Timing between granitoid emplacement and associated gold mineralization: examples from the ca. 2.7 Ga Harare–Shamva greenstone belt, northern Zimbabwe

1996 ◽  
Vol 33 (7) ◽  
pp. 981-992 ◽  
Author(s):  
M. L. Vinyu ◽  
H. A. Jelsma ◽  
R. Frei
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Time Frame ◽  
Gold Deposits ◽  
Isotopic Signatures ◽  
Ore Minerals ◽  
Granitoid Emplacement ◽  
Wide Scale ◽  
Temporal And Spatial ◽  
Favorable Conditions

Structurally controlled Late Archaean gold mineralizations associated with felsic plutons in the Harare–Shamva greenstone belt, Zimbabwe, are synchronous with the emplacement of their hosts. The ages of these mineralizations are identical to those reported from other mesothermal gold deposits elsewhere in the Zimbabwe Craton. The Pb and Nd isotopic signatures of the host plutons are compatible with a direct mantle or a short crustal residence period for the protoliths to the host intrusions. The coincidence of the Pb-isotope data from ore minerals with the whole-rock trends (errorchrons) of their host intrusives strongly suggests that the gold could have a magmatic, rather than a metamorphic, source. There is no evidence from the Pb isotopes of significant involvement of older basement in the genesis of gold deposits associated with felsic intrusions in the Harare–Shamva greenstone belt. On a craton-wide scale, the time frame around 2.65 Ga represents a period of significant crustal growth (through addition of mantle-derived magma), deformation, and metamorphism. The temporal and spatial coincidence of these three parameters has created favorable conditions for the emplacement of the largest class of Archaean gold mineralizations that are currently known in the country.

scholarly journals Oxygen Fugacity and Volatile Content of Syntectonic Magmatism in the Neoarchean Abitibi Greenstone Belt, Superior Province, Canada

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 966
Author(s):  
Baptiste Madon ◽  
Lucie Mathieu ◽  
Jeffrey H. Marsh
Keyword(s):  
Oxygen Fugacity ◽  
Greenstone Belt ◽  
Inductively Coupled Plasma ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Hydrothermal Systems ◽  
Chemical Diversity ◽  
Temporal Association ◽  
Volatile Content ◽  
Abitibi Subprovince

Neoarchean syntectonic intrusions from the Chibougamau area, northeastern Abitibi Subprovince (greenstone belt), may be genetically related to intrusion related gold mineralization. These magmatic-hydrothermal systems share common features with orogenic gold deposits, such as spatial and temporal association with syntectonic magmatism. Genetic association with magmatism, however, remains controversial for many greenstone belt hosted Au deposits. To precisely identify the link between syntectonic magmas and gold mineralization in the Abitibi Subprovince, major and trace-element compositions of whole rock, zircon, apatite, and amphibole grains were measured for five intrusions in the Chibougamau area; the Anville, Saussure, Chevrillon, Opémisca, and Lac Line Plutons. The selected intrusions are representative of the chemical diversity of synvolcanic (TTG suite) and syntectonic (e.g., sanukitoid, alkaline intrusion) magmatism. Chemical data enable calculation of oxygen fugacity and volatile content, and these parameters were interpreted using data collected by electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry. The zircon and apatite data and associated oxygen fugacity values in magma indicate that the youngest magmas are the most oxidized. Moreover, similar oxygen fugacity and high volatile content for both the Saussure Pluton and the mineralized Lac Line intrusion may indicate a possible prospective mineralized system associated with the syntectonic Saussure intrusion.

