摘要
通过对塔里木盆地西缘露头、盆内钻井、测井和地震资料以及大量室内分析化验资料的层序地层综合分析 ,将志留系划分成 5个三级层序 ,层序厚度为 4 0～ 155m。层序界面多为分布范围较广的区域性或局部不整合。层序叠置样式可用具陆棚坡折的Ⅰ型层序地层样式来描述。每个沉积层序可由完整的低位、海侵和高位体系域组成或由其中的一个、两个体系域组成。体系域边界主要依据滨岸上超点位置、岩性组合及准层序叠置样式变化来确定。低位体系域向上粒度变细、砂岩厚度向上减薄的准层序组成 ;海侵体系域表现为向上泥岩厚度加大、砂岩厚度减薄的叠置特点 ;高位体系域表现为加积—进积沉积特征。志留系沉积时期 ,研究区接受了滨外陆棚及滨岸、海湾潮坪沉积 ,发育典型的海相沉积构造 ,表现出明显的旋回特征。
Based on integrated analysis of western margin outcrop, core and well logging, seismic data and analytic data in Tarim Basin,five sequences with thickness of 40～155 m have been identified in Silurian.Sequence boundaries are mainly widely spread regional or local unconformities. Each sequence consists of either complete lowstand, transgressive and highstand system tracts or one or two of them. Sequence pattern of Silurian in Tarim Basin may be described by type I sequence model with shelf break.Boundaries of system tracts are mainly decided on onlap location, lithologic association and variations of parasequence patterns. Lowstand system tracts consist of parasequences with fining in grain size and thinning in sandstone thickness upward. Transgressive system tracts are characterized by thinning in sandstone thickness and thicking in mudstone thickness upward. Highstand system tracts are characterized by acceleration progradation sedimentation. Sedimentary types of Silurian are mainly shelf , offshore, and tidal flat with typical marine sedimentary structures and cycles vertically.
出处
《古地理学报》
CAS
CSCD
2001年第2期64-71,共8页
Journal of Palaeogeography：Chinese Edition
关键词
塔里木盆地
志留系
层序地层
沉积相
Tarim Basin, Silurian, sequence stratigraphy, system tract, sedimentary facies
