秦岭造山带岩石圈动力学模型--来自大地电磁测深的证据

目的 建立秦岭造山带的岩石圈动力学模型是探索大陆动力学的前沿问题。方法 以地质和综合地球物理资料为约束，在对秦岭造山带东、西两段电性结构对比分析基础上建立了相应的动力学模型。结果 自中新生代以来，尤其是晚白垩世之后华北和扬子两地块向秦岭造山带持续陆内深俯冲作用，导致南秦岭岩石圈强烈向北挤入，秦岭造山带的后陆冲断褶带和北秦岭厚皮叠瓦逆冲带，现今处于以岩石圈叠置加厚的构造作用为主与拆沉作用初始发动并存状态；南秦岭正在经历拆沉-底侵的物质再循环作用，佛坪和南阳-邓县之间可能发育新的地幔柱；在造山带北、南深部边界与内部不同岩石圈块体之间还伴随不同性质的强烈走滑作用，导致物质的侧向传输。结论 秦岭造山带现今深部动力学状态直接制约着今后大地构造、气候和地表过程的动态相互作用，潜在地影响着人类社会、经济的可持续发展。

A dynamic model for the lithosphere in the Qinling Orogen:Evidences from the magnetotelluric sounding profilings

AimTo found a model of geodynamics of the lithosphere in the Qinling Orogen is a frontier problem for probing Continental dynamics.MethodsTaking geological and integrated geophysical data as constraints and analyzing the lithospheric electrical structures,we propose a dynamic model for both eastern and western segments of the Qinling Orogen.ResultsSince Mesozoic-Cenozic eras, particularly after late Cretacious period,as a result of intense deep intracontinental subduction beneath the Qinling Orogen by the North China block (NCB) south-towards and the Yangtze block (YZB) north towards to bring about the lithosphere of the South Qinling zone (SQZ) wedging into within that of the North Qinling thick-skinned imbricated thrust zone (NQZ),the present Hinterland fault-bounded fold zone (HLZ) and the NQZ show a mainly superimposed and thickened lithosphere and is simultaneously in initial delamination period.However,the SQZ is probably undergoing delamination and underplating to lead to mass-energy recycling between crust-mantle and as well around Foping region and between Nanyang and Dengxian regions probably developing new plumes.Furthermore,the lithospheres within the Qinling Orogenic belt and its south-north boundaries also accompany different property intensive lithospheric strike-slip processes to cause mass-lateral transfer.ConclusionThe present regime for deep dynamics in the Qinling Orogen directly constrains dynamic interactions between tectonic,climate and earth surface processes and latently effects on sustained developments of the society and economy.