Classification of pyrite types using fractal and stepwise factor analyses in the Chah Zard gold-silver epithermal deposit, Central Iran

2020 ◽  
Vol 20 (4) ◽  
pp. 496-508
Author(s):  
Hossein Kouhestani ◽  
Majid Ghaderi ◽  
Peyman Afzal ◽  
Khin Zaw

The major target of this research is the classification of pyrite types using fractal and stepwise factor analyses in the Chah Zard ore deposit, Central Iran. The ore occurs within a breccia/vein type and the major ore mineral hosting gold mineralization is pyrite. In this study, data were selected using optical, scanning electron microscopy (SEM) and backscattered electron observations as well as laser ablation-inductively coupled plasma–mass spectrometry (LA-ICP–MS) analysis. Conventional interpretations represent four gold-bearing pyrite types of various textures including fractured and porous Py1, oscillatory-rimmed and simple-zoned Py2, colloform Py3 and inclusion-rich Py4. The stepwise factor process was performed on the centred log ratio (clr) transformed data in two phases and Au was grouped with As, Te, Ni and Co in the second factor from the second stage (F2-2). Also, C-N fractal modelling was performed on the As, Au, Te and F2-2 values, all of which demonstrate multifractal nature. Four populations were separated based on F2-2 values and the C-N log–log plot. The main gold mineralization starts from 32 ppm, 2.8%, 7.94 ppm and 1.26 for Au, As, Te concentrations and F2-2, respectively, based on the C-N fractal modelling. These values are correlated with inclusion-rich Py4 and simple-zoned and oscillatory-rimmed Py2. The results obtained in this study show that fractal interpretation of LA-ICP–MS data by stepwise factor analysis may provide a suitable tool for the recognition of ore mineralization in epithermal gold deposits.

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 235 ◽  
Author(s):  
Hinyuen Tsang ◽  
Jingya Cao ◽  
Xiaoyong Yang

The Chaoyangzhai gold deposit is one of the newly discovered medium to large scale turbidite-hosted gold deposits in Southeast Guizhou, South China. In this study, laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) zircon U–Pb dating on the tuffaceous- and sandy-slates of Qingshuijiang Formation, Xiajiang Group, and gold-bearing quartz vein yielded similar age distributions, indicating that zircon grains in gold-bearing quartz vein originated from the surrounding tuffaceous- and sandy-slates. In addition, the youngest weighted mean ages of the zircon grains from the tuffaceous- and sandy-slates were 775 ± 13 Ma and 777 ± 16 Ma, respectively, displaying that the tuffaceous- and sandy-slates of the Qingshuijiang Formation were likely deposited in Neoproterozoic. Based on their major and trace element compositions, the tuffaceous- and sandy-slates were sourced from a felsic igneous provenance. The sandy slates have higher contents of Au (mostly ranging from 0.019 to 0.252 ppm), than those of the tuffaceous slates (mostly lower than 0.005 ppm). The δ34SV-CDT values of pyrite and arsenopyrite of the gold-bearing samples range from +8.12‰ to +9.99‰ and from +9.78 to +10.78‰, respectively, indicating that the sulfur source was from the metamorphic rocks. Together with the evidence of similar geochemical patterns between the tuffaceous- and sandy-slates and gold-bearing quartz, it is proposed that the gold might be mainly sourced from sandy slates. The metamorphic devolatilization, which was caused by the Caledonian orogeny (Xuefeng Orogenic Event), resulted in the formation of the ore-forming fluid. Gold was likely deposited in the fractures due to changes of the physico-chemical conditions, leading to the formation of the Chaoyangzhai gold deposit, and the large-scale gold mineralization in Southeast Guizhou.


Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 966
Author(s):  
Baptiste Madon ◽  
Lucie Mathieu ◽  
Jeffrey H. Marsh

Neoarchean syntectonic intrusions from the Chibougamau area, northeastern Abitibi Subprovince (greenstone belt), may be genetically related to intrusion related gold mineralization. These magmatic-hydrothermal systems share common features with orogenic gold deposits, such as spatial and temporal association with syntectonic magmatism. Genetic association with magmatism, however, remains controversial for many greenstone belt hosted Au deposits. To precisely identify the link between syntectonic magmas and gold mineralization in the Abitibi Subprovince, major and trace-element compositions of whole rock, zircon, apatite, and amphibole grains were measured for five intrusions in the Chibougamau area; the Anville, Saussure, Chevrillon, Opémisca, and Lac Line Plutons. The selected intrusions are representative of the chemical diversity of synvolcanic (TTG suite) and syntectonic (e.g., sanukitoid, alkaline intrusion) magmatism. Chemical data enable calculation of oxygen fugacity and volatile content, and these parameters were interpreted using data collected by electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry. The zircon and apatite data and associated oxygen fugacity values in magma indicate that the youngest magmas are the most oxidized. Moreover, similar oxygen fugacity and high volatile content for both the Saussure Pluton and the mineralized Lac Line intrusion may indicate a possible prospective mineralized system associated with the syntectonic Saussure intrusion.


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.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Stanko Ilić Popov ◽  
Trajče Stafilov ◽  
Robert Šajn ◽  
Claudiu Tănăselia ◽  
Katerina Bačeva

A systematic study was carried out to investigate the distribution of fifty-six elements in the water samples from river Vardar (Republic of Macedonia and Greece) and its major tributaries. The samples were collected from 27 sampling sites. Analyses were performed by mass spectrometry with inductively coupled plasma (ICP-MS) and atomic emission spectrometry with inductively coupled plasma (ICP-AES). Cluster and R mode factor analysis (FA) was used to identify and characterise element associations and four associations of elements were determined by the method of multivariate statistics. Three factors represent the associations of elements that occur in the river water naturally while Factor 3 represents an anthropogenic association of the elements (Cd, Ga, In, Pb, Re, Tl, Cu, and Zn) introduced in the river waters from the waste waters from the mining and metallurgical activities in the country.


2019 ◽  
Vol 157 (3) ◽  
pp. 435-457
Author(s):  
Zhenshan Pang ◽  
Fuping Gao ◽  
Yangsong Du ◽  
Yilun Du ◽  
Zhaojian Zong ◽  
...  

AbstractThe Xiong’ershan area is the third largest gold-producing district in China. The Late Jurassic to Early Cretaceous magmatism in the Xiong’ershan area can be divided into two episodes: early (165–150 Ma) and late (138–113 Ma). Laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) zircon U–Pb dating yields ages of 160.7 ± 0.6 Ma and 127.2 ± 1.0 Ma for the Wuzhangshan and Huashan monzogranites in the Xiong’ershan area, respectively, representing the two magmatic episodes. The Wuzhangshan monzogranites exhibit adakite-like geochemical features (e.g. high Sr/Y ratios, low Yb and Y contents). Their Sr–Nd–Hf isotopic compositions are consistent with those of the amphibolites of the Taihua Group, indicating that the Wuzhangshan monzogranites were formed from partial melting of the Taihua Group metamorphic rocks. Compared to the Wuzhangshan rocks, the Huashan monzogranites have higher MgO, Cr, Co and Ni contents, but lower Sr/Y and Fe3+/Fe2+. All the samples from the Huashan monzogranites plot in the area between the Taihua Group amphibolite rocks and the mantle rocks in the (87Sr/86Sr)t vs εNd(t) and age vs εHf(t) diagrams, suggesting that the Huashan monzogranites were probably generated by mixing of mantle-derived magmas and the Taihua Group metamorphic basement melts. The gold mineralization (136–110 Ma) is coeval with the emplacement of the late-episode magmas, implying that crustal–mantle mixed magma might be a better target for gold mineralization compared to the ancient metamorphic basement melt. The data presented in this study further indicate that the transformation of the lithosphere from thickening to thinning in the Xiong’ershan area probably occurred between ~160 Ma and ~127 Ma, and that the gold mineralization in this area was probably related to lithospheric thinning.


