Provenance Analyses of Lower Cretaceous Strata in the Liupanshan Basin: From Paleocurrents Indicators, Conglomerate Clast Compositions, and Zircon U-Pb Geochronology  

作　　者：Xiaochen Zhao Chiyang Liu Jianqiang Wang Wei Luo Fangpeng Du Li Ma 

机构地区：[1]College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China [2]State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069,China [3]BGP Inc.,China National Petroleum Corporation Southwest Geophysical Research Institute,Chengdu 610000,China [4]College of Energy Engineering,Xi'an University of Science and Technology,Xi'an 710054,China

出　　处：《Journal of Earth Science》2020年第4期757-771,共15页地球科学学刊（英文版）

基　　金：supported financially by the National Natural Science Foundation of China (Nos. 41802119 and 41330315);Natural Science Foundation of Shaanxi (No. 2019JQ-088);China Postdoctoral Science Foundation (No. 2019M663779);Doctor’s Foundation of Xi’an University of Science and Technology (No. 6310117052)。

摘　　要：The Liupanshan Basin constitutes a major portion of the northern North-South tectonic belt. The Lower Cretaceous strata in the Liupanshan Basin recorded the tectono-sedimentary evolution processes of this area and are pivotal for understanding the original sedimentary appearance of the Liupanshan Basin. In this work, we present a study of provenance and tectono-sedimentary evolution of the Liupanshan Basin during the Early Cretaceous. Integrated-paleocurrent directions, gravel clast compositions, and detrital zircon U-Pb isotopic analysis of the Lower Cretaceous Sanqiao and Heshangpu formations were applied to determine the provenance. The gravel clast compositions of Sanqiao Formation conglomerates(mainly including magmatic rocks, metamorphic rocks and limestones) display various features in different places, revealing different rock components of source areas. The paleocurrent directions of the Sanqiao and Heshangpu formations suggest that the sediments were transported from the basin margin to the center. Detrital zircons of two samples from the Huoshizhai Section(northwestern Liupanshan Basin) yield a dominant unimodal distribution from 420 to 500 Ma, suggesting a single-sourced provenance. Based on the above analyses, comparing to the magmatic records in the Qilian-Qinling orogenic belt, the detritus of the Sanqiao and Heshangpu formations were mainly from the proximal metamorphic and magmatic rocks of the Qilian-Qinling orogenic belt and the limestones of the archaic uplift. Combined with sedimentary characteristics, we concluded that the Liupanshan Basin experienced multi-stage evolution history:(1) the early rifting extension stage(Sanqiao Period),(2) the middle spanning and depression stage(Heshangpu–Early Naijiahe Period), and(3) the late extinction stage(Late Naijiahe Period). The evolution of Liupanshan Basin is closely related to that of Ordos Basin and it is further associated with tectonic transition of the northern North-South tectonic belt.

关 键 词：provenance analyses tectono-sedimentary evolution Liupanshan Basin Lower Cretaceous North-South tectonic belt 

分 类 号：P534.5[天文地球—古生物学与地层学] P597.3[天文地球—地质学]