Fluid inclusion evidence for the transport of tungsten by carbonate complexes in hydrothermal solutions

1980 ◽  
Vol 17 (7) ◽  
pp. 823-830 ◽  
Author(s):  
N. C. Higgins
Keyword(s):  
Carbon Dioxide ◽  
Fluid Inclusion ◽  
Hydrothermal Fluid ◽  
Fluid Pressure ◽  
Hydrothermal Fluids ◽  
Hydrothermal Solutions ◽  
High Fluid ◽  
Carbonate Complexes ◽  
Very High ◽  
Tungsten Deposits

Fluid inclusion evidence from the Grey River Tungsten Prospect, Newfoundland, and other tungsten deposits indicates that CO2 is an important component of the hydrothermal fluid. Carbon dioxide is enriched in fluids evolved from granitic melts under high fluid pressure, while lower pressure fluids are chloride-rich. The association of tungsten deposits with these carbon dioxide rich hydrothermal fluids suggests that carbonate/bicarbonate complexes may be important in tungsten transport at very high fluid pressures.

Estimation of paleostress from pore fluid pressure of the quartz veins and its significance in the Cu-Pb-Zn mineralization (Ambaji, Aravalli-Delhi mobile belt, NW India)

2020 ◽  
Author(s):  
Neeraj Kumar Sharma ◽  
Tapas Kumar Biswal
Keyword(s):  
Fluid Inclusion ◽  
Quartz Vein ◽  
Hydrothermal Fluid ◽  
Stress Condition ◽  
Fluid Pressure ◽  
Tectonic Stress ◽  
Mobile Belt ◽  
Mohr Circle ◽  
Quartz Veins ◽  
Ore Minerals

<p>Quartz veins are produced from the crystallization of the last silica enriched hydrothermal phase from granitic magma circulating along the pre-existing fracture of rock. In many instances, these hydrothermal fluid act as a carrier for the ore minerals. The intrusion of quartz veins along fractures depends upon the tectonic stress conditions in the area. Fluid pressure (P<sub>f</sub>) of these ascending liquids should be higher than the normal compressive stress (σ<sub>n</sub>) to dilate the fractures. We are studying the quartz vein intrusion in the Cu‒Pb‒Zn mineralization belt of Ambaji, South Delhi terrane, Aravalli- Delhi mobile belt, NW India. The host rocks include mica schist, amphibolite, calc schist, talc tremolite schist, and four phases of granite intrusion (G<sub>0</sub>‒G<sub>3</sub>). The age of G<sub>0</sub>, G<sub>1</sub>, G<sub>2</sub> and G<sub>3</sub> granite are 960, 860, 800, and 750 Ma respectively. The rocks underwent three phases of folding (F<sub>1</sub>‒F<sub>3</sub>) and show greenschist to amphibolite facies metamorphism. The quartz vein intrusion is related to syn to post F<sub>3</sub> folding and G<sub>3</sub> granite magmatism. This final phase hydrothermal fluid extremely altered host rock and formed biotite-tourmaline-quartz and tremolite-actinolite-talc-chlorite greisen along the contact. The greisen host chalcopyrite-pyrite-galena-sphalerite mineralization suggesting the ore minerals were transported by the quartz vein. Vein orientation, stress condition, fluid pressure fluctuation, and fluid temperature can decide the fracture dilation and mineralization processes. Therefore, this work concentrates on the geometrical distribution of the vein orientation data. From this we deduced (i) girdle distribution pattern of vein data  (ii) σ<sub>1</sub> = 120º/75º, σ<sub>2</sub> = 052º/07º, σ<sub>3</sub> = 323º/07º indicate maximum extension was NW-SE and σ<sub>1</sub>σ<sub>2</sub> plane strikes was N52ºE, (iii) θ<sub>2</sub> =12º, θ<sub>3</sub> = 40º  and (iv) R'(driving pressure ratio) = 0.95, ϕ (tectonic stress ratio) = 0.90 indicates high value for R' leading to dilation of wide range of fractures. Further, the high ϕ value suggests uniaxial extension. Microscopic petrography of fluid inclusions shows three generations of inclusion like primary inclusion, secondary inclusion, and pseudosecondary inclusion. Most of the inclusion has aqueous and vapour phase and some inclusions show solid halite phase. We observed different types of trail bound of inclusion like intragranular inclusion, intergranular inclusion and transgranular inclusion, which suggest deformation and recrystallization in the rock. We are studying microthermometry analysis of fluid inclusion present in the quartz vein and trying to estimate the fluid pressure. With the help of fluid pressure, the 3D Mohr circle will be constructed and paleostress will be quantified. That will help in understanding the stress condition and mineralization in the rock.</p><p>Keywords: Veins, Fractures, Paleostress, 3D Mohr Circle, Mineralisation, Fluid Inclusion, Microthermometry</p>

Anomalous Vp/Vs in highly pressurized rocks: Evidence for anisotropy or mafic composition?

