地质学报2012，Vol.86Issue(7)：1150-1162,13.
鄂尔多斯盆地晚古生代沉积岩源区构造背景及物源分析
Tectonic Setting and Provenance Analysis of Late Paleozoic Sedimentary Rocks in the Ordos Basin
摘要
Abstract
The provenances of Ordos Basin and its surrounding regions, which all comes from the upper crust, are dominated by felsic rocks, which consist of ancient metamorphic rocks, such as metamorphic volcanic rocks and sedimentary rock of Archaeozoic and Proterozoic, and certain amount of granite and alkali basalt. But compositions of source and structural setting of provenances in the north and south are different. Compositions of major and rare earth elements suggest that sedimentary rocks in both north and south show some differences in area and stratum, and the changes of major element, REE and Eu anomaly are in accordance with the variation trend from oceanic island arc, continental island arc, and active continental margin to passive continental margin. Analysis of major elements indicates that the north provenance derived mainly from plate subduction zones and were related to active continental margin and passive continental margin, with minor related to the island arc of passive continental margin, and were related to tectonic setting of active continental margin and passive continental margin until middle-late Paleozoic. REE contrast analysis shows that the source for the northern basin has affinities to Archeozoic and Proterozoic metamorphotic rocks, such as granitic gneiss, diorite gneiss, adamellite, metamorphotic litharenite, phyllite, etc; that for the southern basin was deeply affected by passive continental margin source, characterized by high SiO2, low Na2 O features, and K2 O/Na2 O > 1. All these features are consistent to those (high SiO2 and K2O/Na2O>l) of rocks of Archean-Proterozoic Taihua Group, Qinling Group and Kuanping Group. Until the end of Late Paleozoic, the provenance was not affected gradually by active continental margin. Beiqinling intermontane basins characterized by rapid accumulation m langes belong to the outer margin of Ordos Basin and have continuous transitional relationship with the basin. Therefore, both show some inherited relation. The Gd content and (Gd/Yb)N ratios of the Late Paleozoic sedimentary rocks in the Ordos basin vary with time changing, and the analysis shows that the northern source area in Taiyuan period was in rapid tectonic activity period, while the southern source area in Shanxi period was fast active period. This is consistent with the regional tectonic evolution, i. e. the uplift of the northern source area was earlier than that in the south.关键词
鄂尔多斯盆地/晚古生代/构造背景/物源分析Key words
Ordos basins Late Paleozoic/ structural setting/ provenance analysis引用本文复制引用
陈全红,李文厚,胡孝林,李克永,庞军刚,郭艳琴..鄂尔多斯盆地晚古生代沉积岩源区构造背景及物源分析[J].地质学报,2012,86(7):1150-1162,13.基金项目
本文为国家重点基础研究发展计划"973"项目(编号2003CB214602)资助成果. （编号2003CB214602）
