scholarly journals Age of the lower Cambrian Vanadium deposit, East Guizhou, South China: Evidences from age of tuff and carbon isotope analysis along the Bagong section

2021 ◽  
Vol 13 (1) ◽  
pp. 999-1012
Author(s):  
Tong Wu ◽  
Ruidong Yang ◽  
Junbo Gao ◽  
Jun Li
Keyword(s):  
Carbon Isotope ◽  
Black Shale ◽  
South China ◽  
Inductively Coupled Plasma ◽  
Isotope Analysis ◽  
Middle Part ◽  
Guizhou Province ◽  
Stratigraphic Correlation ◽  
Isotopic Age ◽  
Inductively Coupled

Abstract The early Cambrian is a critical interval of dramatic oceanic and biochemical changes in geological history. The black shale deposits, which are rich in Mo, Ni, V, and platinum group elements (PGE), are a reflection of that interval. Among all known Cambrian black shale deposits in South China, the vanadium deposits are poorly constrained by geochronology. The newly discovered tuff layer in the Sansui Bagong vanadium deposit in Guizhou Province can provide excellent constraints on the age of vanadium deposits. In this study, we obtain a new zircon U–Pb isotopic age, which can constrain the age of the vanadium deposit. This tuff occurs in the middle part of the ore bed, and the age of the tuff layer can reflect the mineralization age of the V deposit. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is used in this study to obtain the zircon U–Pb age of the tuff and indicates that the event of volcanic activity took place at 520.9 ± 1 Ma. This age is close to the boundary between the Cambrian Terreneuvian and Series 2. This result provides a good constraint on the age of the vanadium deposits in South China and makes the vanadium deposits to be comparable with other Mo–Ni–PGE deposits. The alteration of organic carbon isotope (δ 13Corg) values can reflect changes in the marine environment and is widely used in stratigraphic correlation. The analysis of the δ 13Corg values of the ore bed in the present study reveals a positive excursion at the bottom of the deposit and a negative excursion in the V-enriched layer. The δ 13Corg values in the Bagong section are comparable to those in the Xiaotan and Longbizui sections. The ages of the Sansui vanadium deposit constrained by the U–Pb isotopic age of the tuff and the δ 13Corg values are consistent. All of the data lead us to infer that the vanadium deposit formed at approximately 521 Ma.

scholarly journals Weathering characteristics of the Lower Paleozoic black shale in northwestern Guizhou Province, south China

2016 ◽  
Vol 125 (5) ◽  
pp. 1061-1078 ◽  
Author(s):  
YANG LIU ◽  
JINCHUAN ZHANG ◽  
XUAN TANG ◽  
CHAO YANG ◽  
SHUAI TANG
Keyword(s):  
Black Shale ◽  
South China ◽  
Guizhou Province ◽  
Lower Paleozoic

High-precision analysis of potassium isotopes by MC-ICP-MS without collision cell using cool plasma technique in low resolution mode

2021 ◽  
Author(s):  
Hai-Ou Gu ◽  
Sun He
Keyword(s):  
High Precision ◽  
Inductively Coupled Plasma ◽  
Isotope Analysis ◽  
Collision Cell ◽  
Low Resolution ◽  
Inductively Coupled ◽  
Plasma Technique ◽  
Icp Ms ◽  
Cool Plasma ◽  
Plasma Mass Spectrometry

This study presents a method for high-precision stable potassium (K) isotope analysis using Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) without collision cell in low resolution mode. Cold plasma technique...

Assessment of matrix effects associated with Fe isotope analysis using 266 nm femtosecond and 193 nm nanosecond laser ablation multi-collector inductively coupled plasma mass spectrometry

2018 ◽  
Vol 33 (1) ◽  
pp. 68-83 ◽  
Author(s):  
Xin-Yuan Zheng ◽  
Brian L. Beard ◽  
Clark M. Johnson
Keyword(s):  
Laser Ablation ◽  
Inductively Coupled Plasma ◽  
Matrix Effects ◽  
Isotope Analysis ◽  
Nanosecond Laser ◽  
Inductively Coupled ◽  
Nanosecond Laser Ablation ◽  
Plasma Mass Spectrometry ◽  
193 Nm

The nature of matrix effects during in situ Fe isotope analysis using fs- and ns-laser ablation (LA) was characterized and compared.

scholarly journals Mineralogical characteristics and sources of alkali metals in the No. 6 coal seam from the Fukang mining area of the Zhunnan coalfield, Xinjiang province, Northwest China

