摘要
通过采用区域地层对比、古流向测量、轻矿物、重矿物组合分布及沉积相分析等方法,分析鄂尔多斯盆地东南缘延长组物源及其沉积体系特征,研究表明:吕梁隆起并非鄂尔多斯盆地东南缘延长组物源,该区接受了晚三叠世沉积,是在延长期以后才隆起的,东南缘宜川-富县延长组古水流为东北至西南方向,轻重矿物组合特征与北部三角洲类似,总体从志靖—川口—富县地区沉积岩屑含量逐渐降低,不稳定矿物绿泥石等含量则从富县东北部—中部—西南部依次增多,证实鄂尔多斯盆地东南缘延长组物源方向为东北方向,富县三角洲实为延安三角洲东北方向分支朵体,其为既发育台型前缘,又有坡型前缘的曲流河三角洲;台型三角洲前缘主要发育截削式、完整式水下分流河道砂体,坡型前缘主要发育复合式、叠加式河口坝砂体,优质储层主要有截削型分流河道、复合式河口坝。
Provenance and features of depositional system of Yanchang Formation of Triassic in southeast margin of Ordos basin was analyzed through regional stratigraphic correlation, paleoeur- rent measurement, distribution and combination of light minerals and heavy minerals, and sedimentary facies. The results showed that the Luliang uplift which received the late Triassic basin sediments uplifted after Yanchang period and was not the Provenance of Yanchang Formation in the southeastern margin of Ordos basin. The paleocurrent revealed by Yanchang Formation in Yiehuan-Fuxian in southeast margin of Ordos basin was northeast direction. Characteristics of mineral assemblage were similar to those in the north of Yan＇an delta. Sedimentary debris content gradually reduced from Zhijing-Chuankou to Fuxian area, and the content of unstable mineral such as chlorite increased in sequence from the north,middle to the southwest of Fuxian delta,indicating that the provenance direction of Yanchang Formation in the southeastern margin of Ordos basin was northeast direction. In fact, the Fuxian delta was the eastern stretch of Yan/an delta, which developed platform delta front and sloping delta front of meandering river delta. The platform delta front mostly produced the truncated and completed underwater distributary channel sandstone body and the sloping delta front mostly induced the compound and overlap-type channel mouth bar sands. High quality reservoir mostly distributed in the truncated distributary channel and the overlap-type channel mouth bar sands. Determination of the features of depositional system was helpful to the development of further hydrocarbon exploration in the study area.
出处
《矿物岩石》
CAS
CSCD
北大核心
2010年第1期99-105,共7页
Mineralogy and Petrology
基金
国家重点基础研究发展计划(973)项目(No.2003CB214601)
博士后基金(20070420489)
关键词
物源
沉积体系
延长组
鄂尔多斯盆地
provenance
depositional system
Yangchang Formation
Ordos basin
