摘要
横穿郯庐断裂带的五条地学断面揭示,断裂带两侧地壳结构明显不同,这是平移运动造成不同块体拼合的结果。早白垩世走滑期的岩浆活动,指示当时断裂带切入了壳-慢边界。这表明断裂带在走滑中切穿了整个地壳,莫霍面当时应为平缓的大型拆离面,壳一幔之间发生了显著的失耦。断裂带在晚白垩世-早第三纪的伸展活动中,软流圈发生了强烈的上隆,岩石圈出现了显著的细颈化,属于纯剪切伸展模式。在晚第三纪以来的挤压活动中,浅埋软流圈背景上较高的上地幔温度,使郯庐断裂带成为岩石圈薄弱带,从而发生了较强的逆冲活动和大规模幔源玄武岩浆的喷发。
Five geoscience transects across the Tan-Lu Fault Zone show that crustal textures are obviously different on both sides of the fault zone. The difference is caused by strike-slip movement on the fault zone. Early Cretaceous magmatism during the strike-slip movement indicates that the fault zone cut into crust-mantle boundary. These data demonstrate that the fault zone cut through whole crust during the strike-slip movement and the Moho should serve as large-scale gentle detachment while decoupling took place between crust and mantle. During extensional activities of Late Cretaceous to Eogene, intense upwelling of asthenosphere happened under the fault zone, leading to lithospheric necking in pure shear model. In compressive activities since Neogene, higher temperature of upper mantle due to shallower asthenosphere made the fault zone became a weaker belt in lithosphere. Therefore, the fault zone experienced stronger thrusting and large-scale eruption of mantle-derived basalt.
出处
《高校地质学报》
CAS
CSCD
2002年第3期248-256,共9页
Geological Journal of China Universities
基金
国家自然科学基金(编号:49872074)和教育部高等学校骨干教师项目资助
关键词
郯庐断裂带
地学断面
岩石圈结构
软流圈
莫霍面
Tan-Lu Fault Zone
geoscience transect
lithospheric texture
asthenosphere
Moho
