松辽盆地梨树断陷基底结构特征

Study on basement structural characteristics of Lishu fault depression in Songliao Basin,China

梨树断陷是松辽盆地南部印支—燕山运动时期形成,在北东—北北东向和北西-北北西向基底断裂的基础上发育起来的断陷盆地。通过对1∶50 000高精度重磁资料处理,结合钻井揭露认为,基底岩性主要为变质岩,局部有碳酸盐岩出露,大体上有海西期、印支—早燕山期2期火成岩侵入体,推测索伦-林西缝合带由此经过。该区基底结构特征和基底断裂,奠定了晚侏罗世之前盆地的构造形态,并且影响着后期盆地的地层格架和充填样式。

The Lishu fault depression in the south of Songliao Basin formed in the Indo-Yanshan movement and developed on the basis of the NE-NNE and NW-NNW direction basement rifts. Based on the 1 ： 50 000 high-precision gravity and magnetic data processing and combined with drillings, the authors reveal that the basement lithology is mainly metamorphic rock, with carbonate outcropped locally, there are roughly intrusive rocks of Hercynian and lndosinian-early Yanshan periods in the area and infer that the Sauron-Linxi suture zone passes from here. The basement structure and basement fault of this region established the structural form of the basin prior to late Jurassic and influenced the stratigraphic framework and filling pattern of the late basin.