A systematic geological and geochemical study was conducted for the granitoids of different periods in the western Kunlun orogenic belt. The study indicates that the granitoids belong to tholeiitic, calc-alkaline, hig...A systematic geological and geochemical study was conducted for the granitoids of different periods in the western Kunlun orogenic belt. The study indicates that the granitoids belong to tholeiitic, calc-alkaline, high-K calc-alkaline, alkaline and shoshonitic series, and that there are 5 genetic types, i.e., I-, S-, M-, A- and SH-type, of which SH-type is first put forward in this paper, which corresponds to shoshonitic granitoids.展开更多
1 Introduction The western Kunlun orogen,located in the northwest Tibet Plateau,and is a conjunction between the Pan-Asian and the Tethys tectonic domains.From north to south,the Western Kunlun orogen includes four
The western Kunlun orogen in the northwest Tibet Plateau is related to subduction and collision of Proto-and Paleo-Tethys from early Paleozoic to early Mesozoic. This paper presents new LA-ICPMS zircon U-Pb ages and L...The western Kunlun orogen in the northwest Tibet Plateau is related to subduction and collision of Proto-and Paleo-Tethys from early Paleozoic to early Mesozoic. This paper presents new LA-ICPMS zircon U-Pb ages and Lu-Hf isotopes, whole-rock major and trace elements, and Sr–Nd isotopes of two Ordovician granitoid plutons(466–455 Ma) and their Silurian mafic dikes(～436 Ma) in the western Kunlun orogen. These granitoids show peraluminous high-K calcalkaline characteristics, with(^(87)Sr/^(86)Sr)_i value of 0.7129–0.7224, ε_(Nd)(t) values of -9.3 to -7.0 and zircon ε_(Hf)(t) values of -17.3 to -0.2, indicating that they were formed by partial melting of ancient lower-crust(metaigneous rocks mixed with metasedimentary rocks) with some mantle materials in response to subduction of the Proto-Tethyan Ocean and following collision. The Silurian mafic dikes were considered to have been derived from a low degree of partial melting of primary mafic magma. These mafic dikes show initial ^(87)Sr/^(86)Sr ratios of 0.7101–0.7152 and ε_(Nd)(t) values of -3.8 to -3.4 and zircon ε_(Hf)(t) values of -8.8 to -4.9, indicating that they were derived from enriched mantle in response to post-collisional slab break-off. Combined with regional geology, our new data provide valuable insight into late evolution of the Proto-Tethys.展开更多
Based on the statistical and analytical data on more than 170 isotopic ages published since the 1980s of magmatic rocks, metamorphic rocks, tectonites and ores from the Western Kunlun Orogen, and the characteristics o...Based on the statistical and analytical data on more than 170 isotopic ages published since the 1980s of magmatic rocks, metamorphic rocks, tectonites and ores from the Western Kunlun Orogen, and the characteristics of sedimentation, magmatism, metamorphism and tectonic activities in the region studied in conjunction with geological field investigations and necessary supplementary isotope data, five stages of tectono-magmatic evolution, i.e. Ar3-Pt21 tectono-magmatic active stage (Ⅰ) , Pt22 stable stage (Ⅱ), Pt31-P2 active stage (Ⅲ), T1-T2 stable stage (Ⅳ) , and T3-Q active stage (Ⅴ) can be distinguished in the Western Kunlun Orogen. Moreover, the tectono-magmatic active style and general trend, the characteristics of tectonic settings, etc. of each stage and substage in the region studied are also discussed .展开更多
The Kukaazi Pb-Zn-Cu-W polymetallic deposit, located in the Western Kunlun orogenic belt, is a newly discovered skarn-type deposit. Ore bodies mainly occur in the forms of lenses and veins along beddings of the Mesopr...The Kukaazi Pb-Zn-Cu-W polymetallic deposit, located in the Western Kunlun orogenic belt, is a newly discovered skarn-type deposit. Ore bodies mainly occur in the forms of lenses and veins along beddings of the Mesoproterozoic metamorphic rocks. Three ore blocks, KⅠ,KⅡ, and KⅢ, have been outlined in different parts of the Kukaazi deposit in terms of mineral assemblages. The KⅠ ore block is mainly composed of chalcopyrite, scheelite,pyrrhotite, sphalerite, galena and minor pyrite, arsenopyrite,and molybdenite, whereas the other two ore blocks are made up of galena, sphalerite, magnetite and minor arsenopyrite and pyrite. In this study, we obtained a molybdenite isochron Re–Os age of 450.5 ± 6.4 Ma(2σ,MSWD = 0.057) and a scheelite Sm–Nd isochron age of 426 ± 59 Ma(2σ, MSWD = 0.49) for the KⅠ ore block.They are broadly comparable to the ages of granitoid in the region. Scheelite grains from the KⅠ ore block contain high abundances of rare earth elements(REE, 42.0–95.7 ppm)and are enriched in light REE compared to heavy REE, with negative Eu anomalies(δEu = 0.13–0.55). They display similar REE patterns and Sm/Nd ratios to those of the coeval granitoids in the region. Moreover, they also have similar Sr and Nd isotopes [ ^(87)Sr/ ^(86)Sr = 0.7107–0.7118;ε_(Nd)(t) =-4.1 to-4.0] to those of such granitoids, implying that the tungsten-bearing fluids in the Kukaazi deposit probably originate from the granitic magmas. Our results first defined that the Early Paleozoic granitoids could lead to economic Mo–W–(Cu) mineralization at some favorable districts in the Western Kunlun orogenic belt and could be prospecting exploration targets.展开更多
基金supported by the Key Project(No.9502010)of the former Chinese Ministry of Geology and Mineral Resources.
