准噶尔盆地侏罗系八道湾组聚煤作用控制因素分析

Analysis on Controls of the Coal Accumulation in the Jurassic Badaowan Formation, Junggar Basin

从煤层厚度及其在层序地层格架中的平面展布特征入手 ,并在分析煤层在层序格架中的发育和分布规律的基础上 ,探讨了沉积环境、沉积体系演化和湖平面变化对陆相盆地———准噶尔盆地侏罗系层序Ⅰ (八道湾组的主体 )聚煤作用的影响。河流泛滥平原、三角洲平原、湖湾等沉积环境的可容空间变化速率和泥炭堆积速率常能保持有利于泥炭沉积的平衡关系 ,从而成为富煤环境。实质上 ,沉积环境是聚煤作用控制因素的外在表现形式 ,而其最根本的控制因素则是可容空间变化速率。在本研究区 ,主要体现为湖平面变化对煤层分布的控制作用。

According to the thickness and distribution of coals in a sequence stratigraphic framework, the influence of depositional environments, the evolution of depositional system and the fluctuation of lake-level on the coal accumulation, during the deposition of Jurassic Badaowan formation in Junggar basin, has been discussed. The favorable settings for coal accumulation were the interdelta bay, fluvial plain and delta plain during the earlier Jurassic in Junggar basin, which always kept the balance between the rate of peat accumulation and the rate of accommodation creation, and acted as the expressing form of the basic control of the coal accumulation. In fact, the basic control on coal accumulation was the rate of accommodation increase mainly controlled by the fluctuation of relative lake-level for the Jurassic Badaowan formation in Junggar basin.