伊犁盆地侏罗系八道湾组成煤环境与沉积特征

Coal-forming environment and sedimentary characteristics of badaowan formation in Yili basin

八道湾组为伊犁盆地内主要含煤地层之一,本文通过钻井、测井、古生物、野外露头剖面等资料的分析识别出侏罗系中下统主要发育扇三角洲、三角洲、湖泊、沼泽等主要相类型,八道湾组为1套在潮湿、温暖气候条件下形成的以湖泊、三角洲一沼泽相为主的含煤碎屑岩建造。八道湾早期,全区分布有伊宁、尼勒克、巩留3个沉积中心,具有填平补齐的特征;八道湾晚期,沉积范围逐步扩大,沼泽大面积分布,为伊犁盆地重要的成煤期。这对于指导研究区煤炭的勘探具有重要意义。

Badaowan formation is the main coal-bearing formation in Yili Basin.Fan delta,delta,lake,delta,swamp facies can be identified by applying the drilling,logging,palaeontology and outcrop data.The Badaowan Formation,a coal-bearing clastic rock formation,is a suite of lake-delta-swamp faces sediment in the humid warm weather conditions.Three depocenters have been distinguished for the evaporates： Yining,Nileke and Gongliu in Yili Basin with filling characteristics in early period of Badaowan Formation.The late of Badaowan Formation is the important coal-formation period with extended depositional area and swamp.These researches have great significance for exploration of coals in this depression.