柴达木盆地北缘逆掩断裂带及其找油前景

柴达木盆地北缘与南祁连山的衔接地段普遍呈现为西北—东南走向的逆掩断裂带,自西往东由赛南、绿南、锡南、埃南等逆断层或逆掩断层组成,延展总长约375公里。该断裂带的不同地段分别被与之直交的潜西、东苦、哑西等断层所切割。

OVERTHRUST BELTS ON THE NORTHERN MARGIN OF QAIDAM BASIN AND THEIR OIL PROSPECTING

A group of huge faults overthrusting from north to south along the southern sides of Mts.Saishiteng,Luliang,Xitie and Aimnik cn the northern margin of Qaidam Basin are found in outcrops with dip angles of seventy degree or more,but seismic data available show that the dip angles of these fault planes in the lower part of Tertiary are gradually reduced and finally turned to twen-ty or lesser within Prepaleozoic sediments.Another huge fault,Maxian fault,overthrusting from south to north is located at the north side of Mahai and Nanbaxian anticlines on the southern margin of eastern Saishiteng depression with a dip angle of thirty degree.Between these opposite dipping faults,there lays Mahai-Pingtan depression with sediments of Meso-Cenozoic system which measures to 10,000m or more in thickness,among them,more than 1,200 mthick sediments belong to Mesozoic,in which the 5th and 7th members of the Dameigou Formation of Middle Jurassic,the source rock in this area,might be existed and covering a area of about 1,500km