Fluid inclusion study of tin-mineralized greisens and quartz veins in the Penouta apogranite (Orense, Spain)

AbstractThe Penouta deposit is associated with a small Hercynian apogranite stock that intrudes Precambrian-Cambrian gneisses of the Ollo de Sapo Formation. Tin ore occurs as disseminations of cassiterite in the apogranite and as greisenized zones and quartz veins which traverse both the alkaline leucogranite and the surrounding metamorphic country rocks.A fluid-inclusion study, utilizing microthermometric, crushing tests and Raman spectroscopic techniques on quartz from an intragranitic vein and a greisen of the host rock, indicates that the evolution of fluids was similar in both samples and occurred in the three main stages: The first stage is characterized by complex CO2 (CO2-N2-CH4-H2S) and complex CO2 aqueous (H2O-NaCl-CO2-N2-CH4-H2S) fluids of low salinity (Tm ice > −6°C), homogenization temperatures between 250 and 410°C homogenization pressures below 900 bars, and thermobarometric trapping conditions with temperatures below 700°C and pressures below 3250 bars. These fluids were probably responsible for the greisenization of the apogranite and wall rocks, and the precipitation of cassiterite. The second stage is represented by low-salinity aqueous solutions (H2O-NaCl) with Tm ice ⩾ −4.5°C, trapped at homogenization temperatures between 110 and 300 °C and homogenization pressures below 100 bars. This stage can be correlated with kaolinization. The third stage is characterized by higher salinity aqueous fluids (Tm ice ⩾ −16.5°C) containing Na+ and other cations, trapped at homogenization temperatures between 100 and 130°C and homogenization pressures below 5 bars. These fluids can be associated with the epigenetic or supergene phases of the orebody.

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A fluid-inclusion study and genetic model of wolframite-bearing quartz veins, Garganta de los Montes, Spanish Central System

Mineralogical Magazine ◽

10.1180/minmag.1990.054.375.12 ◽

1990 ◽

Vol 54 (375) ◽

pp. 267-278 ◽

Cited By ~ 3

Author(s):

E. Ouilez ◽

J. Sierra ◽

E. Vindel

Keyword(s):

Genetic Model ◽

Fluid Inclusion Study ◽

Central System ◽

Quartz Veins ◽

Low Salinity ◽

Third Stage ◽

Inclusion Study ◽

Moderate Salinity ◽

Spanish Central System

AbstractWolframite-bearing quartz veins from Garganta de los Montes, Madrid province, are hosted by banded gneisses that have undergone intense migmatization processes. The ore deposit is closely related to the La Cabrera granitic batholith. The veins strike 075° and dip 75°S. The mineral association includes wolframite, quartz and minor amounts of scheelite and sulphides (sphalerite, chalcopyrite, pyrrhotite, stannite and marcasite). The fluid phases associated with quartz from the vein margin (early barren quartz) and from the vein centre (late wolframite-bearing quartz) have been studied using microthermometry, scanning electron microscopy and crushing test analyses. Four hydrothermal stages have been distinguished.The earliest fluids, only recognized in the barren quartz, contain brine, daughter phase (halite) and trapped minerals. The second hydrothermal stage is characterized by complex carbonic-aqueous inclusions of low salinity (3 to 7 wt.% eq. NaC1) and low density (0.4 to 0.7 g.cm−3). They mainly homogenize into liquid between 300 and 420°C. The third stage is represented by low to moderate salinity inclusions (<9 wt. % eq. NaCl) of moderate density (0.8 to 0.96 g.cm−3), homogenizing between 120° and 330°C. The latest fluids correspond to aqueous solutions of higher salinities (H2O-NaCl, with Ca2+ and Mg2+) and densities (>1 g.cm−3), with TH ranging between 50 and 130°C. The role of the complex-carbonic aqueous fluids in the transport and precipitation of tungsten is highlighted.

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Comparative mineralogical and fluid inclusion study of the Hnúst'a-Mútnik talc-magnesite and Miková-Jedl'ovec magnesite deposit (Western Carpathians, Slovakia)

Boletim Paranaense de Geociências ◽

10.5380/geo.v50i0.4165 ◽

2002 ◽

Vol 50 ◽

Cited By ~ 1

Author(s):

PETER KODERA ◽

MARTIN RADVANEC

Keyword(s):

