日本海陨击事件与新生代东亚大地构造演化

Cratering events in the Japan Sea and tectonic evolution of East Asia during the Cenozoic

关键词:  日本海  陨击  新生代  东亚大地构造演化

Key words:  Japan Sea  cratering  Cenozoic  East Asia tectonic evolution

摘要:

北太平洋及东亚地区在始新世左右发生了一系列重大地质事件:日本海发生开裂;日本西南和中国板块北部发生顺时针旋转(>20°);NNW向运动的太平洋板块突然改变方向开始NWW向运动;郯庐断裂带由强烈断陷造成快速冷却事件;渤海湾盆地出现地幔热异常开始形成裂谷系;阿尔金断裂开始脉冲式走滑;贝加尔湖裂谷开始形成。这些重大地质事件的发生都与日本海陨击事件相关。

Abstract:

A series of major geological events occurred in Northern Pacific and East Asia during the Eocene about 45 Ma BP.The rifting of the Japan Sea and intracratonic faulting in the eastern part of the Eurasian continent gave rise to the clockwise rotation(>20°) of the eastern part of the Tancheng-Lujiang block including the southwestern part of Japan and northern part of adjacent China blocks during the Eogene.At the ages of about 43 Ma,the NNW-trending Pacific plate recorded by Hawaii hot spots suddenly turned to the NWW direction.The four phases of intense tectonic movements once occurred in the Tancheng-Lujiang fault zone at the ages of 45 to 58 Ma during which the cooling events were caused by the rift faulting of the fault zone.The rift systems were initiated due to the mantle thermal anomaly in the Bohai Bay Basin,and the basin was then in the stage of intense rift faulting at the ages of 46 to 40 Ma.The impulsive strike-slipping occurred in Altun fault at the ages of 43 to 35 Ma.The Baikal Lake rift came into being at the ages of 30 to 25 Ma.All the events outlined above are closely related to the cratering events in the Japan Sea.