (up to 2 m) joint-bounded hornfels clasts [START_REF] Kelly | Geologic, fluid inclusion, and stable isotope studies of the tin-984 tungsten deposits of Panasqueira[END_REF]. The greisenized cupola 143 [START_REF] Bussink | Geochemistry of the Panasqueira tungsten-tin deposit[END_REF]De Amorin, 2017) 147 148 is cut by the quartz-wolframite veins. The evolved granites are typical of the peraluminous rare 149 metal granite (RMG) family [START_REF] Linnen | Granite-related rare-element deposits and experimental 1004 constraints on[END_REF], and are albite-rich, displaying typical 150 "snowball" quartz textures. They contain (rare) cassiterite and columbo-tantalite as accessory 151 minerals [START_REF] Lourenço | Paleofluidos e mineralizações associadas às fases tardias da Orogenia 1012 Hercínica[END_REF]De Amorin, 2017). A porphyritic (K-feldspar megacrysts) biotite-152 (muscovite) granite [START_REF] Bussink | Geochemistry of the Panasqueira tungsten-tin deposit[END_REF] is likely representative of the main granite body responsible for 153 the metamorphic aureole and could be related to the late D3 granites from the nearby Serra de 154 Estrela [START_REF] Sant'ovaia | Magmatic structures 1113 and kinematics emplacement of the Variscan granites from Central Portugal (Serra da Estrela 1114 and Castro Daire areas)[END_REF] and Serra de Gardunha (Fig. 2-A). According to recent gravimetric 155 data (Ribeiro, 2017), the main Panasqueira granite has the shape of a laccolith, with a flattened top, 156 a NNE striking elongated trend (~6.3×3.8 km) and an average thickness of 1 km, but with a 2 km 157 thick keel. The evolved granites have been dated at c. 290 Ma, by whole-rock K-Ar [START_REF] Clark | Potassium-argon ages and regional relationships of the Panasqueira tin-tungsten 908 mineralization[END_REF] or 2004) and the small Argemela RMG intrusion [START_REF] Michaud | From magmatic to 1033 hydrothermal Sn-Li-(Nb-Ta-W) mineralization: The Argemela area (central Portugal): Ore 1034 Geology Reviews[END_REF] are associated with a quartz-160 cassiterite vein system [START_REF] Inverno | Argemela, a high-tonnage Sn-Li deposit in 973 Central Portugal: Geological Society of America Annual Meeting[END_REF]. 161

The Panasqueira deposit first attracted research attention in the second half of the 20 th century 162 [START_REF] Kelly | Geologic, fluid inclusion, and stable isotope studies of the tin-984 tungsten deposits of Panasqueira[END_REF]Polya et al., 2000, and references therein;[START_REF] Lourenço | Paleofluidos e mineralizações associadas às fases tardias da Orogenia 1012 Hercínica[END_REF]Burnard and 163 Polya, 2004) and continues to be the subject of considerable interest. [START_REF] Jaques | Full paleostress tensor reconstruction using quartz veins of 979 Panasqueira Mine, central Portugal; part I: Paleopressure determination[END_REF] and 164 [START_REF] Jacques | Transpressional folding and associated 976 cross-fold jointing controlling the geometry of post-orogenic vein-type W-Sn mineralization: 977 examples from Minas da Panasqueira[END_REF] addressed the tectonic and fluid pressure conditions required for the creation 165 and opening of the quartz vein system. [START_REF] Lecumberri-Sanchez | Fluid-rock 995 interaction is decisive for the formation of tungsten deposits[END_REF], using LA-ICP-MS 166 analyses of fluid inclusions, and [START_REF] Codeço | 910 Chemical and boron isotopic composition of hydrothermal tourmaline from the Panasqueira 911 W-Sn-Cu deposit[END_REF], using B-isotope data from tourmaline, 167 addressed the origin of the fluids. [START_REF] Launay | Deciphering fluid 992 flow at the magmatic-hydrothermal transition: A case study from the world-class Panasqueira 993 W-Sn-(Cu) ore deposit (Portugal)[END_REF] used tourmaline growth features to interpret 168 the direction and velocity of flow of the fluids. 169 170

Samples and methods 171 172

Our work is based on analyses of >250 samples collected in the late 1970s on levels 0 and 1, in 173 the historical centre of the mine, and in 2015-2016 on levels 0 to 3, to the south-west of the 174 historical zones. Following petrographic examination with an OLYMPUS BX51 (transmitted and 175 reflected light) optical microscope and a VHX-200 KEYENCE numeric microscope, selected 176 samples were studied with a Schottky-FEG (Field Emission Gun) JEOL J7600F scanning electron 177 microscope (SEM) equipped with an SDD-type EDS spectrometer at the GeoRessources Laboratory 178 (Nancy, France). Backscattered electron (BSE) images were obtained after setting the acceleration 179 voltage at 15 kV. 180

Major-element mineral compositions were determined for tourmaline and rutile using a 181 CAMECA SX100 Electron microprobe (EPMA) equipped with a wavelength dispersive 182 spectrometer (WDS) and a Schottky-FEG (Field Emission Gun) JEOL J7600F scanning electron 183 microscope (SEM) equipped with a SDD-type EDS spectrometer at the GeoRessources Laboratory 184 (Nancy, France). The analytical conditions were a 12 nA current and an accelerating voltage of 15 185 kV for the EPMA, and a 1 nA current and an acceleration voltage of 15 kV for the SEM, with a 186 counting time of 10 s. The same natural and synthetic oxides and silicate standards were used for 187 the two types of analyses. For tourmaline analysis, these standards were topaz (F), albite (Na), 188 olivine (Mg), orthoclase (Si, K), wollastonite (Ca), MnTiO 3 (Ti, Mn) and hematite (Fe). For rutile 189 analysis, the standards were TiO 2 (Ti), Cr 2 O 3 (Cr), vanadinite (V), hematite (Fe), LiNbO 3 (Nb), 190 LiTaO 3 (Ta), cassiterite (Sn) and scheelite (W). 191

Trace and rare earth elements in tourmaline were analyzed at the GeoRessources Laboratory, 192 using a 193 nm GeoLas Pro ArF Excimer laser at 5 Hz laser frequency, the aerosols being analyzed of 10 mJ.cm -2 and a constant repetition rate of 5 Hz. Helium was used as a carrier gas to transport 196 the laser generated aerosols from the ablation cell to the ICP-MS. Before entering the ICP torch,197 Helium was mixed with Argon at a typical flow rate of 0.5 l.min -1 . The hole produced by the laser 198 was 24 µm in diameter, except for REE measurements, for which it was 120 µm in diameter. A 199 peak hopping ablation mode was initiated ~ 20 s after the beginning of signal acquisition, in order 200 to sample the background signal before ablation (used for data reduction), and was stopped after 201 200 pulses. The return of the background signal to its initial value was checked before ablating a 202 new zone. The NIST reference glasses 610/612 were used as external standards; Si, previously 203 analysed by EPMA, was used as an internal reference. The data were processed using the Iolite 204 software [START_REF] Paton | Iolite: Freeware for the 1063 visualisation and processing of mass spectrometric data[END_REF]. 205

Rutile U-Pb geochronology was conducted by in-situ laser ablation ICP-MS at Géosciences 206 Rennes using an ESI NWR193UC Excimer laser coupled to a quadrupole Agilent 7700x ICP-MS 207 equipped with a dual pumping system to enhance sensitivity [START_REF] Paquette | Sensivity enhancement in LA-ICP-MS by N 2 addition to carrier gas: application to 1061 radiometric dating of U-Th -bearing minerals[END_REF]. The 208 instrumental conditions are reported in Appendix A1, Table A1.The ablated material was carried 209 into helium, and mixed with nitrogen and argon, before injection into the plasma source. The 210 instrument was aligned and calibrated for mass before each analytical session using the NIST SRM 211 612 reference glass, by inspecting the 238 U signal and minimizing the ThO+/Th+ ratio (<0.5%). 212

During the course of an analysis, signals for 204 (Pb+Hg), 206 Pb, 207 Pb, 208 Pb, 232 Th and 238 U masses 213 were acquired. 214

Single analyses consisted of 20 s of background integration followed by 60 s of sample 215 integration with the laser firing and then a minimum delay of 10 s to wash out the previous sample. 216

Ablation spot diameters of 45 µm with repetition rates of 5 Hz were used for all the analyses. For 217 each analytical session, we used the following standard bracketing procedure. Two analyses of the 218 R10 rutile standard [START_REF] Luvizotto | Rutile crystals as 1020 potential trace element and isotope mineral standards for microanalysis[END_REF] were used as the primary rutile reference, and one 219 analysis of the R19 rutile standard (489.5 ± 0.9 Ma, [START_REF] Zack | situ U-Pb rutile dating by LA-ICP-MS: 208 Pb correction and prospects for 1166 geological applications: Contributions to Mineralogy and Petrology[END_REF] was used for quality control, 220 followed by six analyses of the rutile grains. This sequence was repeated three times with an 221 analysis of the R19 standard and two analyses of the R10 standard at the end of the session. 222

