摘要
塔河油田上奥陶统良里塔格组下段以泥微晶灰岩、瘤状灰岩为主,上段以鲕粒灰岩、生屑灰岩、砂砾屑灰岩为主,纵向上构成了一个向上水体变浅的沉积序列。根据层序地层学研究结果,将良里塔格组划分为一个三级层序,细分为两个体系域。通过对各体系域地层单元的岩相学和地球化学分析研究,恢复了各时期的古地理面貌及沉积相带的空间展布。最终研究结果表明良里塔格组沉积相带具有开阔台地、台地边缘和斜坡3种类型,平面上由北向南顺序展布,走向近东西。微量元素分析进一步佐证和完善了该区沉积相带分析,V、Ni和Cr微量元素的含量显示从浅水到深水总体呈增加之势,Ce异常曲线对沉积环境也有良好反映,而台地边缘相的Sr/Ba比值表现出异常高值。
The Upper Ordovician Lianglitag Formation, Tahe Oilfield, mainly consists of micrite, nodular limestone in the lower member and oolitic limestone, bioclastic limestone, calcarenite, calcirudite in the upper member,which constitutes a shallowing upward sedimentary sequence. Based on sequence stratigraphy research, the Lianglitag Formation is a integral three-order sequenee, which is composed by two systems tracts. By means of detail investigation in petrographic and geochemical characteristics of stratigraphic units in every systems tract, the palaeogeographic and sedimentary facies distribution are recognized. There are three kinds of facies belts during upper Ordovician in Tahe Oilfield： platform, platform margin and slope facies,which is approximately east-west strike and distribute orderly from north to south in the plane. Analysis of trace elements and rare earth elements further support and improve the analysis of sedimentary facies. The content of V, Ni and Cr trace elements shows a overall increasing trend from shallow to deep water facies, as well as the abnormal curve of Ce is a good reflection about the sedimentary environment and the Sr/Ba ratio shows abnormally high values in platform margin.
出处
《地质科学》
CAS
CSCD
北大核心
2010年第1期278-291,共14页
Chinese Journal of Geology(Scientia Geologica Sinica)
基金
国家973项目(2006CB202304)
国家重大专项(2008ZX05008-003)资助
