Rodrigo W Lopes

Christophe Renac
email: christophe.renac@unice.fr

Andre Mexias
email: andre.mexias@ufrgs.br

Lauro V S Nardi
email: lauro.nardi@ufrgs.br

Eduardo Fontana
email: eduardo.fontana@ict.ufvjm.edu.br

Marcia E B Gomes

Aurélie Barats
email: aurelie.barats@unice.fr

André S Mexias

Márcia E B Gomes

Mineral assemblages and temperature associated with Cu enrichment in the Seival area (Neoproterozoic Camaquã Basin of Southern Brazil)

Keywords: Late-magmatic and hydrothermal alteration, Albitization, Chlorites

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

The Neoproterozoic Camaquã Basin and its associated igneous rocks contain significant Au, Cu and Ag ore deposits, such as the Uruguay-São Luiz mines and the Lavras do Sul Mining District [START_REF] Remus | A distal magmatic-hydrothermal origin for the Camaquã Cu (Au-Ag) and Santa Maria Pb, Zn (Cu-Ag) deposits, southern Brazil[END_REF][START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF][START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF]). In the central-western section of this basin, volcanogenic [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF] and plutonic rocks [START_REF] Mexias | Geochemical modelling of gold precipitation conditions in Bloco do Butiá Mine, Lavras do Sul/Brazil[END_REF] show pervasive alteration described as latemagmatic albitization and hydrothermal alteration with the influx of meteoric fluids (Mexias et al., 1990a[START_REF] Mexias | Geochemical modelling of gold precipitation conditions in Bloco do Butiá Mine, Lavras do Sul/Brazil[END_REF][START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. The largest Cu deposit in this basin is the Camaquã Mine, which is hosted in a Neoproterozoic sedimentary sequence and was exploited from the 18 th century until 1996 [START_REF] Remus | A distal magmatic-hydrothermal origin for the Camaquã Cu (Au-Ag) and Santa Maria Pb, Zn (Cu-Ag) deposits, southern Brazil[END_REF][START_REF] Laux | Ore genesis at the Camaquã copper mine, a neoproterozoic sediment-hosted deposit in Southern Brazil[END_REF][START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF]. This exploited deposit has an ore reserve of ~30.8 Mt with an average Cu grade of ~1.06%, which is manifested as massive veins, stockworks and disseminated chalcopyrite, pyrite, bornite, chalcocite, gold, silver and hematite. The extrusive and intrusive rocks from the Lavras do Sul Mining District [START_REF] Mexias | Alterações hidrotermais e mineralizações nas rochas da Associação Plutono-Vulcano-Sedimentar da região de Lavras do Sul-RS[END_REF], which are located on the central-western rim of the Camaquã Basin, host nineteen Au and Au-Cu deposits that were exploited during the same time frame [START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF].

The ore zones consist of quartz and sulfide-rich quartz veins [START_REF] Mexias | Geochemical modelling of gold precipitation conditions in Bloco do Butiá Mine, Lavras do Sul/Brazil[END_REF] associated with wall-rock alteration characterized by 'sericite', chlorite, pyrite and chalcopyrite [START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF]. In the vicinity of the Lavras do Sul area, the volcanogenic sequence in the Seival area hosts Cu-Ag deposits [START_REF] Reischl | Mineralizações cupriferas associadas a vulcânicas na Mina do Seival. In: XXX[END_REF][START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF]. The different mines yielded ca. 0.20 Mt of Cu-ore with an average grade of ~1.40%. The chalcopyrite, pyrite, chalcocite, bornite and covellite sulfides occurred in association with chlorite, hematite, calcite, barite and quartz disseminated in andesitic lapilli tuff and volcanic agglomerates or along fault planes cutting the volcanic sequence. A recent study on the Seival Mine [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF] improved current knowledge about the clay minerals in these ore deposits. [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF] described the zoning and lithotypes with the predominant occurrence of smectite, chlorite/smectite mixed-layers, chlorite and corrensite, and suggested that the base-metal deposition was related to the late-magmatic process of albitization and high-temperature hydrothermal alteration. Later low-temperature hydrothermal alteration represented the mixing of magmatic and meteoric fluids. Both albitization and chloritization processes were observed in the granite-related epithermal systems of the Lavras do Sul area [START_REF] Mexias | Alterações hidrotermais e mineralizações nas rochas da Associação Plutono-Vulcano-Sedimentar da região de Lavras do Sul-RS[END_REF][START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] and the Camaquã Mine [START_REF] Laux | Ore genesis at the Camaquã copper mine, a neoproterozoic sediment-hosted deposit in Southern Brazil[END_REF][START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF]. A similar alteration mineralogy in the vicinity of the Lavras do Sul Intrusive Complex, located 10 km west of the Seival area, suggests that the Lavras do Sul porphyry-epithermal system contributes to the alteration of the andesitic rocks and ore deposition in the Seival area, as also occurs in the Potrerill Cu-Mo porphyry deposits and El Hueso Au epithermal deposits [START_REF] Sillitoe | Gold metallogeny of Chile -an introduction[END_REF][START_REF] Marsh | 40 Ar/ 39 Ar geochronolgy of Cu-Au and Au-Ag mineralization in the Potrerillos district, Chile[END_REF].

Consequently, this study focused on the chemical signatures of albite and chlorite to smectite in the hydrothermal alteration products. The petrographic and chemical analyses of the minerals were used to estimate the temperatures and bracket temperatures of latemagmatic to hydrothermal alteration. Petrographic observations and temperatures estimated by chlorite geothermometers were introduced into a thermodynamic model. This model was used to reconstruct the chemical conditions favorable to ore deposition in the process of base-metal migration in the Seival area.

Geological Setting

Regional geology

The Mantiqueira Province extends from the southeast of Brazil to Uruguay (Almeida and Hasui, 1984;[START_REF] Silva | The neoproterozoic Mantiqueira Province and its African connections: a zircon based U-Pb geochronologic subdivision for the Brasiliano/Pan-African systems of orogens[END_REF]. In the Gondwana supercontinent, the southern portion of collision between the Rio de La Plata (Brazil) and the Kalahari (Africa) cratons is characterized by the Sul-rio-grandense Shield (Fig. 1A) with Neoproterozoic ages. This collision is represented by the Braziliano Orogeny and the opening of the Camaquã Basin related to the post-collisional stage [START_REF] Lima | The Lavras do Sul Shoshonitic Association: implications for origin and evolution of neoproterozoic shoshonitic magmatism in southernmost Brazil[END_REF]Gastal et al., 2005a, b). The Sul-rio-grandense Shield comprises four geotectonic units: the Taquarembó Terrane, São Gabriel Terrene, Tijucas Terrene, and Pelotas Batholith. Recovering these units, the Camaquã Basin was considered as a succession of sub-basins [START_REF] Paim | A Bacia do Camaquã[END_REF] that contains volcano-sedimentary sequences. The Maricá Group, which is represented by the volcano-sedimentary rocks of the Maricá Formation, is related to a foreland retro arc-basin setting (630-601 Ma; [START_REF] Paim | A Bacia do Camaquã[END_REF][START_REF] Borba | U-Pb zircon and 40 Ar-39 Ar K-feldspar dating of syn-sedimentary volcanism of the Neoproterozoic Maricá Formation: constraining the age of foreland basin inception and inversion in the Camaquã Basin of southern Brazil[END_REF]. The Bom Jardim Group, in which shoshonitic volcanism was emplaced during the strike-slip movement of the basin (600-590 Ma; [START_REF] Janikian | The continental record of Ediacaran volcanosedimentary successions in southern Brazil and their global implications[END_REF], is represented by the Hilário Formation. The late Santa Bárbara Group (574-544 Ma; [START_REF] Sommer | Potassic and Low-and High-Ti mildly alkaline volcanism In the Neoproterozoic Ramada Plateau, Southermost Brazil[END_REF][START_REF] Bicca | Tectonic evolution and provenance of the Santa Bárbara Group, Camaquã Mines region, Rio Grande do Sul, Brazil[END_REF][START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF][START_REF] Janikian | Ages (U-Pb SHRIMP and LA ICPMS) and stratigraphic evolution of the Neoproterozoic volcano-sedimentary successions from the extensional Camaquã Basin, Southern Brazil[END_REF][START_REF] Matté | Postcollisional Ediacaran volcanism in oriental Ramada Plateau, southern Brazil[END_REF] is mainly represented by the acidic effusive/explosive episodes and minor basic magmatism of the Acampamento Velho Formation and by the sedimentary sequences of the Santa Fé and Santa Bárbara formations (Fig. 1B). The Guaritas Group (547-535 Ma; [START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF][START_REF] Oliveira | U-Pb and Lu-Hf isotopes applied to the evolution of the late to post-orogenic transtensional basins of the Dom Feliciano belt, Brazil[END_REF] is represented by volcanic rocks of the Rodeio Velho Formation associated with a sedimentary sequence represented by the Pedra Pintada and Guaritas formations related to transtensional tectonic stages [START_REF] Paim | A Bacia do Camaquã[END_REF][START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF]. These effusive rocks have basic to intermediate sodic compositions with mildly alkaline to high-K tholeiitic affinities [START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF].