The data were corrected for U-Pb fractionation and for mass bias by repeated measurements of 223 the R10 rutile standard. The R19 rutile standard measurements, treated as unknowns, were used to 224 control the reproducibility and accuracy of the corrections. These standards yielded an age of 490 ± 2253 Ma (MSWD = 1.11; n=13) during the April 2016 session and 493 ± 12 Ma (MSWD=2; n=12) 226 during the December 2017 session. The data reduction was carried out with the data reduction scheme, VizualAge_UcomPbine, a set of Iolite procedures that work with Igor Pro (Chew et al. 228 2014). All the data were plotted at 2 sigma on Tera-Wasserburg Concordia diagrams using the 229 Isoplot 3.75 software [START_REF] Ludwig | User's Manual for Isoplot 3.75, A Geochronological Toolkit for Microsoft 1017 Excel[END_REF]. 230

Analyses of 40 Ar/ 39 Ar were performed at the University of Manitoba (Canada) using a multi-231 collector Thermo Fisher Scientific ARGUS VI mass spectrometer linked to a stainless steel Thermo 232 Fisher Scientific extraction/purification line, a Photon Machines (55 W) Fusions 10.6 CO 2 laser, 233 and a Photon Machines (Analyte Excite) 193 nm laser. Isotope abundances were corrected for 234 extraction-line blanks, which were determined before every sample analysis. Line blanks in both the 235 Excimer and CO 2 system averaged ~3 fA for mass 40 and ~0.013 fA for mass 36. Mass 236 discrimination was monitored by online analysis of air pipettes based on a power law relationship 237 [START_REF] Renne | The isotopic composition of atmospheric 1100 argon and 40Ar/39Ar geochronology: Time for a change?[END_REF], which gave D = 1.0081 ± 0.0002 per amu, based on 71 aliquots interspersed 238 with the unknowns. A value of 295.5 was used for the atmospheric 40 Ar/ 36 Ar ratio (Steiger and 239 Jäger, 1977) for the purpose of routine measurement of mass spectrometer discrimination using air 240 aliquots, and correction for atmospheric argon in the 40 Ar/ 39 Ar age calculation. Corrections were 241 made for neutron-induced 40 Ar from potassium, 39 Ar and 36 Ar from calcium, and 36 Ar from chlorine 242 [START_REF] Roddick | High precision intercalibration of 40 Ar/ 39 Ar standards[END_REF][START_REF] Renne | Inter-calibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating[END_REF][START_REF] Renne | Determination of the half-life of Ar-37 by mass 1095 spectrometry[END_REF]. The data were plotted using 243

DensityPlotter [START_REF] Vermeesch | On the visualisation of detrital age distributions[END_REF]. Complementary information is given in Appendix A2. 244

245

Results

247

Petrography of the tourmalinized wall rocks 248

Tourmaline is a common mineral in the wall rocks to the W-veins in the Panasqueira deposit, but 249 may also be observed far from the deposit, bordering either barren quartz veins or even "dry" joints. 250

The tourmaline-bearing rocks extend from the vein/joint boundaries for distances varying from a 251 few cm (≤10) to 1 m, or roughly 25 cm on average. 252

As first noted by [START_REF] Bussink | Geochemistry of the Panasqueira tungsten-tin deposit[END_REF], and later by [START_REF] Foxford | Textural evolution of W-Cu-Sn bearing 939 hydrothermal quartz veins at Minas da Panasqueira[END_REF], thin quartz veinlets (1-5 mm 253 in average) are common in the tourmaline-bearing wall rocks adjacent to the main veins, and in 254 many cases define the vein margins. They display clear evidence for a crack-seal mechanism of 255 opening, and are labelled Qcs hereafter (Fig. 3

-A). 256

There is a clear organization of the tourmaline in layers parallel to S 0 , preserving the protolith 257 fabric, as pointed out by [START_REF] Codeço | 910 Chemical and boron isotopic composition of hydrothermal tourmaline from the Panasqueira 911 W-Sn-Cu deposit[END_REF]. The tourmalinized wall rocks generally contain more 258 than 50 vol.% tourmaline and tourmaline abundance is locally high enough to classify the rock as 259 tourmalinite. Tourmaline is invariably associated with quartz, and with muscovite in the most 260 pelitic protoliths, where the mica defines the schistosity. It is accompanied by abundant rutile (see 261

Tourmaline textures 275

Tourmaline habit and zoning: The tourmaline habit may be either acicular, with lengths between 276 500 µm and 1 mm and diameters of 20-50 µm, or, more commonly, stocky prismatic, with lengths 277 between 50 and 150 µm and diameters of 10-20 µm (Fig. 4-A, B). The prisms are mostly sub-278 parallel to the schistosity of the Beira schists (Fig. 4-A), but they may be perpendicular to it. 279

Contact metamorphic cordierite was replaced by tourmaline [START_REF] Bloot | Geological features of the Panasqueira tin-tungsten ore-878 occurrence (Portugal)[END_REF]. 280

The tourmaline crystals are brown and weakly zoned in thin section (Fig. 3-B), but display well-281 characterized growth zoning in SEM images (Fig. 3-C and4-C, D) expressed as nearly homogenous 282 Some changes in the relative proportions of the different zones may be observed in relation to the 302 distance from the vein boundaries. Distal to veins, the proportion of Tur0 zones is higher, on development of Tur1b rims is less pronounced. Furthest from the veins, the Tur1b rim may even be 305 absent. Close to the veins, there is a greater development of the Tur1b zone, and the Tur0 cores are 306 less common, corroded, and tend to represent a comparatively smaller proportion of the crystal 307 volume. On the basis of a limited number of examples, it would appear that this tendency is roughly 308 correlated with the presence of abundant wolframite in the nearby vein. Indeed, in the wall rocks of 309 barren quartz veins, either in outcrop, or in the deeper levels of the mine (L3), Tur1b is usually 310

absent. 311

Micro-inclusions are common in the tourmaline, although not systematically distributed. In order 312 of importance, they are: zircon, rutile, quartz, and rare monazite, pyrite, and apatite. Most 313 commonly, the inclusions "overprint" the zone boundaries, and in most cases, the proportion of 314 inclusions is the same in the Tur1a or Tur1b zones. The Tur0 cores are relatively free of inclusions, 315 except for those of quartz. The zircon may be zoned in respect to their U-Th content. In addition, 316 microanalysis revealed the probable presence of concealed micro-inclusions (see below). 317

Tourmaline and Qcs quartz veinlets: Tourmaline prisms are systematically present at the walls 318 of the Qcs veinlets, displaying both Tur1a and Tur1b zones, the latter usually developed to a far 319 higher extent than in the wall rocks (Fig. 4-E, F). Thus, as pointed out by [START_REF] Foxford | Textural evolution of W-Cu-Sn bearing 939 hydrothermal quartz veins at Minas da Panasqueira[END_REF], the 320 development of both the main Tur1a tourmaline prisms and the Tur1b rims was coeval with the first 321 increments of vein opening evident by the Qcs veinlets. This is pictured schematically in Fig. 5. The 322 very existence of Tur0, which is typically absent from the Qcs veinlets, nonetheless demonstrates 323 that the onset of tourmalinization was earlier than these veinlets (stage A in Fig. 5). 324

Tourmaline and other alteration minerals: Irrespective of the nature and the number of 325 hydrothermal minerals in the wall rocks, the tourmaline crystals invariably display the same 326 sequence of Tur0-Tur1a-Tur1b crystallization. Other alteration minerals are typically later. For 327 example, the occurrence of topaz and/or muscovite is accompanied by a distinct overgrowth on 328 Tur1b rims. In the same way, the development of apatite-bearing vugs in the tourmalinized wall 329 rocks was accompanied by distinct overgrowths on the undissolved tourmaline crystals. As sulfides 330 (chalcopyrite, sphalerite, pyrrhotite) and siderite are mainly present as stringers in the wall rocks, it 331 is easy to recognize that these stringers overprint tourmaline 1 prisms and their characteristic 332

zoning. 333

Small euhedral arsenopyrite crystals, a few 100 µm in diameter, are frequently disseminated in 334 the wall rocks (Fig. 3-A), locally (but not commonly) with inclusions of zoned tourmaline prisms. 335

Nevertheless, arsenopyrite grew after the Tur0-Tur1a-Tur1b sequence, because: (i) arsenopyrite with tourmaline but developed as large crystals along the walls of the open fractures. There are rare 339 occurrences of the development of wolframite crystals in the wall rock, close to the mineralized 340 veins (Fig. 4-B). These crystals include zoned tourmaline, and detailed observations show that 341 wolframite growth was either coeval with Tur1b rim development or slightly later (Fig. 4-C, D). 342

This wolframite was, in turn, reworked in relation to the main opening and deposition of the main 343 wolframite, which is consistently devoid of any tourmaline inclusions (stages E and F in Fig. 5). 344 345

