论郯庐断裂带(嘉山—庐江段)A型推覆作用

A TYPE OVERTHRUSTING OF THE TANCHENGLUJIANG FRACTURE ZONE (THE JIASHAN-LUJIANG SECTOR)

郯庐断裂带(嘉山—庐江段)由上太古界阚集群、下元古界肥东群组成。其东缘及邻区为中元古界张八岭群—中生界三叠系出露区。磁场为“薄楔状”异常特征,异常区东缘为一大型逆掩推覆断裂,无为盆地是逆掩推覆作用形成的小型挠曲盆地。强烈的地质构造特征及地球物理场特征是扬子板块沿郯庐断裂带(嘉山—庐江段)A型俯冲活动所造成的。这种俯冲活动是印支运动与燕山运动的产物。

The Jiashan-Lujiang sector of the Tancheng-Lujiang fracture zone is composed of the upper Archean Ganji Group and lower Proterozoic Feidong Group. Its eastern edge and adjacent areas are exposure areas of the Middle Proterozoic Zhangbaling Group-Triassic System. The magnetic field exhibits the features of 'thin wedge-shaped' anomalies. The eastern margin of the anomaly area is represented by a large-scale overthrust fracture. The Wuwei basin is a small flexured basin formed by over thrusting. The strong structural features and geographical field features resulted from A-type subduction of the Yangtze plate along the Tancheng-Lujiang fracture zone (the JiashanLujiang sector). Such subduction is the product of the Indosinian and Yanshanian movements.