2020 ◽  
Author(s):  
Lucas Pimienta ◽  
Alexandre Schubnel ◽  
Jerome Fortin ◽  
Yves Guéguen ◽  
Helene Lyon-Caen ◽  
...  
Keyword(s):  
Subduction Zones ◽  
Laboratory Data ◽  
Fluid Pressure ◽  
Pore Fluid ◽  
S Wave ◽  
Pore Fluid Pressure ◽  
Crustal Rocks ◽  
High Fluid ◽  
Measuring Frequency ◽  
Very High

<p>         Anomalously high seismic P- to S-wave velocity ratios (Vp/Vs) have been observed in subduction zones, in locations where varieties of earthquakes and slips are expected to occur. From qualitative laboratory knowledge of rocks Poisson’s ratio, these results were interpreted as evidence of near-lithostatic pore fluid pressure. Because most laboratory data did not document such high Vp/Vs values, these were further linked to additional constrains of anisotropy or the dominance of minerals of very high intrinsic Vp/Vs, e.g. mafic rocks.However, does high Vp/Vs necessarily imply anisotropy and/or mafic composition?</p><p>         Recently, the measuring frequency (f) was shown to play a major role on rocks’ resulting Poisson’s ratio, so that usual laboratory results (at f = 1 MHz) might not directly transfer to field ones (at f = 1 Hz). From this consideration, we investigate Vp/Vs of a variety of crustal rocks in the elastic regime relevant at the field scale, the undrained elastic regime.Accounting for rocks dispersive properties, this work aims to show that:</p><ul><li>In the laboratory, in isotropic rocks, one might attain Vp/Vs values as high as the anomalous ones observed in subduction zones.</li> <li>No mineralogical control is needed for such high Vp/Vs values, which could be consistent with the inherent mineral variability in different settings across the globe.</li> <li>High pore fluid pressure is a major parameter, but not alone: such high values cannot be achieved without very high degree of micro-fracturing of the rock, opened by high fluid pressures, an information of potential importance to understand those seismogenic zones.</li> </ul>

Fluid Inclusion Study on the Duobaoshan Porphyry Deposit and Sankuanggou Skarn Deposit, Heilongjiang, China

2014 ◽  
Vol 962-965 ◽  
pp. 41-44
Author(s):  
Hao Wei ◽  
Jiu Hua Xu ◽  
Guo Rui Zhang
Keyword(s):  
Fluid Inclusion ◽  
Fluid Inclusions ◽  
Hydrothermal Fluid ◽  
Field Data ◽  
Hydrothermal Fluids ◽  
Fluid Inclusion Study ◽  
Skarn Deposit ◽  
Porphyry Deposit ◽  
Porphyry Cu ◽  
Inclusion Study

In this paper we use new field data, fluid inclummsions, and table isotopes (O, H, and S) to refine the roles of the hydrothermal evolution, evaluate changes in the hydrothermal fluids of Duobaoshan porphyry Cu (Mo) deposit and Sankuanggou skarn Fe-Cu deposit. Four ore-forming stages are recognized at The Duobaoshan porphyry Cu (Mo) deposit. Fluid inclusions are abundant in quartz of various stages. Estimated trapping pressures for stage I, II, III are 110-160MPa, 58-80MPa, and 8-17MPa, corresponding trapping temperatures are 375-650°C, 310-350°C, 210-290°C. The δD and δ18O values of fluids indicate a evolution process from magmtic hydrothermal fluid to a mixing magmtic and meteoric fluid. The δ34S values of sulfides mainly suggest predominantly source of deep magma chamber.

Fluid flow within the damage zone of the Boccheggiano extensional fault (Larderello–Travale geothermal field, central Italy): structures, alteration and implications for hydrothermal mineralization in extensional settings

2010 ◽  
Vol 148 (4) ◽  
pp. 558-579 ◽  
Author(s):  
FEDERICO ROSSETTI ◽  
LUCA ALDEGA ◽  
FRANCESCA TECCE ◽  
FABRIZIO BALSAMO ◽  
ANDREA BILLI ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Fluid Inclusion ◽  
Hydrothermal Fluid ◽  
Damage Zone ◽  
Central Italy ◽  
Fluid Pressure ◽  
Lithostatic Pressure ◽  
Anisotropic Permeability ◽  
Ore Deposit ◽  
Permeability Structure