Geochronological constraints on the timing of magmatism, deformation, and gold mineralization in the Red Lake greenstone belt, northwestern Ontario

1987 ◽  
Vol 24 (7) ◽  
pp. 1302-1320 ◽  
Author(s):  
F. Corfu ◽  
A. J. Andrews
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Time Frame ◽  
Time Interval ◽  
Major Activity ◽  
Red Lake ◽  
Sequence Of Events ◽  
Volcanic Sequence ◽  
Two Phases ◽  
Geochronological Constraints

The paper presents U–Pb ages on zircon, baddeleyite, titanite, rutile, and monazite from volcanic and plutonic rocks of the Red Lake greenstone belt in the northern Superior Province. The purpose of the study was to refine a previously outlined time frame for the volcanic evolution of the belt, define the time of major plutonism and deformation, and constrain the age of formation of gold deposits.Volcanism spanned at least 270 Ma between 3000 and 2730 Ma. New ages of 2989 ± 3 and 2894 ± 2 Ma for units of a lower volcanic sequence and [Formula: see text] and 2744 ± 1 Ma for units of an upper volcanic sequence corroborate and refine the previously established relationships. Local gabbroic and felsic intrusions cutting through the lower sequence yield ages of 2870 ± 15 and [Formula: see text], respectively.Volcanism was succeeded by major plutonism, deformation, alteration, and metamorphism between about 2730 and 2700 Ma. These processes were interrelated and progressed as a relatively continuous sequence of events accentuated by major activity during two phases at about 2720–2715 and 2705–2700 Ma. Early plutonism recorded at 2731 ± 3 Ma in the northern batholith complex was succeeded in the eastern part of the belt by a major tectonic – plutonic phase that includes intrusion of the McKenzie Stock at 2720 ± 2 Ma, the Dome Stock at 2718 ± 1 Ma, alteration and deformation of the Abino dyke at [Formula: see text], and emplacement of a late tectonic dyke at 2714 ± 4 Ma. A subsequent phase is recorded at 2701 ± 1.5 Ma in the Wilmar dyke. Major deformation and metamorphism in the western part of the belt is constrained by an age of 2729 ± 1.5 Ma for the deformed Red Crest Stock and a titanite age of 2705 ± 8 Ma for an undeformed crosscutting mafic dyke at Rowan Lake. Peak activity was probably coeval with emplacement of the adjacent batholithic phases at 2717 Ma. In the central part of the belt the deformation is constrained by ages of 2718 ± 1 Ma for the Dome Stock and 2699 ± 4 Ma for titanite of a crosscutting, undeformed diorite dyke and probably peaked during intrusion of the main phase of the Killala–Baird batholith at 2704 ± 1.5 Ma.Gold mineralization, which is spatially related to zones of intense shear deformation and alteration, is constrained within the time interval of 2720–2700 Ma by U–Pb ages on several felsic to mafic intrusive rocks that both pre- and post-date deformation and mineralization in different sections of the belt. These data indicate that mineralization occurred significantly later than the termination of volcanism.

scholarly journals GEOLOGY AND ORE MINERALISATION OF NEOGENE SEDIMENTARY ROCK HOSTED LS EPITHERMAL GOLD DEPOSIT AT PANINGKABAN, BANYUMAS REGENCY, CENTRAL JAVA, INDONESIA

2015 ◽  
Vol 7 (2) ◽  
pp. 75
Author(s):  
Arifudin Idrus ◽  
Fahmi Hakim ◽  
I Wayan Warmada ◽  
Mochammad Aziz ◽  
Jochen Kolb ◽  
...  
Keyword(s):  
Base Metal ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Epithermal Gold ◽  
Central Java ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Miners

