地质学报2017，Vol.91Issue(10)：2196-2211,16.
中亚造山带中段南缘圆包山组碎屑锆石U-Pb年龄、物源及其构造演化意义
Detrital Zircon U-Pb dating and Provenance of the Yuanbaoshan Formation in the Southern Margin of the Middle Central-Asian Orogenic Belt and their Tectonic Evolution Significance
摘要
Abstract
LA-ICP-MS dating of detrital zircons from the Yangbaoshan Formation sandstone samples yielded two ages of 409～431Ma (peaking 420 Ma) and 458～488Ma (peaking 488 Ma).Graptolite found at the bottom of the Yuanbaoshan Formation and the zircon with a peaking age of 420 Ma constrain the time of the Yuanbaoshan Formation within the Early Silurian,and comparison study with the tectonic evolution of the Xing-Meng orogenic belt indicates that the age of Yuanbaoshan Formation should be he Early Silurian to Middle Devonian.The analysis of paleocurrent direction of the sedimentary structures in the Yuanbaoshan Formation also shows that the provenance area is located in the northwest.And the provenance area may be the Huhetaoergai area according to the previous research results about the age of magmatic rocks.The study reveals three generations of Proterozoic zircons:Neoproterozoic (559Ma and 952Ma),Mesoproterozoic (from 1011Ma to 1460Ma) and Paleoproterozoic (from 1629Ma to 2490Ma).Based on the summary of zircon ages in the southern Siberian block,the Tarim block and the southern Mongolia microplate,it can be concluded that the main difference between the North China plate and the surrounding plate is that there is no or less records of late Mesoproterozoic to early Neoproterozoic zircon age,and the Alxa block is lack of the zircon age record of 1.0 ～ 1.2Ga in this study area.Therefore,it can be considered that the study area tectonically belonged to the southern part of the southern Mongolia microplate in the Paleozoic,and the provenance in this period derived from the Tarim craton.In addition,based on the distribution characteristics of detrital zircon age in the strata,the study area was characterized by obvious uplift and strong tectonic activity after the early Devonian,indicating that the study area was affected increasingly by the Tarim Plate.关键词
中亚造山带/阿拉善北部/圆包山组/砂岩碎屑锆石/构造演化Key words
Central Asian Orogenic Belt/northern margin of Alxa/Yuanbaoshan Formation/sandstone detrital zircon/tectonic evolution引用本文复制引用
尹海权,周洪瑞,徐东卓,张维杰,郑小明,王晟宇,高磊..中亚造山带中段南缘圆包山组碎屑锆石U-Pb年龄、物源及其构造演化意义[J].地质学报,2017,91(10):2196-2211,16.基金项目
本文为中国综合地球物理场观测—大华北地区项目(编号:201508009),中国地震局监测预报司专项(编号:17A37ZX228)和中国地质调查局项目(编号:基[2010]矿评0109-11)联合资助的成果. （编号:201508009）
