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摘要: 辽东湾地区是沿着郯庐断裂系发展的新生代大陆裂谷型断陷,其深部构造制约浅部结构。总结和分析辽东湾地区的重力场、磁力场、地震波场、热流场、地温分布及岩石层速度研究成果,表明辽东湾地区具有高值深部重力、浅居里等温面、浅壳幔电性高导体、相对低热流值等特征。该区Pn波平均速度较低,可能由于上地幔顶部热流物质向上侵入所致。NE向快波方向体现的是东侧右旋走滑响应,推测是辽东湾东部走滑作用弱于莱州湾及渤中地区,西部更弱或者未发生走滑的结果。辽东湾地壳发生明显减薄,居里等温面抬升区对应地壳厚度减薄区,在地壳减薄过程中很可能发生了伸展拆离。Abstract: The Liaodong bay is a Cenozoic continental rift developed along the Tanlu Fault. The deep structure constrains the shallow. A detailed summarization and an integrated analysis of gravity field, magnetic field, seismic wave, heat flow, geothermal distribution and lithosphere speed are made for the Laodong bay in the paper. The study demonstrates that the Liaodong Bay is characterized by high deep gravity, relatively low heat flow with shallow Curie isothermal surface and intra-crustal and intra-mantle high conductive layers. The lower average velocity of Pn wave in this area may owe its origin to the heat flow intrusion into the top of upper mantle. Based on the direction of fast wave towards NE-trend, it is inferred that the strike slipping of eastern Liaodong bay is weaker than that of the Laizhou Bay and the Bozhong with the western Liaodong Bay as the weakest close to zero. The crust of the Liaodong Bay is obviously thinning and the uplifted Curie isothermal surface corresponds to the crust thinning area. It is very likely that the extensional detachment occurs in the process of crust thinning.
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Key words:
- geophysical field /
- lithosphere /
- Liaodong Bay
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