Rutile textures 346

Rutile is systematically associated with tourmaline, being present both in the wall rocks, as small 347 (from 10 µm to 80-100 µm) crystals, scattered or densely disseminated, or as large (up to 500 µm or 348 more) isolated crystals in the Qcs veinlets, where they were clearly coeval with Tur1b growth (Fig. 349 4-E, F). Micro-to nano-inclusions (from about 1 µm, to <100 nm) of wolframite are common. They 350 are usually located at crystallographic boundaries (e.g., faces intersections, twin planes, quartz 351 inclusion boundaries) showing that they were coeval with the host rutile (Fig. 6-A inclusions of ilmenite lamellae (Fig. 6-B). 364 365

Tourmaline chemical composition 366

Major element crystal chemistry: For reasons made explicit in Appendix A0, most analyses were 367 performed using SEM-EDS. A total of 86 crystals from 19 representative samples was analyzed 368 (Appendix A3: Table A3). No systematic variation in the compositions of the different zones was 369 evident, however, either as a function of the distance to the vein boundary, or among tourmaline 370 crystals from different settings (wall rock, Qcs veinlet, inclusions in early wolframite). 371

The structural formulae were calculated by normalizing to 26.5 (O, OH, F), which (with the 372 assumption of stoichiometric boron) allowed us to take into consideration the fluorine content and 373 not assume the filling of the Y site, which may contain Li, and possibly vacancies [START_REF] Bosi | Tourmaline crystal chemistry[END_REF]. The 374 generalized structural formula of the tourmaline super-group is XY 3 Z 6 (T 6 O 18 )(BO 3 ) 3 V 3 W (Bosi, 375 2018). The T site is occupied primarily by Si, which may be replaced by minor Ti, Al or B. The 376 nine-coordinated site X may be occupied by Na + and Ca 2+ , or minor K + , and vacancies ( X ) may be 377 present. This defines the main chemical groups of tourmaline: alkali, calcic and alkali-deficient 378 groups (Henry et al. 2011). The V, or (O)3, site is occupied mainly by OH (and possibly O), 379 whereas the W, or (O)1, site is occupied by OH, F or O, defining the hydroxy, fluor, and oxy 380 groups, depending on the dominant anion in the site. The six-coordinated Z site is mainly occupied 381 by trivalent cations (mainly, Al 3+ , but also Fe 3+ , Cr 3+ ), but may contain divalent cations, mainly Mg 382 [START_REF] Bosi | Tourmaline crystal chemistry[END_REF]. The six-coordinated Y site is occupied by mono-(Li + ), bi-(Mg 2+ , Fe 2+ , Mn 2+ ) and tri-383 valent (mainly Al 3+ , and possibly Fe 3+ , Cr 3+ ) cations, but vacancies ( Y ) may also be present (Bosi, 384 2018). Following the criteria of Henry and Dutrow (2011), calculated tourmaline formula were 385 rejected if Si was > 6.15 atoms per formula unit (apfu), the sum of the Y + Z + T cations was >15.5 386 apfu, or the sum of the X-site cations exceeded 1.1 apfu. For reasons given in Appendix A0, all 387 analyses yielding Si apfu values > 6.12 were rejected. Using the empirical formula of [START_REF] Bosi | Tourmaline crystal chemistry[END_REF], 388 the Z Al apfu content of the Z site was found to be relatively constant, ~5.23 apfu, irrespective of the 389 zone, and, whereas there was sufficient Mg to fill this site in Tur0 and Tur1a, a small 390 complementary content of Z Fe was necessary in Tur1b (Table A3, Appendix A3). 391

Based on the classification diagram of Henry et al. (2011), which compares the normalized X-392 vacancy to the Mg# (Mg/Mg+Fe) ratio, the tourmaline classifies mainly as schorl (Fig. 7-A). There 393 is a systematic shift from Mg-rich (ferro-dravite) to Fe-rich compositions for the sequence Tur0 to A l

Fe apfu

Mg apfu

Fe 3+ +1 O +1 (OH) -1 Mg -1 Al +1 O +1 (OH) -1 Mg -1 Fe 3+ +1 Al -1 Mg +1 Fe 2+
+ 1 N a -1 R 2 + -1 Al +1 O +1 (OH) -1 R 2+ -1 Fe 3+ +1 Al -1 +1 Al +2 R 2+

413

responsible for an Y-site vacancy [START_REF] Bosi | Stereochemical constraints in tourmaline: from a short-range to a long-range 880 structure[END_REF], seems to have been equally important. Indeed, a Y-414 site vacancy is observed in our analyses, commonly larger than 0.1 apfu, and also those of Codeço 415 et al. (2017) and [START_REF] Launay | Deciphering fluid 992 flow at the magmatic-hydrothermal transition: A case study from the world-class Panasqueira 993 W-Sn-(Cu) ore deposit (Portugal)[END_REF] (Table 3,Appendix 3). This vacancy cannot be due to ignored 416 Li, because the LA-ICP-MS results (see below) show that the Li content is negligible, being at most 417 of ~330 ppm and averaging ~170 ppm (Tur1a) or ~290 ppm (Tur 1b); these contents would be 418 reflected by an amount of no more than 0.05 apfu Li and more commonly 0.02-0.04 apfu. (8) reference fields from [START_REF] Henry | Tourmaline as a petrogenetic indicator mineral: an example 968 from the staurolite-grade metapelites of NW Maine[END_REF]: (l) Li-rich granitoids, (2) Li-poor granitoids, (3) Fe 3+ -rich quartz-422 tourmaline rocks (hydrothermally altered granites), (4) Al-buffered metapelites, (5) not Al-buffered metapelites, (6)

423

Fe 3+ -rich quartz-tourmaline rocks, calc-silicate rocks, and metapelites, (7) low-Ca meta-ultramafics and Cr,V-rich 424 metasediments, and (8) metacarbonates and meta-pyroxenites. Compositions of CIZ schists from Oosterom et al. (1984) 425 and De Amorin (2017). The grey arrow emphasizes the global increase in Fe/Fe+Mg ratio from Tur0 to Tur1b. B.

426

Enlargement of A, illustrating the sequence Tur0-Tur1a-Tur1b: (a) individual paths, (b) synthesis. Note that, if there is a 427 jump from a zone to another, the starting and final compositions differ for each individual crystal.

429

In contrast to Tur0, which appears to be essentially free of fluorine, there is a distinct and similar 430 fluorine enrichment (up to ~1% F) of Tur1a and Tur1B, and a trend of increasing F apfu with X-site 431 charge (Fig. 7-D). The latter is due to the high X-site Na content; Tur1a and Tur1b are Ca-poor, 432 whereas Tur0 is enriched in Ca, which, in turn, explains the higher X-site charge of Tur0 in Figure 433 7-D. 434

The complex covariations between aluminum, iron and magnesium that are depicted in Figure 7 435 are conveniently summarized in the AFM diagram of Figure 8-A, in which it is also possible to 436 identify the most common compositional paths from Tur0 to Tur1a and then Tur1b at the crystal 437 443 444 scale (Fig. 8-B). This figure illustrates an apparently continuous variation of the Fe to Fe+Mg ratio 445 (Fe#) from Tur0 to Tur1b, although detailed profiles show that there were small-scale modulations 446 of the Fe# during crystal growth (Fig. 9). 447

Trace element contents: As LA-ICP-MS analyses produce laser pits with a diameter of at least 448 24 µm, analysis to the desired detection limits was possible only for the largest Tur1 zones in a 449 limited number of crystals. Moreover, the tourmaline cores (Tur0) were too small for them to be 450 reliably analyzed, so analyses were restricted to the two external rims, Tur1a and Tur1b. A total of 451 77 spots, in 47 crystals from 7 samples were analyzed for their trace element concentrations. The 452 REE concentrations were also analyzed, but to obtain the required signal, a laser beam diameter of 453 120 µm was necessary, and therefore only two crystals, from two samples, could be analyzed for 454 the REE. This yielded an average composition of Tur1a and Tur1b zones from the two crystals. The 455 results are summarized in Table 1 and detailed in Appendix A4 (Table A4). 456

For some elements, several LA-ICP-MS spectra displayed anomalous peaks (anomalous values 457 in Table A4), interpreted as recording the presence of concealed micro-to nano-inclusions. Thus, a 458 Mn outlier at 2,600 ppm was likely due to siderite, and a Zn outlier at 8,500 ppm is interpreted to be 459 due to sphalerite. Several W anomalies record the presence of W-bearing minerals: W-bearing 460 rutile, where correlated with both Ti and Nb- The results of the trace element analyses are illustrated in Figure 10-A Amorin (2017), [START_REF] Bussink | Geochemistry of the Panasqueira tungsten-tin deposit[END_REF], Oosterom et al. (1984), [START_REF] Pinto | Estudo da distribuição do Estanho na Mina da Panasqueira: Mestrado em Geologia[END_REF] and [START_REF] Valladares | Contrasting geochemical 1135 features of the Central Iberian Zone shales (Iberian Massif, Spain): implications for the 1136 evolution of Neoproterozoic-Lower Cambrian sediments and their sources in other peri-1137 Gondwanan areas[END_REF].

