鄂尔多斯东胜矿区色连井田延安组层序地层分析

Sequence stratigraphy regularity in Yan'an Formation of Selian Minefield of Dongsheng district in Ordos Basin

通过对色连井田内主要含煤地层侏罗系中统延安组钻孔测井资料、钻探岩芯及含煤地层孢粉组合的综合分析,认为:孢粉组合符合延安组孢粉特征;以沉积拐点或岩性拐点为层序界面,对研究区进行层序地层的划分和对比,将延安组划分为1个长期基准面旋回,5个中期基准面,以及10～15个短期基准面旋回,大致对应于煤层(或煤线)。在此基础上建立了等时地层格架。探讨了短期基准面的叠置方式和层序特征,分析了层序的成因控制因素,认为短期基准面旋回主要由自旋回控制,中期基准面和长期基准面旋回由构造、气候和沉积物供给综合控制。

Comprehensive analysis of the logging curves,drilling cores and sporo pollen assemblage in main coal-bearing strata of the Yan＇an Formation in middle Jurassic of Selian minefield,considered that sporo pollen assemblage is consistent with the palynological characteristics of the Yan＇an Formation,division and correlation andsequence stratigraphic used the deposition and lithology inflection point be the sequence boundaries in the study area,the Yan＇an Formation can be divided into a long-term cycle,segmented into five middle cycles,and ten to fifteen short-term cycles,roughly corresponds to the strata of coal seam（or seam line）.Established the isochronous sequence stratigraphy framework in this basis,discussed on the superimposed pattern and sequence characteristics of short-term base-level,and the causes of the factors that control the sequence,considered that the short-term base-level cycles is controled by autogenetic cycle,the medium-term base level and long-term base level cycle are integrated controlled by tectonics,climate and sediment supply.