大兴安岭北部中侏罗统漠河组砂岩LA-ICP-MS碎屑锆石U-Pb年龄:对漠河盆地源区的制约  

Detrital zircon U-Pb dating of Middle Jurassic Mohe Formation in northern Da Hinggan Mountains: Reconstruction of the provenance of Mohe Basin

作　　者：王少轶[1] 许虹[1] 杨晓平 张文龙 

机构地区：[1]中国地质大学(北京),北京100083 [2]黑龙江省地质调查研究总院齐齐哈尔分院,黑龙江哈尔滨150036

出　　处：《中国地质》2015年第5期1293-1302,共10页Geology in China

基　　金：天然气水合物资源勘查与试采工程:东北冻土区天然气水合物资源勘查项目(GZHL20120302)资助

摘　　要：对大兴安岭北部漠河盆地中侏罗统漠河组砂岩进行了碎屑锆石LA-ICP-MS U-Pb年龄测试,获得的碎屑锆石U-Pb年龄为1425~170 Ma,反映了中侏罗时期漠河盆地源区的复杂性。该时期漠河盆地物源主要有：中元古代变质火山岩,碎屑锆石年龄1425~1064 Ma;新元古代变质侵入岩,碎屑锆石年龄888~550 Ma;寒武—奥陶纪变质表壳岩与深成侵入岩,碎屑锆石年龄517~441 Ma;石炭—二叠纪侵入岩,碎屑锆石年龄327~252 Ma;三叠纪—中侏罗世侵入岩,碎屑锆石年龄250~170 Ma。这一测试数据与盆地现在南缘分布的地质体的时代基本对应,说明盆地的物源主要来自南部的中元古代—中侏罗世地质体,碎屑锆石中最小年龄为170 Ma,反映漠河组沉积下限不早于中侏罗世早期。这一成果对研究漠河盆地源区的物质组成、盆地沉积年代和油气成藏条件提供了新的素材。With the method of U-Pb isotope dating of detriatal zircon from Middle Jurassic Mohe Formation, the authors detected that detrital zircon ages are clustered in the range of 1425-170 Ma, which suggests that the basement of Mohe Basin has complex provenance. The provenance of Mohe Basin is mainly made up of Mesoproterozoic metamorphic volcanic rocks with the detrital zircon age of 1425-1064 Ma, Neoproterozoic metamorphic intrusive rock with the detrital zircon age of 888-550 Ma, CambrianOrdovician metamorphic supracrustal rock and metamorphosed plutonic intrusive rock with the detrital zircon age of 517-441 Ma,Permian-Carboniferous intrusive rock with the age of 327-252 Ma, and Triassic and Middle Jurassic intrusive rock with the age of250-170 Ma. These data correspond to the ages of geological bodies on the south margin of the basin, which shows that the source of the basin was from the Middle Proteronic-Middle Jurassic geologic body in the south, with the youngest age of detrital zircon being 170 Ma. It is therefore held that the lower sedimentary limit of the Mohe Formation is not earlier than early Middle Jurassic.The results achieved by the authors provide new evidence for the study of the evolution of Mohe Basin

关 键 词：漠河组 U-PB年龄 漠河盆地物源 

分 类 号：P588.212.3[天文地球—岩石学] P597.3[天文地球—地质学]