Fluid Inclusion ◽

Aqueous Fluid ◽

Fluid Inclusion Study ◽

Low Salinity ◽

The Third ◽

Magnesite Deposit ◽

Major Stage ◽

Third Stage ◽

Inclusion Study ◽

High Concentrations

Two type localities, located in two different geological and metamorphic units, have been studied. The Hnúst'a-Mútnik deposit is located in amphibolite facies rock sequences of the Veporic unit, while the Miková-Jedl'ovec deposit (a part of the Dúbrava massive) is located in greenschists facies sequences of the Gemeric unit. On both localities successive crystallisation occurred during three stages of replacement. The first two belong to an older metamorphic process M1, the third corresponds to a younger M2 metamorphic process. During the first stage dolomite1 and calcite1 has formed on the expense of protolithic limestone. The second (major) stage is characterized by crystallization of magnesite. The third stage is represented by dolomite2, talc, chlorite, pyrite. At Hnúst'a-Mútnik this stage is much better developed and is further accompanied by tremolite, phlogopite, clinozoisite, zoisite. Based on the carbonate geothermometry at Hnúst'a-Mútnik the first stage occurred at 280-400°C and the third stage at 490-540°C; at Miková-Jedl'ovec the first stage crystallized at 370-420°C. Fluid inclusion study in magnesite showed the presence of primary brine inclusions, with high concentrations of salts other than NaCl, probably highly evolved evaporated marine waters. Brines from Miková-Jedl'ovec are slightly less saline (23-24 wt% NaCl eq.) and homogenised at lower temperatures (195-248°C) than the brines from Hnúst'a-Mútnik (29-32 wt% NaCl eq., 299- 348°C). Brines are accompanied by CO 2 -rich inclusions with nearly identical parameters at both deposits (1-8 wt% NaCl eq., CO 2 density 0.53 to 0.69 g.cm -3 , Th 307 to 336°C). CO 2 fluids probably result from dissolution of carbonates and are coeval or younger than brines. At Miková-Jedl'ovec also low salinity aqueous fluid inclusions have been identified (3-8 wt% NaCl eq., Th 132-249°C), corresponding to the stage 3. Microthermometric data have been also used to determine pressure and temperature limits related to the second and partially to the third stage of replacement.

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Fluid inclusion study of quartz veins from the orogenic Klecza gold deposit in the Kaczawa Mountains (SW Poland)

Mineral Deposit Research: Meeting the Global Challenge ◽

10.1007/3-540-27946-6_142 ◽

2005 ◽

pp. 553-556

Author(s):

S. Z. Mikulski ◽

S. Speczik ◽

A. Kozlowski

Keyword(s):

Fluid Inclusion ◽

Gold Deposit ◽

Fluid Inclusion Study ◽

Quartz Veins ◽

Inclusion Study ◽

Sw Poland

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Genesis of the Pb–Zn deposit at Sant’Antonio di Val D’Aspra, Southern Tuscany (Italy): disparity between geo-petrographic data and fluid inclusion microthermometry

Mineralogical Magazine ◽

10.1180/minmag.1990.054.375.14 ◽

1990 ◽

Vol 54 (375) ◽

pp. 289-294 ◽

Cited By ~ 1

Author(s):

M. Giamello ◽

F. Riccobono ◽

G. Sabatini

Keyword(s):

Fluid Inclusion ◽

Carbonate Rocks ◽

Fluid Inclusion Study ◽

Mississippi Valley ◽

Ore Minerals ◽

Inclusion Study ◽

History Of ◽

Homogenization Temperatures ◽

The One ◽

Internal Sediments

AbstractThe Pb–Zn deposit at Sant'Antonio di Val d'Aspra in the Farma Valley (Southern Tuscany) is hosted by Lower Moscovian carbonate rocks and shows many characters commonly found in Mississippi Valley type (MVT) deposits. Ore minerals (essentially sphalerite and galena) are closely confined to dolomitized portions of an only partly preserved black limestone. Mineralized carbonate rocks appear to have been eroded before the deposition of the overlying Upper Moscovian (Late Podolskian) shales. The diffuse presence of structures frequently found in internal sediments of karstic cavities indicates that supergene mechanisms have played an important role in the history of the deposit. A fluid inclusion study carried out on ore and gangue minerals revealed the presence of two different types of inclusions. The homogenization temperatures ranged from 120°C to 225°C but the most frequently found values were around 170°C. Salinity ranged from moderately low values up to 20 eq. wt. % NaCl. Lead isotopic composition rules out any relationship between the Sant'Antonio mineralization and Tertiary hydrothermal base metal occurrences in the same area. When all the data are taken together, a contrast is evident between geo-petrographic and isotopic data on the one hand, and fluid-inclusion microthermometry on the other.

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Fluid inclusion study of shear zone hosted lode gold type deposits: El Bagre mining district, Antioquia-Colombia

Earth Sciences Research Journal ◽

10.15446/esrj.v24n3.80653 ◽

2020 ◽

Vol 24 (3) ◽

pp. 245-257

Author(s):

Edwin Naranjo Sierra ◽

Mauricio Alvaran Echeverri

Keyword(s):

Fluid Inclusion ◽

Shear Zone ◽

Gold Deposits ◽

Fluid Inclusion Study ◽

Mining District ◽

Type I ◽

Lode Gold ◽

Calcite Veins ◽

Inclusion Study ◽

Homogenization Temperatures

The shear zone hosted lode gold type deposits are located at the northeast part of Antioquia department of Colombia. The characteristics of ore-forming fluids were discussed using fluid inclusion petrography and microthermometry analysis. Two stages, namely quartz-pyrite pre-mineralization stage (1) and reactivation-sulfides-tellurides mineralization stage (2) were included in this study. Two types of fluid inclusions were observed: primary aqueous-carbonic inclusions (type I) are characterized by the presence of clathrate, with salinities between 1.5 and 8.3 %wt NaCl equiv. and homogenization temperatures (to liquid) occurs between 238.1° and 297.1°C. Secondary aqueous inclusions (type II) were trapped in reactivated quartz (type IIa) and cross-cutting calcite veins (type IIb), salinity estimates display a mixing trend from a relatively saline with 9.21 %wt NaCl member (type IIa) to a low salinity one with 3.82 %wt NaCl (type IIb), homogenizations to a liquid phase occur between 150.8° and 184.6°C for type IIa inclusions and 130.3° to 190.4°C for type IIb. Based on these results, the shear zone hosted lode gold type deposits from El Bagre mining district, share similar characteristics with orogenic gold deposits.

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