492

From Figure 10-A, it can be seen that Tur1a and Tur1b compositions are quite similar, although 493 there are minor but significant differences between them with most of the trace elements being 494 499 500 depleted in Tur1b relative to Tur1a. The notable exceptions to this are Li, Mn and Zn, which are 501 depleted in Tur 1a. This is also evident from the differences in the average values (Table 1, and 502 insert in Figure 10-A), and from the shift between the full boxes (lower quartile to upper quartile 503 interval) in the box plot of Figure 10-A. 504

A principal component analysis was performed on the trace element data (using the JM Pro 505 software), the results of which are presented in Figure 12. Three axes (PC1-3) explain 52.7 % of the 506 Copper, Ti, and W behave independently, and W appears uncorrelated to Nb-Ta. 516

In binary plots, elements of group A display rough linear trends expressing positive correlations 517 (when outliers are excluded), as seen for example in Figures 13-A to C, and predicted by the 518 principal component analysis. Similarly, elements of group A display negative correlations with 519 elements of group B, as seen, for example, in Figures 13-D to H. Less expected were the linear 520 relationships between elements from the various B subgroups, as seen for example in Figures 13-I 525 to K. The rare metals (W, Nb, Ta) behave differently. Whereas Nb-Ta show a very loose negative 526 correlation with Li (Fig. 13-L), there is no correlation between W and Li (Fig. 13-M), nor between 527 W and Nb-Ta (Fig. 13-N). Finally, Sn is not correlated with Nb-Ta (Fig. 13-O) or with W (Fig. 13-528 P). 529 530

Rutile composition: 531

The composition and zoning of the Panasqueira rutile have been described in detail in Carocci et 532 al. (2019) and only a summary is given here. This rutile contains variable proportions of: Fe from 533 0.18 to 2.95 wt%, V from <1000 ppm to 3.48 wt%, Cr from <1000 ppm to 2.41 wt%, Nb from 534 <1000 ppm to 1.64 wt%, Ta from <1000 ppm to 2.17 wt%, and W from 0.20 to 10.7 wt%. Despite 535 locally high values, Nb and Ta concentrations are usually low; the Nb+Ta content is usually < 0.5 536 wt% and the Nb/Nb+Ta ratio varies from 0.05 to 0.97 (on average 0.6). 537

The crystals display marked sector zoning, exhibited mostly by W and Fe and, to a lesser extent, 538 by Nb and Ta; Sn, V (and Cr), and display less evidence of zoning (Fig. 6-C to G). The maximum 539 W concentration varies from 1.12 to 10.7 wt.% in the metal-rich sectors, depending on the sample; 540 W concentrations in the metal-poor sectors vary between 0.26 to 1.40 wt %. As metal-rich sectors 541 reach their highest W contents in wall rocks adjacent to veins in which wolframite is abundant, 542 whereas in barren wall rocks the metal-rich sectors are less endowed in W (no more than 3.5 wt% 543 W), it would appear that the W enrichment in rutile is related to the wolframite endowment in the 544 nearby veins. Association of a very W-rich rutile with wolframite was also observed in the Puy-les-545

Vignes breccia-pipe tungsten deposit in the French Massif Central [START_REF] Harlaux | Les systèmes métallogéniques hydrothermaux à tungstène et métaux rares[END_REF]. 546

The sector zoning is superimposed on a conspicuous compositional zoning, expressed from the 547 crystal scale down to the 10 µm to µm scale of the doublets characteristic of oscillatory zoning (Fig. 548 6-C). The zoning, however, is qualitatively and quantitatively the same irrespective of the rutile 549 setting. All the minor elements, W, Nb(Ta), Fe, V, Cr and Sn, are involved in the compositional 550 zoning. At all scales, W and Nb(Ta) are inversely-correlated, whereas Sn and V display inconsistent 551 behavior, being either correlated with Nb(Ta) and inversely-correlated with W or the opposite. 552

The bulk evolution during crystal growth was variable from one crystal to the next, even at the 553 sample scale. In some crystals, there is continuous evolution from a Nb-rich and W-poor core to a 554 Nb-poor and W-rich rim, whereas the opposite is observed in others. Most commonly, however, the 555 zoning displays moderate deviations from the average W content. 556 557

Age determinations 558

565

Rutile: Petrographic examination suggests that rutile from both the tourmalinized wall rocks and 566 the Qcs veinlets were coeval with the early tourmaline and the earliest wolframite deposition. 567

Unfortunately, the number of rutile crystals suitable for U-Pb dating was limited by the size of the 568 laser spot (45 µm). Some crystals from Qcs crack-seal veins are large enough to be analyzed, but very few crystals in the wall rocks reach 50 µm in diameter. Thus, only 22 crystals from 5 samples 570 could be analyzed for their U-Pb isotopic compositions. 571

The analyzed crystals have variable concentrations of common lead, and low radiogenic Pb 572 contents (Appendix 6, Table A6). On a Tera-Wasserburg diagram they plot in a discordant to a very 573 discordant position, except for one sample (PAN-III-8-c1), which plots close to the Concordia 574 curve. Figure 14 illustrates three regression lines: (i) using all the data, the regression line results in 575 a discordia with a lower intercept at 302.7 ±8.9 Ma (2σ, MSWD =5.3) (Fig. 14-A), the poor quality 576 of this age determination being due to large lead losses, (ii) a discordia in which data corresponding 577 to the greater lead losses were ignored (Fig. 14-B), passes through the concordant data and yields a 578 lower intercept at 305.2 ± 5.7 Ma (2σ, MSWD = 1.9), the upper intercept yielding a common lead 579 207 Pb/ 206 Pb ratio of 0.906, which is slightly higher than the 0.855 value predicted by the Stacey and 580 Kramers (1975) model for the same age; and (iii) a discordia, anchored to the Stacey and Kramers 581 composition at 305 Ma, yielding a lower intercept at 303.7 ± 6.6 Ma (2σ, MSWD = 3.9) (Fig. 14-582 C). A similar date of 303.7 ± 6.6 Ma, with a slightly higher MSWD value of 3.9 is obtained by 583 constraining the regression to fit the [START_REF] Stacey | Approximation of terrestrial lead isotope evolution by a two-1124 stage model[END_REF] common lead composition,. A 584 critical issue is the 207 Pb/ 206 Pb value of the common lead in the CIZ at c 305 Ma. At c. 320 Ma, the 585 207 Pb/ 206 Pb ratio of the Ediacaran and Tremadocian metasediments was between 0.885 and 0.96 586 (calculated from [START_REF] Nägler | A new approach for the determination of the age 1036 of partial or complete homogenization of Pb isotopes Example: anchimetamorphic, detrital 1037 sediments of the Central Iberian Zone[END_REF]Nägler et al. , 1995 data) data). It thus evident that the 0.906 value for the common 587 lead in the Panasqueira rutile is in accordance with the regional values, and, consequently, the date 588 of 305.2 ± 5.7 Ma is interpreted as the best estimate for the crystallization age of the rutile. As 589 [START_REF] Polya | Evolution and 1087 paragenetic context of low δD hydrothermal fluids from the Panasqueira W-Sn de-posit, 1088 Portugal: new evidence from microthermometric, stable isotope, noble gas and halogen 1089 analyses of primary fluid inclusions[END_REF] demonstrated that the Qcs veins immediately preceded the main opening of the 590 quartz vein system and wolframite deposition, the age of c. 305 Ma is also interpreted to be the age 591 of the main wolframite deposition. 592

593

Figure 15. Synthesis of radiometric ages for the Panasqueira deposit, comparing results of the present work with 594 those of [START_REF] Snee | Thermochronology of economic mineral deposits: 1121 dating the stages of mineralisation at Panasqueira, Portugal, by high-precision 40 Ar-39 Ar age 1122 spectrum techniques on muscovite[END_REF]. Explanation in the text.