Low suphidation (LS) epithermal gold deposits were recently found in the Paningkaban area, Central Java province, Indonesia, with more than five hundred artisanal gold miners currently operating in the area. This study is aimed to understand the geological factors controlling the gold mineralization and to characterize the alteration and ore mineralogy of the deposit. Several epithermal veins/veinlets trending N–S, NW–SE, and NE–SW are hosted by Tertiary turbiditic volcanoclastic sedimentary rocks of the Halang formation. This formation is composed of looping gradation of sandstone and siltstone units. Pre- and syn-mineralization structures such as extension joints, normal sinitral fault and sinitral fault control the gold mineralization. Fault movements formed dilational jogs manifested by NW-SE-trending en-echelon tension gash veins. Four main alteration zones are identified: (a) phyllic, (b) argillic, (c) sub propylitic and (d) weak subpropylitic. Ore minerals consist of native gold, electrum, native silver, pyrite, chalcopyrite, sphalerite, galena, arsenopyrite, cubanite, marcasite, covellite and tennantite, which are commonly associated withargillic alteration. Vein structures such as massive, swarm and low angle veins, stockwork and veins dispersed in diatreme breccia are present. Normal banded, cockade, crustiform, bladed carbonates as well as, comb and saccharoidal features are the typical vein textures. It is noteworthy that the veins are basically composed of carbonate with minor quartz at gold grades of up to 83 g/t Au. Based on the vein structures and textures, four stages of ore mineralization were developed consisting of (a) early stage (fluidized breccia and quartz vein), (b) middle stage (carbonate base metal), (c) late stage (late carbonate), and supergene stage. Gold mineralization originated mainly during middle and late stages, particularly in association with cockade, crustiform, bladed carbonate base metal veins. Based on those various features, the LS epithermal deposit in the study area is categorized as carbonate-base metalgold mineralization type.

Geology, lithogeochemistry, and significance of porphyry intrusions associated with gold mineralization within the Timmins–Porcupine gold camp, Canada

2019 ◽  
Vol 56 (4) ◽  
pp. 399-418 ◽  
Author(s):  
Peter J. MacDonald ◽  
Stephen J. Piercey
Keyword(s):  
Partial Melting ◽  
Greenstone Belt ◽  
Deformation Zone ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Crustal Thickening ◽  
Abitibi Greenstone Belt ◽  
Crustal Structures ◽  
Intrusive Rocks ◽  
Intrusive Suite

The Timmins–Porcupine gold camp, Abitibi greenstone belt, is host >60 Moz of Au with many gold deposits spatially associated with porphyry intrusions and the Porcupine–Destor deformation zone (PDDZ). Porphyry intrusions form three suites. The Timmins porphyry suite (TIS) consists of high-Al tonalite–trondjhemite–granodiorite (TTG) with calc–alkalic affinities and high La/Yb ratios and formed during ∼2690 Ma D1-related crustal thickening and hydrous partial melting of mafic crust where garnet and hornblende were stable in the residue. The Carr Township porphyry intrusive suite (CIS) and the granodiorite intrusive suite (GIS) also have high-Al TTG, calc-alkalic affinities, but were generated 10–15 million years after the TIS; the CIS were generated at shallower depths (during postorogenic extension?) with no garnet in the crustal residue, whereas the GIS formed during D2 thrust-related crustal thickening and partial melting where garnet was stable in the residue. Gold mineralization is preferentially associated with the TIS, and to a lesser extent the GIS, proximal to the PDDZ. Intrusions near mineralization have abundant sericite, carbonate, and sulphide alteration. These intrusions exhibit low Na2O and Sr, and high Al2O3/Na2O, K2O, K2O/Na2O, Rb, and Cs, (i.e., potassic alteration); sulfide- and carbonate-altered porphyries have high (CaO + MgO + Fe2O3)/Al2O3 and LOI values. Although porphyries are not genetically related to gold mineralization, they are spatially related and are interpreted to reflect the emplacement of intrusions and subsequent Au-bearing fluids along the same crustal structures. The intrusive rocks also served as structural traps, where gold mineralization precipitated in dilatant structures along the margins of intrusions during regional (D3?) deformation.

