十万大山前陆盆地早中生代冲断构造(带)成因机制讨论  

DISCUSSION ON THE GENETIC MECHANISM OF EARLY MESOZOIC THRUST BELT IN SHIWANDASHAN FORELAND BASIN

作　　者：薛凤吉 周倩玉 李成 Xue Fengji;Zhou Qianyu;Li Cheng(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Downhole Operation Branch of Bohai Drilling Engineering Co.,LTD.,Renqiu,Hebei 062550,China;School of Geosciences,China University of Geosciences,Wuhan,Hubei 430074,Province,China)

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]渤海钻探工程有限公司井下作业分公司,河北任丘062550 [3]中国地质大学地球科学学院,湖北武汉430074

出　　处：《矿物岩石》2022年第3期58-66,共9页Mineralogy and Petrology

基　　金：中国地质调查局油气资源调查中心项目(编号:12120115005101)。

摘　　要：位于云开造山带的十万大山前陆盆地通常被认为是晚二叠世—中三叠世印支运动形成的盆地。已有的研究工作主要集中在前陆盆地形成的时限、逆冲推覆的构造样式和盆地的沉积充填序列等方面。有关十万大山前陆盆地中构造层底部滑脱层是否发育和冲断裂组合样式发育的机制尚未开展深入研究,前人研究表明研究区内海西运动不整合面滑脱构造广泛发育,海西运动不整合面上滑脱层发育情况仍不明确,本次研究在前人对该区地质、地震、盆地构造样式等研究基础之上,设计了两组实验,模型1无滑脱层,模型2为单滑脱层,通过构造物理模拟实验结果对比,进一步揭示了早中生代十万大山前陆盆地的逆冲构造样式和滑脱层是否发育的问题:(1)物理模拟实验结果显示十万大山前陆盆地逆冲断裂组合样式表现为前展式的推覆构造,且构造垂向分层不明显,这可能与十万大山前陆盆地海西运动不整合面上泥盆系滑脱层不发育有关。(2)十万大山前陆盆地的形成是受到了SE-NW方向的区域性挤压作用的控制。随着印支期挤压作用的加强,十万大山前陆盆地呈现出由SE向NW方向逆冲。The Shiwandashan foreland basin located in Yunkai orogenic belt is generally considered to have been formed by the Late Permian-Middle Triassic Indosinian movement.Previous research has mainly focused on the formation time of foreland basin,the structural style of thrust nappe and the sedimentary filling sequence of the basin.However,the mechanism of the development of thrust fault assemblage and the detachment layer at the bottom of the structural layer in the foreland basin has not been thoroughly studied.It was suggested that the detachment structure of Hercynian movement unconformity surface is widely developed in the study area,but the development of detachment layer on the Hercynian movement unconformity surface is not clear.According to the research results of geology,seismic and basin structural style,this study designed two groups of experiments.Model 1has no detachment layer,and Model 2 has a single detachment layer.The two models are used for structural physical simulation experiments,and the results of the two experiments are compared to reveal the thrust structural style and the development of detachment layer in the Early Mesozoic Shiwandashan foreland basin.Physical simulation results show that the thrust fault assemblage of the Shiwandashan foreland basin displays a piggyback propagation nappe structure,and the vertical stratification of the structure is not obvious,which may be related to the lack of Devonian detachment layer on Hercynian movement unconformity surface in the Shiwandashan foreland basin.The formation of the Shiwandashan foreland basin is considered to be controlled by regional southeast-northwest direction compression.With the strengthening of Indosinian compression,the Shiwandashan foreland basin experienced a thrust movement from southeast to northwest direction.

关 键 词：十万大山前陆盆地 区域挤压 逆冲推覆构造 物理模拟 

分 类 号：P542[天文地球—构造地质学]