scholarly journals Mineralogical and Geochemical Characteristics of Lead-zinc Ore Deposits, and Potential Accompanying Components in the Cho Don - Cho Dien Area, Bac Kan Province, Vietnam

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Tien Dung NGUYEN ◽  
Khac Du NGUYEN ◽  
Ngoc Thom NGUYEN

The Pb-Zn mineralization in the Cho Don - Cho Dien ore districts often occurs in 2 types: (1)oxidized ore near to the surface and (2) sulfide ore at deeper section. Based on microscopic observations,sulfide ores can be divided into sphalerite-galena-pyrite and/or galena-sphalerite mineralization types. Toexamine the geochemical features of the Pb-Zn ores, SEM-EDX and ICP-MS analytical methods wereperformed in this study. Previous δ34S data of Pb-Zn concentrates, and sulfide minerals from variousdeposits suggest that the Pb-Zn ore-forming fluids might be related to the felsic-granitic magmaticactivities rather than a genesis of stratiform type. Geochemical data show that the major, minor, and traceelement compositions of lead-zinc ores have wide ranges of variation even in each deposit. The sulfideores are generally higher in economic components than those in the oxidized ores. The positivecorrelations between Pb-Ag can be found in the entire dataset, whereas excellent Zn-Cd correlation canonly be observed from Cho Don ore samples. Apart from the principal components (Pb and Zn), the oresalso contain other accompanying elements that supply high-technological manufacturing industries. Ofwhich As, Cu, Ag, Sb, and Cd could be potential by-products and can be extracted during smelting Pb/Znconcentrate processes, and need more detailed studies for every deposit.

2021 ◽  
Vol 116 (6) ◽  
pp. 1253-1265
Author(s):  
Xiao-Ye Jin ◽  
Jian-Xin Zhao ◽  
Yue-Xing Feng ◽  
Albert H. Hofstra ◽  
Xiao-Dong Deng ◽  
...  

Abstract The ages of Carlin-type gold deposits in the Golden Triangle of South China have long been questioned due to the general lack of minerals unequivocally linked to gold deposition that can be precisely dated using conventional radiogenic isotope techniques. Recent advances in U-Pb methods show that calcite can be used to constrain the ages of hydrothermal processes, but few studies have been applied to ore deposits. Herein, we show that this approach can be used to constrain the timing of hydrothermal activity that generated and overprinted the giant Shuiyindong Carlin-type gold deposit in the Golden Triangle. Three stages of calcite (Cal-1, Cal-2, and Cal-3) have been recognized in this deposit based on crosscutting relationships, cathodoluminescence colors, and chemical (U, Pb, and rare earth element [REE]) and isotope (C, O, Sr) compositions. Cal-1 is texturally associated with ore-stage jasperoid and disseminated Au-bearing arsenian pyrite in hydrothermally altered carbonate rocks, which suggests it is synmineralization. Cal-2 fills open spaces and has a distinct orange cathodoluminescence, suggesting that it precipitated during a second fluid pulse. Cal-1 and Cal-2 have similar carbonate rock-buffered chemical and isotopic compositions. Cal-3 occurs in veins that often contain realgar and/or orpiment and are chemically (low U, Pb, and REE) and isotopically (higher δ13C, lower δ18O and Sri values) distinct from Cal-1 and Cal-2, suggesting that it formed from a third fluid. U-Pb isotope analyses, by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) for U-rich Cal-1 and Cal-2 and by LA-multicollector (MC)-ICP-MS for U-poor Cal-3, yield well-defined age constraints of 204.3 to 202.6, 191.9, and 139.3 to 137.1 Ma for Cal-1, Cal-2, and Cal-3, respectively. These new ages suggest that the Shuiyindong gold deposit formed in the late Triassic and was overprinted by hydrothermal events in the early Jurassic and early Cretaceous. Given the association of Cal-3 with orpiment and realgar, and previous geochronologic studies of several other major gold deposits in the Golden Triangle, we infer that the latest stage of calcite may be associated with an early Cretaceous regional gold metallogenic event. Combined with existing isotopic ages in the region, these new ages lead us to propose that Carlin-type gold deposits in the Golden Triangle formed during two metallogenic episodes in extensional settings, associated with the late Triassic Indochina orogeny and early Cretaceous paleo-Pacific plate subduction. This study shows that the calcite U-Pb method can be used to constrain the timing of Carlin-type gold deposits and successive hydrothermal events.