INSERT Figure 1

The volcano-sedimentary units that occur in the Seival area (Fig. 2) have dominant intermediate compositions with basic and acidic end-members. The Bom Jardim Group, as previously described, consists of the effusive units of the Hilário Formation in the study area [START_REF] Ribeiro | Associacões petrotectônicas do Escudo Sul-Riograndense: I Tabulação e distribuicão das associações petrotectônicas do Escudo do Rio Grande do Sul[END_REF]. The deformation of the Hilário Formation along the Lavras do Sul contact suggests that the Hilário Formation is older than the Lavras do Sul Intrusive Complex [START_REF] Gastal | Lavras granite emplacement and gold mineralization during the development of the post-collisional volcano-plutonic center, west of the Sul-riograndense Shield: Geophysical and structural data[END_REF]. The Hilário Formation consists of dominantly andesitic rocks represented by andesitic lava flows, lapilli tuff, volcanic agglomerates, and dikes with a shoshonitic geochemical affinity [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. The Ar-Ar radiogenic dating of plagioclase suggests an age of 600 to 590 Ma [START_REF] Janikian | The continental record of Ediacaran volcanosedimentary successions in southern Brazil and their global implications[END_REF] that might be thermally influenced by intrusive magmas such as dikes or the Lavras do Sul granitoids. The other vesicular lava flows and volcanic clastic materials are represented by the polymictic conglomerates of the Santa Fé Formation. The Acampamento Velho Formation occurs as rhyolite dikes that cross-cut the Hilário Formation.

INSERT Figure 2

The granitoids of the Lavras do Sul Intrusive Complex with U-Pb ages varying from 601 to 587 Ma (SHRIMP in zircon, [START_REF] Remus | Shrimp U-Pb zircon ages of volcanism from the São Gabriel Block, southern Brazil[END_REF][START_REF] Remus | A distal magmatic-hydrothermal origin for the Camaquã Cu (Au-Ag) and Santa Maria Pb, Zn (Cu-Ag) deposits, southern Brazil[END_REF][START_REF] Gastal | Reinterpretação do Complexo Intrusivo Lavras do Sul -RS, de acordo com os sistemas vulcano-plutônicos de subsidência. Parte I: Geologia, geofísica e geocronologia ( 207 Pb/ 206 Pb e 206 Pb/ 238 U)[END_REF][START_REF] Liz | Petrologia e sucessão estratigráfica das rochas monzoníticas da associação shoshonítica de Lavras do Sul (RS)[END_REF], comprise a ring structure composed of porphyritic quartz-monzonite granodiorite and syenogranite to monzogranite with monzonitic intrusions in its northeastern margin [START_REF] Gastal | Reinterpretação do Complexo Intrusivo Lavras do Sul -RS, de acordo com os sistemas vulcano-plutônicos de subsidência. Parte I: Geologia, geofísica e geocronologia ( 207 Pb/ 206 Pb e 206 Pb/ 238 U)[END_REF][START_REF] Liz | Petrologia e sucessão estratigráfica das rochas monzoníticas da associação shoshonítica de Lavras do Sul (RS)[END_REF]. In the contact zone between the Lavras do Sul granitoids and the Hilário Formation is a hectometer-thick metamorphic halo (Mexias et al., 1990a, b;[START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] attesting to the thermal influence of granitoids on the volcano-sedimentary pile.

Ore geology

The Seival hosts six inactive Cu-bearing deposits and several prospects. This reserve was estimated at ~0.20 Mt of ore with an average grade of ~1.40% of Cu and 10-70 ppm of Ag (Fig. 3A; [START_REF] Reischl | Mineralizações cupriferas associadas a vulcânicas na Mina do Seival. In: XXX[END_REF][START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF]. The ore deposits in the Seival area were associated with the development of NE-SW-oriented shear zones that cross-cut the Camaquã Basin [START_REF] Fernandes | Deformation patterns in the Southern Brazilian branch of the Dom Feliciano Belt: a reappraisal[END_REF][START_REF] Philipp | Tectonic evolution of the Dom Feliciano Belt in Southern Brazil: Geological relationships and U-Pb geochronology[END_REF]. The emplacement of metallic mineralizations are bracketed between 600 and 580 Ma ago based on the ages of lava flows [START_REF] Janikian | The continental record of Ediacaran volcanosedimentary successions in southern Brazil and their global implications[END_REF], tectonic activity [START_REF] Gastal | Lavras granite emplacement and gold mineralization during the development of the post-collisional volcano-plutonic center, west of the Sul-riograndense Shield: Geophysical and structural data[END_REF] and the Lavras do Sul magmatism [START_REF] Gastal | Reinterpretação do Complexo Intrusivo Lavras do Sul -RS, de acordo com os sistemas vulcano-plutônicos de subsidência. Parte I: Geologia, geofísica e geocronologia ( 207 Pb/ 206 Pb e 206 Pb/ 238 U)[END_REF][START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF].

The sulfides are represented by chalcopyrite, bornite, chalcocite and covellite [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF] and are part of the main Cu-bearing veins that fill fractures and faults. The alteration halos are related to the distances of mineralized structures [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. The mineral association of chlorite, epidote and calcite formed at temperature of ~300 °C (Mexias et al., 1990b;[START_REF] Mexias | Alterações hidrotermais e mineralizações nas rochas da Associação Plutono-Vulcano-Sedimentar da região de Lavras do Sul-RS[END_REF][START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] in the volcanogenic rocks of the Hilário Formation close to the Lavras do Sul granitoids.

The mineral assemblages allow for the characterization of hydrothermal zones [START_REF] Seedorff | Porphyry deposits: characteristics and origin of hypogene features[END_REF][START_REF] Sillitoe | Porphyry copper systems[END_REF]. Propylitic alteration was related to chlorite, C/S mixed-layer, hematite, titanite, calcite, barite and quartz associated with pyritechalcopyrite and chalcocite-bornite, while argillic alteration was related to smectite and quartz (Fig. 3B; [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. Cu enrichment was associated with propylitic alteration and the formation of albite (600 to 250 °C; [START_REF] Fontana | Mass balance and origin of fluids associated to smectite and chlorite/smectite alteration in Seival Mine Cu-Mineralization -Camaquã Basin -Brazil (Part II)[END_REF] and Mg-chamosite to Fe-clinochlore (251 to 180 °C). The late-hydrothermal veins are composed of barite, calcite and minor proportion of veins with calcite-quartz assemblage.

