scholarly journals Precious Metal Enrichment at the Myra Falls VMS Deposit, British Columbia, Canada

Geosciences ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 422
Author(s):  
Daniel Marshall ◽  
Carol-Anne Nicol ◽  
Robert Greene ◽  
Rick Sawyer ◽  
Armond Stansell ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Precious Metal ◽  
Metal Enrichment ◽  
Sea Floor ◽  
North West ◽  
Low Salinity ◽  
Volcanogenic Massive Sulphide ◽  
Igneous Fluids ◽  
Homogenization Temperatures ◽  
Water Depths

Gold, present as electrum, in the Battle Gap, Ridge North-West, HW, and Price deposits at the Myra Falls mine, occurs in late veinlets cutting the earlier volcanogenic massive sulphide (VMS) lithologies. The ore mineral assemblage containing the electrum comprises dominantly galena, tennantite, bornite, sphalerite, chalcopyrite, pyrite, and rarely stromeyerite, and is defined as an Au-Zn-Pb-As-Sb association. The gangue is comprised of barite, quartz, and minor feldspathic volcanogenic sedimentary rocks and clay, comprised predominantly of kaolinite with subordinate illite. The deposition of gold as electrum in the baritic upper portions of the sulphide lenses occurs at relatively shallow water depths beneath the sea floor. Primary, pseudosecondary, and secondary fluid inclusions, petrographically related to gold, show boiling fluid inclusion assemblages in the range of 123 to 173 °C, with compositions and eutectic melt temperatures consistent with seawater at approximately 3.2 wt % NaCl equivalent. The fluid inclusion homogenization temperatures are consistent with boiling seawater corresponding to water depths ranging from 15 to 125 m. Slightly more dilute brines corresponding to salinities of approximately 1 wt % NaCl indicate that there is input from very low-salinity brines, which could represent a transition from subaqueous VMS to epithermal-like conditions for precious metal enrichment, mixing with re-condensed vapor, or very low-salinity igneous fluids.

scholarly journals Precious Metal Enrichment at the Myra Falls VMS Deposit, British Columbia, Canada

2018 ◽  
Author(s):  
Daniel Marshall ◽  
Carol-Anne Nicol ◽  
Robert Greene ◽  
Rick Sawyer ◽  
Armond Stansell ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Precious Metal ◽  
Metal Enrichment ◽  
Sea Floor ◽  
North West ◽  
Low Salinity ◽  
Igneous Fluids ◽  
Homogenization Temperatures ◽  
Water Depths ◽  
Eutectic Melt

Gold, present as electrum, in the Battle Gap, Ridge North-West, HW, and Price deposits at the Myra Falls mine, occurs in late veinlets cutting the earlier VMS lithologies. The ore mineral assemblage containing the electrum comprises dominantly galena, tennantite, bornite, sphalerite, chalcopyrite, pyrite and rare stromeyerite is defined as an Au-Zn-Pb-As-Sb association.  The gangue is comprised of barite, quartz, and minor feldspathic volcanogenic sedimentary rocks and clay.  Deposition of gold as electrum in the baritic upper portions of the sulphide lenses occurs at relatively shallow water depths beneath the sea floor. Primary, pseudosecondary, and secondary fluid inclusions, petrographically related to gold, show boiling fluid inclusion assemblages in the range of 123 to 173 °C, with compositions and eutectic melt temperatures consistent with seawater at approximately 3.2 wt% NaCl equivalent. The fluid inclusion homogenization temperatures are consistent with boiling seawater corresponding to water depths ranging from 15 to 125 metres. Slightly more dilute brines corresponding to salinities of approximately 1 wt% NaCl indicate that there is input from very low-salinity brines, which could represent a transition from subaqueous VMS to epithermal-like conditions for precious metal enrichment, mixing with re‑condensed vapour, or very low-salinity igneous fluids.

scholarly journals Fluid Inclusion and Oxygen Isotope Constraints on the Origin and Hydrothermal Evolution of the Haisugou Porphyry Mo Deposit in the Northern Xilamulun District, NE China