596

Complementary dating: To complement the U-Pb age determinations, a muscovite selvage (Canada) and yielded a good plateau age of 296±2 (1σ) Ma, which is indiscernible within the limits 599 of error (Appendix A7-Table A7) from the preceding 39 Ar/ 40 Ar age of 296.3±0.6 Ma (1 σ) obtained 600 by [START_REF] Snee | Thermochronology of economic mineral deposits: 1121 dating the stages of mineralisation at Panasqueira, Portugal, by high-precision 40 Ar-39 Ar age 1122 spectrum techniques on muscovite[END_REF] on muscovite selvages. Until now, this age was considered to be the age of the 601 main mineralization (OSS stage of [START_REF] Polya | Evolution and 1087 paragenetic context of low δD hydrothermal fluids from the Panasqueira W-Sn de-posit, 1088 Portugal: new evidence from microthermometric, stable isotope, noble gas and halogen 1089 analyses of primary fluid inclusions[END_REF], assuming that this muscovite preceded 602 wolframite deposition. The new results show, however, that the muscovite selvages are at least 2 603 2018), the trace element partition coefficients between tourmaline and the 611 medium from which it crystallizes are close to unity. Thus, the relative proportions of the trace 612 elements in tourmaline reflect the relative proportions of trace elements in the fluid from which it 613 crystallized. Fluorine concentration is subject to crystallographic constraints, because of its 614 dependence on the X-charge in the structural formula (Henry and Dutrow, 2011). Within these 615 constraints, the incorporation of F into the tourmaline structure is controlled by external factors, in 616 particular, the F availability, and thus tourmaline may also be considered a F proxy. 617

In the absence of measurable fluid inclusions (FI) in the tourmalinized wall rocks at Panasqueira, 618 information on the nature of the fluids responsible for the tourmalinization can be obtained 619 indirectly, using the tourmaline composition. The major and trace element concentrations differ 620 from Tur1a to Tur1b, pointing to a change in the fluid composition. Consideration of Figure 8-A 621 and 10-A shows a shift from a Co, (Cu), Pb, Sc, Sr, V, Cr, Sn, Nb, Ta package in Tur1a, towards a 622 Li, Fe, Mn, Zn, W rich package in Tur1b. The correlations shown in Figure 13 are clear evidence of 623 a continuous evolution. This evolution could, however, have resulted from either the differentiation 624 of a single fluid or the mixing between two fluid end-members. 625

Discussion of single fluid models 626

Single fluid models for the Panasqueira system have been favored by previous workers (Bussink, 627 1984;[START_REF] Lecumberri-Sanchez | Fluid-rock 995 interaction is decisive for the formation of tungsten deposits[END_REF][START_REF] Codeço | 910 Chemical and boron isotopic composition of hydrothermal tourmaline from the Panasqueira 911 W-Sn-Cu deposit[END_REF]. [START_REF] Codeço | 910 Chemical and boron isotopic composition of hydrothermal tourmaline from the Panasqueira 911 W-Sn-Cu deposit[END_REF] assumed that the 628 Fe# increase was the result of a decrease in the temperature of a single fluid, from ~ 480°-460°C 629 during alteration of the wall rocks to 360°-230°C in the mineralized quartz veins. The former 630 temperature was estimated using the Ti-in-quartz thermometer [START_REF] Codeço | 910 Chemical and boron isotopic composition of hydrothermal tourmaline from the Panasqueira 911 W-Sn-Cu deposit[END_REF], whereas the 631 latter come from earlier fluid inclusion studies (e.g., [START_REF] Kelly | Geologic, fluid inclusion, and stable isotope studies of the tin-984 tungsten deposits of Panasqueira[END_REF]. Recent fluid inclusion studies [START_REF] Dejean | Fluides minéralisateurs dans le gisement de Panasqueira: Reconstruction P-T-X[END_REF][START_REF] Cathelineau | Are we sure to 896 know the fluids responsible for W mineralization at Panasqueira (Portugal): the case for loss 897 of information due to intense quartz recrystallization and FI natural decrepitation[END_REF]2018;[START_REF] Carocci | Tungsten transport ad deposition in magmatic-hydrothermal environments : the 888 example of Panasqueira (Portugal)[END_REF] have concluded, however, that 633 the temperature of the main quartz-wolframite deposition stage was 450°±50°C. Therefore, a strong 634 temperature decrease cannot be the explanation for the change in Fe#. 635 [START_REF] Lecumberri-Sanchez | Fluid-rock 995 interaction is decisive for the formation of tungsten deposits[END_REF] related the wolframite deposition to wall rock alteration. They 636 concluded that the muscovitized parts, which commonly (but not systematically) fringe the 637 mineralized quartz veins were coeval with the more distal tourmalinized zone, and that wolframite 638 deposited due to the interaction of a Fe-poor, but W-bearing fluid, with the schists as a result of the 639 release of Fe from the latter during muscovitization. This model is unsupported because: ( 1) 640 muscovitization at the vein borders post-dated tourmalinization (see above), ( 2) the muscovitized 641 fringes formed synchronously with the muscovite selvages of the mineralized quartz veins, and ( 3) 642 the geochronological data reported in this study show that muscovite formed later than the wall-643 rock tourmalinization. 644

A fractional crystallization model could explain the Fe# increase from Tur1a to Tur1b but would 645 require that the system was closed, which is inconsistent with the crack-seal textures of the Qcs 646 veinlets associated with fluid influx into the wall rocks. It is difficult to reconcile this model with 647 the differential behavior of the trace elements between Tur1a and Tur1b, some having been 648

enriched, and others impoverished, something which cannot be explained by the effect of 649 differences between partition coefficients. This model also explains the significant overlap of the 650 trace element compositions of Tur1a and Tur1b (Fig. 13).

651

A final single fluid model that could be considered is one in which the system evolved 652 continuously from wall rock-controlled (Tur0) to fluid-controlled (Tur1b stage) conditions during 653 the course of fluid-rock interaction. High water-rock ratios are indicated by the absence of 654 compositional differences in either the Tur1a or Tur1b zones, with respect to the position of 655 tourmaline in the system, irrespective of whether the tourmaline is in Qcs veinlets or part of the 656 tourmalinized wall rock, proximal or distal to the veinlets. Furthermore, the widespread evidence of 657 corrosion of the Tur0 cores points to sudden changes in the ambient fluid composition, which is 658 difficult to reconcile with the single fluid model. During such fluid-rock interaction, the Tur0 659 composition would reflect the host-rock composition prior to the alteration, masking the 660 characteristics of the incoming fluid. Petrographic observations indicate that tourmaline grew at the 661 expense of earlier ferro-magnesian minerals (biotite, cordierite). Thus, the Fe# in the Tur0 cores 662 would be expected to reflect the Fe# of the Beira schist, which is not the case (Fig. 8A). In addition, 663 the lack of F in Tur0 is in strong contrast with the high F content of the Beira schists (570 ppm in 664 average: Oosterom et al., 1984). Also, despite the high Ti content (0.6 to 1.0 wt% TiO 2 ) of the Beira 665 schists [START_REF] Bussink | Geochemistry of the Panasqueira tungsten-tin deposit[END_REF], the tourmaline is Ti-poor, which may, however, be due, at least in part, to competition with the coeval rutile. The Tur1a and Tur1b trace element package is, in order of 667 decreasing abundance (Figure 10-A In conclusion, no single fluid evolution model is able to fully explain all the data, and a two-fluid 673 model must be seriously considered. 674

A two-fluid mixing model 675

We propose a fluid-mixing model involving two end-members, the first of which (F1) was 676 associated with the formation of Tur0, and the second (F2) of which mixed with F1 to form Tur1a 677 and then Tur1b. The F1 fluid end-member composition, like Tur1a, was enriched in Co, (Cu), Pb, 678 Sc, Sr, V, Cr, Sn, Nb, Ta, depleted in F and more magnesian than F2. The F2 fluid end-member 679 composition, like Tur1b, was enriched in Li, Mn, Zn, Fe and F (Fig. 7-D). As tungsten 680 concentration does not correlate with that of Nb, Ta and Sn (Fig. 12 and 13), we propose that it was 681 enriched in the F2 fluid, despite the fact that Tur1b is generally depleted in W relative to Tur1a 682 (Fig. 10-A) and attribute this apparent contradiction to competition for tungsten between Tur1b and 683 the coeval W-rich rutile. This proposal is supported by the abundance of W-bearing nano-inclusions 684 in Tur1b (as inferred from tungsten anomalies in the LA-ICP-MS record, see above) and the 685 occurrence of the coeval W-rich rutile. 686

The fluid-mixing model explains the inter-element correlations and anti-correlations displayed in 687

Figure 13. The corrosion exhibited by the Tur0 core may mark the arrival of F2 into the system and 688 the onset of the mixing process. The evidence for a continuous process and the conflicting evidence 689 of a sharp transition between Tur1a and Tur1b, could indicate a sudden increase in the F2 to F1 690 fluid ratio. This increase could have been related to an interruption in deposition due to a temporary 691 closure of the vein system. Local corrosion, or overprinting (Fig. 9), of Tur1a by Tur1b is a further 692 evidence for this explanation. The small scale oscillations of Fe# during crystal growth, as well as 693 the recurrence of low Fe# at the end of the Tur1b growth, could reflect also temporary variations in 694 the F2 to F1 fluid ratio, explaining the overlap between Tur1a and Tur1b trace element 695 compositions in Figure 13. 696 697

