下扬子复合地体与含油气性特征

COMPOSITE TERRANE AND ITS HYDROCARBON POTENTIAL IN LOWER YANGTZE REGION

下扬子区基底性质、盖层岩相、构造特征,以及岩浆活动等,存在明显的南北分异。造成这些差异的原因,是存在南(钱塘)、北(扬子)两个地体,经长期的构造演化,至三叠纪末期才拼贴成一个统一的复合地体的结果。钱塘地体下古生界和扬子地体上古生界(含三叠系)是烃类生成、聚集的有利领域;应以钱塘地体作为油气勘探的重点。

The basement nature,the cover facies,the structural feature and magmatic activityin the lower Yangtze Region have presented obvious differentiae in the north and southparts of the region.The reason caused these differences is the existence of south (theQiantang) and north (the Yangtze) terranes.These two terranes,underwent long tectonicevolution,were connected as a unified composite terrane in the end of the Triassic.The Qiantang Terrane is the primary place for hydrocarbon generation and accumu-lation from Lower Paleozoic;the Yangtze Terrane is the most favourable place for thatfrom Upper Paleozoic (including the Middle and Lower Triassic).The former will be themain target for oil and gas exploration.