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Qihai Shu ◽  
Yong Lai
Keyword(s):  
Fluid Inclusion ◽  
Meteoric Water ◽  
Early Time ◽  
Low Oxygen ◽  
Potassic Alteration ◽  
Low Salinity ◽  
Oxygen Isotopic ◽  
Homogenization Temperatures ◽  
Porphyry Mo Deposit ◽  
Positive Correlations

The Haisugou porphyry Mo deposit is located in the northern Xilamulun district, northeastern China. Based on alteration and mineralization styles and crosscutting relationships, the hydrothermal evolution in Haisugou can be divided into three stages: an early potassic alteration stage with no significant metal deposition, a synmineralization sericite-chlorite alteration stage with extensive Mo precipitation, and a postmineralization stage characterized by barren quartz and minor calcite and fluorite. The coexistence of high-salinity brine inclusions with low-salinity inclusions both in potassic alteration stage (~440°C) and locally in the early time of mineralization stage (380–320°C) indicates the occurrence of fluid boiling. The positive correlations between the homogenization temperatures and the salinities of the fluids and the low oxygen isotopic compositions (δ18Ofluid < 3‰) of the syn- to postmineralization quartz together suggest the mixing of magmatic fluids with meteoric water, which dominated the whole mineralization process. The early boiling fluids were not responsible for ore precipitation, whereas the mixing with meteoric water, which resulted in temperature decrease and dilution that significantly reduced the metal solubility, should have played the major role in Mo mineralization. Combined fluid inclusion microthermometry and chlorite geothermometer results reveal that ore deposition mainly occurred between 350 and 290°C in Haisugou.

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

1991 ◽  
Vol 55 (379) ◽  
pp. 211-223 ◽  
Author(s):  
J. Mangas ◽  
A. Arribas
Keyword(s):  
Fluid Inclusion ◽  
Fluid Inclusion Study ◽  
Spectroscopic Techniques ◽  
Raman Spectroscopic ◽  
Quartz Veins ◽  
Low Salinity ◽  
Second Stage ◽  
Third Stage ◽  
Inclusion Study ◽  
Homogenization Temperatures

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.

Progress in Platinum Group Element (PGE) in Black Shale Series

2013 ◽  
Vol 353-356 ◽  
pp. 1183-1186 ◽  
Author(s):  
Jun Liu ◽  
Ying Chen ◽  
Zhen Xiu Liao ◽  
Yong Zhan ◽  
You Fei Guan
Keyword(s):  
Mineral Resource ◽  
Fluid Inclusion ◽  
Black Shale ◽  
Precious Metal ◽  
Platinum Group Element ◽  
Platinum Group Elements ◽  
Group Element ◽  
Metal Elements ◽  
Platinum Group

The black shale enriched in various precious metal elements and platinum group elements. And the PGE deposit in black shale series is a new promising mineral resource. Comprehensive research on the geology, geochemistry, petrology, mineralogy, fluid inclusion and geochronology of the PGE in black shale series has been carried out and made a series of achievements. This paper summarized the advances in PGE in black shale series and pointed out the controversial views about the source of the PGE.

Simple harpacticoid composition observed at deep hydrothermal vent sites on sea knoll calderas in the North-west Pacific

2022 ◽  
pp. 1-10
Author(s):  
Futa Nakasugi ◽  
Motohiro Shimanaga ◽  
Hidetaka Nomaki ◽  
Hiromi Kayama Watanabe ◽  
Tomo Kitahashi ◽  
...  
Keyword(s):  
Deep Sea ◽  
Hydrothermal Vent ◽  
Hydrothermal Vents ◽  
Environmental Parameters ◽  
Sea Floor ◽  
North West ◽  
Isotopic Signatures ◽  
Carbon Isotopic ◽  
The North ◽  
Spatial Differences