2021 ◽  
Vol 106 (1) ◽  
pp. 135-149
Author(s):  
Hong-Wei Peng ◽  
Hong-Rui Fan ◽  
Xuan Liu ◽  
Bo-Jie Wen ◽  
Yong-Wen Zhang ◽  
...  

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.


2020 ◽  
Vol 16 (8) ◽  
pp. 1259-1264
Author(s):  
Francesco Caridi ◽  
Maurizio D’Agostino ◽  
Alberto Belvedere ◽  
Antonio F. Mottese

Background and Objectives: In this article, a comprehensive study was carried out for food authenticity evaluation through chemometric analyses, correlating botanical and geographical origins with food chemical composition. Methods: A total of eighteen Calabrian red, rose and white wines were analyzed through Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results: The mineral concentrations, determined by ICP-MS in the investigated wine samples, followed the subsequent order: K > P > Mg > Na > Ca > Fe > Cu > Zn > Mn > V. : The 2D Scatterplot and loading plot (Principal Component Analysis) showed that all red, rose and white wine samples from “Cirò” DOP area were grouped in the fourth, second and third quadrant, respectively, clearly separated from each other. Samples from “Cirò” red showed positive PC1 and were characterized by higher K, Fe, Mn, Na, V and Zn concentrations. Moreover, the points corresponding to two red wines from the “Terre di Cosenza” DOP area fall into the first quadrant; those corresponding to two rose wines from the “Donnici” and “Sant’Anna di Isola di Capo Rizzuto” DOP areas fall into the third and fourth quadrants, respectively; the point corresponding to a white wine from the “Donnici” DOP area falls into the second quadrant. Conclusions: Experimental results demonstrated that it is possible to strictly relate, through the PCA, wines to their geographical and botanical provenance, thus becoming a useful tool for evaluating the product authenticity and guaranteeing it to the consumers.


2020 ◽  
Vol 115 (3) ◽  
pp. 671-685 ◽  
Author(s):  
Jun Deng ◽  
Kun-Feng Qiu ◽  
Qing-Fei Wang ◽  
Richard Goldfarb ◽  
Li-Qiang Yang ◽  
...  

Abstract The Jiaodong gold province, the largest gold producer in China, formed in a setting dominated by a 30-m.y. episode of Izanagi plate rollback and widespread extension, concomitant with late Mesozoic craton destruction. This study presents new high precision in situ sensitive high-resolution ion microprobe (SHRIMP) U-Th-Pb and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb ages for hydrothermal monazite from the largest of the Jiaodong gold deposits, which were previously dated as indicating ore formation over a few tens of millions of years when applying sericite Ar-Ar, zircon U-Pb, and less robust analytical techniques. Our U-Pb dating on monazite from the Jiaojia and Linglong deposits in western Jiaodong yielded consistent ages at ca. 120 Ma. The new geochronologic results, coupled with recently reported in situ monazite dates from smaller deposits in western Jiaodong, reveal that the deposits that host most of the ≥4,000-t Au resource formed during a relatively brief period at ca. 120 Ma. In eastern Jiaodong, the much smaller resource may have formed about 5 m.y. later, recorded by 114.2 ± 1.5 Ma gold mineralization at the Rushan deposit. The postsubduction opening of a slab gap at ca. 120 Ma is the most likely cause of the extensive gold mineralization in Jiaodong. The gap induced a local and rapid devolatilization of the hydrated mantle wedge at submelt temperatures. The transient event included release of a major volume of gold-transporting aqueous-carbonic fluid that was stored in the wedge into major NNE-trending structures in the overlying lithosphere.


