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大坂山地区新发现晚寒武世侵入岩LA-MC-ICP-MS锆石U-Pb年龄及其地质意义(增刊)
引用本文:保广普,刘春娥,陈静,付军,张林. 大坂山地区新发现晚寒武世侵入岩LA-MC-ICP-MS锆石U-Pb年龄及其地质意义(增刊)[J]. 中国矿业, 2016, 25(S1)
作者姓名:保广普  刘春娥  陈静  付军  张林
作者单位:青海省青藏高原北部地质过程与矿产资源重点实验室,青海省青藏高原北部地质过程与矿产资源重点实验室,青海省青藏高原北部地质过程与矿产资源重点实验室,青海省青藏高原北部地质过程与矿产资源重点实验室,青海省青藏高原北部地质过程与矿产资源重点实验室
基金项目:青海省门源县青石嘴地区矿产远景调查 项目编号:1212011121217
摘    要:通过对北祁连与中祁连结合部大坂山结合带中灰色中细粒石英闪长岩的野外调查和岩石地球化学、时空分布及同位素年龄资料研究,灰色中细粒石英闪长岩属典型的钙碱性系列岩石,显示了岛弧的特点。利用激光等离子体质谱法(LA-MC-ICP-MS)获得灰色中细粒石英闪长岩中25颗岩浆锆石的207Pb/235U年龄加权平均值为504±1Ma(MSWD=0.67) 为晚寒武世,这个年龄被解释为岩体的侵位年龄。前人将加里东旋回中北祁连向南俯冲的起始时间界定在早奥陶世,笔者通过综合分析认为,大坂山灰色中细粒石英闪长岩的侵位代表加里东旋回中北祁连向南俯冲事件的开始阶段为晚寒武世。

关 键 词:北祁连  灰色中细粒石英闪长岩  LA-MC-ICP-MS锆石U-Pb测年   晚寒武世   俯冲.
收稿时间:2016-04-15
修稿时间:2016-04-15

LA-ICP-MS zircon U - Pb dating of the newly discovered late Cambrian intrusion from Osakayama area and its geological significance
Bao Guang-pu,LIU Chun-e,CHEN Jing,FU Jjun and ZHANG Lin. LA-ICP-MS zircon U - Pb dating of the newly discovered late Cambrian intrusion from Osakayama area and its geological significance[J]. CHINA MINING MAGAZINE, 2016, 25(S1)
Authors:Bao Guang-pu  LIU Chun-e  CHEN Jing  FU Jjun  ZHANG Lin
Affiliation:Qinghai Geological Survey Institute,Qinghai Geological Survey Institute,Qinghai Geological Survey Institute,Qinghai Geological Survey Institute,Qinghai Geological Survey Institute
Abstract:Studies on the geochemistry, time and space distribution and isotopic ages show that the fine-grained quartz diorite belong to typical calc-alkalic series from Osakayama area, in the Junction region of north and middle Qilian, with the characteristics of island arc. LA -ICP-MS U-Pb dating shows the weighted average age of 504±1Ma, with 25 magmatic zircon grains, interpreted as the result of the Late Cambrian magmatism, which yeilds emplacement age of the quartz diorite. Predecessors defined the initiation time of the North Qilian southward subduction in early Ordovician, the author consider it as late Cambrian by the comprehensive analysis of Osakayama gray fine-grained quartz diorite.
Keywords:the North Qilian   gray fine-grained quartz diorite   LA-ICP-MS zircon U - Pb dating   late Cambrian   subduction
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