The fluid source 698

Magmatic or metamorphic source: boron and REE constraints

London, 2011), and this interpretation has been adopted for Panasqueira in the recent works of 701 [START_REF] Lecumberri-Sanchez | Fluid-rock 995 interaction is decisive for the formation of tungsten deposits[END_REF], Codeço et al. (2018) and [START_REF] Launay | Deciphering fluid 992 flow at the magmatic-hydrothermal transition: A case study from the world-class Panasqueira 993 W-Sn-(Cu) ore deposit (Portugal)[END_REF]. According to 702 these studies, fluids released from the Panasqueira granite, and in particular, from the greisenized 703 cupola, provided the boron required for tourmalinization. [START_REF] Codeço | 910 Chemical and boron isotopic composition of hydrothermal tourmaline from the Panasqueira 911 W-Sn-Cu deposit[END_REF] reported that the 704 δ 11 B values of the Panasqueira tourmaline are between -4‰ and -13‰ (with 90% of the data 705 between -7‰ and -11‰) and display a Gaussian distribution. These values are consistent with 706 either a magmatic or a metasedimentary source for the boron. 707

Tourmaline replaced the contact metamorphic aureole minerals related to the emplacement of the 708 main Panasqueira granite, and is therefore later than this magmatic stage. Consequently, 709 tourmalinization is unlikely have been caused by magmatic fluids issued from this large body by 710 itself. In fact, the cupola, as well as the sheet-like body of rare metal granite (RMG) type, at the top 711 of the main granite body (De Amorin, 2017), may have been emplaced later, and, consequently may 712 have been a source of boron, and the fluid to transport it. A mass balance calculation (details 713 presented in Appendix A8) shows that the cupola could not by itself have supplied the quantity of 714 boron needed for wall rock tourmalinization, at the deposit scale. By the same calculation, the 715 subjacent sheet-like RMG body could, however, have supplied a significant part of this boron, 716 although certainly not all that was required. The calculations were done under the assumption of a 717 tourmaline-saturated melt. Yet, tourmaline is typically absent from the cupola or the subjacent 718 RMG, and observation of the cupola/schist contact did not reveal evidence for tourmalinization of 719 the wall rock. The calculated B deliveries are therefore greatly overestimated. Another problem is 720 the volume of fluid that was needed for tourmalinization. The Panasqueira RMG sheet-like body 721 could only have supplied an order of magnitude less than the required volume of fluids (Appendix 722 A8). Another source of boron (and fluids) is clearly required. 723

Concentrations of boron are around 0.5 to 1%, at tourmaline saturation in aqueous fluids 724 buffered in respect to aluminium silicate at temperatures between 500 and 600°C, according to 725 experimental data (Weisbrod et al., 1986;London, 2011). Consequently, metamorphic fluids may 726 have the capacity to extract and transport boron. The Beira schists contain on average ~ 100 ppm B 727 (Oosterom et al., 1984). Mass balance calculations (Appendix A8) show that the 410 to 810 kt of 728 boron required to account for the observed tourmaline, and the 2.2 to 4.3 km3 of fluid, necessary to 729 dissolve, transport and deposit this amount of boron, may be produced by the devolatilization of no 730 more than 20 km 3 to 40 km 3 of Beira schists. equilibrated with metasedimentary rocks at high temperature. Similar REE profiles are observed in 734 tourmaline from deposits for which a metamorphic origin of the fluid is accepted, as for example 735 the orogenic gold deposit of Sarekoubu [START_REF] Xu | The source of hydrothermal fluids for the 1162 Sarekoubu gold deposit in the southern Altai, Xinjiang, China: Evidence from fluid inclusions 1163 and geochemistry[END_REF] (Fig. 9). In contrast, magmatic-736 hydrothermal fluids, as well as fluids that equilibrated with granite at a high subsolidus temperature, 737 display a pronounced negative europium anomaly (e.g., [START_REF] Banks | REE composition of an 869 aqueous magmatic fluid: A fluid inclusion study from the Capitan Pluton[END_REF][START_REF] Poitrasson | Hydrothermal remobilization of rare earth elements 1081 and its effect on Nd isotopes in rhyolite and granite[END_REF], 738 which is absent from the REE patterns of Panasqueira tourmaline (Fig. 11). A significant magmatic 739 contribution to the tourmalinizing fluids is therefore unlikely. 740 741 Distinguishing F1-F2 fluids: trace elements constraints 742

The characteristic Ti, V, Cr, Sr, Sn, Sc, Pb, Ni, Be, Co, Cu, Y, Nb, Ta trace element package 743 deduced for the F1 end-member in a preceding section is consistent with F1 having been 744 equilibrated with a metasedimentary sequence like the Beira Schists. Indeed, it is known that 745 metamorphic fluid compositions reflect those of the related metamorphic rocks (e.g., Tang and Liu, 746 2002). 747

The F2 composition characterized by the Fe, F, Mn, Li, Zn, W package could suggest 748 equilibrium with a granitic magma. Magmatic fluids issued from RMG melts (e.g., Harlaux et al., 749 2017) rich in F, Li, Fe and Mn, however, are richer in Sn than W, contain similar W and Nb-Ta 750 contents, and are depleted in Zn. These significant differences with the F2 package consequently do 751 not support a magmatic origin for the F2 fluid. 752

This apparent paradox may be resolved in the context of the processes occurring in the CIZ 753 middle crust at the end of the Carboniferous. Dehydration-melting in migmatite domains involving 754 biotite breakdown and the formation of granitic melts (Pereira Gomez et al., 2000) likely took place 755 at the end of the Carboniferous, as in equivalent domains of the Variscan belt at this time (e.g., 756 Guttierez-Alonso et al., 2011;[START_REF] Barbey | Multiphase melting[END_REF]. It is known that biotite from the high-grade 757 (unmelted) Beira schists contains significant proportions of F, Li, as well as Fe, Mn, Zn and W 758 (Acosta-Vigil et al., 2011). Biotite breakdown is therefore a potential source for Li, F, Fe, Mn, Zn, 759 and rare metals. The dehydration-melting anatectic domains are also potential sources of large fluid 760 volumes (larger than those released by most granite plutons), produced only through the biotite 761 incongruent melting. During crystallization of the haplogranitic leucosome melt, the unmixed 762 migmatitic fluid would therefore bear the biotite signature in trace elements. This signature, which 763 differs from that of metamorphic fluids issued from unmelted areas, is consistent with the F2 trace 764 element package. Final melting of tourmaline in the anatectic domains delivered boron (Acosta- Panasqueira granite. Owing to the NNW-SSE elongation of the body (Ribeiro, 2017), this 790 postulated fault should have a similar direction. In addition, fluid ascent was facilitated by the 791 vertical permeability (S 0 and schistosity) in the core of the Panasqueira anticline. 792

At a level corresponding roughly to the bottom of the dispersion level of [START_REF] Connolly | Mid-crustal focused fluid movement: thermal consequences and silica 913 transport[END_REF], the 793 ascending F2 fluid encountered the Panasqueira granite body and was forced around it, as a 794 consequence of the thermal boundary layer hindering penetration of the flowing fluids into the 795 granite body (this implies that the initiation of the hydrothermal system immediately succeeded 796 granite emplacement). Thereafter, it was driven towards the main permeability channel (the system 797 of joints that guided the future vein system), where it met the resident fluid. As seen in Figure 16, at 798 c. 305 Ma, a continuous cap of thick impermeable Ordovician quartzite (Armorican Quartzite) 799 covered the Beira schists, defining a reservoir for the metamorphic fluids released by either the first 800 LP-HT event in the CIZ at c. 320-317 Ma or by the contact metamorphism of the main Panasqueira 801 granite or both. These fluids are interpreted to represent the F1 end-member. The continuous 802 transfer of heat by the F2 fluid and the resulting heating of the dispersion zone [START_REF] Connolly | Mid-crustal focused fluid movement: thermal consequences and silica 913 transport[END_REF], is 803 thought to have driven convective flow of F1 in the Panasqueira reservoir, promoting the mixing of 804 F1 with F2 fluids in the high permeability domain, which resulted in tourmaline deposition (Fig. 805 16). Cooling of the Panasqueira granite pluton, could have contributed to the thermal anomaly. 806 [START_REF] Launay | Deciphering fluid 992 flow at the magmatic-hydrothermal transition: A case study from the world-class Panasqueira 993 W-Sn-(Cu) ore deposit (Portugal)[END_REF] described an outwardly flow pattern in the close vicinity of the "greisen 807 cupola", which they interpreted as the radial flow of magmatic fluids out from the cupola. As 808 suggested in Figure 16, this remarkable pattern could as well have resulted from the limited 809 penetration of the F2 fluid in the uppermost granite layers (F2' pattern in Figure 16). Because the 810 F2 input may have varied with time, the model in Figure 16 is consistent with the short-term 811 variations in the F1 to F2 ratios that are inferred from the rutile zoning and tourmaline profiling. the first appearance of wolframite. This new age is greater than the currently accepted age of c. 296 830 Ma, which was obtained on muscovite selvages that post-dated wolframite deposition. 831 5. The Panasqueira hydrothermal system was active for more than 6-8 Ma and was the product 832 of a much deeper crustal system than proposed in previous studies, in which the W mineralizing 833 fluids were released by a single granite intrusion. 834 6. Two fluids, both of metamorphic origin, were involved in tourmaline growth. The first, rich in 835 Ti, V, Cr, Sr, Sn, Sc, Pb, Ni, Co, Cu, Y, Nb, Ta, and of "local" derivation, was replaced 836 progressively by a second fluid, rich in Li, F, Fe, Mn, W, of deeper origin (biotite dehydration). 837

