Analysis of Au content in sedimentary rocks around the Hishikari gold deposit, Japan

2005 ◽  
pp. 585-588
Author(s):  
Kenzo Sanamatsu ◽  
Akira Imai ◽  
Koichiro Watanabe ◽  
Tetsuya Nakanishi
Keyword(s):  
Gold Deposit ◽  
Sedimentary Rocks

scholarly journals Tourmaline from Late Quartz Veins of the Murtykty Gold Deposit, Republic of Bashkortostan

2020 ◽  
Vol 6 (1) ◽  
pp. 69-83
Author(s):  
M.A. Rassomakhin ◽  
E.V. Belogub ◽  
K.A. Novoselov ◽  
P.V. Khvorov
Keyword(s):  
Gold Deposit ◽  
Sedimentary Rocks ◽  
Gold Deposits ◽  
Sulfide Mineralization ◽  
Porphyry Deposits ◽  
Quartz Veins ◽  
Orogenic Gold Deposits ◽  
Eastern Zone ◽  
Republic Of Bashkortostan ◽  
Intermediate Member

Tourmaline, an intermediate member of the oxyschorl–oxydravite–oxymagnesio-foitite-bosiite series with a predominance of the oxy-dravite-bosiite end-member, was studied from late calcite-quartz veins in the eastern zone of the Murtykty gold deposit (Republic of Bashkortostan). Sulfide mineralization in veins includes rare chalcopyrite, pyrite, sphalerite and galena. Accessory minerals are xenotime-(Y), vanadium-containing rutile and fine high-fineness gold. Supergene mineralization resulted from decomposition of carbonates, sulfides and rock-forming silicates includes kaolinite, hydroxides of Mn (chalcophanite, psilomelane) and Fe (goethite and limonite ochers), mainly developed in vein cavities ; chalcopyrite is replaced by cuprite and malachite. The composition of tourmaline is close to metamorphic dravite of orogenic gold deposits and tourmaline of gold-porphyry deposits, transitioning from porphyry to epithermal. Two possible B sources for the formation of tourmaline are considered: sedimentary rocks of the paleoisland-arc complex and granodiorites of the Mansurovo pluton. Figures 9. Table 1. References 36. Key words: tourmaline, boron, gold, xenotime-(Y), Murtykty deposit, Republic of Bashkortostan.

scholarly journals Quantitative Mineral Mapping of Drill Core Surfaces I: A Method for µXRF Mineral Calculation and Mapping of Hydrothermally Altered, Fine-Grained Sedimentary Rocks from a Carlin-Type Gold Deposit

2020 ◽  
Author(s):  
Rocky D. Barker ◽  
Shaun L.L. Barker ◽  
Siobhan A. Wilson ◽  
Elizabeth D. Stock
Keyword(s):  
Gold Deposit ◽  
Sedimentary Rocks ◽  
Potassium Feldspar ◽  
Ore Deposits ◽  
Drill Core ◽  
Raster Data ◽  
X Ray ◽  
Fine Grained ◽  
Core Samples ◽  
Wavelength Dispersive Spectrometry

Abstract Mineral distributions can be determined in drill core samples from a Carlin-type gold deposit, using micro-X-ray fluorescence (µXRF) raster data. Micro-XRF data were collected using a Bruker Tornado µXRF scanner on split drill core samples (~25 × 8 cm) with data collected at a spatial resolution of ~100 µm. Bruker AMICS software was used to identify mineral species from µXRF raster data, which revealed that many individual sample spots were mineral mixtures due to the fine-grained nature of the samples. In order to estimate the mineral abundances in each pixel, we used a linear programming (LP) approach on quantified µXRF data. Quantification of µXRF spectra was completed using a fundamental parameters (FP) standardless approach. Results of the FP method compared to standardized wavelength dispersive spectrometry (WDS)-XRF of the same samples showed that the FP method for quantification of µXRF spectra was precise (R2 values of 0.98–0.97) although the FP method gave a slight overestimate of Fe and K and an underestimate of Mg abundance. Accuracy of the quantified µXRF chemistry results was further improved by using the WDS-XRF data as a calibration correction before calculating mineralogy using LP. The LP mineral abundance predictions were compared to Rietveld refinement results using X-ray diffraction (XRD) patterns collected from powders of the same drill core samples. The root mean square error (RMSE) for LP-predicted mineralogy compared to quantitative XRD results ranges from 0.91 to 7.15% for quartz, potassium feldspar, pyrite, kaolinite, calcite, dolomite, and illite. The approaches outlined here demonstrates that µXRF maps can be used to determine mineralogy, mineral abundances, and mineralogical textures not visible with the naked eye from fine-grained sedimentary rocks associated with Carlin-type Au deposits. This approach is transferrable to any ore deposit, but particularly useful in sedimentary-hosted ore deposits where ore and gangue minerals are often fine grained and difficult to distinguish in hand specimen.