These late precipitations represent the lowest temperatures of hydrothermal alteration (150 to 80 °C; [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. In the preserved parts of these inactive mines, mineralization occurs as a stockwork of veins or disseminated in volcaniclastic rocks and andesitic lava flows [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. The faults, mineralized structures and dikes are considered contemporaneous based on the mineralogy and alteration type. Thus, the hydrothermal processes can be associated with the intrusion of NE-SW-oriented andesite [START_REF] Lopes | Au-Cu-Ag mineralization controlled by brittle structures in Lavras do Sul Mining District and Seival Mine deposits, Camaquã Basin, southern Brazil[END_REF] and local hydrothermal cells.

INSERT Figure 3

Analytical methods

Field work consisted of sample collection and logging of drill cores. The samples collected were representative of lapilli tuff, amygdaloidal to porphyritic andesitic lava flows and dikes. Petrographic observations of thin sections allowed the description of magmatic and hydrothermally altered crystals. The minerals, after of crushing and sieving, were separated using a magnetic separator, heavy liquids and hand-picking under a binocular microscope. Products of alteration were either collected under a binocular microscope in the altered phenocrysts or identified in the clay-size fraction. These petrographic observations, mineral separation and clay-size fraction were characterized by scanning electron microscopy combined with energy-dispersive spectrometry (SEM-EDS, Zeiss EVO LS15, 20 kV, 2.5 nA with X-Max Oxford EDS detectors, IAEA Monaco) and X-ray diffraction (Siemens D5000, KαCu, 40 kV and 25 mA, Geoscience Institute-CPGq-UFRGS). X-ray patterns of the clay minerals were obtained in < 0.4 μm clay-size fraction.

Major element composition as oxides (SiO2, TiO2, Al2O3, FeOtotal, MnO, MgO, CaO, Na2O, F and K2O) in minerals from thin section were quantified by electron microprobe (CAMECA, SXFive model equipped with TAP, PET and LIF crystal detectors) at the Geoscience Institute, Universidade Federal do Rio Grande do Sul, Brazil. The beam diameter is about 10 to 4 µm with an acceleration voltage of 15 kV and 15 nA with counting time per element of 10 sec and background counting times of 5 sec per element.

Chemical calibrations were performed on albite, jadeite, diopside, sanidine, rutile, rhodonite and hematite standards mounted in epoxy resin. The mineral composition in thin section were calculated of atom per formula unit (a.p.f.u.) assumed the following number of oxygen atoms for ideal compositions of feldspar (32), pyroxene (12), biotite (22), titanite

(5), smectite (22), chlorite/smectite mixed-layer (28) and chlorite (28). Charge balance of structural formula was obtained by the adjustment of Fe 2+ and Fe 3+ proportions, including for smectite and biotite, where only Fe 2+ was considered. Analyzes in ten thin sections were performed to follow changes from preserved magmatic minerals to mineral transformed or precipitated by the hydrothermal alteration. Based on major element compositions, chemical changes will then be related to albitization and chloritization processes. The complete dataset of primary and hydrothermal minerals analyzed are available in

Supplementary Table A-G.
The major element changes observed in plagioclase were completed by rare earth elements (REE; lanthanides, Y and Sc) analyzes. These REEs have been measured from plagioclase separates preliminary recovered for phenocrysts and the microlithic groundmass subsequently recognized with different major element compositions. These REE concentrations were measured from feldspar separates preliminary acid leached with ultrapure HNO3 (1N) to dissolve traces carbonates and oxides on the surface of the grains separated then clean in ultrapure pure MQ water. Later, cleaned grains were then acid digested in ultrapure HNO3 (15N) and HF (20N). Inductively-coupled plasma mass spectrometry analyzed all digested samples diluted in 1% HNO3 solutions (ICP-MS: Elan DRCII, Perkin Elmer at the University of Nice Sophia-Antipolis). Quantification limits are below 50 ng/L. Element concentration was expressed as ppm and then normalized with respect to chondrite values [START_REF] Mcdonough | Composition of the Earth[END_REF]. The Eu* the values of the Eu anomaly were calculated using [Eu*]= [((EuN)/(SmN x GdN) 1/2 )] from [START_REF] Worrall | Water-rock interaction in an acidic mine discharge as indicated by rare earth element patterns[END_REF] or [Eu*] = [((EuN)/(SmN 2 x TbN) 1/3 )] from [START_REF] Lawrence | The behavior of the rare earth elements during estuarine mixing -revisited[END_REF].

The different mineralogical and chemical data of magmatic minerals were used with the petrogenetic model (MELTS software modeling; [START_REF] Ghiorso | Chemical mass transfer in magmatic processes IV. A revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid-solid equilibria in magmatic systems at elevated temperatures and pressures[END_REF] to reconstruct magmatic conditions. The magmatic and hydrothermal minerals were combined in a thermodynamic model (PHREEQC interactive;[START_REF] Parkhurst | User's guide to PHREEQC-A computer program for speciation, reaction-path, advective-transport, and inverse geochemical calculations[END_REF] to estimate the favorable conditions for precipitation of hydrothermal phases and sulfides.

Results

Textures and petrographic observations

The host rocks of the Cu deposits in the Seival area are predominantly andesitic lava flows and lapilli tuff (Fig. 4A) to volcanic agglomerates with rounded andesitic pyroclasts.

Their aphyric groundmasses are dark to glassy and green with disseminated microlites of plagioclase and fragments of pyroxene. Amygdaloidal and porphyritic andesitic lava flows are predominant in the southern and northeastern parts of the Seival area and are in contact with the Santa Fé Formation (Fig. 2). Subvolcanic rocks have andesitic (Fig. 4B) to trachyandesitic compositions with feldspar phenocrysts, dominant pyroxene and scarce biotite phenocrysts.

Most of the rocks are intensively fractured and brecciated, particularly those with higher Cu sulfide contents. The andesitic pyroclasts in the lapilli tuff show vesicles or amygdaloids. The amygdaloidal groundmass in the lapilli tuff consists of fragments of igneous plagioclase and pyroxene. The petrographic observations of pyroxene revealed the replacement by clay minerals and calcite or intergranular spaces filled by clay minerals, quartz, calcite, titanite, pyrite, chalcopyrite, and minor hematite (Fig. 4C).

Porphyritic andesitic lava flows have phenocrysts of plagioclase and clinopyroxene in a trachytic groundmass with oriented plagioclase. Andesitic dikes host subhedral grains of feldspars further identified as plagioclase with rims of K-feldspar (Fig. 4D) and phenocrysts of pyroxene. Some trachyandesitic dikes have subhedral phenocrysts of plagioclase, pyroxene and biotite. Some plagioclase and biotite phenocrysts have inclusions of apatite, zircon (50 to 200 µm) and titanite, while the oxidized groundmass contains hematite. The titanite grains occur as euhedral grains associated with biotite and pyroxene and as anhedral grains of smaller granular agglomerates in the altered groundmass.

As previously described [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF], the Hilário volcanic sequence in the studied area is pervasively altered to clay minerals, calcite, barite and quartz. The original igneous mafic minerals and different groundmasses have a light green material recognized as chlorite/smectite mixed-layer (Fig. 4E). Albite, chlorite and sulfide occur in the more altered rocks with traces of calcite and specular hematite, and euhedral or agglomerates of titanite occur with albite and microscopic euhedral quartz (Fig. 4F).