The sequence of magmatic and mineralization events in the Abitibi greenstone belt: isotopic evidence from Taylor Township, Timmins area, northern Ontario, Canada

1995 ◽  
Vol 32 (8) ◽  
pp. 1221-1235 ◽  
Author(s):  
J. M. Worden ◽  
G. L. Cumming ◽  
D. Krstic
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Pb Isotope ◽  
Northern Ontario ◽  
Abitibi Greenstone Belt ◽  
Igneous Activity ◽  
The Difference ◽  
A Minor ◽  
Hydrothermal Event

Samples from the Porphyry deposit and the Shoot zone prospect of St. Andrew Goldfields Ltd. in Taylor Township near Matheson, Ontario, have been dated by several different techniques and utilized as a test of the use of Pb-isotope measurements in determining the time of mineralization in gold deposits of the Abitibi greenstone Belt. Clear and abraded zircons from an altered "sulfidic porphyry" unit yield a well-defined age of 2697.3 ± 1.3 Ma, indicating that the original intrusive rock unit containing these zircons was either latest synvolcanic or earliest syntectonic. Larger "bulk" samples of zircon from the same unit contain many altered and cracked grains, and yield an age of 2682 ± 4 Ma, close to the peak of syntectonic igneous activity. Pb/Pb isochrons determined from sulfide samples in mineralized material from the Taylor "porphyry zone" yield a two-stage model age of 2663 ± 17 Ma, and suggest that mineralization postdates the syntectonic granitoids. These Pb-isotope data are compared with isotope ratios determined on samples from the Dome mine. For these latter samples, the isotopic ratios indicate that an earlier mineralization event was reset at 2266 ± 49 Ma, suggesting to us that the sulfides, and hence gold mineralization, were remobilized at this later time. It is proposed that this remobilization is responsible for a significant benefaction of the gold ore and may make the difference between a mineable orebody and an uneconomic prospect. This time of remobilization corresponds well with some Rb/Sr dates in the Abitibi Province and may represent a previously unrecognized, but significant hydrothermal event. Rb/Sr ages on volcanic units yield ages of 2520–2580 Ma, consistent with similar ages in the surrounding area. They may represent cooling following a thermal event associated with the intrusion of the latest granitic plutons. A minor hydrothermal event at ~1600 Ma seems to have reset the Rb/Sr system in some micas and affected some pyrite samples, resulting in the formation of late carbonate and hematite.

scholarly journals Structural Evolution of the Rio das Velhas Greenstone Belt, Quadrilátero Ferrífero, Brazil: Influence of Proterozoic Orogenies on Its Western Archean Gold Deposits

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 983
Author(s):  
Orivaldo Ferreira Baltazar ◽  
Lydia Maria Lobato
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Structural Evolution ◽  
Shear Zones ◽  
Gold Deposits ◽  
Normal Faults ◽  
Small Scale ◽  
Crenulation Cleavage ◽  
Quadrilátero Ferrífero ◽  
Tectonic Transport

The Quadrilátero Ferrífero region is located in the extreme southeast of the Brasiliano São Francisco craton, Minas Gerais state, Brazil. It is composed of (i) Archean TTG granite-gneaissic terranes; (ii) the Archean Rio das Velhas greenstone belt; (iii) the Proterozoic metasedimentary and metavolcano-sedimentary covers. The Rio das Velhas rocks were deposited in the synformal NW–SE-directed Nova Lima basin. The Archean deformation converted the Nova Lima basin into an ample synclinorium with an eastern inverted flank. Archean orogenic gold mineralization within the Rio das Velhas greenstone belt rocks is controlled by NNW–SSE-directed, Archean regional shear zones subparallel to the strata of the Nova Lima synclinorium borders. Transamazonian and Brasiliano orogenies are superposed onto the Archean structures that control gold mineralization. In the eastern domain, Brasiliano fold-and-fault belts prevail, whereas in the western domain Archean and Transamazonian structures abound. The present study focus mainly is the western domain where the Cuiabá, Morro Velho, Raposos, Lamego and Faria deposits are located. Gold orebodies plunge to the E–NE and are tectonically controlled by the Archean D1–D2 deformation. The D3 Transamazonian compression—Which had a SE–NW vector sub-parallel to the regional mineralized Archean foliation/bedding—Buckled these structures, resulting in commonly open, synformal and antiformal regional folds. These are well documented near the gold deposits, with NE–SW axial traces and fold axes plunging to E–NE. Such folds are normal to inverted, NW-verging, with an axial planar foliation dipping moderately to the SE. The Transamazonian compression has only been responsible for the reorientation of the mineralized Archean gold ores, due to coaxial refolding characterized by an opposite tectonic transport. It has therefore not caused any other significant changes. Thrust shear zones, sub-parallel to the strong Transamazonian foliation, have given rise to localized metric segmentation and to the dislocation of gold orebodies. Throughout the region, along the towns of Nova Lima to Sabará, structures pertaining to the Brasiliano Araçuaí orogeny are represented only by gentle folding and by a discrete, non-pervasive crenulation cleavage. Thrust-shear zones and small-scale normal faults have caused, at most, metric dislocations along N–S-oriented planes.

