东北地区复合造山作用与松辽盆地深部找藏方向探讨

我国的东北地区为西伯利亚板块、华北板块及太平洋板块所挟持。自元古代古大陆裂解以来,经历了兴凯期、加里东期、华力西-印支期、燕山期及喜山期的造山作用,形成增生镶嵌状结合的地质块体。区内复合造山活动具有多期性、叠置性、结构复杂性、造山过程长期性和大陆增生性等特征。在晚古生代,沿华北板块北缘的华力西造山带范围内,沉积有呈三角形的石炭-二叠纪海相盆地。全区现今的构造组合,主要取决于晚侏罗世-早白垩世的构造-岩浆事件。区内含油盆地的成因是与地表-地壳-岩石圈＂三层式＂构造结构呈＂立交桥式＂的样式相关,同时据地震S波资料证实的太平洋俯冲与软流圈呈＂蘑菇云状＂的地幔隆升也有联系。由于地壳相互之间碰撞、挤压、底侵、拆沉、熔蚀、减薄、下沉等复杂的深部过程影响,形成了中新生代裂谷型陆相盆地与石炭-二叠纪海相盆地叠合而成,故命名为延变型复合盆地。针对控藏的地质条件,提出今后深部找藏的主攻方向和建议。

Composite orogeny in northeast China and deep reservoir prospecting in Songliao basin

The Northeast China is held by the Siberian plate,the North China Plate and the Pacific plate.Since ancient continental break-up during Proterozoic this area was exposed to Xingkai,Caledonian,Hercynian,Indosinian,Yanshanian and Himalyanian orogenic activities with accretive and mosaic terrains formed.Composite orogeny in this area is characterized by multi-phase,overriding,structural complexity,long-term process and continental accretion,etc.In late Paleozoic,there was a triangular C-P marine sedimentary basin within the Variscan orogenic belt at northern margion of North China Plate.The current structural frame of the area depends on the structure-magma events during the J3-K1 periods.Oil-bearing basin in the area is genetically related to the ＂surface-crust-lithosphere three-layered stereo bridge＂ structural pattern and also to Pacific subduction and asthenospheric mushroom uplift shown by S seismic wave.Due to the complex deep processes of plate collision,compression,underplating,delamination,resorption,thinning,subsidence of crust the composite basin was formed by overprint of Cenozoic continental rift basin on Carboniferous-Permian marine basin.In view of the geological conditions for reservoir-controlling,the main direction and recommendations for future deep reservoir prospecting is proposed.