2012 ◽  
Vol 150 (1) ◽  
pp. 50-71 ◽  
Author(s):  
TAO YANG ◽  
LAIMIN ZHU ◽  
FEI WANG ◽  
HUJUN GONG ◽  
RUKUI LU

AbstractThe Liziyuan goldfield is located along the northern margin of the western part of the Qinling Orogen (WQO). The goldfield consists of five gold-only deposits hosted by metavolcanic rocks, and one polymetallic (Au–Ag–Pb) deposit hosted by the Tianzishan Monzogranite. As the Liziyuan goldfield appears to be spatially and temporally related to the Jiancaowan Porphyry, the study of the deposit provides a crucial insight into the relationship between tectonic-magmatic events and gold metallogenesis in the WQO. In this paper, we present whole-rock major and trace element geochemistry, and in situ zircon U–Pb and Lu–Hf isotopic data from the Tianzishan Monzogranite and Jiancaowan Porphyry. The two granitic plutons are enriched in LILEs and LREEs, depleted in HFSEs and have zircon εHf(t) values between −14.1 and −5.1 for the Tianzishan Monzogranite and between −21.0 and −8.4 for the Jiancaowan Porphyry. These characteristics indicate that the granites are derived from the crust. The Tianzishan Monzogranite has LA-ICP-MS zircon U–Pb ages of 256.1 ± 3.7 to 260.0 ± 2.1 Ma, which suggests that it was emplaced in the WQO during the convergence of the North and South (Yangtze) China cratons in the early stage of the Qinling Orogeny. In contrast, the porphyry has a LA-ICP-MS zircon U–Pb age of 229.2 ± 1.2 Ma, which is younger than the peak collision age, but corresponds to the widespread Late Triassic post-collisional granitic plutons in the WQO. The Tianzishan Monzogranite has somewhat higher Sr contents (196–631 ppm), lower Y (2.23–19.6 ppm) and Yb (0.20–2.01 ppm) contents, and a positive Eu/Eu* averaging 1.15. These characteristics suggest the pluton was derived from partial melting of the thickened crust. In contrast, the relatively higher MgO content (0.85–2.08 wt%) and Mg no. (43.4–58.2) of the Jiancaowan Porphyry indicates that insignificant amounts of subcontinental lithospheric mantle-derived mafic melts were involved in the generation of the magma. The Liziyuan goldfield is hosted by faults in greenschist-facies metamorphic rocks. Fluid inclusion studies suggest that gold was precipitated from CO2-rich, low-salinity and medium temperature fluids. This feature is consistent with the other orogenic gold deposits throughout the world. The field relationships and zircon U–Pb ages of the two granitic plutons suggest that gold mineralization is coeval with or slightly younger than the emplacement of the Jiancaowan Porphyry. Therefore, both the porphyry and deposit formed during the post-collisional stage of the Qinling Orogen.


Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 349
Author(s):  
Natasa P. Kalogiouri ◽  
Natalia Manousi ◽  
Dimitris Klaoudatos ◽  
Thomas Spanos ◽  
Vilson Topi ◽  
...  

Pistachios are a nutritionally beneficial food source widely consumed all over the world. Pistachios exhibit high content of antioxidants, vitamins and other beneficial micronutrients, including nutrient elements and rare earth elements (REEs). Considering that the concentration of REEs depends on the climate and soil characteristics that vary among different geographical regions, REEs could constitute markers responsible for the geographical discrimination of this nut type. In this study, Greek pistachios with a protected designation of origin (PDO) label from Aegina Island and Fthiotida and Turkish pistachios from Adana were analyzed with inductively coupled plasma mass spectrometry (ICP-MS) to assess their REE profile. La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb were determined and quantified. The quantification results were further analyzed using the main effect plot, permutational analysis of variance (PERMANOVA), nonmetric multidimensional scaling (nMDS), principal component analysis (PCA) and hierarchical clustering (HCA) to investigate the similarities between the pistachios. A decision tree (DT) was developed for the classification of pistachios according to their geographical origin proving to be a promising and reliable tool for verifying the authenticity of food products on the basis of their REE profile.


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