Chapter 26: Geology of the Hishikari Gold Deposit, Kagoshima, Japan

2020 ◽  
pp. 545-558
Author(s):  
Takayuki Seto ◽  
Yu Yamato ◽  
Ryota Sekine ◽  
Eiji Izawa
Keyword(s):  
Fluid Flow ◽  
Gold Deposit ◽  
Sedimentary Rocks ◽  
Alteration Zone ◽  
Volcanic Area ◽  
Mineral Zone ◽  
Temperature Controlled ◽  
Hydrothermal Alteration Zones ◽  
Low Sulfidation ◽  
Ore Grade

Abstract The bonanza-grade, low-sulfidation epithermal Hishikari gold deposit is located in the Plio-Pleistocene volcanic area of southern Kyushu, Japan. The concealed veins were discovered in 1981 and the mine has since produced 5.462 million metric tons (Mt) of ore averaging 44.3 g/t Au (242 t Au) from 1985 to the end of 2018, at which time reserves were 7.98 Mt at 20.9 g/t Au. The Hishikari deposit consists of the Honko, Sanjin, and Yamada ore zones, which occur in a NE-trending area 2.8 km long and 1.0 km wide. The veins are hosted by basement sedimentary rocks of the Cretaceous Shimanto Supergroup and by overlying Hishikari Lower Andesites of Pleistocene age. Sinter occurs about 100 m above the Yamada ore zone. Temperature-controlled hydrothermal alteration zones occupy an area of >5 km long and 2 km wide. The Honko and Sanjin veins occur within a chlorite-illite alteration zone (paleotemperature >230°C), whereas the Yamada veins occur within an interstratified clay mineral zone (150°–230°C). The marginal alteration comprises quartz-smectite (100°–150°C) and cristobalite-smectite (<100°C) zones. Ore-grade veins are located between –60- and 120-m elev, with the paleowater table over the Honko-Sanjim veins at ~300-m elev. Overall, the Ag/Au wt ratio is about 0.6. Vein-forming minerals consist of quartz, adularia, and clay minerals plus truscottite, with electrum and minor pyrite, chalcopyrite, naumannite, galena, and sphalerite. The major veins formed from repeated episodes of boiling and strong fluid flow inferred from bands of quartz, adularia, and smectite with bladed quartz, columnar adularia, and truscottite.

Mineralogical and textural controls on spectral induced polarization signatures of the Canadian Malartic gold deposit: Applications to mineral exploration

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. B135-B151 ◽  
Author(s):  
Charles L. Bérubé ◽  
Gema R. Olivo ◽  
Michel Chouteau ◽  
Stéphane Perrouty
Keyword(s):  
Gold Deposit ◽  
Mineral Exploration ◽  
Sedimentary Rocks ◽  
Sulfide Mineral ◽  
Induced Polarization ◽  
Spectral Induced Polarization ◽  
Mineral Phases ◽  
Mineralized Zone ◽  
Mineral Interfaces ◽  
Liberation Analysis

