The Nangqên basin is one of the Tertiary pull-apart basins situated in the east of the Qiangtang block. Similar to the adjacent Dengqên basin and Baxoi basin, there occurred a series of potassic volcanic and...The Nangqên basin is one of the Tertiary pull-apart basins situated in the east of the Qiangtang block. Similar to the adjacent Dengqên basin and Baxoi basin, there occurred a series of potassic volcanic and sub-volcanic rocks, ranging from basic, intermediate to intermediate-acid in lithology.展开更多
A series of Cenozoic potassium-rich volcanic rocks developed in the Xiaoguli-Keluo-Wudalianchi-Erkeshan districts,northeast China.The source region and potassium-rich mechanism of the potassic rocks remain highly disp...A series of Cenozoic potassium-rich volcanic rocks developed in the Xiaoguli-Keluo-Wudalianchi-Erkeshan districts,northeast China.The source region and potassium-rich mechanism of the potassic rocks remain highly disputed.In this paper,the major elements,trace elements,and Sr-Nd-Pb isotopes of the volcanic rocks in Keluo(KL)and Wudalianchi(WDLC)volcanic districts were analyzed systematically.The results show that the volcanic rocks are characterized by high K2O(4.36wt.%-6.13wt.%),remarkable enrichment in LREEs and LILEs,as well as the strong fractionation of HREEs.The isotopic characteristics with high 87Sr/86Sr(0.704990-0.705272),low 143Nd/144Nd(0.512306-0.512417),low 206Pb/204Pb(16.546-17.135)and 207Pb/204Pb(15.002-15.783)of the volcanic rocks suggest the involvement of EM-I-type mantle.On the basis of the geochemical characteristics,the potassium-rich volcanic magma originated from the new SCLM forming after delamination of the ancient SCLM,with metasomatism of the potassium-rich fluids released from the ancient lower crust during the Late Mesozoic.The proposed genetic model assumes the source which represented by a phlogopite-bearing garnet peridotite(with modal garnet in the range of 2%-10%)experienced very low degrees(i.e.,~0.5)of partial melting.During Cenozoic,the lithosphere in northeast China was affected by the extension and decompression of continental rift,and the metasomatized SCLM underwent low degree partial melting,resulting in the formation of potassium-rich primitive basaltic magma.展开更多
文摘The Nangqên basin is one of the Tertiary pull-apart basins situated in the east of the Qiangtang block. Similar to the adjacent Dengqên basin and Baxoi basin, there occurred a series of potassic volcanic and sub-volcanic rocks, ranging from basic, intermediate to intermediate-acid in lithology.
基金supported by the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2021QNLM020001-1)Natural Science Foundation of Shandong Province(No.ZR2021MD083)+1 种基金National Natural Science Foundation of China(Grant Nos.41302102 and 41772190)Graduate Innovation Project of China University of Petroleum(East China)(No.YCX2021020).
文摘A series of Cenozoic potassium-rich volcanic rocks developed in the Xiaoguli-Keluo-Wudalianchi-Erkeshan districts,northeast China.The source region and potassium-rich mechanism of the potassic rocks remain highly disputed.In this paper,the major elements,trace elements,and Sr-Nd-Pb isotopes of the volcanic rocks in Keluo(KL)and Wudalianchi(WDLC)volcanic districts were analyzed systematically.The results show that the volcanic rocks are characterized by high K2O(4.36wt.%-6.13wt.%),remarkable enrichment in LREEs and LILEs,as well as the strong fractionation of HREEs.The isotopic characteristics with high 87Sr/86Sr(0.704990-0.705272),low 143Nd/144Nd(0.512306-0.512417),low 206Pb/204Pb(16.546-17.135)and 207Pb/204Pb(15.002-15.783)of the volcanic rocks suggest the involvement of EM-I-type mantle.On the basis of the geochemical characteristics,the potassium-rich volcanic magma originated from the new SCLM forming after delamination of the ancient SCLM,with metasomatism of the potassium-rich fluids released from the ancient lower crust during the Late Mesozoic.The proposed genetic model assumes the source which represented by a phlogopite-bearing garnet peridotite(with modal garnet in the range of 2%-10%)experienced very low degrees(i.e.,~0.5)of partial melting.During Cenozoic,the lithosphere in northeast China was affected by the extension and decompression of continental rift,and the metasomatized SCLM underwent low degree partial melting,resulting in the formation of potassium-rich primitive basaltic magma.
