渤海湾盆地中—新生代岩石圈热结构与热-流变学演化  

Evolution of Meso-Cenozoic thermal structure and thermal-rheological structure of the lithosphere in the Bohai Bay Basin,eastern North China Craton

作　　者：邱楠生[1,2] 许威[1,2] 左银辉[3] 常健[1,2] 刘春黎 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)地球科学学院,北京102249 [3]成都理工大学能源学院,四川成都610059 [4]中国石油华北油田公司,河北任丘062552

出　　处：《地学前缘》2017年第3期13-26,共14页Earth Science Frontiers

基　　金：国家自然科学基金项目(41125010;91114202)

摘　　要：文章主要利用中—新生代热史、地壳分层结构以及流变学参数,模拟计算渤海湾盆地中—新生代岩石圈热结构和热-流变结构演化特征。结果表明,盆地由三叠纪—侏罗纪时期的"冷幔热壳"型岩石圈热结构转变为白垩纪至今的"热幔冷壳"型岩石圈热结构。从济阳坳陷岩石圈热-流变结构演化特征来看,中生代早期上地壳上部、中地壳上部及上地幔顶部表现为厚的脆性层;早白垩世初期中地壳上部及上地幔顶部的脆性层完全转变为韧性层;晚白垩世开始,中地壳上部出现薄层的脆性层;古近纪早期中地壳上部脆性层变薄变浅;现今则除了发育上地壳上部、中地壳上部脆性层外,上地幔顶部开始在浅部发育薄的脆性层。中—新生代岩石圈总强度演化表明在早白垩世晚期和古近纪早期经历了两期减弱,中生代早期岩石圈总强度远大于中侏罗世之后的岩石圈总强度。岩石圈热-流变结构和强度演化与华北克拉通破坏过程中岩石圈厚度的变化具有良好的对应关系,从侧面反映太平洋板块俯冲和回撤导致华北克拉通东部破坏的地球动力学过程。因此,岩石圈热-流变结构可以为盆地形成、大陆边缘和造山带等的动力学演化过程研究提供科学依据。The Meso-Cenozoic thermal structure and thermal-rheological structure of the lithosphere in the Bohai Bay basin are calculated here in this paper, using the Meso-Cenzoic thermal history, crustal layer structure and rheological data. The results show that the lithosphere of the Bohai Bay Basin transformed its thermal structure during the Meso-Cenozoic, from the ＂cold mantle but hot crust＂ stage in the Triassic- Jurassic to the ＂hot mantle but cold crust＂ stage in the Cretaceous and Cenozoic. The thermal-theological structure of the Jiyang depression exhibits obvious theological stratification and changed with time during the Meso-Cenozoic. During the Early Mesozoic, the uppermost of the upper ＆ middle crust and the top of the upper mantle were of thick brittle layers. During the early Early Cretaceous, the brittle layer of the uppermost of the middle crust was thinned, while the uppermost of the upper mantle almost occupied by the ductile layer. During the late Early Cretaceous, the brittle layers of the middle crust and the upper mantle changed into the ductile ones. Then, the uppermost of the middle crust began to occur of the thin brittle layer in the late Cretaceous. During the early Paleogene, the middle crust was of the thin brittle layer. At present, the top of the upper ＆ middle crust and the uppermost of upper mantle are of brittle layers. The lithospheric total strength of the Meso-Cenozoic experienced two weakened stages in the late Early Cretaceous and the early Paleogene, and the strength in the Early Mesozoic was greater than that after the Middle Jurassic. Furthermore, the evolution of the Meso-Cenozoic thermal-lithospherie structure has a good correspondence with the evolution of thermal lithosphere thickness during the destruction process of the North China Craton （NCC）, reflecting also the geodynamic process of the eastern NCC destruction caused by the Pacific plate subduetion and rollback. The thermal-rheological structure of the lithosphere provides a scientific basis for the st

关 键 词：渤海湾盆地 热历史 岩石圈热结构 热岩石圈厚度 热-流变结构 

分 类 号：P314[天文地球—固体地球物理学]