AbstractThe Neogene extensional province of southern Tuscany in central Italy provides an outstanding example of fossil and active structurally controlled fluid flow and epithermal ore mineralization associated with post-orogenic silicic magmatism. Characterization of the hydrodynamic regime leading to the genesis of the polysulphide deposit (known as Filone di Boccheggiano) hosted within the damage zone of the Boccheggiano Fault is a key target to assess modes of fossil hydrothermal fluid circulation in the region and, more generally, to provide inferences on fault-controlled hydrothermal fluid flow in extensional settings. We provide a detailed description of the fault zone architecture and alteration/mineralization associated with the Boccheggiano ore deposit and report the results of fluid inclusion and stable oxygen isotope studies. This investigation shows that the Boccheggiano ore consists of an adularia/illite-type epithermal deposit and that sulphide ore deposition was controlled by channelling of hydrothermal fluids of dominantly meteoric origin within the highly anisotropic permeability structure of the Boccheggiano Fault. The low permeability structure of the fault core compartmentalized the fluid outflow preventing substantial cross-fault flow, with focused fluid flow occurring at the hangingwall of the fault controlled by fracture permeability. Fluid inclusion characteristics indicate that ore minerals were deposited between 280° and 350°C in the upper levels of the brittle extending crust (lithostatic pressure in the order of 0.1 GPa). Abundant vapour-rich inclusions in ore-stage quartz are consistent with fluid immiscibility and boiling, and quartz ore vein textures suggest that mineralization in the Boccheggiano ore deposit occurred during cyclic fluid flow in a deformation regime regulated by transient and fluctuating fluid pressure conditions. Results from this study (i) predict a strongly anisotropic permeability structure of the fault damage zone during crustal extension, and (ii) indicate the rate of secondary (structural) permeability creation and maintenance by active deformation in the hangingwall of extensional faults as the major factor leading to effective hydraulic transmissivity in extensional terranes. These features intimately link ore-grade mineralization in extensional settings to telescoping of hydrothermal flow along the hangingwall block(s) of major extensional fault zones.

Quantitative models of very high fluid pressure: the possible role of lateral stresses

Terra Nova ◽  
1995 ◽  
Vol 7 (1) ◽  
pp. 68-79 ◽  
Author(s):  
Olivier Bour ◽  
Ian Lerche ◽  
Dominique Grauls
Keyword(s):  
Fluid Pressure ◽  
Quantitative Models ◽  
High Fluid ◽  
Very High ◽  
High Fluid Pressure

scholarly journals Structural and hydrogeological features of Pleistocene shear zones in the area of Rome (Central Italy)

1994 ◽  
Vol 37 (1) ◽  
Author(s):  
C. Faccenna
Keyword(s):  
Central Italy ◽  
Fluid Pressure ◽  
Shear Zones ◽  
Fault Zones ◽  
Strike Slip ◽  
Hydrothermal Fluids ◽  
Upper Pleistocene ◽  
Impermeable Barrier ◽  
Hydrothermal Springs ◽  
High Fluid

The last tectonic episode observed in the Latium Tyrrhenian margin (Central Italy), few km cast of Rome, is represented by a set of middIe-upper Pleistocene N-S shear zones, characterised by complex geometric and kinematic setting. The easternmost of these shear zones displays a strike-slip component of motion and is located at the boundary between the Apennine carbonate chain and the volcanic areas. The distribution of travertine deposits and hydrothermal springs suggests that this fault zone acts as an impermeable barrier for lateral flow derived from superficial karstic circuit, and as a preferential upwelling surface for deep hydrothermal fluids. We propose that high fluid pressure could develop inside these fault zones favouring the reactivation of buried pre-existing crustal discontinuities and the local re-orientation of the stress field, as testified by the geometry and the kinematics of the surface fault pattern.

scholarly journals Analysis of Hydrothermal Systems Beneath Tayukeng through Long-Term Geochemical Signals of Hydrothermal Fluids in Tatun Volcano Group, Taiwan

2021 ◽  
Vol 18 (14) ◽  
pp. 7411
Author(s):  
Hsin-Fu Yeh ◽  
Hung-Hsiang Hsu
Keyword(s):  
Surface Temperature ◽  
Hydrothermal System ◽  
Hydrothermal Fluid ◽  
Thermal Water ◽  
Hydrothermal Systems ◽  
Hydrothermal Fluids ◽  
Geochemical Variations ◽  
Northern Taiwan

The Tatun Volcano Group (TVG) is located in northern Taiwan and consists of many springs and fumaroles. The Tayukeng (TYK) area is the most active fumarole site in the TVG. In this study, we analyzed the long-term geochemical variations of hydrothermal fluids and proposed a mechanism responsible for the variation in TYK. There are two different aquifers beneath the TYK area: a shallow SO42−-rich aquifer and a deeper aquifer rich in Cl−. TYK thermal water was mainly supplied by the shallow SO42−-rich aquifer; therefore, the thermal water showed high SO42− concentrations. After 2015, the inflow of deep thermal water increased, causing the Cl− concentrations of the TYK to increase. Notably, the inferred reservoir temperatures based on quartz geothermometry increased; however, the surface temperature of the spring decreased. We inferred that the enthalpy was lost during transportation to the surface. Therefore, the surface temperature of the spring does not increase with an increased inflow of deep hydrothermal fluid. The results can serve as a reference for understanding the complex evolution of the magma-hydrothermal system in the TVG.

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