This second fluid carried the metals necessary for wolframite deposition and in particular Fe and 838 Mn, which were not inherited from the host rocks. For the comparison, the more suitable crystals, of sufficiently large size, appear to belong to a 1210 second generation of tourmaline (Tur2), not addressed in the manuscript, of which two sets of 1211 crystals were available, in samples PAN XIX-16-a2-b1 and PAN-III-8-c1/2; in the latter, however, 1212 sufficiently contrasted zoned crystals of the first generation (Tur1) found in crack-seal quartz 1213 veinlets (see Figure 4 in main text) could also be measured by the two method, as well as late 1214 (Tur3) overgrowths on Tur2. 1215 1216

1219

Comparison is made in a series of diagrams in Fig. A0-2 mode 1 (Siapfu < 6.06) mode 2 (6.06 < Siapfu < 6.12) mode 3 (Siapfu > 6.12)

(ii) In all the diagrams, the mode 2 values yield basically the same relations, and in particular, 1247 the boundaries between "Tur0", "Tur1a" and "Tur1b" fields are very consistent in the three Fe vs.

Figure 1 .

 1 Figure 1. Geologic map of the Iberian Massif, with Panasqueira location. The map is adapted and simplified from 104 Diez Fernandez et al. (2016), with complementary data from Alcock et al. (2015), Llana-Furez and Marcos (2007),

Figure 2 .

 2 Figure 2. Panasqueira geological setting. A. Geologic map of the Panasqueira area (redrawn from Ribeiro, 2017), 145 with location of the cross section in B. Note the tight synform roots picked out by Ordovician quartzites. B. Cross

Figure 3 .

 3 Figure 3. A. Typical tourmalinized wall-rock, with Qcs quartz veinlets. Sn, regional schistosity. Note the numerous 263 overprinting arsenopyrite (Apy) crystals. Sample PAN-III-8-c1 (NL). B. Poorly zoned tourmaline 1 seen in natural

  zircon and fluor-apatite and sporadic monazite or xenotime crystals, usually no more than 268 10-20 µm, and commonly only a few µm in diameter. Aggregates of micrometer-scale crystals of 269 zircon and xenotime or zircon and monazite are common. In addition to these ubiquitous 270 accessories to the tourmaline, a number of other hydrothermal minerals were later involved in the 271 alteration of the Panasqueira wall rocks, and include quartz (silicification), topaz, muscovite, 272 sulfides (pyrrhotite, sphalerite, chalcopyrite, arsenopyrite), apatite and siderite. 273 274

Figure 4 .

 4 Figure 4. A. Typical early assemblage in the tourmalinized wall-rock, with Tur1 elongated along (erased) schistosity 284 and disseminated rutile. Sample PAN-III-8-c1 (SEM). B. Acicular tourmaline in a silicified wall-rock. Sample PAN-

  287 PAN-VII-6-b1 (SEM). E-F. Evidence for coeval growth of Tur1b and the W-rich rutile in a Qcs veinlet. Sample PAN-288 III-8-c1 (SEM).

Figure 5 .

 5 289present, although not systematically, but there is no evidence for sector zoning. These cores are 292 interpreted to be relicts of the early tourmaline and are labelled Tur0 hereafter. The outer parts of 293 the tourmaline prisms comprise a medium grey zone, labelled Tur1a and a clearer rim, labelled 294 Tur1b. In rare cases, there is an outermost rim characterized by the recurrence of a darker hue. 295 296 Synthesis of the stage Ia tourmalinization. A. Initialization of alteration (Tur0) in relation to simple "dry" 297 joints. B. Main tourmaline development (Tur1a) and first increments of opening in Qcs veinlets. C. Growth of Tur1b 298 tourmaline relative to increments of Qcs opening and coeval rutile growth. D. Local variant with early wolframite 299 growing in the wall-rock coevally with Tur1b. E. Transition to the main wolframite deposition stage 300 301

Figure 6 .

 6 ). Their 352 compositions, estimated from SEM-EDS measurements, are ferberitic, with Fe/Fe+Mn ratios 353 between 0.67 and 0.83. 354 355 Panasqueira rutile. A, B, C: Back-scattered SEM images. of Panasqueira rutile. A. Crystal aggregate from 356 the wall-rock of a wolframite-bearing vein. Note the primary wolframite nano-inclusions (Wfm). B. Crystal in the wall 357 rock of a barren vein from the deep L3 level. Note the ilmenite lamellae (Ilm) and the late apatite (Ap), overprinting the 358 rutile crystal. C. Large isometric crystal from a Qcs vein in the wall-rock of a wolframite-bearing vein. Note the 359 superimposition of sector zoning (SZ) on the compositional (oscillatory) zoning. Square: location of images D to G. D 360 to G: false-color X-ray (EPMA) images, showing the differential effect of SZ on the minor element concentrations, and 361 the anti-correlation of W and Nb in the OZ.

Figure 7 .

 7 Figure 7. Crystal chemistry of the Panasqueira tourmaline, illustrating the characteristics of the Tur0, Tur1a and 398 Tur1b zones. Note in all the diagrams the continuity of composition variations among the three zones. A. Classification

  species) corresponding to the operation of the Al +1 x +1 Na -1 R 2+ -1 vector, which leads 409 to a solid solution between schorl-dravite and foitite-Mg-foitite. From Figure7-C, E and G, it is 410 evident that other vectors combined to displace the observed trends from the preceding trend. The 411 Al +1 O +1 (OH) -1 (Mg, Fe) -1 vector seems to have been particularly important, implying an oxy-schorl 412

  -dravite) component, but the intervention of another exchange vector Y +1 Al +2 R 2+ -3,

  A. AFM diagram for the Panasqueira tourmaline, with location of the main tourmaline end-members. (1)-421

Figure 9 .

 9 Figure 9. Profile of the Fe# ratio (Fe/Fe+Mg) along an acicular prism of tourmaline 1 (EPMA analyses), compared to 439 the false color X-image of the same crystal (sample PAN-VII-6-b2). The height of the elliptical symbol corresponds to

  anomaly (a rare occurrence); and wolframite, where no correlation was observed with 467 either Ti or Cu. Most of these W anomalies were found in the Tur1b zones. 468

  (trace elements except 469 REE) and Figure11(REE profiles). As seen in Figure10-A, Ti, (530 to 4,360 ppm), Zn (160 to 930 470 ppm) and Mn (135 to 600 ppm) are the most abundant trace elements, followed by Li (40 to 330 471 ppm), V (10 to 740 ppm) and Cr (10 to 1,000 ppm). Strontium (7 to 285 ppm) and Sn (4 to 160 472 ppm), are present in lower concentrations, followed by Sc (5 to 30 ppm), Be (3 to 20 ppm), and Pb 473(1 to 18 ppm). Concentrations of other elements were commonly below the detection level (bdl), 474 e.g., Ni (up to 56 ppm), Co (up to 13 ppm) and Y (up to 7 ppm). Most measured tungsten 475 concentrations were between 0.4 and 30 ppm, but for ~25 % of analyses of Tur1a and 50 % of 476 Tur1b, the W concentration was below the detection level of 0.4 ppm. The measured concentrations 477 for Nb are between 0.1 and 3.2 ppm, but for ~ 75% of the analyses, they were below the detection 478 level of 0.3 ppm; the few measured Ta values were between 0.3 and 1.6 ppm; the overwhelming 479 majority of analyses yielded values below the detection level of 0.3 ppm. From the limited REE 480 data, the ∑REE concentration is low (between 1.2 and 12 ppm), and the REE profiles are characterized by high La N to Yb N ratios of 6.37 to 6.77, and slightly negative Eu N /Eu* N anomalies 482 (0.65 to 0.83) (Fig. 11). 483 484 Figure 10. Trace-element patterns in Panasqueira tourmaline 1. A. Box plots of LA-ICP-MS results for tourmaline 1a 485 and 1b. The full box represents the lower quartile to upper quartile interval. The whiskers represent the 5%-95% 486 interval. Black circle: average value, black vertical line: median value. Open circle: outlier value, comprised in the 5% 487 lowest or highest data. Inset: normalization of average values of Tur1a to the Tur1b reference. B. Comparison of trace-488 element distribution (average values) between Panasqueira tourmaline 1a and Beira schists. The elements are arranged 489 from left to right in accordance with their increasing concentration in tourmaline 1a. Data for Beira schists are from De 490

Figure 11 .

