Thermal regime transition in eastern North China and its tectonic implication

作     者：FU Mingxi HU Shengbiao WANG Jiyang 

作者机构：Institute of Geology & Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology & Geophysics Chinese Academy of Sciences Beijing 100029 China Institute of Geology & Geophysics Chinese Academy of Sciences Beijing 100029 China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2005年第48卷第6期

页      面：840-848页

核心收录：

学科分类：07[理学] 08[工学] 0708[理学-地球物理学] 0704[理学-天文学] 

基　　金：the Chinese Academy of Sciences(Grant No.KZCX1-07) the National Basic Research Programme(973)(Grant No.G1999075504) the National Natural Science Foundation of China(Grant No.40172100) 

主　　题：eastern North China, thermal regime, paleo-heat flow, "thermal" lithospheric thickness, thinning of litho-sphere. 

摘      要：The pre-Cenozoic formation in the Cenozoic depositon centres in eastern North China reached its maximum temperature at present, and the earlier paleo-temperature, therefore, has been overprinted, but the record of paleo-temperature by the vitrinite reflectance (Ro) has not been overprinted by the later thermal events in the pre-Cenozoic formation located in the uplift or in the Paleozoic-Mesozoic residual basins out of the Cenozoic depositon centres. The reconstruction of paleo-temperature gradient and paleo-heat flow, based on the vitrinite reflectance in the Paleozoic and the Mesozoic structural layers in boreholes, indicated that the eastern North China was characterized by much higher paleo-temperature gradient (40-55℃/km) and heat flow (80 mW/m2) during the Middle-Late Mesozoic than those in the Early Mesozoic and at present. The higher paleo-heat flow during the Middle-Late Mesozoic implies that the thickness of the thermal lithosphere at that time was just 50-55 km, it had been much thinned relative to the thickness (135-148 km) at the Early Mesozoic. The transition of near-surface thermal regime in eastern North China occurred around 110 Ma, and the corresponding deep tectonothermal processes should take place at ~160 Ma.