The Experts below are selected from a list of 5037 Experts worldwide ranked by ideXlab platform
Dongtian Wei - One of the best experts on this subject based on the ideXlab platform.
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multistage Pyrites in the nibao disseminated gold deposit southwestern guizhou province china insights into the origin of au from textures in situ trace elements and sulfur isotope analyses
Ore Geology Reviews, 2020Co-Authors: J A Steadman, Dongtian Wei, Yong Xia, Daniel D Gregory, Qinping Tan, Zhuojun Xie, Xijun LiuAbstract:Abstract Nibao is a unique thrust fault-controlled and strata-bound disseminated gold deposit in southwestern Guizhou Province, China. In Nibao, pyrite is the major sulfide mineral and Au is structurally bound (Au+) within the pyrite lattice. In this study, we conducted detailed analyses of the pyrite chemistry and S isotope composition in Nibao using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), respectively. Through petrographic and pyrite chemical studies, four pyrite generations (Py1–Py4) were distinguished: framboidal pyrite (Py1, pre-ore sedimentary stage), clean pyrite overgrowing framboidal pyrite (Py2, pre-ore diagenetic stage), “spongy” pyrite (Py3, early ore stage), and overgrowth of narrow pyrite rims surrounding Py2/Py3 and disseminated pyrite associated with arsenopyrite (Py4, main ore stage). Among these, Py2 and Py4 are the most abundant. The trace element content in Py2 is characterized by a wide range of As, Cu, Sb, and Pb concentrations (∼2,480–58,100 ppm, ∼55.4–1,610 ppm, ∼29.1–232 ppm, and ∼24.1–376 ppm, respectively), while Py4 has the highest Au, As, Cu, and Se contents (∼70 ppm, ∼4,200, ∼1,630 ppm, and ∼38.3 ppm, respectively). The δ34S values of pre-ore Pyrites measured by LA-MC-ICP-MS in this study and the available data in the literature range broadly from -53.3 to 114.8‰, indicating that they were most likely generated by bacterial reduction from marine sulfate during sedimentation/diagenesis. Meanwhile, the δ34S values of ore Pyrites have relative narrow δ34S values, mostly varying from -5 to 5‰, and indicating that the S was derived either from the average of sedimentary rocks or from a magmatic source. Since igneous rocks are scarce in the region and the exposed (∼77–99 Ma) are clearly younger than the mineralization age of the Nibao gold deposit (∼141 Ma), a magmatic source is unlikely in Nibao. All Pyrites in this study show a positive correlation (R2=0.71) between Co and Ni, and the Co/Ni and Zn/Ni ratios of main stage Py4 are close to or within the range defined for a sedimentary–diagenetic origin, suggesting a sedimentary source is more likely in Nibao.
Tomaso R.r. Bontognali - One of the best experts on this subject based on the ideXlab platform.
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In Situ Fe and S isotope analyses in pyrite from the 3.2 Ga Mendon Formation (Barberton Greenstone Belt, South Africa): Evidence for early microbial iron reduction
Geobiology, 2020Co-Authors: Johanna Marin-carbonne, Vincent Busigny, Jennyfer Miot, Claire Rollion-bard, Elodie Muller, Nadja Drabon, Damien Jacob, Sylvain Pont, Martin Robyr, Tomaso R.r. BontognaliAbstract:On the basis of phylogenetic studies and laboratory cultures, it has been proposed that the ability of microbes to metabolize iron has emerged prior to the Archaea/ Bacteria split. However, no unambiguous geochemical data supporting this claim have been put forward in rocks older than 2.7-2.5 giga years (Gyr). In the present work, we report in situ Fe and S isotope composition of pyrite from 3.28-to 3.26-Gyr-old cherts from the upper Mendon Formation, South Africa. We identified three populations of microscopic Pyrites showing a wide range of Fe isotope compositions, which cluster around two δ 56 Fe values of −1.8‰ and +1‰. These three pyrite groups can also be distinguished based on the pyrite crystallinity and the S isotope mass-independent signatures. One pyrite group displays poorly crystallized pyrite minerals with positive Δ 33 S values > +3‰, while the other groups display more variable and closer to 0‰ Δ 33 S values with recrystallized pyrite rims. It is worth to note that all the pyrite groups display positive Δ 33 S values in the pyrite core and similar trace element compositions.
