中国地质2017，Vol.44Issue(3)：556-574,19.DOI:10.12029/gc20170312
鄂尔多斯盆地西南部上古生界碎屑锆石U-Pb年龄及其构造意义
The Upper Paleozoic detrital zircon U-Pb geochronology and its tectonic significance in southwestern Ordos Basin
摘要
Abstract
Aimed at exploration of provenance and basin-mountain coupling relationship in southwestern Ordos Basin, the authors selected detrital zircons from the first member of Shanxi Formation and the eighth member of Shihezi Formation of the late Paleozoic in southwestern Ordos Basin and conducted LA-ICP-MS detrital zircon U-Pb isotope analysis. The result reveals that the 105 analytical points of the magma-genetic detrital zircons yielded four age groups:(1) The first group which ranges from 260 to 340Ma accounting for 21.9% of the total analytical points, indicating that the provenance might have come from the North Qinling orogenic belt and the West Qinling orogenic belt;(2) The second group which ranges from 370 to 470 Ma accounting for 24.8%of the total analytical points, suggesting that the provenance was mainly derived from the North Qinling orogenic belt, the West Qinling orogenic belt and the North Qilian orogenic belt; (3) The third group which ranges from 1600 to 2000 Ma accounting for 32.4%of the total analytical points, implying that the provenance might have come from the North Qinling orogenic belt and the North Qilian orogenic belt; (4) The last group which ranges from 2300 to 2600 Ma accounting for 15.2% of the total analytical points, indicating that the provenance was derived from the North Qinling orogenic belt, the West Qinling orogenic belt, the North Qilian orogenic belt and the crystalline basement of the North China plate. This study indicates that the provenance of southwestern Ordos Basin had multiple origins:the North Qinling orogenic belt, the West Qinling orogenic belt, the North Qilian orogenic belt and the crystalline basement of the North China plate, mainly from the North Qinling orogenic belt and the North Qilian orogenic belt. The Paleozoic detrital zircons have also proved that the southwestern Ordos Basin passive continental margin was developed during the Ordovician, then it evolved into continent-continent collisional orogenic belt during the Silurian-Devonian, and finally gradually evolved into a sedimentary basin during the Carboniferous-Permian period.关键词
鄂尔多斯盆地西南部/碎屑锆石LA-ICP-MSU-Pb年龄/物源区/盆山耦合Key words
southwestern Ordos Basin/detrital zircons LA-ICP-MS U-Pb age/provenance/basin-mountain coupling分类
天文与地球科学引用本文复制引用
罗顺社,潘志远,吕奇奇,何维领,文硕..鄂尔多斯盆地西南部上古生界碎屑锆石U-Pb年龄及其构造意义[J].中国地质,2017,44(3):556-574,19.基金项目
国家自然科学基金项目(41672099)、"构造与油气资源"教育部重点实验室开放课题(TPR-2015-13)资助. Supported by National Natural Science Foundation of China (No. 41672099), Key Laboratory of Tectonics and Petroleum Resources, Ministry of Education (No. TPR-2015-13). （41672099）