Chapter 8: The World-Class Gold Deposits in the Geita Greenstone Belt, Northwestern Tanzania

2020 ◽  
pp. 163-183
Author(s):  
P.H.G.M. Dirks ◽  
I. V. Sanislav ◽  
M. R. van Ryt ◽  
J.-M. Huizenga ◽  
T. G. Blenkinsop ◽  
...  
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Normal Faulting ◽  
Rock Interaction ◽  
Northwestern Tanzania ◽  
The Matrix ◽  
Igneous Activity ◽  
History Of ◽  
Gold Bearing

Abstract The Geita mine is operated by AngloGold Ashanti and currently comprises four gold deposits mined as open pits and underground operations in the Geita greenstone belt, Tanzania. The mine produces ~0.5 Moz of gold a year and has produced ~8.3 Moz since 2000, with current resources estimated at ~6.5 Moz, using a lower cut-off of 0.5 g/t. The geologic history of the Geita greenstone belt involved three tectonic stages: (I) early (2820–2700 Ma) extension (D1) and formation of the greenstone sequence in an oceanic plateau environment; (II) shortening of the greenstone sequence (2700–2660 Ma) involving ductile folding (D2–5) and brittle-ductile shearing (D6), coincident with long-lived igneous activity concentrated in five intrusive centers; and (III) renewed extension (2660–2620 Ma) involving strike-slip and normal faulting (D7–8), basin formation, and potassic magmatism. Major gold deposits in the Geita greenstone belt formed late in the history of the greenstone belt, during D8 normal faulting at ~2640 Ma, and the structural framework, mineral paragenesis, and timing of gold precipitation is essentially the same in all major deposits. Gold is hosted in iron-rich lithologies along contacts between folded metaironstone beds and tonalite-trondhjemite-granodiorite (TTG) intrusions, particularly where the contacts were sheared and fractured during D6–7 faulting. The faults, together with damage zones created along D3 fold hinges and D2–3 hydrothermal breccia zones near intrusions, formed microfracture networks that were reactivated during D8. The fracture networks served as conduits for gold-bearing fluids; i.e., lithologies and structures that trap gold formed early, but gold was introduced late. Fluids carried gold as Au bisulfide complexes and interacted with Fe-rich wall rocks to precipitate gold. Fluid-rock interaction and mineralization were enhanced as a result of D8 extension, and localized hydrofracturing formed high-grade breccia ores. Gold is contained in electrum and gold-bearing tellurides that occur in the matrix and as inclusions in pyrrhotite and pyrite. The gold mineralization is spatially linked to long-lived, near-stationary intrusive centers. Critical factors in forming the deposits include the (syn-D2–6) formation of damage zones in lithologies that enhance gold precipitation (Fe-rich lithologies); late tectonic reactivation of the damage zones during extensional (D8) faulting with the introduction of an S-rich, gold-bearing fluid; and efficient fluid-rock interaction in zones that were structurally well prepared.