Xijun Liu - One of the best experts on this subject based on the ideXlab platform.
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multistage Pyrites in the nibao disseminated gold deposit southwestern guizhou province china insights into the origin of au from textures in situ trace elements and sulfur isotope analyses
Ore Geology Reviews, 2020Co-Authors: J A Steadman, Dongtian Wei, Yong Xia, Daniel D Gregory, Qinping Tan, Zhuojun Xie, Xijun LiuAbstract:Abstract Nibao is a unique thrust fault-controlled and strata-bound disseminated gold deposit in southwestern Guizhou Province, China. In Nibao, pyrite is the major sulfide mineral and Au is structurally bound (Au+) within the pyrite lattice. In this study, we conducted detailed analyses of the pyrite chemistry and S isotope composition in Nibao using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), respectively. Through petrographic and pyrite chemical studies, four pyrite generations (Py1–Py4) were distinguished: framboidal pyrite (Py1, pre-ore sedimentary stage), clean pyrite overgrowing framboidal pyrite (Py2, pre-ore diagenetic stage), “spongy” pyrite (Py3, early ore stage), and overgrowth of narrow pyrite rims surrounding Py2/Py3 and disseminated pyrite associated with arsenopyrite (Py4, main ore stage). Among these, Py2 and Py4 are the most abundant. The trace element content in Py2 is characterized by a wide range of As, Cu, Sb, and Pb concentrations (∼2,480–58,100 ppm, ∼55.4–1,610 ppm, ∼29.1–232 ppm, and ∼24.1–376 ppm, respectively), while Py4 has the highest Au, As, Cu, and Se contents (∼70 ppm, ∼4,200, ∼1,630 ppm, and ∼38.3 ppm, respectively). The δ34S values of pre-ore Pyrites measured by LA-MC-ICP-MS in this study and the available data in the literature range broadly from -53.3 to 114.8‰, indicating that they were most likely generated by bacterial reduction from marine sulfate during sedimentation/diagenesis. Meanwhile, the δ34S values of ore Pyrites have relative narrow δ34S values, mostly varying from -5 to 5‰, and indicating that the S was derived either from the average of sedimentary rocks or from a magmatic source. Since igneous rocks are scarce in the region and the exposed (∼77–99 Ma) are clearly younger than the mineralization age of the Nibao gold deposit (∼141 Ma), a magmatic source is unlikely in Nibao. All Pyrites in this study show a positive correlation (R2=0.71) between Co and Ni, and the Co/Ni and Zn/Ni ratios of main stage Py4 are close to or within the range defined for a sedimentary–diagenetic origin, suggesting a sedimentary source is more likely in Nibao.
J A Steadman - One of the best experts on this subject based on the ideXlab platform.
