• 责任者：Zhang Jin (Institute of Geology ; Chinese Academy of Geological Sciences ; Beijing 100037 ; China) ; Li Jinyi
• 刊名：Geological Bulletin of China
• 出版年：2013
• 卷期：32(2/3)
• 关键词：玄武岩 ; basalts ; 铀—铅计时 ; U-Pb dating ; 内蒙古 ; Inner Mongolia
• 页码：p.287-296
• 图表：illus., 1 table, 62 refs.
• 分类号：0801
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

Recent found pillow lava basalts in the southwestern Langshan and its preliminary dating has been reported here. Previous survey had assigned its age at the Early Paleozoic. 32 zircons from pillow lava basalts have been dated using LA-ICP-MS. Most zircons from basalts are captured from the basement, the distribution of ages and internal structures of which are complicated. Four groups of zircons have been distinguished by their internal structures. Among them the tabular zircons have been believed as the autogenetic zir- cons of pillow lava basalts, the ages of these zircons range from the end of Permian to the Early Triassic. The rest zircons in the samples are all from the Alashan basement, among which Paleoproterozoic and Newarchaeozoic zircons and Paleozoic zircons are most. The latest Late Permian Langshan basalts may developed in the extensional tectonics resulting from the delamination of the lithosphere after the closure of the Paleoasian Ocean, the extension of this period occurred along the whole north margin of the North China Plate including the Alashan block, which means that the Alashan block jointed with the North China Plate at least before the Late Paleozoic.