Alteration mineralogy, fluid inclusions and stable isotope studies from Chigargunta and Bisanatham gold deposits, South Kolar Greenstone Belt, Dharwar Craton, India: Implications on genesis of gold mineralization

2019 ◽  
Vol 111 ◽  
pp. 102946
Author(s):  
Debasis Pal ◽  
Sakthi Saravanan Chinnasamy ◽  
Swapnendu Goon ◽  
Manish M. John ◽  
Subhasish Ghosh
Keyword(s):  
Stable Isotope ◽  
Fluid Inclusions ◽  
Greenstone Belt ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Dharwar Craton ◽  
Isotope Studies

scholarly journals A succession of near-orthogonal horizontal tectonic shortenings in the Paleoproterozoic Central Lapland Greenstone Belt of Fennoscandia: constraints from the world-class Suurikuusikko gold deposit

2019 ◽  
Vol 55 (8) ◽  
pp. 1605-1624 ◽  
Author(s):  
M. Sayab ◽  
F. Molnár ◽  
D. Aerden ◽  
T. Niiranen ◽  
J. Kuva ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Greenstone Belt ◽  
Gold Mineralization ◽  
Structural Features ◽  
Gold Deposits ◽  
Strike Slip ◽  
Aerial Images ◽  
Stress Regime ◽  
Slip Regime ◽  
Central Lapland Greenstone Belt

Abstract The relative and absolute timing of orogenic gold deposits in complex structural settings are active and challenging topics of research, especially in Precambrian greenstone belts. The Suurikuusikko gold deposit in Central Lapland Greenstone Belt is currently the largest primary gold producing deposit in Europe, located on a slight bend of the strike-slip Kiistala shear zone (KiSZ). Gold is refractory and locked inside arsenopyrite and pyrite. In this study, different structural features were investigated along the KiSZ from the recently stripped Etelä pit, which is the southern extension of the Suurikuusikko ore body. Our data source ranges from aeromagnetic to high-resolution aerial images, X-ray computed tomography scans of selected rock samples and regional geological and geophysical datasets. The KiSZ has recorded five discrete deformation phases, spanning between ca. 1.92 and 1.76 Ga. The refractory gold at the Suurikuusikko deposit formed during E-W contraction related to the D1 thrusting phase. This was followed by a N-S shortening event (D2), where most of the strain was taken up by the northern and southern thrusts. Tectonic vectors then switched from N-S to NE-SW and, as a result, dextral strike-slip regime (D3) commenced along the KiSZ. This event exsolved invisible gold from the sulfides and remobilized it along with fractures. A near-orthogonal switch of the regional stress regime from NE-SW to NW-SE flipped the kinematics of the KiSZ from dextral to sinistral (D4). The last deformation phase (D5) produced widespread veining under E-W contraction and secured gold mineralization at the Iso-Kuotko gold deposit within the KiSZ.

scholarly journals CLASSIFICAÇÃO DOS VEIOS QUARTZO-CARBONÁTICOS DE DEPÓSITOS AURÍFEROS NO LINEAMENTO CÓRREGO DO SÍTIO, QF, MG

2013 ◽  
Author(s):  
Marco Aurélio Sequetto Pereira ◽  
Lydia Maria Lobato ◽  
Carlos Alberto Rosière ◽  
Rosaline C. Figueiredo e Silva
Keyword(s):  
Greenstone Belt ◽  
Gold Mineralization ◽  
Mineralogical Composition ◽  
Shear Zones ◽  
Gold Deposits ◽  
Lode Gold ◽  
Free Gold ◽  
Quadrilátero Ferrífero ◽  
Lode Gold Deposits ◽  
Mineral Replacement

