准噶尔盆地南缘超压泥岩层及其构造地质意义

THE SUPERPRESSURE MUD SEAMS IN THE SOUTHERN MARGIN OF THE JUNGGAR BASIN AND THEIR SIGNIFICANCE IN STRUCTURAL GEOLOGY

准噶尔盆地南缘西端托斯台地区上三叠统小泉沟组、下侏罗统三工河组及南缘下第三系安集海河组泥岩层为超压层。小泉沟组和三工河组泥岩层超压系后期大幅度的构造抬升及自身良好的封闭条件所致,安集海河组泥岩层的超压是由泥岩层压实-排依不平衡和生烃作用形成。超压层不仅形成了挤出构造,亦是重力滑脱构造的良好滑脱席。

The superpressure mud seams developed in the mudstone layers of the Xiaoquangou Formation of the U. Triassic and the Jianghe Formation of the L. Jurassic in the Tuositai Area of the west end on the southern margin of the Junggar Basin and those in the Anjihaihe Formation on the south margin. The superpressure mud seams in the first two formations occurred during the late stages under the major tectonic uplifts and the excellent self-closed conditions while those in the Anjihaihe Formation formed under the disequilibrium between the compaction-discharge flows of the mud seams and the hydrocarbon generation. However, the superpressure mud seams could be the cause both for the well-development of extrusion structures and the excellent sliding sheet for the gravity decollement structures.