Less-altered material occurs in the amygdaloidal andesitic lava flows from the south and west. Nevertheless, these lava flows are partially altered to dark clay minerals (Fig. 4G) between crystals or exhibit quartz, pyrite-chalcopyrite and calcite filling vesicles. A). According to the structural formula of augite (Table 1), the atomic ratios of [Mg/(Mg+Fetot)= 0.67-0.85] are high and those of [Na/(Ca+Na)= 0.02-0.05)] are low.

Prismatic biotite phenocrysts recognized in trachyandesitic dikes are classified as Mg-biotite with the structural formula expressed in Supplementary Table B. The less pristine Mg-biotites show slightly different compositions (Table 1), with increases in Al VI (Fig. 5B) and lower contents of Fe, Mg and Mn (Table 1). The euhedral to agglomerate titanite grains (Fig. 5C; Table 1 andSupplementary Table C) are associated with albite and biotite phenocrysts, and the anhedral grains in the groundmass have similar chemical compositions.

The chemical compositions of feldspars were analyzed in thin section. The plagioclase phenocrysts have compositions of andesine-labradorite (An 0.43-0.53 Ab 0.43-0.54 Or 0.03-0.05) (Table 1). Moreover, some of the andesine-labradorite phenocrysts have a thin rim of K-feldspar (An 0-0.01 Ab 0-0.33 Or 0.66-1; Fig. 4B and Fig. 5D; Table 1), further described as Group I. In contrast, the microlites and phenocrysts of plagioclase (Supplementary Table D) from altered lapilli tuff, porphyritic andesitic lava flows and andesitic dikes consist of dominant albite (An 0-0.06 Ab 0.89-1 Or 0-0.10; Table 1), further described as Group II. The feldspar separates were characterized by X-ray diffraction and observed by SEM-EDS. The separates with traces of illite or quartz were removed from further REE measurements. The total REE content of andesine-labradorite (Group I) and albite (Group II) have similar patterns and are slightly higher in albite. However, the andesine-labradorite (Group I) and albite (Group II) have both positive have positive Eu anomalies (Group I: [Eu*]= 0.90-1.22; Group II: [Eu*]= 1.04-4.60; Table 2). 5 INSERT Table 1 INSERT Table 2

INSERT Figure

Mineralogy and major elemental compositions of clay minerals

Petrographic observations show "green clays" replacing pyroxene, biotite or feldspars that fill vesicles and intergranular porosity. Similar to [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF], using X-ray diffraction techniques on clay-size fractions allowed for the identification of dominant trioctahedral smectite and smectite-rich (C/S) in less altered andesitic lava flows, as well as chlorite-rich chlorite/smectite mixed-layer and chlorite in more altered andesitic lava flows and lapilli tuff. The occurrence of different clay minerals for similar andesitic lithotypes suggests that hydrothermal alteration is not completely related to the primary magmatic mineralogy but to the influx of external fluid. The in-situ electron microprobe analyses allowed for the identification of the composition of the large chlorite flakes (Fig. 6) in the cleavage of andesine-labradorite and albite and the replacement of augite phenocrysts or micrometer vugs in the andesitic dikes with a light green color (Table 1).

Based on the Fe 2+ /(Fe 2+ +Mg) ratio, these chlorites have compositions of Fe-clinochlore to Mg-chamosite (Supplementary Table E). The observed Fe 2+ /(Fe 2+ +Mg) atomic ratios between 0.47 and 0.64 suggest that values < 0.5 are Fe-clinochlore and those of > 0.5 are Mg-chamosite. These two types of chlorite were also recognized in a regional epithermal system (Fig. 7; Mexias et al., 1990b;[START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] and distal-epithermal halo from the Camaquã Mine (Fig. 7; [START_REF] Troian | Cloritização na Mina Uruguai, Minas do Camaquã, RS, Brasil[END_REF][START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF]. Low Fe 2+ /(Fe 2+ +Mg) proportions are structurally compensated by tetrahedral and octahedral aluminum (Al IV = 1.7 to 3.4; Al VI = 2.7 to 3.11). The Fe-clinochlore to Mg-chamosite in andesitic lava flows and lapilli tuff have lower Fe 2+ +Mg atomic proportions (7.5 to 8.5; atomic ratios of Fe 3+/ Fetot= 0.01 to 0.06) than in andesitic dikes (Fe 2+ +Mg= 9 to 10.1; atomic ratio of Fe 3+ /Fetot= 0.05). However, the chloritization of augite and filling of vugs reflect increasing contents of Fe+Al and Fe+Mg total contents in lapilli tuff and andesitic dikes, respectively.

In addition, the Fe-clinochlore to Mg-chamosite compositions are very similar (Fig. 8A; Table 1) and were described using the same structural formula. 6 INSERT Figure 7 INSERT Figure 8 The occurrence of dominant chlorite/smectite, trioctahedral smectite and corrensite recognized by their dark green color and identified using X-ray diffraction (Fig. 8) was confirmed by electron microprobe measurements. The smectite-rich chlorite/smectite, smectite (Supplementary Table F) and corrensite (Fig. 8B and Figs. 9A-B) represent the dominant hydrothermal phase of andesitic lava flows and andesitic dikes. The dominant trioctahedral smectite (Fig. 8C) has a Mg-saponite composition (Table 1). The dominant chlorite-rich chlorite-smectite (Fig. ,8D; Supplementary Table G) with micrometer-scale fan-shaped particles (Fig. 4C) occurs in altered porphyritic and amygdaloidal andesitic lava flows. The chlorite-rich chlorite-smectite have Al VI and IV contents (Altot 2.21+ 1.25 to 2.46+ 1.48 a.p.f.u.) that are higher in the porphyritic andesitic lava flows than the chloriterich chlorite-smectite (Altot= 1.59+ 0.77 to 1.93+ 1.47) in the amygdaloidal andesitic lava flows. The proportion of Fe and its valency balance are represented by changes in tetrahedral and octahedral Al. The chlorite-rich chlorite-smectite structural formulas vary between porphyritic and amygdaloidal andesitic lava flows (Table 1).

INSERT Figure

INSERT Figure 9

It is possible to confirm the association of albite and chlorite minerals with Cu enrichment. The magmatic and post-magmatic stages were related to albite and chlorite crystallization, while chlorite, chlorite/smectite mixed-layer and the destabilization of sulfides were related to the precipitation of chalcocite-bornite. These mineral associations suggest a sequence of crystallization and hydrothermal alteration over time.

Discussion

Chemistry of magmatic and late-magmatic minerals

The volcanogenic rocks in the Seival area are interpreted as part of the Lavras do Sul Shoshonitic Association [START_REF] Lima | The Lavras do Sul Shoshonitic Association: implications for origin and evolution of neoproterozoic shoshonitic magmatism in southernmost Brazil[END_REF], which are related to the Lavras do Sul granitoids and lamprophyres. The occurrence of lamprophyres [START_REF] Lima | The Lavras do Sul Shoshonitic Association: implications for origin and evolution of neoproterozoic shoshonitic magmatism in southernmost Brazil[END_REF][START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF], andesitic dikes and various volcanic events in the region suggests long and intense episodes of magmatism in the Seival area constrained by the dating of zircon [START_REF] Almeida | Late to Post-Orogenic Brasiliano-Pan-African volcano-sedimentary basins in the Dom Feliciano Belt, Southernmost Brazil[END_REF][START_REF] Janikian | Ages (U-Pb SHRIMP and LA ICPMS) and stratigraphic evolution of the Neoproterozoic volcano-sedimentary successions from the extensional Camaquã Basin, Southern Brazil[END_REF] between 600 ± 2 to 590 ± 6 Ma. The mineralogy of andesitic rocks with andesine-labradorite, augite and Mg-biotite phenocrysts and their whole-rock compositions [START_REF] Lima | The Lavras do Sul Shoshonitic Association: implications for origin and evolution of neoproterozoic shoshonitic magmatism in southernmost Brazil[END_REF][START_REF] Sommer | Potassic and Low-and High-Ti mildly alkaline volcanism In the Neoproterozoic Ramada Plateau, Southermost Brazil[END_REF][START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF] suggest a petrogenetic link with the Lavras do Sul Shoshonitic Association.

