新疆北三台苍房沟群碎屑岩粒度特征及沉积环境

GRAIN-SIZE CHARACTERISTICS AND SEDIMENTARY ENVIRONMENT OF CANGFANGGOU GROUP IN BEI SHANTAI AREA,XINJIANG

对苍房沟群碎屑岩粒度资料进行分析对比,划分出八种粒度曲线类型。通过对曲线的垂向组合及各总体的分析,结合其它资料,认为苍房沟群的沉积环境为冲积扇、河流(低弯度河沉积)、三角洲和湖泊沉积。指出概率累计曲线和 C-M 图在沉积环境研究中具有较好的效果。

Clastic rocks of the Permian-Triassic Cangfanggou Group that consist ofconglomerate,sandstone,siltstone,muddy siltstone and mudrock are the main reservoirrocks in Bei Shantai area.Based on typical probability curves and their vertical combina-tion,C-M patterns and grain-size parameters combining with sedimentary sequences andtheir primary structures,log curves,the sedimentary environment of the group is consi-dered as follows:1.alluvial fan including braided stream and fan interval deposition;2.fluvial depositional systems containing meandering stream,low sinuosity stream and in-terfluvial lake;3.delta and lake system.It is suggested that comprehensive analysis ofgrain-size distribution is a useful tool in sedimentary facies identification.