Stratigraphic Subdivision and Isotope Geochronology Study on the Baoligaomiao Formation in the East Ujimqin County , Inner Mongolia
详细信息
- 责任者：Xin Houtian (China University of Geosciences ; Beijing 100083 ; China) ; Teng Xuejian
- 刊名：Geological Survey and Research
- 出版年：2011
- 卷期：34(1)
- 关键词：晚石炭世 ; Upper Carboniferous ; 铀—铅计时 ; U-Pb dating ; 地层划分 ; stratigraphic classification ; 内蒙古 ; Inner Mongolia
- 页码：p.1-9
- 图表：5 illus., 3 tables, 16 refs.
- 分类号：1200
- issnNo：ISSN1672-4135
- isbnNo：CN12-1353/P
摘要
During the 1:50 000 mineral resource prospect investigation in the Mahonondor area of East Ujimqin Qi, Inner Mongolia, the authors firstly divided the Baoligaomiao Formation into two rock unite members: the lower member is made of the andesites, andesitic volcaniclastices and sandstone-conglomerates, and the upper member consists of the rhyolites, dacitic tuff, carbonaceous slate and the fluvial deposit sandstone-conglomerates. In this study, zircons were chosen from the andesite, rhyolites and dacitic tuff to analyze their U-Pb isotope. Their SHRIMP ages are 303.4±6.7 Ma, 304.9±3.1 Ma in the upper member and 320.1±7.2 Ma in the lower member, which means they formed in late Carboniferous Period. This conclusion has a very important significance for studying the Paleo-Asian Ocean and ore-forming geological background in late Hercynian.