Petrogenetic modeling (MELTS Software: Ghiorso and Sack, 1995) used with whole-rock compositions [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF] estimates a liquidus temperature of ca. 1080 °C. The modeling shows a sequence of crystallization initiated by calcic plagioclase followed by low-Ca-pyroxene, late orthoclase and high-Ca pyroxene or biotite (ca. 800 °C). The stages below 800 °C include late-magmatic minerals formed by volatile-rich melt (c.f. [START_REF] Dixon | An experimental study of water and carbon dioxide solubilities in mid-ocean ridge basaltic liquids. Part 1: Calibration and solubility models[END_REF]. In this context, the biotites observed with the higher Al IV contents of less pristine biotite compared with the biotite phenocrysts might represent two stages of biotite crystallization or slightly altered crystals. The late-magmatic stage initiated at solidus temperatures (800 to 500 °C) with volatile oversaturation and the degassing of the melt (c.f. [START_REF] Dixon | An experimental study of water and carbon dioxide solubilities in mid-ocean ridge basaltic liquids. Part 1: Calibration and solubility models[END_REF]. This interpretation is reinforced by the oxygen isotopic values of andesine-labradorite (δ 18 O andesine-labradorite: 6.6 to 8.2 ‰; [START_REF] Fontana | Mass balance and origin of fluids associated to smectite and chlorite/smectite alteration in Seival Mine Cu-Mineralization -Camaquã Basin -Brazil (Part II)[END_REF] showing the magmatic signature of fluids in equilibrium with feldspars [START_REF] Taylor | Stable isotope geochemistry of low temperature processes[END_REF] evolving toward the mixing of meteoric and magmatic fluids for albite (δ 18 O albite: 14.2 to 16.2 ‰; [START_REF] Fontana | Mass balance and origin of fluids associated to smectite and chlorite/smectite alteration in Seival Mine Cu-Mineralization -Camaquã Basin -Brazil (Part II)[END_REF]. Consequently, presume that observed Mg-biotite formation, euhedral F-rich titanite grains and albite are related to late-magmatic crystallization and albitization processes of andesine-labradorite. According to thermodynamic modelling and the literrature (c.f. Higgins and Ribb, 1976;[START_REF] Franz | Aluminous titanite (sphene) from the eclogite zone, south-central Tauern Window, Austria[END_REF][START_REF] Enami | Al-Fe 3+ and F-OH substitution in titanite and constraints on their P-T-dependence[END_REF][START_REF] Tropper | The substitution of Al and F in titanite at high pressure and temperature: experimental constraints on phase relations and solid solution properties[END_REF][START_REF] Harlov | Formation of Al-rich titanite (CaTiSiO4O-CaAlSiO4OH) reaction rims on ilmenite in metamorphic rocks as a function of fH2O and fO2[END_REF][START_REF] Hövelmann | The replacement of plagioclase feldspars by albite: observations from hydrothermal experiments[END_REF][START_REF] Kaur | Two-Stage, extreme albitization of A-type granites from Rajasthan, NW India[END_REF] this albitization process occurs at temperatures below 800 °C, presumably from ca. 600 to 250 °C. The widely observed albite suggests a magmatic to high-temperature hydrothermal system (epithermal-porphyry: [START_REF] Richards | Tectono-magmatic precursors for porphyry Cu-(Mo-Au) deposit formation[END_REF]Sillitoe, 2010 or Iron Oxide-Copper-Gold;[START_REF] Sillitoe | Iron oxide-copper-gold deposits: An Andean view[END_REF][START_REF] Williams | Iron oxide copper-gold deposits: Geology, Space-time distribution, and possible modes of origin[END_REF][START_REF] Groves | Iron oxide copper-gold (IOCG) deposits through Earth history; implications for origin, lithospheric setting, and distinction from other epigenetic iron oxide deposits[END_REF]. The alkaline and acidic fluids in these systems are related to the albitization process and K-rich alteration [START_REF] Perez | An empirically derived kinetic model for albitization of detrital plagioclase[END_REF][START_REF] Boulvais | Cretaceous albitization and dequartzification of Hercynian peraluminous granite in the Salvezines Massif (French Pyrénées)[END_REF] that, to some degree, participated or started the leaching of base metals from the lava [START_REF] Moody | An experimental investigation of the albitization of plagioclase[END_REF][START_REF] Perez | An empirically derived kinetic model for albitization of detrital plagioclase[END_REF][START_REF] Hövelmann | The replacement of plagioclase feldspars by albite: observations from hydrothermal experiments[END_REF][START_REF] Kontonikas-Charos | Albitization and redistribution of REE and Y in IOCG systems: Insights from Moonta-Wallaroo, Yorke Peninsula, South Australia[END_REF]. Non-magmatic basinal brine has also reported in the albitization process [START_REF] Barton | Iron oxide(-Cu-Au-REE-P-Ag-U-Co) systems[END_REF][START_REF] Barton | Evaporitic source model for igneous-related Fe oxide-(REE-Cu-Au-U) mineralization[END_REF]2000), such as in the Nevada porphyry, IOCG deposits [START_REF] Carten | Sodium-calcium metasomatism; chemical, temporal, and spatial relationships at the Yerington, Nevada, porphyry copper deposit[END_REF][START_REF] Dilles | Wall-rock alteration and hydrothermal flow paths about the Ann Mason porphyry copper deposit, Nevada; a 6-km vertical reconstruction[END_REF][START_REF] Dilles | Overview of the Yerington porphyry copper district: magmatic to nonmagmatic sources of hydrothermal fluids, their flow paths, alteration affects on rocks, and Cu-Mo-Fe-Au ores[END_REF][START_REF] Sillitoe | Iron oxide-copper-gold deposits: An Andean view[END_REF][START_REF] Mark | Insights into the genesis and diversity of epigenetic Cu-Au mineralization in the Cloncurry district, Mt Isa Inlier, northwest Queensland[END_REF][START_REF] Kendrick | Mid-crustal fluid mixing in a Proterozoic Fe oxide-Cu-Au deposit, Ernest Henry, Australia: Evidence from Ar, Kr, Xe, Cl, Br[END_REF] or Chilean "Manto-type" deposits, such as Michilla, with the mixing of magmatic and basinal brine [START_REF] Barton | Iron oxide(-Cu-Au-REE-P-Ag-U-Co) systems[END_REF]. In the Seival area, the change of andesine-labradorite (An 0.43-0.53 Ab 0.43-0.54 Or 0.03-0.05) to albite (An 0-0.06 Ab 0.89-1 Or 0-0.10) with rare K-feldspar rims on andesine-labradorite or rare illite attest to the circulation of alkaline fluid. Moreover, the sizes of the quartz and calcite crystals with liquid inclusions did not allow fluid inclusion microthermometry to recognize high-density fluid, as in IOCG-type deposits [START_REF] Reeve | Olympic Dam copperuranium-gold-silver deposit[END_REF][START_REF] Davidson | Proterozoic copper-gold deposits[END_REF]. The REE patterns of albite-rich separates (Group II: Eu*= 1.04-4.60) are similar to the whole-rock (Fig. 10; [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF]. The more positive Eu anomaly of group II and whole-rock (whole-rock: Eu*= 6.23) compared to Group I (Labradorite Eu*= 0.90-1.20). These overall, positive Eu positive anomalies (Eu*= >1; Table 2) higher in the albite (group II; Fig. 10A-B) than andesine-labradorite-rich grains (group I) seem unrealistic assuming, first crystallization of Ca-feldspar then Na-rich feldspar. However, the more positive Eu anomalies of whole-rock and Group II might be related to trace minerals such as apatite inclusions in plagioclase, as mentioned in the petrography section and whole-rock. These inclusions have not been remove totally by preliminary acid-leaching used to clean feldspars of carbonates, Ca-phosphates and Fe oxides [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. The REE signature of Ca-rich feldspar would then represent a chronologically primitive signature in the magmatic chamber, while, the late crystallization include dominant Na-rich feldspar and phosphate traces.

