地质学报2011，Vol.85Issue(9)：1452-1463,12.DOI:11-1951/P.20110907.1101.004
滩间山群的重新厘定——来自柴达木盆地周缘玄武岩年代学和地球化学证据
Redetermination of the Tanjianshan Group: Geochronological and Geochemical Evidence of Basalts from the Margin of the Qaidam Basin
摘要
Abstract
The Tanjianshan Group distributed widely on the margin of the Qaidam basin is characterized by distinct differences in rock assemblages, isotopic chronology and geochemical features of basalts, as well as regional mineralization. It has different rock assemblages and sedimentary formation on the northern and southern margins of the Qaidam basin. The Group on the north consists of intermediate-basic marine-facies volcanic rocks on the bottom, and classic rocks and carbonate rocks on the top, whereas the Group on the south consists of intermediate-basic and intermediate-acidic volcanic rocks intercalated with minor clastic rocks, clastic rock interlayed with minor intermediate-basic volcanic rock in the middle, and carbonatic rock intercalated with minor clastic rocks. The isotopic geochronology and geochemical comparison of basalt from the Tanjianshan Group on the southern and northern margins of the Qaidam basin show that the basalt on the north formed ca. 510 to 460 Ma, representing the Cambrian-Ordovician magmatism, while the basalt from the south formed at ca. 450 to 440 Ma and was the product of Middle Ordovician-Early Silurian magmatic eruption. In general, the basalt of the Tanjianshan Group in the north margin of the Qaidam basin has the features of island-arc volcanic rocks, and should be the product of subduction of regional oceanic continent during the Early Paleozoic, while the basalt on the southern margin has the features of E-MORE lavas and should represent the remnants of fragmented oceanic crust during the opening of the Paleo-Qimantege ocean (post-arc basin).关键词
地球化学/玄武岩/滩间山群/柴达木盆地Key words
geochemistry/basalt/Tanjianshan Group/Qaidam basin引用本文复制引用
高晓峰,校培喜,贾群子..滩间山群的重新厘定——来自柴达木盆地周缘玄武岩年代学和地球化学证据[J].地质学报,2011,85(9):1452-1463,12.基金项目
本文得到中国地质调查局工作项目《昆仑-阿尔金成矿带基础地质综合研究》(编号1212010911025)资助的成果. （编号1212010911025）