1971 ◽  
Vol 36 (3) ◽  
pp. 286-321 ◽  
Author(s):  
Clair C. Patterson

AbstractThe weathered zones of ore deposits, which no longer exist, are reconstructed by inference to provide estimates of relative abundances of usable nuggets of native copper, silver, and gold in ancient times. New analyses and selected data from the literature summarize metallic impurities in native copper, silver, gold, and lead and in the oxidized copper minerals, oxide, silicate, carbonate, chloride, and sulfate, together with impurities in lead carbonate and silver halide minerals. The influence that these occurrences and compositions exerted upon the origin and development of metallurgy in Mesoamerica and South America is discussed in relation to new analyses of artifacts and selected data from the literature. Topics emphasized are: the discovery of smelting and melting by the Moche; the inability of New World metallurgists to smelt copper from sulfide ores or silver from lead ores; and the lack of influence by transoceanic contacts. This paper is contribution number 1702 of the Division of Geological Sciences, C.I.T.


Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 106
Author(s):  
Xing-Yuan Li ◽  
Jing-Ru Zhang ◽  
Chun-Kit Lai

Jiangxi Province (South China) is one of the world’s top tungsten (W) mineral provinces. In this paper, we present a new LA-ICP-MS zircon U-Pb age and Hf isotope data on the W ore-related Xianglushan granite in northern Jiangxi Province. The magmatic zircon grains (with high Th/U values) yielded an early Cretaceous weighted mean U-Pb age of 125 ± 1 Ma (MSWD = 2.5, 2σ). Zircon εHf(t) values of the Xianglushan granite are higher (−6.9 to −4.1, avg. −5.4 ± 0.7) than those of the W ore-related Xihuanshan granite in southern Jiangxi Province (−14.9 to −11.2, avg. −12.5 ± 0.9), implying different sources between the W ore-forming magmas in the northern and southern Jiangxi Province. Compiling published zircon geochemical data, the oxygen fugacity (fO2) of the late Yanshanian granitic magmas in Jiangxi Province (the Xianglushan, Ehu, Dahutang, and Xihuashan plutons) were calculated by different interpolation methods. As opposed to the W ore-barren Ehu granitic magma, the low fO2 of the Xianglushan granitic magma may have caused W enrichment and mineralization, whilst high fO2 may have led to the coexistence of Cu and W mineralization in the Dahutang pluton. Additionally, our study suggests that the absence of late Mesozoic Cu-Mo mineralization in the Zhejiang, Jiangxi, and Anhui Provinces (Zhe-Gan-Wan region) was probably related to low fO2 magmatism in the Cretaceous.


Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1236
Author(s):  
Sylwia Svorová Pawełkowicz ◽  
Barbara Wagner ◽  
Jakub Kotowski ◽  
Grażyna Zofia Żukowska ◽  
Bożena Gołębiowska ◽  
...  