Nevertheless, the similar REE contents with LREE and HREE variations from albites and andesine-labradorite suggest a similar source of REE (REE) that was not affected by fluid dilution, such as that by meteoric fluids. Therefore, the albitization process in the Hilário Formation was related to the neutral to mildly acidic water circulation of Narich magmatic fluid, such as late-magmatic glass interactions with outgassing magmatic fluids (CO2 and H2O), but these data cannot decipher between a magmatic to latemagmatic crystallization with the mixing of magmatic fluids and brine (e.g. IOCG: [START_REF] Barton | Iron oxide(-Cu-Au-REE-P-Ag-U-Co) systems[END_REF][START_REF] Barton | Evaporitic source model for igneous-related Fe oxide-(REE-Cu-Au-U) mineralization[END_REF]2000).

INSERT Figure 10

No mineralization model has yet been proposed for the Seival Mine. [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF] indicated mineralization associated with magmatic and meteoric fluids. The aligned Cu-Ag ore bodies and disseminated mineralizations (see Figure 3) with similar mineral assemblages (albite, chlorite, chlorite/smectite mixed-layers, chalcocite-bornite, barite, and minor calcite, hematite and quartz) could be typical of epithermal deposits [START_REF] Sillitoe | Porphyry copper systems[END_REF] associated with the geothermal influence of andesitic dikes or the Lavras do Sul granitoids.

These observations and interpretations suggest that Seival would be a superficial part of the Lavras do Sul porphyry [START_REF] Mexias | Alterações hidrotermais e mineralizações nas rochas da Associação Plutono-Vulcano-Sedimentar da região de Lavras do Sul-RS[END_REF][START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF]. We assumed that lowhematite contents in the Seival area associated with calcite in small veins and ore deposits without an iron-oxide caprock are clues discarding the hypotheses of an IOCG type deposit or a metallic enrichment related to weathering profile such as Gossan genetic model of ore deposits.

Clay minerals and chlorite during hydrothermal stages

The hydrothermal stages associated with saponite, chlorite/smectite and chlorite precipitations surrounding albite suggest hydrothermal fluids of below 350 °C. Previous studies [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF][START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF] characterized the occurrence of Fe-Curich sulfides associated with chlorite/smectite. The association of Cu-rich sulfides with Fe -Al -Mg rich chlorite/smectite suggests that the Fe 2+ , Mg and Al contents of the clay minerals are related to ore deposition [START_REF] Wilkinson | The chlorite proximitor: A new tool for detecting porphyry ore deposits[END_REF][START_REF] Yoneda | Mineralogical aspects of interstratified chlorite-smectite associated with epithermal ore veins: A case study of the Todoroki Au-Ag ore deposit[END_REF].

Nevertheless, the origin, chemistry and temperature of the fluids are not well characterized.

In the Seival area, crystallography realized by X-ray diffraction and mineral chemistry obtained by electron electron microprobe analyses identified Mg-saponite (smectite), chlorite/smectite mixed-layer and corrensite infilling the porosity or intergranular spaces. The occurrence of dominant clay minerals with Mg-saponite, chlorite/smectite and corrensite in different lithotypes was interpreted as a lithological control of alteration rather than being derived from local equilibrium [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF].

The comparison of the major element compositions of magmatic minerals (Part 4.2), clay mineral (part 4.3) and whole-rock samples [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF] provided information to support this hypothesis. The predominant Fe-Mg-rich clay minerals and their Fetot/Fetot+Mg atomic ratios compared to augite (0.14 to 0.27) and biotite (0.37 to 0.44) indicate that Mg-saponite (0.22 to 0.27) and chlorite/smectite mixed-layers may be derived from the alteration of magmatic minerals and glass. In contrast, the high Fe-clinochlore to Mg-chamosite ratio (0.47 to 0.63; Supplementary Table E) suggests the addition of Fe and Mg during the chloritization process. This interpretation as confirmed by mass-balance calculations performed by [START_REF] Fontana | Mass balance and origin of fluids associated to smectite and chlorite/smectite alteration in Seival Mine Cu-Mineralization -Camaquã Basin -Brazil (Part II)[END_REF].

We estimated the temperatures of chlorites using chemical thermometers [START_REF] Inoue | Application of chemical geothermometry to low-temperature trioctahedral chlorites[END_REF][START_REF] Bourdelle | Low-temperature chlorite geothermometry: a graphical representation based on a T-R 2+ diagram[END_REF]. These thermometers are the only available temperature constraint considering the small sizes of the fluid inclusions [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. We discarded the chemical thermometer of chlorite related to metamorphic conditions and selected one determined in similar lithotypes and pressure conditions. The chosen chemical thermometers use a structural formula with an uncertainty dominantly controlled by the Fe valency and different octahedral layers. Assuming an error of 20% in the Fe distribution, the uncertainty is approximately 50 °C in both calculations. The calculated temperatures of Fe-clinochlore to Mg-chamosite (Supplementary Table E) vary from 129 to 275 °C in the lapilli tuff-andesite (median= 183 ± 39 °C; n= 18) and 172 to 312 °C in andesitic dikes (median= 251 ± 56 °C; n= 8). Moreover, the compositional changes in chlorite in the Seival area compared to those in the Lavras do Sul area (Mexias et al., 1990b;[START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] or the Camaquã Mine [START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF] yield comparable temperatures. These different uncertainties (± 50 °C) and calculated temperatures reflect chloritization below of the minimum temperature of albitization. The higher temperature of chlorite associated with andesitic dikes suggests a temperature related to intrusive bodies or different thermal gradients between lapilli tuff and andesitic dikes.

Hydrothermal evolution and thermodynamic modeling

The chlorite and chlorite/smectite mixed-layers associated with sulfides are typical mineralogical assemblages of hydrothermal deposits [START_REF] Barnes | Geochemistry of Hydrothermal Ore Deposits[END_REF][START_REF] Pirajno | Hydrothermal processes and mineral systems[END_REF][START_REF] Sillitoe | Porphyry copper systems[END_REF]. In the Seival area, different Fe-Cu -rich sulfide assemblages occur in the intergranular space or are mixed with clay minerals [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF].