Applications of the spectral induced polarization (SIP) method to mineral exploration are limited by our knowledge of the relationships among rock texture, mineral composition, and electrical properties. Laboratory SIP responses were measured on rock samples from the Canadian Malartic gold deposit. Field SIP responses were also measured at the outcrop scale, along a profile that intersects a well-studied mineralized zone. The mineralogy and the texture of sedimentary rocks from this deposit were quantitatively determined with mineral liberation analysis. A systematic decrease (Pearson [Formula: see text]) in total chargeability with increasing fraction of the sulfide mineral interfaces associated with feldspar minerals (namely, K-feldspar and albite) was observed. On the other hand, total chargeability increased with the fraction of sulfide mineral interfaces associated with carbonates and micas (Pearson [Formula: see text]). At Canadian Malartic, proximal alteration in the mineralized zones is marked by rocks that lack a foliation plane and that were subjected to pervasive K-feldspar, albite, and pyrite alteration. In contrast, distal alteration in sedimentary rocks is marked by biotite, albite, carbonate, and pyrite that are oriented along the regional [Formula: see text] foliation. In the least-altered (LA) sedimentary rocks, quartz and biotite are associated with pyrrhotite and ilmenite as the main sulfide and oxide mineral phases, respectively. SIP measurements conducted at district and outcrop scales and along a drill core indicated that proximally altered sedimentary rocks were characterized by low total chargeability values ([Formula: see text] to [Formula: see text] in the laboratory and [Formula: see text] in the field). In contrast, the LA sedimentary rocks were characterized by total chargeability values up to [Formula: see text] in the laboratory and [Formula: see text] in the field. We conclude that mineralized zones associated with this type of ore deposit are characterized by low chargeability anomalies.

Geochemistry and Diagenetic Pattern of Ore-Bearing Rocks about Two Types of Gold Deposit in Fengxian-Taibai Basin, South Qinling

2012 ◽  
Vol 616-618 ◽  
pp. 240-245
Author(s):  
Qiang Li
Keyword(s):  
Gold Deposit ◽  
Sea Water ◽  
Sedimentary Rocks ◽  
Gold Deposits ◽  
Upper Devonian ◽  
Low Density ◽  
Positive Anomaly ◽  
South Qinling ◽  
Diagenetic Fluid ◽  
Ree Patterns

Baguamiao and Shuangwang gold deposit are two important gold types in Fengxian-Taibai basin. The gold deposits are all located at the bottom of the Upper-Devonian Xing-hongpu Formation. However the ore-bearing rocks are different between them. The ore-bearing rock of Baguamiao gold deposit is ankerite rocks, which is concordant with the strata by bedded or stratoid and assume rhythmic layering form. The ore-bearing rock of Shuangwang gold deposit is albite breccias, which are mostly lens-shaped. The data of petrochemistry show that both of them are poor in Fe2O3 and K2O, which are different from normal sedimentary rocks. The elements contents of Cu, Pb and Zn are close to Clarke value. But the content of dispersed element Ge is rich in rocks, which reflect hydrothermal sedimentary origin. The characteristic of REE are different between them. The REE contents of ankerite rocks are low and elements of Ce and Eu are positive anomaly. The REE contents of albite breccias are close to regional strata and elements of Ce and Eu are middle negative. The chondrite-normalized REE patterns are also alike. It’s shown that the diagenetic fluid are high-density which been mixed by sea water slightly. So the ankerite rocks hold the REE characteristic of thermal fluid. The diagenetic fluid of albite breccias are low-density thermal fluid which been mixed by sea water intensively. It has same REE characteristic to normal sedimentary rocks.

Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

1977 ◽  
Vol 35 ◽  
pp. 162-163
Author(s):  
Thomas R. McKee ◽  
Peter R. Buseck
Keyword(s):  
Crystallite Size ◽  
Sedimentary Rocks ◽  
Carbonaceous Material ◽  
Low Grade ◽  
X Ray ◽  
Graphitized Carbon ◽  
Transmission Electron ◽  
Heat Treated ◽  
Commercial Carbon ◽  
Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

Stabilizing pyritic material

1989 ◽  
Vol 4 ◽  
pp. 244-248 ◽  
Author(s):  
Donald L. Wolberg
Keyword(s):  
Significant Contribution ◽  
Organic Materials ◽  
Sedimentary Rocks ◽  
Iron Sulfides ◽  
Decomposition Products ◽  
Iron Minerals ◽  
Pyrite Formation ◽  
Organic Sediments ◽  
Freshwater Environments

The minerals pyrite and marcasite (broadly termed pyritic minerals) are iron sulfides that are common if not ubiquitous in sedimentary rocks, especially in association with organic materials (Berner, 1970). In most marine sedimentary associations, pyrite and marcasite are associated with organic sediments rich in dissolved sulfate and iron minerals. Because of the rapid consumption of sulfate in freshwater environments, however, pyrite formation is more restricted in nonmarine sediments (Berner, 1983). The origin of the sulfur in nonmarine environments must lie within pre-existing rocks or volcanic detritus; a relatively small, but significant contribution may derive from plant and animal decomposition products.

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