吉黑高压带岩石圈结构

——大地电磁测深与深地震反射数据联合约束

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中图分类号：P631 文献标志码：A

Abstract：As the most significant geological units in Northeast China， the tectonic nature and evolutionary history of the Jilin-Heilongjiang high-pressure belt remain controversial. To reveal the crust-mantle-scale structure of this belt and constrain the subduction-accretion processes of the  Heilongjiang Ocean，this paper constructs a deep geophysical model based on magnetotelluric and deep seismic reflection data. The model reveals pronounced lateral heterogeneity in both electrical conductivity and seismic reflectivity across different tectonic units. A key finding is a west-dipping zone of high resistivity and strong seismic reflectivity，which extends from the crust into the lithospheric mantle within the tectonic convergence zone. We interpret this feature as a fossil subduction zone associated with the closure of the Heilongjing Ocean. In the upper crust，both the Heilongjiang and the Zhangguangcai Range complexes exhibit consistent high resistivity and short， arcuate reflection packages. In contrast， the middle to lower crust of the Zhangguangcai Range is characterized by a pronounced high-conductivity anomaly and a distinctive reversed U-shaped reflection pattern. Integrating these geophysical observations with existing geological understanding， we propose that the Zhangguangcai Range complex is not an integral part of the Songliao block. Instead，our data support a model of westward subduction of the Heilongjiang Ocean， with successive accretion of the Zhangguangcai Range and the Heilongjiang complexes as major components of the accretionary wedge. The Zhangguangcai Range complex thus records the early stage of the subduction-accretion process.

Key Words： Central Asian orogenic belt； Jilin-Heilongjiang high-pressure belt； lithospheric structure; tectonic transition zone; integrated geophysical study

0 引言

中亚造山带夹持于西伯利亚克拉通、塔里木克拉通和华北克拉通之间，是世界上最显著的增生型造山带。（剩余19553字）