塔里木盆地台盆区中西部中下奥陶统鹰山组沉积环境研究

Sedimentary Environment of Lower-Middle Ordovician Yingshan Formation in Mid-Western Tarim Basin

关于鹰山组的等时性,前人已作过论述,在此基础上,通过露头、地震相、地层等厚图和岩心分析等手段,恢复了鹰山组沉积环境,明确了以下几个问题:1)道保湾阶和大湾阶台地边缘相带展布及台地边缘类型,指出台带边缘相带上高能礁滩体分布的不连续性;2)碳酸盐台地台缘滩和台内滩广泛发育,滩体形状多为长条形或椭圆型,其走向多平行于台地边缘;3)台地内部有台内洼地存在,台内洼地周围有颗粒滩和生物丘分布,通常在迎风面为滩体,在背风面为生物丘。台内洼地内的沉积物通常是"深水"的富含有机质的碳酸盐,具有较好的生油条件。

The time equivalent Yingshan Formation in Tarim Basin has been discussed. Based on this, the sedimentary environment of Yingshan Formation was reconstructed, with the aid of outcrops, seismic facies, strata contour map and core analysis, and draw three conclusions as follows：①The distribution characteristic of platform edge at Daobaowanian Stage and Dawanian Stage and the type of platform were definite. Besides, the viewpoint that the discontinuity of reef and beach along the platform edge was put forward. ②Carbonate sands are wild range and the shape is multifarious. Generally, they are elongate or elliptical and strike of sands is parallel to the platform edge. ③The existence of intrashelf basin was proved. Along the edge of intrashelf basin there are carbonate sands and bioherm, generally sands on windward side and bioherm on lee side. In intrashelf basin sediments predominatly consist of pelagic carbonates, which are commonly rich in organic content.