 11 Figure 11. Chondrite-normalized REE profile for the Panasqueira tourmaline (samples PAN-I-3-c2 and PAN-III-8-496 c1) compared to the profiles for the Panasqueira metasediments (1: De Amorin, 2017), the fluids associated to the

Figure 12 .

 12 Figure 12. PCA analysis of the trace element composition of the Panasqueira tourmaline, allowing the definition of 508 several groups of trace elements, namely: Mn-Zn-Li, Cr-V-Sc, Co-Ni-Sr-Y-Sn, Be-Pb, and Nb-Ta (explanations in the

Figure 13 .

 13 Figure 13. Binary plots of selected trace elements from Panasqueira tourmaline, showing contrasting behaviour, 522including positive, negative and null correlations, depending on the elements (explanation in the text).

Figure 14 .

 14 Figure 14. Results of U-Pb age determinations of wall-rock Panasqueira rutile (Tera-Wasserburg Concordia 560 diagrams). Note the highly discordant behaviour of the rutile. A. All data, showing the importance of lead loss in the

  or two fluids? 608 Tourmaline as a fluid proxy 609 According to von Goerne et al. (2001), van Hinsberg (2011), Berryman et al. (2016) and 610 Vereshchagin et al. (

  ): Ti-Zn-Mn-(V, Cr)-(Sr,Li)-Sn-(Sc,Ni)-Be-Pb-W-(Cu,Co)-Y-668 Nb-Ta. A compilation of local data (Figure 10-B) reveals that in the Beira schists, these elements 669 are in a significantly distinct order of decreasing abundance: Ti-Mn-(Zn,V,Li)-(Cr,Sr)-Ni-Cu-670 (Co,Y,Sc)-Nb-Pb-(W,Sn)-Be-Ta. Therefore, concentrations in Tur0 and Tur1a are not strictly 671 mimetic of the Beira schist composition. 672

Figure 16 .O

 16 Figure 16. Conceptual model of the crustal scale hydrothermal system at the onset of the main wolframite stage at 780Panasqueira. A geothermal gradient of ~ 40°C.km -1 is assumed[START_REF] Cathelineau | Nouvelle approche du chemin P-T-t des fluides dans le gisement à W-Sn-902 Cu de Panasqueira (Portugal): persistence d'une anomalie thermique d'origine profonde en 903 cours d'exhumation[END_REF]. The model involves two

1 . 2 .

 12 The earliest hydrothermal event in the Panasqueira system was wall rock tourmalinization. 816Zoned tourmaline replaced ferro-magnesian minerals in the protolith in a Tur0-Tur1a,b sequence. 817This event coincided with the first fluid-overpressure-induced opening of crack-seal fractures (Qcs 818 veinlets). 819 The early Tur1 tourmaline, and in particular, the development of Tur1b rims, was coeval with 820 the formation of W-bearing rutile (which is among the richest in W anywhere) and the first 821 appearance of wolframite.the presence/abundance of wolframite in quartz veins and the relative importance in the adjacent 824 altered wall rock of Tur1b rims, and a high content of tungsten in rutile. The poor development of 825 the Tur1b rim, and limited W enrichment in the rutile, together with the presence of ilmenite 826 lamellae, are indicators of barren veins. This is of potential interest for evaluating exploration drill 827 holes from a resource and mine development perspective. 828 4. The early rutile crystallized at 305.2 ± 5.7 Ma and coincided with early tourmalinization and 829

  in particular AE William-Jones are thanked for constructive criticism and 842 detailed suggestions that helped to improve the first drafts of the manuscript. Additional corrections 843 from F. B. Wadsworth (Durham University) and A. Samper (OTELO, Lorraine University) were 844 greatly appreciated. 845 This work benefited from the analytical capabilities of the GeoRessources Laboratory 846 (Université de Lorraine, CNRS, CREGU), and the authors gratefully acknowledge Olivier Rouer, 847 Andrei Lecomte, Lise Salsi and Chantal Peiffert for their technical help. LA-ICP-MS equipment 848 was financed by CPER program (National Funds -Lorraine region -FEDER). 849 This work was financed by the ERAMIN project NewOres financed by ANR (ANR-14-EMIN-850 0001), and Labex Ressources 21 (supported by the French National Research Agency through the 851 national program "Investissements d'avenir") with reference ANR -10 -LABX 21 -LABEX 852 RESSOURCES 21. 853 We are most grateful to Beralt Tin and Wolfram S.A. for permitting access to the Panasqueira 854 underground mine, and technical help during field work. 855

Figure A2 .

 A2 Figure A2. Comparison of EPMA and SEM-EDS measurements on selected sets of tourmaline crystals in two samples

  Figure A0-4. Checking the internal consistency of SEM-EDS analyses using classical crystal chemistry diagrams. The

XIX

  1242A0-5.1243(i) A first result is that in the Al vs [] and Na+R 2+ vs Al+[] diagrams, the whole of the mode 1 1244 values behave as the ones in sample III-8-c, as indeed expected. The crystal chemistry diagrams of 1245 these mode 1 analyses may thus be in turn used as reference for the other sets of analyses. 1246

  Figure A0-5. Checking the internal consistency of SEM-EDS analyses in the AFM triangle. A: mode 1 ("low Si");

Table 1 .

 1 Ta-Sn anomalies; cuprotungstite, where correlated Tur1a Tur1b detectio Summary of LA-ICP-MS trace element analyses for the Panasqueira tourmalines. All contents in ppm. For 462 the purpose of average calculations, the bdl (below detection level) in TableA4were taken at half the detection level 463 values (i.e., the without bias best estimates) when needed (italics). As a result, the averages for Nb (0.2 ppm) and Ta464(0.2 ppm) are not provided in the table.

		min	max	average	min	max	average	level
	Li	26	170	72	48	288	130
	Be	1	21	8	0,8	21	4
	Sc	5	32	17	7	26	12	2
	Ti	530	4360	1753	849	2840	1714
	V	37	613	341	11	742	282
	Cr	4	1027	271	9	601	156	8
	Mn	135	528	421	310	606	468	20
	Co	0.2	13	2	0.2	3	1	0.3
	Ni	3	56	16	0.2	23	7	0.3
	Cu	0.3	12	2	0.3	23	1	0.5
	Zn	237	856	631	161	925	656
	Sr	10	285	79	7	131	40
	Y	0.2	7	1.4	0.2	5	0.9	0.3
	Nb	0.2	12	0.6	0.2	2	0.2	0.3
	Ta	0.2	0.5	0.2	0.2	0.2	0.2	0.3
	Sn	4	54	24	4	157	19	3
	W	0.2	29	4	0.2	21	3	0.4
	Pb	2	33	6	1	15	4

Rb-Sr[START_REF] Priem | Tracing crustal evolution in the NW Iberian Peninsula 1092 through the Rb-Sr and U-Pb systematics of Paleozoic granitoids: a review: Physics of the[END_REF] methods. Close to the deposit, the Fundão granodiorite(Garcia,

mostly replaced tourmaline prisms, and (ii) arsenopyrite overprinted Qcs veinlets (Fig.3-A).

Tur1a to Tur1b, and a tendency towards foitite compositions. Indeed, as shown in Figure7-B, the

X-site vacancy is between ~0.2 and ~0.6 pfu (and thus, the Panasqueira tourmaline trends toward

(sample PAN-XIV-181-1) was dated using the 39 Ar/ 40 Ar method at the University of Manitoba

11), suggesting that the fluids responsible for tourmalinization were of metamorphic origin or

the dispersion region[START_REF] Connolly | Mid-crustal focused fluid movement: thermal consequences and silica 913 transport[END_REF].

On the basis of a limited number of observations, it seems that there is a correlation between

Lorraine (France), Laboratoire Géoressources, 451 p.

system Na-Mg-Al-Si-B-O-H. Applications to the boron content of natural hydrothermal

and Geochemistry (Nancy),Abstracts,

Proposed conceptual model 768

In order to integrate the preceding results into a workable model for the tourmalinization at 769 Panasqueira, a starting point is to consider the upward transfer of the boron-rich F2 fluid from the 770 inferred source at depth to the deposit level. Here, the concept of a mid-crustal channelized fluid 771 flow [START_REF] Connolly | Mid-crustal focused fluid movement: thermal consequences and silica 913 transport[END_REF]) may be called for. According to the modelling by [START_REF] Connolly | Mid-crustal focused fluid movement: thermal consequences and silica 913 transport[END_REF], deep 772 fluids issued from biotite dehydration gather into a collection zone, and are then focused and 773 channelled into a mid-crustal fault zone, ascending at high rates up to a dispersion region in cooler 774 rocks. The half-width of the collection and dispersion zones is typically in the 3-5 km range, and the 775 height of the system is on the order of 10 to 15 km. The flow results in upward heat advection on a Appendix A1-Table A1 (Paton et al., 2010), VizualAge_UcomPbine [START_REF] Chew | U-Pb LA-ICPMS dating using accessory 906 mineral standards with variable common Pb[END_REF] Quality control / Validation