The East Tianshan contains many late Paleozoic magmatic and polymetallic deposits.Recent studies demonstrate that the early Paleozoic volcanic rocks discovered in the northern region of East Tianshan can be subdivided...The East Tianshan contains many late Paleozoic magmatic and polymetallic deposits.Recent studies demonstrate that the early Paleozoic volcanic rocks discovered in the northern region of East Tianshan can be subdivided into the Daliugou,Hongliuxia and Kalatag formations.Here,we report zircon U-Pb ages of volcanic rocks and quartz diorite porphyry,together with whole-rock geochemical and Sr-Nd isotope data of early Paleozoic volcanic rocks,in order to investigate their petrogenesis and geodynamic setting.Zircon U-Pb analyses of the rocks suggest that the Kalatag Formation formed at ca.438-413 Ma.Geochemical characteristics of the early Paleozoic volcanic rocks exhibit typical subduction-related features.They have high Mg^(#)(44-75),positiveε_(Nd)(t)values(0.25-7.88),low^(87)Sr/^(86)Sr ratios(0.70457 to 0.70588)and young two-stage Hf isotope model ages(551-446 Ma),consistent with a depleted mantle origin with limited crustal contamination.The basaltic andesite and andesite have relatively high MgO contents(6.1-9.4 wt%),suggesting that they belong to high-magnesian andesites.They were most likely derived from the partial melting of mantle peridotite caused by the addition of fluids released by subducted oceanic slab.Based on regional geology,geochemical characteristics and previous studies,we infer that the southward subduction of the Junggar Ocean slab resulted in the generation of early Paleozoic volcanic rocks and arc setting-related metallogenic systems in the Kalatag area.展开更多
1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et ...1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et al.,2006).The Dannanhu belt in eastern part of the area is interpreted as a volcanic arc and forms an important mineralized zone bordered by the Turpan-Hami Basin to the north and Kanggur back-arc basin to the south.展开更多
The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inc...The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inclusions and H, O, and S stable isotopic compositions of the deposit. The fluid-inclusion data indicate that aqueous fluid inclusions were trapped in chalcopyrite-bearing quartz veins in the gangue minerals. The homogenization temperatures range from 108°C to 299°C, and the salinities range from 0.5% to 11.8%, indicating medium to low temperatures and salinities. The trapping pressures range from 34.5 MPa to 56.8 MPa. The δ^(18)O_(H_2O) values and δD values of the fluid range from -6.94‰ to -5.33‰ and from -95.31‰ to -48.20‰, respectively. The H and O isotopic data indicate that the ore-forming fluid derived from a mix of magmatic water and meteoric water and that meteoric water played a significant role. The S isotopic composition of pyrite ranges from 1.9‰ to 5.2‰, with an average value of 3.1‰, and the S isotopic composition of chalcopyrite ranges from -0.9‰ to 4‰, with an average value of 1.36‰, implying that the S in the ore-forming materials was derived from the mantle. The introduction of meteoric water decreased the temperature, volatile content, and pressure, resulting in immiscibility. These factors may have been the major causes of the mineralization of the Hongshi copper deposit. Based on all the geologic and fluid characteristics, we conclude that the Hongshi copper deposit is an epithermal deposit.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFC2903305)the National Natural Science Foundation of China Program(Grant No.42072100)Xinjiang Uygur Autonomous Region'Tianchi Talents'Introduction Program。
文摘The East Tianshan contains many late Paleozoic magmatic and polymetallic deposits.Recent studies demonstrate that the early Paleozoic volcanic rocks discovered in the northern region of East Tianshan can be subdivided into the Daliugou,Hongliuxia and Kalatag formations.Here,we report zircon U-Pb ages of volcanic rocks and quartz diorite porphyry,together with whole-rock geochemical and Sr-Nd isotope data of early Paleozoic volcanic rocks,in order to investigate their petrogenesis and geodynamic setting.Zircon U-Pb analyses of the rocks suggest that the Kalatag Formation formed at ca.438-413 Ma.Geochemical characteristics of the early Paleozoic volcanic rocks exhibit typical subduction-related features.They have high Mg^(#)(44-75),positiveε_(Nd)(t)values(0.25-7.88),low^(87)Sr/^(86)Sr ratios(0.70457 to 0.70588)and young two-stage Hf isotope model ages(551-446 Ma),consistent with a depleted mantle origin with limited crustal contamination.The basaltic andesite and andesite have relatively high MgO contents(6.1-9.4 wt%),suggesting that they belong to high-magnesian andesites.They were most likely derived from the partial melting of mantle peridotite caused by the addition of fluids released by subducted oceanic slab.Based on regional geology,geochemical characteristics and previous studies,we infer that the southward subduction of the Junggar Ocean slab resulted in the generation of early Paleozoic volcanic rocks and arc setting-related metallogenic systems in the Kalatag area.
基金financially supported by Chinese National Basic Research 973 Program(2014CB440803)the National Natural Science Foundation of China(41572077)China Geological Survey Bureau(12120114065801,121201001000150010 and 121201004000150017-43)
文摘1 Introduction The eastern Tianshan region covers around 60000 km2in area and is located in the eastern part of Xinjiang.The district contains various types mineral commodities including Cu,Ni,Au,Fe,Pb and Zn(Wang et al.,2006).The Dannanhu belt in eastern part of the area is interpreted as a volcanic arc and forms an important mineralized zone bordered by the Turpan-Hami Basin to the north and Kanggur back-arc basin to the south.
基金financially supported by the National Key R&D Program of China(2017YFC0601201-2)funds from the Chinese Ministry of Land and Resources for public welfare industry research(201411026-1)the Chinese Geological Survey Project(DD20160071)
文摘The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu-Tousuquan island-arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inclusions and H, O, and S stable isotopic compositions of the deposit. The fluid-inclusion data indicate that aqueous fluid inclusions were trapped in chalcopyrite-bearing quartz veins in the gangue minerals. The homogenization temperatures range from 108°C to 299°C, and the salinities range from 0.5% to 11.8%, indicating medium to low temperatures and salinities. The trapping pressures range from 34.5 MPa to 56.8 MPa. The δ^(18)O_(H_2O) values and δD values of the fluid range from -6.94‰ to -5.33‰ and from -95.31‰ to -48.20‰, respectively. The H and O isotopic data indicate that the ore-forming fluid derived from a mix of magmatic water and meteoric water and that meteoric water played a significant role. The S isotopic composition of pyrite ranges from 1.9‰ to 5.2‰, with an average value of 3.1‰, and the S isotopic composition of chalcopyrite ranges from -0.9‰ to 4‰, with an average value of 1.36‰, implying that the S in the ore-forming materials was derived from the mantle. The introduction of meteoric water decreased the temperature, volatile content, and pressure, resulting in immiscibility. These factors may have been the major causes of the mineralization of the Hongshi copper deposit. Based on all the geologic and fluid characteristics, we conclude that the Hongshi copper deposit is an epithermal deposit.
