松辽盆地石炭—二叠系分布与构造特征

松辽盆地深层拥有丰富的天然气资源,具备现实的勘探前景。松辽中新生界盆地基底与基底为地台型的盆地在地震反射上有显著的差异,地震剖面上有许多缓倾的反射,并卷入盖层的变形,盆地内晚海西—印支期逆冲推覆断裂,拆离带、贺根山—绥化早海西叠接带、大量的海西期、印支期花岗岩等表明松辽中新生界盆地基底属褶皱带性质。松辽盆地主体位于早海西褶皱带和晚海西褶皱带之上,属西伯利亚南缘,盆地南端位于华北地台北缘的加里东—海西褶皱带之上。石炭—二叠系未变质或轻微变质的泥板岩主要分布于东、西部两个断陷,面积约19万km2,厚度在1000～7500m,现今石炭—二叠系呈NNE向展布。有三个厚度高值区:①林甸地区,最厚达7500m;②东北隆起区,最厚5500m;③东南隆起区,最厚4500m。从现今石炭—二叠系等厚图看,东南隆起区保存相对较完整,黑鱼泡—大庆一带厚度大且分布广。通过该项研究无论对于深层找气,还是对盆地中新生代地层的油气勘探都具有十分重要的地质意义。

DISTRIBUTION OF THE CARBONIFEROUS PERMIAN AND ITS TECTONIC CHARACTERISTICS IN SONGLIAO BASIN

The pre-Mesozoic basement of the Son gliao basin is different from a platf orm one in the seismic reflec-tion,whose reflection is slow dippi ng and entangled into the overlying c over.The overthrust nappe fault and denudational zone is formed during t he Late Hercynian-Indosinian perio d,the imbricate zone is formed durin g the Early Hercynian from Hegenshan to Su ihua area and a lot of granites are formed during the Hercynian-Indosinia n period,which indicates that the basement of the Songliao basin is of a fold belt.Majority of Songliao basin in the south of the Siberian Plate is overla pped on the Early and Late Hercynian f old belt,and the south of the Songlia o basin in the North China Platform is o verlapped on the Caledonian-Hercyn ian fold belt.The unmetamorphic and a little metamorphic slates of the Carboniferous-Permian mainly occur in the east and west fault depression,w ith a covering area of 190000km 2 and the thickness of 1000-7500m.The Carboniferous-Permian occur in NNE-direction with three areas of high th ickness:the first is the Lindian are a,with the greateast thickness of 7500m;the second is the northeast uplift area,with the greatest thickness of 5500m;the third is the southeast uplif t area,with the greatest thickness of 4500m.The Carboniferous-Permian in sout heast uplift area is preserved well,and distributes widely from Heiyupao to Daqing area.It's very important for this research to find gas resources in the depth as well as to explore oil and gas in the Mesozoic and Cenozoic strata.