Abstract Dirivultid copepods (Siphonostomatoida), one of the most successful meiobenthic organisms found at deep-sea hydrothermal vents, have been the focus of most previous ecological studies among meiofauna in these habitats. The ecology of Harpacticoida, a major benthic copepod group in typical deep-sea floor, however, is not well understood in terms of variations in community structure and controlling factors at venting sites. The spatial heterogeneities in benthic harpacticoid composition and their association with environmental parameters were investigated at hydrothermal vent chimney structures in the calderas of three neighbouring sea knolls (Bayonnaise Knoll, Myojin Knoll and Myojin-sho Caldera) in the western North Pacific. While a previous study had reported the distribution of dirivultids was strongly associated with spatial differences in stable carbon isotopic signatures (δ13C) of organic matter in the detritus on active chimneys in the field, multivariate analyses detected no significant corelation between the parameter and harpacticoid composition in this study. Instead, high associations of the harpacticoid composition with differences in water depth and total organic carbon (TOC) concentration were detected. Ectinosomatidae dominated at vent sites with lower TOC values in the shallowest Bayonnaise Knoll, while they were less prevalent at deeper vent fields in the other knolls, where Miraciidae was the most abundant family. This study indicated the availability of vent chemoautotrophic carbon is not a primary factor controlling the composition of harpacticoids even in the habitats on the hydrothermal vents, but instead by the food amount, regardless of its resources (including marine snow from the sea surface), in the study area.

Variant Offset-Type Platinum Group Element Reef Mineralization in Basal Olivine Cumulates of the Kapalagulu Intrusion, Western Tanzania

2021 ◽  
Author(s):  
M. D. Prendergast
Keyword(s):  
Precious Metal ◽  
Platinum Group Element ◽  
Early Stage ◽  
Precious Metals ◽  
Parental Magma ◽  
Group Element ◽  
Metal Enrichment ◽  
Reef Development ◽  
Platinum Group ◽  
Olivine Cumulates

Abstract The Kapalagulu intrusion in eastern Tanzania hosts a major, 420-m-thick, stratiform/stratabound platinum group element (PGE)-bearing sulfide zone—the Lubalisi reef—within a prominent, chromititiferous, harzburgite unit close to its stratigraphic base. Several features of the vertical base and precious metal distributions (in a composite stratigraphic section based upon two deep exploration drill holes) display similarities to those of offset-type PGE reefs that formed under the overall control of Rayleigh fractionation: (1) composite layering (at several scales) defined by systematic vertical variations of sulfide and precious metal contents and intermetallic ratios, indicating repeated cycles of PGE enrichment and depletion in the order Pd-Pt-Au-Cu, and (2) in the lower part of the reef, stratigraphic offsets of the precious metal peaks below peak sulfide (Cu) content. The form and geochemistry of the reef are consistent with overturns of basal liquid layers within a liquid layering system (i.e., stable density-driven stratification of a magma chamber), plus at least two minor inputs of parental magma during which the resident magma was recharged with sulfur and metals, and the effective depletion of precious metals in the magma midway through reef development. The Lubalisi reef differs from classic offset-type PGE reefs, however, principally because individual Pd, Pt, and Au enrichment peaks are coincident, not offset. The reef is set apart from other offset-type PGE reefs in three additional ways: (1) its association with olivine cumulates that crystallized soon after initial magma emplacement and well below the first appearance of cumulus pyroxene or plagioclase (implying attainment of sulfide saturation and precious metal enrichment without prolonged concentration of sulfur and chalcophile metals by normal magma cooling and differentiation), (2) the probable role of chromite crystallization in not only triggering sulfide segregation during reef formation but also facilitating precious metal enrichment in the early stages of reef development, and (3) its great width. The early stage of fractionation may also help explain the coincident precious metal peaks through its effect on apparent precious metal partition coefficients.