2019 ◽  
Vol 37 (3) ◽  
pp. 1162-1181 ◽  
Author(s):  
Yun Xu ◽  
Handong Liang ◽  
Ning Zhang
Keyword(s):  
Coal Seam ◽  
Inductively Coupled Plasma ◽  
Alkali Metals ◽  
Northwest China ◽  
Mining Area ◽  
Major Elements ◽  
Middle Part ◽  
X Ray ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Minerals in coal are of great significance in determining coal properties, washing, combustion, gasification, and liquefaction. The content of alkali metals in coal is an important factor determining corrosion and/or erosion in combustion boilers. Eleven coal samples were taken from the No. 6 coal seam of the Fukang mining area, Zhunnan coalfield, Xinjiang province, China. X-ray fluorescence, inductively coupled plasma-mass spectrometry, low-temperature ashing-X-ray diffraction, and electron probe microanalyzer were used for analyzing the minerals, major elements, and trace elements of the coal. The results indicated that the minerals mainly consist of dawsonite, dolomite, albite, calcite, kaolinite, quartz. The average content of Na2O in the ash of the No. 6 coal seam samples was 10.91%. Na mainly occurs in the form of organic compounds in the No. 6 coal seam, then in the form of inorganic minerals, such as dawsonite and albite. Na in surface and underlying strata was brought into the coal by water and combined with organic matter, resulting in relatively high Na contents in the upper and bottom parts of the coal seam and relatively low Na contents in the middle part.

New Insights Into the Control of Visible Gold Fineness and Deposition: A Case Study of the Sanshandao Gold Deposit, Jiaodong, China

2021 ◽  
Vol 106 (1) ◽  
pp. 135-149
Author(s):  
Hong-Wei Peng ◽  
Hong-Rui Fan ◽  
Xuan Liu ◽  
Bo-Jie Wen ◽  
Yong-Wen Zhang ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Inductively Coupled Plasma ◽  
Gold Mineralization ◽  
Isotope Analysis ◽  
Trace Element Analysis ◽  
Sulfide Minerals ◽  
Element Analysis ◽  
Rock Interaction ◽  
Inductively Coupled ◽  
Icp Ms

Abstract Mineralogical distribution, textures, electron probe microanalysis of visible gold, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) trace element analysis of pyrite, and LA-multicollector (MC-)ICP-MS sulfur isotope analysis of sulfide minerals are examined in an ore zone extending obliquely to –4 km depth in the Sanshandao gold deposit Jiaodong, China. We relate these results to the temporal and spatial ore-forming processes in the deposit to further elucidate the controls on the deposition of visible Au and fineness variation. Two generations of Au mineralization are identified. The early generation is represented by beresitization and quartz-pyrite veins in which visible Au grains are associated with pyrite (Py1 and Py2) and are characterized by high fineness [729–961; fineness = 1000×Au/(Au+Ag)]. Py1 and Py2 are both enriched in Co, Ni, and Bi and depleted in As and Au. Texturally, gold and pyrite are pristine crystals, homogeneous in composition. These features are attributed to the sulfidation of the granitic wallrock (fluid/rock interaction) that effectively destabilizes Au in the ore-forming fluids during pyrite deposition. Fineness decreases continuously from 870 at –2650 m depth to 752 at –420 m depth. The Co and Ni contents of Py1 and Py2 decrease significantly from –4000 m to –420 m depth, whereas the As contents increase. The mean δ34S values of Py1 increase from 10.5 to 11.8‰. The spatial variations are interpreted to be related to gradual cooling, decompression, and an enhanced degree of fluid/rock interaction with decreasing depth, which facilitated the initiation of visible gold mineralization at ca. –2700 m depth. The late generation of Au mineralization is represented by quartz-polysulfide veins in which visible Au grains are associated with multiple sulfide minerals (Py3, galena, chalcopyrite, arsenopyrite, and sphalerite). It is characterized by low fineness (549–719), and heterogeneous textures with Ag-rich parts (218–421). Py3, occurring as the rim of pyrite grain, is interpreted to form by replacement via a dissolution-reprecipitation reaction. Py3 is distinctly enriched in As (median of 10 000 ppm) and Au (2.2 ppm), but depleted in Co, Ni, and Bi. The δ34S values of the polysulfide minerals decrease sharply by 4 to 5‰ at depths from –1909 to –1450 m. These features are interpreted to be generated by significant decompression and phase separation of fluid, where most ore elements (e.g., Au, Ag, As, and base metal elements) are destabilized. Our study suggests that remobilization did not affect the generation of visible Au mineralization at Sanshandao.

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