合肥盆地侏罗纪构造沉积特征与含油气性

合肥盆地是一个以中生界为主体的沉积盆地,受燕山运动Ⅰ幕不同期次挤压逆冲造山的影响,依次形成一系列平行分布的逆冲推覆构造带和前渊盆地。不同时期的前渊盆地既有继承性,又有新生性;从南向北,构造幅度逐渐减小,从而形成合肥盆地侏罗系南厚北薄以磨拉石建造为主体的地质体,仅在不同期次盆地的边缘斜坡带上发育河流—平原沼泽相的杂色砂泥岩夹灰黑色炭质泥岩、薄煤层沉积。扬子地质体向北大规模的推覆和挤压导致的区域性高地温,以及侏罗纪的快速堆积,使盆地深坳处古生界烃源岩在侏罗纪时期即达到过成熟演化阶段,其生烃潜力有限。

TECTONIC AND SEDIMENTARY FEATURES OF JURASSIC AND PETROLIFEROUS CHARACTER IN THE HEFEI BASIN

A series of parallel thrusting structural belts and foredeep basins were formed in the Hefei Basin of Mesozoic,affected by different stages compression and thrusting orogenesis of Yanshanian Mvt.1.Foredeep basin had both inheritance and rebirth in different stages,and structural extent gradually diminsh from south to north,then,Molasse formation was formed which was thick in south and thin in north in Jurassic of the Hefei Basin,and sediment of variegation sand-mudstone and gray-black carbonaceous-mudstone and thin coal layer of fluvial-plain marsh facies only grow on marginal slope of different stage basins.As Yangzi geological body thrust and squeeze toward north so as earth temperature is high regionality,and Jurassic accumulate quickly,source rocks of Palaeozoic reached overmature evolution stage during Jurassic in depression ,which is limited in producing hydrocarbon.