scholarly journals LA-ICP-MS Trace-Element Analysis of Pyrite from the Huanxiangwa Gold Deposit, Xiong’ershan District, China: Implications for Ore Genesis

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 157
Author(s):  
Fuping Gao ◽  
Yangsong Du ◽  
Zhenshan Pang ◽  
Yilun Du ◽  
Fengpei Xin ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Inductively Coupled Plasma ◽  
Trace Element Analysis ◽  
Hydrothermal Activity ◽  
Coarse Grained ◽  
First Episode ◽  
Yangtze Craton ◽  
Element Analysis ◽  
The North ◽  
Icp Ms

The Huanxiangwa deposit is a major gold deposit in the Xiong’ershan district, which is the third-largest gold-producing district in China. Pyrites from the Huanxiangwa deposit were investigated using ore microscopy and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Pyrite is the dominant Au-bearing mineral in the Huanxiangwa deposit and can be divided into two types: medium- to fine-grained subhedral-anhedral pyrite (Py1) disseminated in altered rocks and coarse-grained subhedral-euhedral pyrite (Py2) hosted in auriferous quartz veins. LA-ICP-MS time-resolved depth profiles show that invisible gold occurs primarily as solid solution or as homogeneously distributed nanoparticles of native gold, electrum, or Au-Ag-Te minerals in Py1, whereas it is present mainly as nano- to submicron-sized inclusions of complex Au-Ag-Cu-Pb-Zn domains in Py2. The presented data indicate that the Huanxiangwa deposit resulted from two episodes of hydrothermal mineralization associated with two distinct source reservoirs. The first episode of mineralization was linked to the dehydration of deep-seated mafic-ultramafic metamorphic rock during the Triassic collision of the North China Craton with the Yangtze Craton. The second episode of mineralization was related to hydrothermal activity resulting from Early Cretaceous I-type granitic magmatism.

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.

3D-printed total consumption microflow nebuliser development for trace element analysis in organic matrices via inductively coupled plasma mass spectrometry

2020 ◽  
Vol 35 (8) ◽  
pp. 1552-1557 ◽  
Author(s):  
Victor Garcia-Montoto ◽  
Sylvain Mallet ◽  
Carine Arnaudguilhem ◽  
Jan H. Christensen ◽  
Brice Bouyssiere
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Trace Element Analysis ◽  
Element Analysis ◽  
Total Consumption ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Organic Matrices ◽  
Plasma Mass Spectrometry ◽  
3D Printed

A new total consumption micronebuliser for ICP-MS was developed and optimised in this work.

LA-ICP-MS trace element analysis of arsenopyrite from the Samgwang gold deposit, South Korea, and its genetic implications

2019 ◽  
Vol 114 ◽  
pp. 103147 ◽  
Author(s):  
Moontaek Lee ◽  
Dongbok Shin ◽  
Bongchul Yoo ◽  
Heonkyung Im ◽  
Sangjoon Pak ◽  
...  
Keyword(s):  
South Korea ◽  
Trace Element ◽  
Gold Deposit ◽  
Trace Element Analysis ◽  
Element Analysis ◽  
Icp Ms
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