Impurities in paint layers executed with green and blue copper pigments, although relatively common, have been studied only little to date. Yet, their proper identification is a powerful tool for classification of paintings, and, potentially, for future provenance studies. In this paper, we present analyses of copper pigments layers from wall paintings situated in the vicinity of copper ore deposits (the palace in Kielce, the palace in Ciechanowice, and the parish church in Chotków) located within the contemporary borders of Poland. We compare the results with the analyses of copper minerals from three deposits, two local, and one historically important for the supply of copper in Europe, i.e., Miedzianka in the Holy Cross Mountains, Miedzianka in the Sudetes, and, as a reference, Špania Dolina in the Slovakian Low Tatra. Optical (OM) and electron microscopy (SEM-EDS), Raman spectroscopy, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) have been used for a detailed investigation of the minute grains. Special attention has been devoted to antimony and nickel phases, as more unusual than the commonly described iron oxides. Analyses of minerals from the deposits helped to interpret the results obtained from the paint samples. For the first time, quantitative analyses of copper pigments’ impurities have been described.


Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 295
Author(s):  
Tumisi Beiri Jeremiah Molelekoa ◽  
Thierry Regnier ◽  
Laura Suzanne da Silva ◽  
Wilma Augustyn

The food and pharmaceutical industries are searching for natural colour alternatives as required by consumers. Over the last decades, fungi have emerged as producers of natural pigments. In this paper, five filamentous fungi; Penicillium multicolour, P. canescens, P. herquie, Talaromyces verruculosus and Fusarium solani isolated from soil and producing orange, green, yellow, red and brown pigments, respectively, when cultured on a mixture of green waste and whey were tested. The culture media with varying pH (4.0, 7.0 and 9.0) were incubated at 25 °C for 14 days under submerged and solid-state fermentation conditions. Optimal conditions for pigment production were recorded at pH 7.0 and 9.0 while lower biomass and pigment intensities were observed at pH 4.0. The mycelial biomass and pigment intensities were significantly higher for solid-state fermentation (0.06–2.50 g/L and 3.78–4.00 AU) compared to submerged fermentation (0.220–0.470 g/L and 0.295–3.466 AU). The pigment intensities were corroborated by lower L* values with increasing pH. The λmax values for the pigments were all in the UV region. Finally, this study demonstrated the feasibility of pigment production using green waste:whey cocktails (3:2). For higher biomass and intense pigment production, solid-state fermentation may be a possible strategy for scaling up in manufacturing industries.


2015 ◽  
Vol 81 ◽  
pp. 149-177 ◽  
Author(s):  
Christopher D. Standish ◽  
Bruno Dhuime ◽  
Chris J. Hawkesworth ◽  
Alistair W. G. Pike

Lead isotope analyses of 50 Irish Chalcolithic and Early Bronze Age gold artefacts favour a gold source in southern Ireland. However when combined with major element analysis, the artefacts are not consistent with any Irish gold deposit analysed to date. Understanding the lead isotope signatures of ore deposits within a study region allows informed inferences to be drawn regarding the likelihood that an unanalysed ore deposit was exploited in the past. If an Irish gold source is assumed, then the gold is most likely to have originated from deposits hosted by Old Red Sandstone in the Variscan ore field of south-west Ireland. However, based on our current understanding of mineralisation in the region, this scenario is considered unlikely. A non-Irish source for the gold is therefore preferred – a scenario that may favour cosmologically-driven acquisition, ie, the deliberate procurement of a material from distant or esoteric sources. Available geochemical data, combined with current archaeological evidence, favour the alluvial deposits of south-west Britain as the most likely source of the gold.


Author(s):  
John D. Greenough ◽  
Alejandro Velasquez ◽  
Mohamed Shaheen ◽  
Joel Gagnon ◽  
Brian J. Fryer ◽  
...  