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multistage Pyrites in the nibao disseminated gold deposit southwestern guizhou province china insights into the origin of au from textures in situ trace elements and sulfur isotope analyses
Ore Geology Reviews, 2020Co-Authors: J A Steadman, Dongtian Wei, Yong Xia, Daniel D Gregory, Qinping Tan, Zhuojun Xie, Xijun LiuAbstract:Abstract Nibao is a unique thrust fault-controlled and strata-bound disseminated gold deposit in southwestern Guizhou Province, China. In Nibao, pyrite is the major sulfide mineral and Au is structurally bound (Au+) within the pyrite lattice. In this study, we conducted detailed analyses of the pyrite chemistry and S isotope composition in Nibao using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), respectively. Through petrographic and pyrite chemical studies, four pyrite generations (Py1–Py4) were distinguished: framboidal pyrite (Py1, pre-ore sedimentary stage), clean pyrite overgrowing framboidal pyrite (Py2, pre-ore diagenetic stage), “spongy” pyrite (Py3, early ore stage), and overgrowth of narrow pyrite rims surrounding Py2/Py3 and disseminated pyrite associated with arsenopyrite (Py4, main ore stage). Among these, Py2 and Py4 are the most abundant. The trace element content in Py2 is characterized by a wide range of As, Cu, Sb, and Pb concentrations (∼2,480–58,100 ppm, ∼55.4–1,610 ppm, ∼29.1–232 ppm, and ∼24.1–376 ppm, respectively), while Py4 has the highest Au, As, Cu, and Se contents (∼70 ppm, ∼4,200, ∼1,630 ppm, and ∼38.3 ppm, respectively). The δ34S values of pre-ore Pyrites measured by LA-MC-ICP-MS in this study and the available data in the literature range broadly from -53.3 to 114.8‰, indicating that they were most likely generated by bacterial reduction from marine sulfate during sedimentation/diagenesis. Meanwhile, the δ34S values of ore Pyrites have relative narrow δ34S values, mostly varying from -5 to 5‰, and indicating that the S was derived either from the average of sedimentary rocks or from a magmatic source. Since igneous rocks are scarce in the region and the exposed (∼77–99 Ma) are clearly younger than the mineralization age of the Nibao gold deposit (∼141 Ma), a magmatic source is unlikely in Nibao. All Pyrites in this study show a positive correlation (R2=0.71) between Co and Ni, and the Co/Ni and Zn/Ni ratios of main stage Py4 are close to or within the range defined for a sedimentary–diagenetic origin, suggesting a sedimentary source is more likely in Nibao.
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Multistage Pyrites in the Nibao disseminated gold deposit, southwestern Guiz‐ hou Province, China: insights into the origin of Au from textures, in situ trace elements, and sulfur isotope analyses
'Elsevier BV', 2020Co-Authors: Dt Wei, J A Steadman, Xia Y, Dd Gregory, Qp Tan, Zj Xie, Xj LuiAbstract:Nibao is a unique thrust fault-controlled and strata-bound disseminated gold deposit in southwestern Guizhou Province, China. In Nibao, pyrite is the major sulfide mineral and Au is structurally bound (Au+) within the pyrite lattice. In this study, we conducted detailed analyses of the pyrite chemistry and S isotope composition in Nibao using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), respectively. Through petrographic and pyrite chemical studies, four pyrite generations (Py1–Py4) were distinguished: framboidal pyrite (Py1, pre-ore sedimentary stage), clean pyrite overgrowing framboidal pyrite (Py2, pre-ore diagenetic stage), “spongy” pyrite (Py3, early ore stage), and overgrowth of narrow pyrite rims surrounding Py2/Py3 and disseminated pyrite associated with arsenopyrite (Py4, main ore stage). Among these, Py2 and Py4 are the most abundant.The trace element content in Py2 is characterized by a wide range of As, Cu, Sb, and Pb concentrations (∼2,480–58,100 ppm, ∼55.4–1,610 ppm, ∼29.1–232 ppm, and ∼24.1–376 ppm, respectively), while Py4 has the highest Au, As, Cu, and Se contents (∼70 ppm, ∼4,200, ∼1,630 ppm, and ∼38.3 ppm, respectively). The δ34S values of pre-ore Pyrites measured by LA-MC-ICP-MS in this study and the available data in the literature range broadly from -53.3 to 114.8‰, indicating that they were most likely generated by bacterial reduction from marine sulfate during sedimentation/diagenesis. Meanwhile, the δ34S values of ore Pyrites have relative narrow δ34 values, mostly varying from -5 to 5‰, and indicating that the S was derived either from the average of sedimentary rocks or from a magmatic source.Since igneous rocks are scarce in the region and the exposed (∼77–99 Ma) are clearly younger than the mineralization age of the Nibao gold deposit (∼141 Ma), a magmatic source is unlikely in Nibao. All Pyrites in this study show a positive correlation (R2=0.71) between Co and Ni, and the Co/Ni and Zn/Ni ratios of main stage Py4 are close to or within the range defined for a sedimentary–diagenetic origin, suggesting a sedimentary source is more likely in Nibao
