石油与天然气地质 ›› 2011, Vol. 32 ›› Issue (1): 29-37.doi: 10.11743/ogg20110104

• 石油与天然气地质 • 上一篇    下一篇

海退型陆棚相:烃源岩形成的重要部位 ——以中、上扬子地区北缘上二叠统大隆组为例

  

  • 出版日期:2011-02-28 发布日期:2011-04-28

Regressive continental shelf as an important location for the development of source rocks—an example from the Upper Permian Dalong Farmation in the northern margin of the UpperMiddle Yangtze region

  • Online:2011-02-28 Published:2011-04-28

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摘要：

通过对中、上扬子地区北缘上二叠统大隆组沉积特征、生物群面貌组合、有机碳特征的深入研究，探讨了海退型序列与优质烃源岩的关系。中、上扬子地区北缘晚二叠世大隆组沉积环境具有从早期外陆棚到中、晚期内陆棚变化的特征，属于海退型陆棚相。沉积相带的转变为该区带来了较浅水的生物，尤其是大量菌藻类出现，为中、上扬子地区大隆组优质烃源岩的形成提供了源源不断的有机质生产率,造成大隆组上部有机碳含量比下部高。此外，该区多次上升洋流作用同时将下层营养盐类携带到表层水，使得生物群更加繁盛，促进了有机质生产力的激增，有利于大隆组大范围内优质烃源岩的发育。研究表明，海退型陆棚也是地史中烃源岩形成的重要部位。

关键词: 优质烃源岩, 大隆组, 上二叠统, 海退型陆棚, 中、上扬子地区

Abstract:

This paper examines carefully the sedimentary features, biological associations and characteristics of organic carbon of the Upper Permian Dalong Formation in the northern margin of the MiddleUpper Yangtze region. We also discuss the relationship between regressive sequences and highquality source rocks. According to the study, we believe that the depositional setting of the Upper Permian Dalong Formation belong to regressive continental shelf facies which changes from the outer shelf in the early period to the inner shelf in the middletolate period. The change of facies belt brought about shallowwater organism, especially plenty of bacillusalga, which continuously provided organic materials for the development of highquality source rocks in the Dalong Formation in the MiddleUpper Yangtze region. The organic carbon content in the upper part is higher than that in the lower part of the Dalong Formation. In addition, ascending current repeatedly brought nutritious salt from deep water to sallow water, which made the biological groups thrive and promoted the productivity of organic matter. Therefore, highquality source rocks developed in large scale in the Dalong Formation. From this study we come to the conclusion that the regressive continental shelf is also an important location for the development of source rocks.

Key words:  , Key words：highquality source rock, Dalong Formation, Upper Permian, regressive continental shelf, MiddleUpper Yangtze region