文摘A systematic geological and geochemical study was conducted for the granitoids of different periods in the western Kunlun orogenic belt. The study indicates that the granitoids belong to tholeiitic, calc-alkaline, high-K calc-alkaline, alkaline and shoshonitic series, and that there are 5 genetic types, i.e., I-, S-, M-, A- and SH-type, of which SH-type is first put forward in this paper, which corresponds to shoshonitic granitoids.
基金funded by the State Technology Support Program(2015BAB05B03-02)
文摘1 Introduction The western Kunlun orogen,located in the northwest Tibet Plateau,and is a conjunction between the Pan-Asian and the Tethys tectonic domains.From north to south,the Western Kunlun orogen includes four
基金funded by the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDA20070304the Fundamental Research Funds for the Chinese Academy of Geological Sciences(YYWF201601)+1 种基金projects of China Geological Survey(DD20160004,20160083-1,12120115000801,121201101000150014)the National Natural Science Foundation of China(grant 41772232)
文摘The western Kunlun orogen in the northwest Tibet Plateau is related to subduction and collision of Proto-and Paleo-Tethys from early Paleozoic to early Mesozoic. This paper presents new LA-ICPMS zircon U-Pb ages and Lu-Hf isotopes, whole-rock major and trace elements, and Sr–Nd isotopes of two Ordovician granitoid plutons(466–455 Ma) and their Silurian mafic dikes(～436 Ma) in the western Kunlun orogen. These granitoids show peraluminous high-K calcalkaline characteristics, with(^(87)Sr/^(86)Sr)_i value of 0.7129–0.7224, ε_(Nd)(t) values of -9.3 to -7.0 and zircon ε_(Hf)(t) values of -17.3 to -0.2, indicating that they were formed by partial melting of ancient lower-crust(metaigneous rocks mixed with metasedimentary rocks) with some mantle materials in response to subduction of the Proto-Tethyan Ocean and following collision. The Silurian mafic dikes were considered to have been derived from a low degree of partial melting of primary mafic magma. These mafic dikes show initial ^(87)Sr/^(86)Sr ratios of 0.7101–0.7152 and ε_(Nd)(t) values of -3.8 to -3.4 and zircon ε_(Hf)(t) values of -8.8 to -4.9, indicating that they were derived from enriched mantle in response to post-collisional slab break-off. Combined with regional geology, our new data provide valuable insight into late evolution of the Proto-Tethys.
基金Project supported by the State Key Science and Technology Program (No. 305) for the Ninth Five-Year Plan Period of China.
文摘Based on the statistical and analytical data on more than 170 isotopic ages published since the 1980s of magmatic rocks, metamorphic rocks, tectonites and ores from the Western Kunlun Orogen, and the characteristics of sedimentation, magmatism, metamorphism and tectonic activities in the region studied in conjunction with geological field investigations and necessary supplementary isotope data, five stages of tectono-magmatic evolution, i.e. Ar3-Pt21 tectono-magmatic active stage (Ⅰ) , Pt22 stable stage (Ⅱ), Pt31-P2 active stage (Ⅲ), T1-T2 stable stage (Ⅳ) , and T3-Q active stage (Ⅴ) can be distinguished in the Western Kunlun Orogen. Moreover, the tectono-magmatic active style and general trend, the characteristics of tectonic settings, etc. of each stage and substage in the region studied are also discussed .
基金funded by a "Chinese NSF" Project (41272114) to Xingchun Zhanga "CAS Western Light Talent Culture" Project to Chengbiao Lenga "CAS Hundred Talents" Project to Jianfeng Gao
文摘The Kukaazi Pb-Zn-Cu-W polymetallic deposit, located in the Western Kunlun orogenic belt, is a newly discovered skarn-type deposit. Ore bodies mainly occur in the forms of lenses and veins along beddings of the Mesoproterozoic metamorphic rocks. Three ore blocks, KⅠ,KⅡ, and KⅢ, have been outlined in different parts of the Kukaazi deposit in terms of mineral assemblages. The KⅠ ore block is mainly composed of chalcopyrite, scheelite,pyrrhotite, sphalerite, galena and minor pyrite, arsenopyrite,and molybdenite, whereas the other two ore blocks are made up of galena, sphalerite, magnetite and minor arsenopyrite and pyrite. In this study, we obtained a molybdenite isochron Re–Os age of 450.5 ± 6.4 Ma(2σ,MSWD = 0.057) and a scheelite Sm–Nd isochron age of 426 ± 59 Ma(2σ, MSWD = 0.49) for the KⅠ ore block.They are broadly comparable to the ages of granitoid in the region. Scheelite grains from the KⅠ ore block contain high abundances of rare earth elements(REE, 42.0–95.7 ppm)and are enriched in light REE compared to heavy REE, with negative Eu anomalies(δEu = 0.13–0.55). They display similar REE patterns and Sm/Nd ratios to those of the coeval granitoids in the region. Moreover, they also have similar Sr and Nd isotopes [ ^(87)Sr/ ^(86)Sr = 0.7107–0.7118;ε_(Nd)(t) =-4.1 to-4.0] to those of such granitoids, implying that the tungsten-bearing fluids in the Kukaazi deposit probably originate from the granitic magmas. Our results first defined that the Early Paleozoic granitoids could lead to economic Mo–W–(Cu) mineralization at some favorable districts in the Western Kunlun orogenic belt and could be prospecting exploration targets.
