杨友运. 鄂尔多斯盆地南部延长组沉积体系和层序特征[J]. 地质通报, 2005, 24(4): 369-372.
    引用本文: 杨友运. 鄂尔多斯盆地南部延长组沉积体系和层序特征[J]. 地质通报, 2005, 24(4): 369-372.
    Characteristics of the depositional systems and sequence evolution of the Yanchang Formation in the southern Ordos basin[J]. Geological Bulletin of China, 2005, 24(4): 369-372.
    Citation: Characteristics of the depositional systems and sequence evolution of the Yanchang Formation in the southern Ordos basin[J]. Geological Bulletin of China, 2005, 24(4): 369-372.

    鄂尔多斯盆地南部延长组沉积体系和层序特征

    Characteristics of the depositional systems and sequence evolution of the Yanchang Formation in the southern Ordos basin

    • 摘要: 鄂尔多斯盆地南部延长组沉积体系类型形成于不同的地质背景,物源方向和沉积环境也不同,因此沉积特征和分布规律差异较大。以主力含油层段长8油组为例,辫状河三角洲体系主要位于盆地西南缘较陡坡带,砂体为长石砂岩,以槽状层理构造发育、前三角洲中有重力流沉积为特征;重力流沉积主要分布在盆地南部渭北地区的长7油层段,以岩屑砂岩为主,形成于深湖环境中,发育的鲍玛组合层序有ABCE、ADE、AE和BCE型序列;东北方向水系形成了曲流河三角洲体系,主要位于盆地东北缓坡带上,三角洲分流河道伸展距离长,朵体规模大,以长石细砂岩为主,河口砂坝发育。

       

      Abstract: The depositional systems of the Yanchang Formation in the south of the Ordos basin originated in different geological settings and have their different provenance directions and depositional environments. Thus they show appreciable differences in depositional and distribution characteristics. Take for example oil set Chang 8 of the main oil section in the Ordos basin. The braided-stream delta depositional systems are located in a steep slope zone on the southwestern margin of the Ordos basin; their sand bodies consist of arkose and are characterized by development of trough bedding and occurrence of gravity-flow deposits in the prodelta. Gravity-flow deposits, mainly distributed in the Chang 7 oil section in the Weibei area, southern Ordos basin, consist predominantly of lithic sandstone and formed in a deep lake environment, where the Bouma sequence includes the ABCE, ADE, AE and BCE divisions. The meandering-river delta system formed by the northeast-directed river system lies mainly in a gentle slope zone in the northeast of the basin; the distributary channels of the delta extend over a long distance and their sand bodies are large in scale, most of which consist predominantly of feldspathic fine sandstone, and debouch bars are well developed.

       

    /

    返回文章
    返回