摘要
本文通过重力、航磁、大地电磁测深和地面石油地质调查等工作,将虎林盆地划分了七个二级构造单元,确定了虎林盆地存在一个大型推覆构造,其基本特征不仅表现在1000～5000Ωm的高阻层覆盖在3～20Ωm的低阻层之上,而且在宏观与微观的构造变形与变位方面也有显示。说明虎林盆地确实经历了塑性流变和剪切滑脱构造事件,即经历了拉张、推覆碰撞、第三纪盆地形成三个阶段;并且指出由于推覆构造的存在,便可有望在推覆体之下发现油气田,扩大油气勘探新领域。
Based on the work of gravitional exploration, air-magnetic survey, geodigit electromagnet sounding and field geology survey, Hulin baisin, to the east of Song-liao basin, is divided into seven secondary tectonic divisions, i. e., Hulin central uplifting, Qihulin faulting, Yunshan faulting, Molinhe faulting, Jinyinku uplifting, Xingkaihu downwarping and Dongfanghong uplifting divisions. The authors hold that a larger overthrust exists in the Hulin basin. The main characteristics of the overthrust in the Hulin basin are that the high resistance layers of 1 000-5000 Ωm overlie the low resistance layers of only about 3-20 Ωm. In addition,the deformed and displaced structures (macroscopic or microscopic) display the existences of the overthrust. The tectonic evidences supporting our conclusion are that a series of napes and reversed faults are found in the central uplifting area; the overturned folds, mylonite zones, foliations,lineations, microfolds and other mic-rostructures are in the Heilongjiangfortaation. These tectonic featurer show that the Hulin basin has undergone the stages of plastic flowage and plastic shear, and that the tectonic sliding event occurred in evolution of the Hulin basin.Based on the evidences described above and the geological data obtained from adjacent area of the basin,the authors proposed the following evolutional stages of the basin: extentional stage, overthrust stage in the Mesozoic and the construction stage of basin in the Tertiary. Finally,the authors discussed the traces of the overthrusts existing in the eastern Shanjiang basin,in the eastern Jixi-Tangyan basin and in the western margin of the Yi-Shu Graben. Meanwhile, the authors made a conclusion that the recognition of overthrust structures can enlarge oil and gas prospecting area, and the best oil and gas prospecting targets can be delimited under the over thrusts.
关键词
松辽盆地
推覆构造
油气勘探
Songliao basin, overthrust, oil-gas prospecting
