下扬子区早寒武世“石煤”沉积特征与成因机理探讨——兼论与含油气性关系

ON THE MECHANISM AND THE CHARACTERISTICS OF EARLY CAMBRIAN“STONE COAL”IN LOWER YANGTZE REGION AND THEIR RELATION TO PETROLIFEROUS POTENTIALS

周浩达

Zhou Haoda

地矿部华东石油地质局

East China Bureau of Petroleum Geology, MGMR

早寒武世早期,是下扬子区寒武纪地史中形成"石煤"的唯一时期,含"石煤"岩系基本遍及全区。"石煤"是由菌藻类等生物遗体与胶状硅质等同时沉积而成,其形成明显受宁静缺氧滞流盆地环境控制,主要发育在盆地斜坡部位,而盆地斜坡上的凹陷是更有利子"石煤"形成的古地理位置。"石煤"的形成条件主要取决于三方面因素:(1)菌藻类的丰度。(2)古地理位置。(3)沉积作用(埋藏)条件。"石煤"含有丰富的有机质,有机组分一般在50—55%;形成"石煤"的缺氧滞流盆地环境是最有利的生油环境。因此,"石煤"是重要的生油岩系,在地质时期中曾有过油气的生成与运移。

Through Cambrian geohistory of Lower Yangtze area,only at the beginning of early Cambrian could"stone coal"be formed and wide spreaded throughout the area.The stone coal was the result of synsedimentation of fungous algal organic remains and gel siliceous deposits.The conditions of its formation are dominated by the following three decisive factors 1.abundance of fungous-algae;2.palaeogeographic location-the slope section of basins with anoxic viscous flow;3.the sedimentation(the condition of burial history)."Stone coal" contains abundant organic matter,with organic compositions of 50-55%.The environments of anoxic viscous flow basin in which "stone coal" formed is the most favourable to oil generation.Thus the "stone coal" is considered as major source series and oil and gas have been generated and migrated during its geological history.

https://doi.org/10.11781/sysydz199001036