Hydrothermal alteration minerals are associated with a sequence of precipitations rather than a paragenetic assemblage, as occurs in metamorphic reactions. Therefore, thermodynamic modeling can be erroneous when based on the assumption of an output represented by all of the hydrothermal phases observed. Consequently, we tested the different equilibrium conditions of the hydrothermal stage (below 350 °C) with thermodynamic modeling (PHREEQC interactive; Parkhurst, 1995, rather than SUPCRIT or the equivalent CHONZ Rpackage). The PHREEQC thermodynamic models primarily use minerals with an initial water content and propose secondary minerals as outputs with the new composition of the final fluid. In our case, reactions involved observed magmatic minerals observed (feldspars: andesine-labradorite and albite and Ca-pyroxene: augite) and late-magmatic minerals (biotite, titanite, Fe-titanium oxides and silica-rich glass) reacting with initial fluid (low-concentration water similar to rainfall, [START_REF] Salve | Chemical composition of major ions in rainwater[END_REF], and carbonic fluids (CO2 as recognized in fluid inclusions [START_REF] Fontana | Hydrothermal alteration of volcanic rocks in Seival Mine Cumineralization -Camaquã Basin -Brazil (Part I): Chloritization process and geochemical dispersion in alteration halos[END_REF]. The temperature domain of these calculations was bracketed by the albitization process (< 350 °C) and the calculations of the chlorite thermometer (120 to 320 °C). Each calculation considers a molar proportion of water a hundred times higher than those of minerals and fluids for varying pH values and temperatures below 350 °C. Consequently, the thermodynamic changes in calculated fluids and the dissolution or precipitation of primary and secondary minerals equilibrated at 350, 300, 250, 200 and 150 °C with pH and Eh were adjusted for charge balance and redox conditions. These preliminary calculations indicate multiple solutions with more products than were identified in the altered rocks. Therefore, we forced the software to uniquely consider results with chlorite, calcite, quartz and Fe-Cu rich sulfide or barite, which are here assumed to be products of hydrothermal reactions, without any constraints related to their precipitation or dissolution. These thermodynamic calculations were obtained for neutral (pH: 7) and acidic (pH: 4) initial water conditions. Regardless of the considered temperature, all final waters remained neutral for an initial fluid with a neutral pH (pH: 7 to 7.3), whereas acidic waters changed to a neutral pH (pH 4 to 7.3).

The high-temperature (350 °C) calculations indicate the coprecipitation of albite and titanite with the total consumption of the Ca-rich feldspars and pyroxene, but no minor chlorite or smectite. The conservation of some pyroxene and andesine-labradorite observed in the petrography and the lack of clay minerals suggests unrealistic solutions for hydrothermal alteration forming albite with titanite and chlorite. Consequently, we forced the precipitation of chlorites in a second data set.

-For temperatures between 350 and 250 °C, the chlorite, quartz and calcite associated with pyrite and chalcopyrite can be formed, whereas silica-rich glass, titanite and Ti-magnetite are consumed anorthite, albite and pyroxene are partially dissolved.

-For temperatures between 250 and 150 °C, neutral or acid water dissolved magmatic minerals with predicted precipitations of chlorite, barite, calcite, quartz and hematite with bornite-chalcocite. Mg-saponite (smectite) was precipitated below 200 °C.

-Below 150 °C, the lower activities of Fe 2+ with decreasing HS -/(HS -+SO4) molar ratios increased the saturation with respect to chalcocite and sulfate and Fe oxides, such as barite and hematite. These calculations confirm that pyrite and chalcopyrite were probably precipitated from a dominant magmatic fluid at temperatures between 350 to 250 °C. The further mixing of the magmatic fluid with meteoric water or basinal brine at temperatures varying from 250 to 150 °C promoted chalcocite-bornite deposition. Considering the domain of barite saturation and the lack of supergene alteration or gossan profiles in this region, the lower temperature of the Cu enrichment of sulfide ranged from 150 to 50 °C.

Conclusions

The Seival area contains hydrothermal Cu-sulfide deposits hosted in volcanic rocks with a shoshonitic affinity. Interpretations based on mineralogical and chemical data suggest that volatile-rich magma produced Mg-biotite, followed by late-magmatic alteration with titanite and the albitization of andesine-labradorite (650 to 250 °C), as suggested by the REE contents of albite. Thermodynamic modeling indicates that late albitization (ca. < 350 °C) was associated with the formation of primary pyritechalcopyrite, or that high-temperature chloritization (350 to 250 °C) was associated with bornite-chalcocite. Moreover, the Fetot/Fetot+Mg atomic ratios of Fe-clinochlore to Mgchamosite suggest that fluids altered the pyroxene or residual material with the addition of external Fe compared to smectite precipitation. The high Fetot/Fetot+Mg atomic ratios and high Fe 2+ /Fe 3+ atomic ratios of these chlorites suggest an Fe-rich and reduced fluid in agreement with the migration of Fe, Cu and S species producing sulfides. However, the origin of fluid, whether the mixing of magmatic and meteoric fluids or basinal brines (IOCG, Chilean 'Manto type'), was not identified. Nevertheless, the chloritization process occurred from 312 to 120 °C. Despite the errors related to chlorite thermometers, the ranges [START_REF] Velde | Clay minerals: a physico-chemical explanation of their occurrence[END_REF]adapted from Inoue et al., 1984) with detail showing the smectite, chlorite-rich chlorite-smectite mixed-layer (C/S) and chlorite compositions from Seival Mine, as well as comparison between chlorites analyzes from epithermal Lavras do Sul (Mexias et al., 1990b, c;[START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] and Camaquã Mine [START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF]. normalized to chlorite atom per formula (28 oxygen total anions atoms) in comparison with epithermal system from Lavras do Sul (Mexias et al., 1990b;[START_REF] Bongiolo | Evidence of Ediacaran glaciation in southernmost Brazil through magmatic to meteoric fluid circulation in the porphyry-epithermal Au-Cu deposits of Lavras do Sul[END_REF] and Camaquã Mine [START_REF] Renac | Isotopic fluid changes in a Neoproterozoic porphyry-epithermal system: the Uruguay mine, southern Brazil[END_REF] and graphical representation of low-temperature chlorite geothermometry [START_REF] Bourdelle | Low-temperature chlorite geothermometry: a graphical representation based on a T-R 2+ diagram[END_REF]. Table 1. Summary of mineral, host rock and structural formula of magmatic, magmatic to late-magmatic and hydrothermal phases. Nomenclature of chlorites after [START_REF] Bayliss | Nomenclature of the trioctahedral chlorites[END_REF]. [START_REF] Mcdonough | Composition of the Earth[END_REF] in separate plagioclase grains of the Seival Mine, andesitic lava flows located outside of the area (black line) and whole-rock analyzes [START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF] [((EuN)/(SmN 2 x TbN) 1/3 )] from [START_REF] Lawrence | The behavior of the rare earth elements during estuarine mixing -revisited[END_REF].

Table 2. Measured REE analyzes and normalized values to

Sample (mg

  Petrographic observations indicate the predominance of clay minerals associated with sulfides in the intergranular porosity that are further recognized as chlorite and dominant pyrite-chalcopyrite, or the association of chlorite/smectite mixed-layer (Fig. 4H) with minor pyrite-chalcopyrite and dominant chalcocite-covellite or chalcocite-bornite. The malachite and azurite observed in the different open pits are the product of the recent weathering of Cu-rich sulfides. element compositions of magmatic to late-magmatic minerals and REE compositions of feldspars Phenocrysts and microlites or crystalloclasts of pyroxene in porphyritic andesitic lava flows and andesitic dikes are augite (Wo 0.40-0.47 En 0.32-0.41 Fs 0.12-0.28; Fig. 5A; Supplementary Table

  of temperatures in the lapilli tuff (275 to 129 °C; median= 183 ± 39 °C) and andesitic dikes (312 to 172 °C, median= 251 ± 56 °C) suggest the existence of changing thermal gradients related to the cooling of the lava pile or intrusive dike and fluids with different temperatures at different times. The lowest-temperature stage was related to the widespread formation of Mgsaponite and smectite-rich C/S (200 to 50 °C). The formations of chlorites, chlorite/smectite mixed-layers and Mg-saponite were related to the influx of fluids (meteoric water or basinal brine) at lower thermal fluxes associated with the sulfide assemblage of bornite-chalcocite, chalcocite, and barite with the increasing concentration of sulfate. Consequently, the petrographic association of albite and chlorite with pyrite and chalcopyrite suggests that the albitization to chloritization stage and structural control may be prospective guides for Cu fertile magmatic systems. The chlorite/smectite mixed-layers emphasized favorable Cu-enriched zones, such as fluid circulation in faults or along dikes and percolation in the porosity of the lapilli tuff.