Clumped isotope geothermometry of an Ordovician carbonate mound, Hudson Bay Basin

2020 ◽  
Vol 178 (1) ◽  
pp. jgs2020-102
Author(s):  
Josué J. Jautzy ◽  
Martine M. Savard ◽  
Denis Lavoie ◽  
Omid H. Ardakani ◽  
Ryan S. Dhillon ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Oil And Gas ◽  
Fission Track ◽  
Hudson Bay ◽  
Apatite Fission Track ◽  
Burial Diagenesis ◽  
Carbonate Mound ◽  
History Of ◽  
Homogenization Temperatures ◽  
Clumped Isotope

The Hudson Bay sedimentary basin was overlooked geologically until two decades ago. Recent efforts to understand the palaeogeothermal history of this basin have led to the evaluation of fluid inclusion microthermometry, apatite fission track, organic matter reflectance and Rock–Eval analyses. Although apatite fission track and organic maturity indicators tend to show relatively low maximum burial temperatures (60–80°C), evidence of potential oil slicks on the sea surface and oil and gas shows in offshore wells have been reported across Hudson Bay. Fluid inclusion microthermometry in a carbonate mound sequence suggests homogenization temperatures of 118 ± 25 and 93 ± 10°C for recrystallized synsedimentary marine calcite and late pore-filling burial calcite, respectively. This sequence provides an interesting geological framework to test the application of clumped isotope thermometry against independent geothermometers. Here, we present clumped isotope data acquired on the late calcite cements and diagenetically altered early marine phases. The integration of clumped isotopic data with other thermal indicators allows the reconstruction and refinement of the thermal–diagenetic history of these carbonates by confirming an episode of heating, probably of hydrothermal origin and prior to normal burial diagenesis, that reset both fluid inclusions and the clumped isotope indicators without recrystallization.

OIL MIGRATION HISTORY OF THE OFFSHORE CANNING BASIN

2000 ◽  
Vol 40 (2) ◽  
pp. 133 ◽  
Author(s):  
M. Lisk ◽  
J. Ostby ◽  
N.J. Russell ◽  
G.W. O’Brien
Keyword(s):  
Fluid Inclusion ◽  
Acid Leaching ◽  
Reservoir Quality ◽  
Oil Migration ◽  
North West ◽  
Canning Basin ◽  
Carbonate Cement ◽  
Migration History ◽  
Potential Reservoir ◽  
Porosity And Permeability

The dual issues of the presence or absence of a viable, oil-prone petroleum system and reservoir quality represent key exploration uncertainties in the lightly explored Offshore Canning Basin, North West Shelf. To better quantify these factors, a detailed fluid inclusion investigation of potential reservoir horizons within the basin has been undertaken. The results have been integrated with regional petroleum geology and Synthetic Aperture Radar (SAR) oil seep data to better understand the oil migration risk in the region.The fluid inclusion data provide confirmation of widespread oil migration at multiple Mesozoic and Palaeozoic levels, including those wells that are remote from the likely source kitchens. The lack of evidence for present or palaeo-oil accumulations is consistent with the proposition that none of the currently water-wet wells appear to have tested a valid structure. These observations, when combined with the presence of numerous direct hydrocarbon indicators on seismic data and a number of oil slicks (from SAR data) at the basin’s edge, suggest that the potential for oil charge to valid structures is much higher than previously recognised.Petrographic analysis of the tight, gas-bearing, Triassic sandstones in Phoenix–1 suggests that the low porosity and permeability is the result of late poikilotopic carbonate cement. Significantly, the presence of oil inclusions within quartz overgrowths that pre-date the carbonate indicates that oil migration began prior to crystallisation of carbonate. Fluid inclusion palaeotemperatures combined with a 1D basin model suggest that trapping of oil as inclusions occurred in the Early to Middle Cretaceous and that predictions of reservoir quality using available water-wet wells could seriously under-estimate porositypermeability levels in potential traps that were charged with oil at about 100 Ma. Indeed, acid leaching of core plugs from Phoenix–1 indicates that removal of diagenetic carbonate results in significant permeability increase with obvious implications for the producibility of any future oil discovery. Further, evidence of Early Cretaceous oil charge has implications for the size and locality of source kitchens compared to that observed at the current day.Collectively, the data indicate the area has received widespread oil migration and suggest future exploration, even to relatively deep levels, may be successful if valid traps can be delineated.

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