摘要
阿拉善右旗下石炭统白山组碎屑岩中锆石CL图像的特征和微量元素Th/U>0.4表明绝大多数属于岩浆锆石,锆石年龄分布于412～498Ma之间,集中分布于443～466Ma之间,加权平均年龄为(454.6±8.3)Ma(n=28),MSWD=3.5,置信度95%,与研究区西侧南天山洋在奥陶纪—早泥盆世向北俯冲消减,在中天山南缘形成岩浆弧可能对应,揭示了研究区恩格尔乌苏断裂可能为哈萨克斯坦板块与华北板块早古生代缝合带,该断裂具有多期活动的特征。白山组物源来自恩格尔乌苏断裂以北的加里东期构造岩浆岩带和早古生代浅变质盖层沉积。
The CL images and trace element（Th/U0.4） of clastic zircons from Lower Carboniferous Baishan Formation in Alxa Right Banner indicate that most of them were derived from magma.The age of zircons varies from 412Ma to 498Ma,concentrated on 443~446Ma,the weighted average age is（454.6±8.3）Ma（n=28）,MSWD=3.5,and the degree of confidence is 95%,corresponding probably to that of magmatic arc generated in Middle Tianshan Mountain during the northward subduction and attenuation of Southern Tianshan Ocean on the western lateral of the study area from Ordovician to Early Devonian.These data reveal that Engeerwusu fault is likely to be an Eopaleozoic suture zone belonging to Kazakhstan plate and Huabei plate.The provenance of Baishan Formation is a Caledonian tectonic magmatite zone.
出处
《地质通报》
CAS
CSCD
北大核心
2011年第6期955-961,共7页
Geological Bulletin of China
基金
中国地质调查局国土资源大调查项目<西北地区中小盆地群油气资源远景调查>(编号:1212010733506)