Figures

  Figures and Tables Legends

Figure 1 .

 1 Figure 1. Geological setting of the study area. A) Schematic Sul-rio-grandense Shield map (modified from Hartmann et al., 2007); B) Central-western Camaquã Basin geological map with Seival Mine area and Cu occurrences localization (modified from[START_REF] Toniolo | Projeto BANEO-Metalogenia das Bacias Neoproterozóico-Eopaleozóicas do Sul do Brasil -Bacia do Camaquã[END_REF][START_REF] Gastal | Lavras granite emplacement and gold mineralization during the development of the post-collisional volcano-plutonic center, west of the Sul-riograndense Shield: Geophysical and structural data[END_REF]. Keys: 1= Seival Mine (Cu and Ag); 2= Silveira Mine (Cu); 3= Crespos Mine (Cu); 4= Volta Grande and Merita Mine (Cu and Au).

Figure 2 .

 2 Figure 2. Geological map of the Seival Mine. Sequence of lapilli tuff, andesitic lava flows and volcanic agglomerate with andesitic and trachyandesitic dike (NE direction) from Hilário Formation (HF), polymictic conglomerate and vesicular lava flows from Santa Fé Formation (SFF), rhyolite dikes of Acampamento Velho Formation (AVF), faults, mineralization projections, inactive open pit mines and bore-hole localization (modified from[START_REF] Reischl | Mineralizações cupriferas associadas a vulcânicas na Mina do Seival. In: XXX[END_REF][START_REF] Lopes | Caracterização petrográfica e geoquímica da sequência magmática da Mina do Seival, Formação Hilário (Bacia do Camaquã -Neoproterozoico)[END_REF]. Keys: 1= Barita Mine; 2= João Dahne Mine; 3= Morcego Mine; 4= Meio Mine; 5= Cruzeta Mine; 6= Alcides Mine.

Figure 3 .

 3 Figure 3. Mineralization in the Seival Mine area. A) Cu soil anomaly (modified from Reischl, 1978) and inactive open pit mines, faults and Cu-mineralization; B) Schematic section of alteration zones in Hilário Formation. Keys: Chl= Chlorite; C/S= Chlorite/smectite mixed-layer; Hem= Hematite; Tit= Titanite; Cal= Calcite; Qtz= Quartz; Cc= Chalcocite; Bn= Bornite; Smec= Smectite.

Figure 4 .

 4 Figure 4. Macroscopic photograph (A and B), photomicrograph in natural (C and F) and polarized light (D, E, G and H). A) Hand sample containing altered pyroclasts of lapilli tuff; B) Hand sample with plagioclase and altered groundmass in andesite dike; C) Pervasive clay minerals alteration in lapilli tuff; D) Zoned phenocryst of plagioclase with indication of unaltered andesine-labradorite and altered plagioclase with albite composition in andesitic dike; E) Clinopyroxene and vesicle fulfilled by smectite-rich chlorite/smectite in less altered amygdaloidal andesitic lava flows; F) Amygdaloidal andesitic lava flows pyroclast of lapilli tuff fulfilled by chlorite, calcite, sulfide, titanite and quartz; G) Smectite in less altered andesitic lava flows; H) Vesicle fulfilled by chlorite/smectite mixed-layers in andesitic lava flows. Keys: Pl= Plagioclase; Sul= Sulfide; Cal= Calcite; Tit= Titanite;

Figure 5 .

 5 Figure 5. Plots of mineral compositions. A) Ca-Mg-Fe clinopyroxenes showing augite compositions in andesitic lava flows and andesitic dike; B) Biotite (white point) and less pristine biotite (gray point) in the Altot vs Al VI diagram; C) Al+Fe 3+ vs Ti and Al vs Fe binary diagram of the hydrothermal titanite compositions (diagram extracted from Cao et al., 2015); D) An-Ab-Or ternary feldspar diagram showing albitization in andesine-labradorite and rims with K-feldspar in some zoned plagioclase (An= Anorthite; Ab= Albite; Or= Orthoclase).

Figure 6 .

 6 Figure 6. Chemical compositions of a series of saponite, chlorite and chlorite/smectite mixed-layers in projection M + , 4Si and 3R 2+[START_REF] Velde | Clay minerals: a physico-chemical explanation of their occurrence[END_REF] adapted from Inoue et al., 1984)

Figure 7 .

 7 Figure 7. Atomic proportions of chlorites in vein and groundmass of andesitic dikes presented in Wiewiora and Weiss diagram (1990), of Si and divalent transition metals

Figure 8 .

 8 Figure 8. X-ray diffraction patters of < 0.4 μm clay-size fraction of chlorite (A), corrensite (B), smectite (C) and chlorite/smectite (C/S) mixed-layer (D). Keys: Air dried (black line); EG= Ethylene glycol solvation (gray line); Heating treatment (light gray line); Chl= Chlorite; Smec= Smectite.

Figure 9 .

 9 Figure 9. S.E.M. images obtained from drill hole fresh rock sample fragment of amygdaloidal andesitic lava flows described by Fontana et al. (2017). A) Albite fragment associated with corrensite clay minerals of the andesitic lava flows groundmass; B) Detail of corrensite morphology of the altered andesitic lava flows groundmass. Keys: Ab= Albite; Cor= Corrensite.

Figure 10 .

 10 Figure 10. REE normalized patterns by the chondrite values (McDonough and Sun, 1995). A) Andesine-labradorite with slight albitization of group I; B) Albite-rich plagioclases of group II.

  . Keys: And= Andesitic lava flows; AD= Andesitic dike; Outs. area= Andesitic lava flows located of outside studied area; Light REE= La to Sm; Heavy REE= Eu to Lu; ΣREE= Sum of total concentration of not normalized rare earth elements; Eu*= The value of the Eu anomaly calculated by the formula [Eu*]= [((EuN)/(SmN x GdN) 1/2 )] from Worrall and Pearson (2001) or [Eu*]=

Acknowledgements

This study is part of the cotutelle doctoral thesis of Rodrigo Winck Lopes at Universidade Federal do Rio Grande do Sul and Université Côte d´Azur. We wish to thank the Conselho Nacional do Desenvolvimento e Pesquisa (CNPq), CAPES and Programa Ciências Sem Fronteiras (Process number: 200081/2014-4) for financial support. We thank Votorantim Metais for allowing access to drill-cores. We thank Robert Ayuso, Karel Breiter, Douglas Kreiner, Bruno Lemiere, David Lentz and anonymous reviewer for their constructive remarks during the reviewing and editing processes. We wish to thank Everton Bongiolo and Maria José Mesquita for additional revision. We wish to thank the members of the research group Marcelo Lindenberg, Bruno Petracco and the technician laboratory: Denise Canarim, Susan Drago, Edgar Bercht and Lucas Jantsch.

Supplementary Table

Representative compositions of pyroxene (A), biotite (B), titanite (C), feldspar (D) and clay minerals as chlorite (E), smectite (F) and chlorite/smectite mixed-layer (G) analyzes and structural formula. Chlorite temperatures values are showed in Supplementary Table E [START_REF] Inoue | Application of chemical geothermometry to low-temperature trioctahedral chlorites[END_REF][START_REF] Bourdelle | Low-temperature chlorite geothermometry: a graphical representation based on a T-R 2+ diagram[END_REF].