马家滩矿区李新庄勘查区延安组聚煤及其构造特征分析

Coal accumulation and structural characteristics of Yan'an Formation in Lixinzhuang exploration area of Majiatan Mining District

  • 摘要: 【目的及方法】李新庄勘查区处于鄂尔多斯盆地西缘逆冲带的前锋和后冲带的接合部,断裂发育,构造活动强烈,地层变形复杂且重复剧烈,地质结构复杂。基于该区近年来新的钻井和高精度二维地震资料的基础上,研究含煤地层延安组沉积特征与构造特征,【结果】认为勘查区延安组地层的沉积环境划分为浅湖三角洲体系与河流沉积体系两个大类,且前者占绝对优势。勘查区位于马家滩构造带的中段,中部反转−冲断断裂系统的逆冲推覆构造带的锋带,横向断层在地层缩短过程中起调节作用,底板断层是断层与褶皱置换的桥梁。【结论】分析李新庄勘查区的聚煤特征与构造特征,不但能够了解马家滩地区特有的逆冲推覆体系乃至整个鄂尔多斯盆地西缘逆冲带的构造,而且对于查明该地区地下矿产资源分布和有序开发利用等具有极其重要的意义。

     

    Abstract: Located at the junction of the leading edge of the thrust belt and the rear thrust belt on the western margin of the Ordos Basin, Li Xinzhuang exploration area is characterized by well-developed faults, intense tectonic activities, complex strata deformation with severe repetition, and very complex geological structure. Based on the new drilling and high-precision 2D seismic data of this area in recent years, we believe that the sedimentary environment of the Yan'an Formation in the exploration area can be divided into two major categories: shallow lake delta system and fluvial sedimentary system, with the former being dominant. The exploration area is located in the middle section of the Majiataan structural belt and at the leading edge of the thrust and reverse fault system. The lateral faults play a regulatory role in the shortening of the strata, and the floor faults are the bridges for the replacement of faults and folds. Analyzing the coal accumulation characteristics and structural features of the Li Xinzhuang exploration area not only helps to understand the unique thrust and nappe system of the Majiataan area and even the entire thrust belt on the western margin of the Ordos Basin, but also has important significance for clarifying the distribution of underground mineral resources in this area and their orderly development and utilization.

     

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