摘要
对于雪峰山及其北西侧邻区发育的厚皮-薄皮构造样式前人已进行过较多研究,但关于厚皮和薄皮构造组合样式间的关系及转换过程则较少涉及,因此难以建立起区域性运动学模式;并导致对华南大地构造,特别是中—新生代构造体制的不同认识。对穿越雪峰山北东段及其北西侧邻区的薄皮-厚皮(桑植—安化)剖面进行了详细的构造样式、运动学与变形过程分析,结合地震剖面和大地电磁测深对深部构造的解释,综合区域构造关系,我们认为:早志留世至中泥盆世雪峰山板溪群等基底沿高角度断层逆冲抬升形成厚皮构造;中三叠世至侏罗纪,厚皮构造重新活化,大庸断裂带(亦称慈利—张家界—保靖断裂带)由一系列高角度断层向下收敛并沿板溪群内的板岩发育平缓的顺层滑脱断层,同时向北西侧逆冲形成薄皮构造。其薄皮构造样式主要为箱状向斜及受由深至浅的断坪-断坡式拆离断层控制的平缓背斜。
Thick-skinned thrust separating from thin-skinned thrust by the Dayong fault in Xuefeng Mountain and area on its northwest,brings variable interpretations of Mesozoic tectonic process in South China,and thus the structural style and origin of the Dayong fault are the keys to well understand tectonics of Xuefeng Mountain.Field investigation,interpretation of the data of seismic section and magnetotelluric sounding along Sangzhi-Anhua tectonic section are applied in this paper.The results indicate that the thick-skinned thrust was produced by thrusting the Banxi Group over the Lower Paleozoic in Early Silurian to Middle Devonian.The re-activation of the thick-skinned thrust during Middle Triassic to Jurassic turned Dayong fault into a detachment fault along weak layer of Banxi Group with tiny dip angle towards southeast,which overprinted the old thick-skinned thrust in the meantime.This late deformation also resulted in a NW-ward overthrusting,fault-related chevron syncline and flat-ramp thrust fault,known as the thin-skinned thrust.Therefore,we conclude that the original thick-skinned thrust developed in Paleozoic era was overprinted,with a detachment fault in Xuefeng Mountain,by the NW-ward thrust in Mesozoic era which also produced the thin-skinned thrust on its northwest side.
出处
《现代地质》
CAS
CSCD
北大核心
2011年第1期22-30,共9页
Geoscience
基金
国家自然科学基金项目(40872140
40921062)
国家重点基础研究发展计划项目(2009CB421001)
高等学校学科创新引智计划项目(B07011)
关键词
雪峰山
厚皮构造
薄皮构造
构造转换
Xuefeng Mountain
thick-skinned thrust
thin-skinned thrust
deformational process