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pyrite compositions from vhms and orogenic au deposits in the yilgarn craton western australia implications for gold and copper exploration
Ore Geology Reviews, 2016Co-Authors: I A Belousov, Sebastien Meffre, J A Steadman, Leonid V. Danyushevsky, Ross R. Large, T BeardsmoreAbstract:Abstract The Archaean Yilgarn Craton (Western Australia) is a world-class metallogenic province, hosting considerable resources of Au, Ag, Ni, Cu, Zn and Fe. Here we present trace element compositions of pyrite from > 30 orogenic Au and 5 volcanic hosted massive sulphide (VHMS) deposits across the Yilgarn. Pyrites from VHMS deposits tend to have higher Sn, Se, Cu, Pb, Bi and lower Ni relative to orogenic deposits. VHMS deposit Pyrites commonly have Co > Ni, As > 100Au, Te > Au, Se > Te. Orogenic gold deposits could be subdivided based on association of Au with As or Te. Pyrites from Au As ores generally have Pb/Bi > 5, Se/Te > 5, Pb/Sb 100 and the majority of Au is refractory (in pyrite structure). At the same time Au Te association Pyrites are characterised by lower values of Pb/Bi, Se/Te and Tl/Te, higher values of Ag/Au, Pb/Sb and Au generally resides in inclusions of different compositions. Our data can be used at the exploration stage to distinguish between VHMS vs Orogenic Au signatures. For all studied deposits inclusion populations are summarised with implications for Au and Ag deportment. Orogenic Au deposits from the Yilgarn mostly have multistage formation histories reflected in the presence of multiple generations of Pyrites. However, only some deposits record multiple high Au mineralisation events.
Daniel D Gregory - One of the best experts on this subject based on the ideXlab platform.
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multistage Pyrites in the nibao disseminated gold deposit southwestern guizhou province china insights into the origin of au from textures in situ trace elements and sulfur isotope analyses
Ore Geology Reviews, 2020Co-Authors: J A Steadman, Dongtian Wei, Yong Xia, Daniel D Gregory, Qinping Tan, Zhuojun Xie, Xijun LiuAbstract:Abstract Nibao is a unique thrust fault-controlled and strata-bound disseminated gold deposit in southwestern Guizhou Province, China. In Nibao, pyrite is the major sulfide mineral and Au is structurally bound (Au+) within the pyrite lattice. In this study, we conducted detailed analyses of the pyrite chemistry and S isotope composition in Nibao using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS), respectively. Through petrographic and pyrite chemical studies, four pyrite generations (Py1–Py4) were distinguished: framboidal pyrite (Py1, pre-ore sedimentary stage), clean pyrite overgrowing framboidal pyrite (Py2, pre-ore diagenetic stage), “spongy” pyrite (Py3, early ore stage), and overgrowth of narrow pyrite rims surrounding Py2/Py3 and disseminated pyrite associated with arsenopyrite (Py4, main ore stage). Among these, Py2 and Py4 are the most abundant. The trace element content in Py2 is characterized by a wide range of As, Cu, Sb, and Pb concentrations (∼2,480–58,100 ppm, ∼55.4–1,610 ppm, ∼29.1–232 ppm, and ∼24.1–376 ppm, respectively), while Py4 has the highest Au, As, Cu, and Se contents (∼70 ppm, ∼4,200, ∼1,630 ppm, and ∼38.3 ppm, respectively). The δ34S values of pre-ore Pyrites measured by LA-MC-ICP-MS in this study and the available data in the literature range broadly from -53.3 to 114.8‰, indicating that they were most likely generated by bacterial reduction from marine sulfate during sedimentation/diagenesis. Meanwhile, the δ34S values of ore Pyrites have relative narrow δ34S values, mostly varying from -5 to 5‰, and indicating that the S was derived either from the average of sedimentary rocks or from a magmatic source. Since igneous rocks are scarce in the region and the exposed (∼77–99 Ma) are clearly younger than the mineralization age of the Nibao gold deposit (∼141 Ma), a magmatic source is unlikely in Nibao. All Pyrites in this study show a positive correlation (R2=0.71) between Co and Ni, and the Co/Ni and Zn/Ni ratios of main stage Py4 are close to or within the range defined for a sedimentary–diagenetic origin, suggesting a sedimentary source is more likely in Nibao.