Os depósitos tipo lode-gold orogênicos Cachorro Bravo, Laranjeiras e Carvoaria, associados ao lineamento regional Córrego doSítio (CdS), estão localizados na porção leste do Quadrilátero Ferrífero, sudeste do cráton São Francisco. São hospedados em rochasmetassedimentares turbidíticas arqueanas do greenstone belt Rio das Velhas e controlados por zonas de cisalhamento NE-SW. Diques esoleiras metamáficos pré- a pós-deformacionais ocorrem intimamente associados à mineralização aurífera e constituem excelentes guiasprospectivos em lineamentos regionais como CdS. Cinco sistemas de veios, V1 a V5, são classificados de acordo com a composiçãomineralógica, textura, orientação, distribuição espacial e geometria. Dois tipos de quartzo ocorrem nestes veios, sendo o tipo 1predominantemente fumê, cedo-hidrotermal, e o tipo 2 leitoso, recristalizado. Apenas os veios V1 (fault-fill veins) são relacionados àmineralização aurífera através da paragênese arsenopirita+pirita+pirrotita+berthierita+ ouro livre; se desenvolvem concordantes à foliaçãomilonítica, S1m, e estão deformados. Veios V2 (oblique-extension veins) são associados temporalmente aos V1 e, embora não estejammineralizados nos depósitos estudados, são contemporâneos ao estágio mineralizador. Estes dois sistemas foram formados em regimedúctil-rúptil. Veios V3 (extension e breccia veins) são tardios à mineralização e representam um estágio posterior do fluido em regimedúctil-rúptil a rúptil; podem estar relacionados à mudança do campo de tensão regional e colocação dos diques tardios Db1. Os veios V4(extension veins) possuem reações de substituição mineral que marcam a hidratação do sistema e podem se associar ao relaxamento dasforças compressivas. Já os veios V5 (vein stockworks) ocorrem apenas em diques e soleiras metamáficos Db1 e estudos de inclusões fluidasindicam que esses contêm fluido diferente dos outros sistemas.Palavras Chave: Classificação de veios quartzo-carbonáticos, ouro orogênico, zonas de cisalhamento, diques e soleiras. ABSTRACTQUARTZ-CARBONATE VEIN CLASSIFICATION OF AURIFEROUS DEPOSITS IN CÓRREGO DO SÍTIO LINEAMENT, QF, MG. Theorogenic-type, lode-gold deposits Cachorro Bravo, Laranjeiras and Carvoaria, associated with the Córrego do Sítio (CdS) regional lineamentare located in the eastern portion of the Quadrilátero Ferrífero region, southern São Francisco craton, Brazil. They are hosted in Archeanmetaturbiditic rocks of the Rio das Velhas greenstone belt and controlled by NE-SW shear zones. Pre- to post-deformational dikes/sills areclosely related to gold mineralization and constitute excellent prospective guides in these regional lineaments such as CdS. Five veinsystems have been classified, V1 to V5, in accordance to their mineralogical composition, texture, orientation, spatial distribution andgeometry. Two types of quartz occur in these veins, with type 1 being predominantly smoky, early hydrothermal, and type 2 a milky,recrystallized quartz. Only V1 veins (fault-fill vein) are related to gold and have a paragenesis with arsenopyrite+pyrite+pyrrhotite+berthierite+ free gold; they develop along the mylonitic foliation S1m, and have been deformed. The V2 veins (oblique-extension veins) areassociated temporally with V1 and although non-mineralized, in the studied deposits they are contemporaneous to the gold stage. Thesetwo systems are formed under a ductile-brittle regime. The V3 veins (extension and breccias veins) are post gold and represent a late-stagehydrothermal fluid under ductile-brittle to brittle regime; they may be related to changes in the stress field and to the emplacement oflate-stage Db1 dikes. The V4 veins (extension veins) have mineral replacement reactions that represent hydration of the system associatedwith the relaxation of the compressive field. The V5 veins (stockwork style) are limited to metamafic Db1 dykes/sills and fluid inclusionstudies indicate that they contain a different fluid from the others systems.Keywords: Quartz-carbonate vein classification, orogenic gold, shear zones, dikes/sills

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