Trace elements in native gold provide a “fingerprint” that tends to be unique to individual gold deposits. Fingerprinting can distinguish gold sources and potentially yield insights into geochemical processes operating during gold deposit formation. Native gold grains come from three historical gold ore deposits; Hollinger, McIntyre (quartz-vein ore), and Aunor near Timmins, Ontario, at the western end of the Porcupine gold camp and the south-western part of the Abitibi greenstone belt. Laser-ablation, inductively-coupled plasma mass spectrometry (LA ICP MS) trace element concentrations were determined on 20 to 25 µm wide, 300 µm long rastor trails in ~ 60 native gold grains. Analyses used Ag as an internal standard with Ag and Au determined by a scanning electron microscope with an energy dispersive spectrometer. The London Bullion Market AuRM2 reference material served as the external standard for 21 trace element analytes (Al, As, Bi, Ca, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Pd, Pt, Rh, Sb, Se, Si, Sn, Te, Ti, Zn; Se generally below detection in samples). Trace elements in native gold associate according to Goldschmidt’s classification of elements strongly suggesting that element behavior in native Au is not random. Such element behavior suggests that samples from each Timmins deposit formed under similar but slightly variable geochemical conditions. Chalcophile and siderophile elements provide the most compelling fingerprints of the three ore deposits and appear to be mostly in solid solution in Au. Lithophile elements are not very useful for distinguishing these deposits and element ABSTRACT CUT OFF BY SOFTWARE


2021 ◽  
pp. 63-73
Author(s):  
IRINA GABLINA

Based on long-term studies of cupriferous sandstone and shale deposits, as well as deepsea sulfide ores, various types of geochemical barriers where sulfides form are shown. Cupriferous sandstones and shales form as metals precipitate from redbed reservoir waters on H2S geochemical barrier. Syngenetic and epigenetic barrier types are identified. Oceanic sulfide ores from the Central Atlantic region were studied; as a result, a new hydrothermal-metasomatic sediment-hosted mineralization type was found, along with previously known sulfide ore types (massive ores on the seafloor and stockwork ores in substrate rocks). Geochemical seafloor sulfide formation environments and those in biogenic carbonate bottom sediments are examined.


2021 ◽  
Author(s):  
Qingqing Zhao ◽  
Degao Zhai ◽  
Ryan Mathur ◽  
Jiajun Liu ◽  
David Selby ◽  
...  

Abstract Whether giant porphyry ore deposits are the products of single, short-lived magmatic-hydrothermal events or multiple events over a prolonged interval is a topic of considerable debate. Previous studies, however, have all been devoted to porphyry Cu and Cu-Mo deposits. In this paper, we report high-precision isotope dilution-negative-thermal ionization mass spectrometric (ID-N-TIMS) molybdenite Re-Os ages for the newly discovered, world-class Chalukou porphyry Mo deposit (reserves of 2.46 Mt @ 0.087 wt % Mo) in NE China. Samples were selected based on a careful evaluation of the relative timing of the different vein types (i.e., A, B, and D veins), thereby ensuring that the suite of samples analyzed could be used to reliably determine the age and duration of mineralization. The molybdenite Re-Os geochronology reveals that hydrothermal activity at Chalukou involved two magmatic-hydrothermal events spanning an interval of 6.92 ± 0.16 m.y. The first event (153.96 ± 0.08/0.63/0.79 Ma, molybdenite ID-N-TIMS Re-Os age) was associated with the emplacement of a granite porphyry dated at 152.1 ± 2.2 Ma (zircon laser ablation-inductively coupled plasma-microscopic [LA-ICP-MS] U-Pb ages), and led to only minor Mo mineralization, accounting for <10% of the overall Mo budget. The bulk of the Mo (>90%) was deposited in less than 650 kyr, between 147.67 ± 0.10/0.60/0.76 and 147.04 ± 0.12/0.72/0.86 Ma (molybdenite ID-N-TIMS Re-Os ages), coincident with the emplacement of a fine-grained porphyry at 148.1 ± 2.6 Ma (zircon LA-ICP-MS U-Pb ages). The high-precision Re-Os age determinations presented here show, contrary to the finding of a number of studies of porphyry Cu and Cu-Mo systems, that the giant Chalukou porphyry Mo deposit primarily formed in a single, short-lived (<650 kyr) hydrothermal event, suggesting that this may also have been the case for other giant porphyry Mo deposits.


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