新疆和什托洛盖盆地中侏罗统西山窑组层序地层及聚煤规律研究

发布时间：2018-05-11 04:28

本文选题：和什托洛盖盆地 + 西山窑组　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：准噶尔盆地的西北缘和什托洛盖盆地中侏罗统西山窑组发育多套煤层。本文综合利用野外露头、钻井岩心、测井和地震等资料,研究和什托洛盖盆地中侏罗统西山窑组地层格架及沉积体系的空间展布及演化,在此基础上分析煤的聚集规律,取得如下主要成果:(1)详细研究了和什托洛盖盆地下、中侏罗统层序界面特征,将下、中侏罗统地层划分为一个二级层序,七个三级层序。其中西山窑组划分两个层序(SQ6和SQ7),分别发育低位体系域、湖扩体系域和高位体系域三个完整的体系域。(2)研究区主要发育辫状河、三角洲和湖泊三种沉积体系类型。SQ6和SQ7形成时期,湖域面积逐渐减少,三角洲广泛发育。总体上研究区南北缘沉积相较为接近,主要为辫状河三角洲,但北部由于地势较陡,局部发育冲积扇。(3)研究区物源主要分别来自盆地南北两个方向,但南部地区物源供给速率和强度在不同时期有所差别。SQ6形成时期,北部的赛米斯台山和阿尔加提山为盆地主要的物源供给区。物源的充足供应,加之可容纳空间的增加,为成煤提供了良好的条件。SQ7形成时期,在北部的赛米斯台山和阿尔加提山物源供给持续不减的情况下,南缘的哈拉阿拉特山输送大量物质进入盆地,加之构造沉降迅速,盆地南缘沉积地层厚度剧增,发育大量煤层。(4)将基准面旋回理论运用于聚煤规律的研究,认为可容纳空间增长速率与物源供给速率相近的滨浅湖-三角洲相环境有利于成煤,低位体系域内煤层不发育,高位体系域形成中、晚期是煤炭发育的最佳时期。
[Abstract]:The northwest margin of Junggar Basin and the Middle Jurassic Xishanyao formation in the Shitorogei Basin developed multiple sets of coal seams. In this paper, the spatial distribution and evolution of the stratigraphic framework and sedimentary system of the Xishanyao formation of the Middle Jurassic in the Middle Jurassic are studied by using the field outcrop, drilling core, logging and seismic data. On this basis, the regularity of coal accumulation is analyzed. The main achievements are as follows: 1) the sequence interface characteristics of the Middle Jurassic are studied in detail in the Lower and Lower Jurassic basins. The Lower Middle Jurassic stratigraphy is divided into a secondary sequence and seven third-order sequences. The Xishanyao formation is divided into two sequences, SQ6 and SQ7, respectively. Three complete system tracts, I. e., low system tract, lacustrine extension system tract and high system tract, are developed in Xishanyao formation, and braided rivers are mainly developed in the study area. During the formation of deltaic and lacustrine sedimentary systems. SQ6 and SQ7, the lake area gradually decreased and the delta developed widely. On the whole, the sedimentary facies in the northern and southern margin of the study area are relatively close, mainly braided river delta, but in the northern part of the study area, because of steep topography, the alluvial fan. 3) the provenance of the study area mainly comes from the north and south directions of the basin. However, the rate and intensity of provenance supply in the southern region are different in different periods. SQ6 was formed in the northern part of the basin, and the Simis-Taishan and Algatti Mountains in the north were the main provenance areas in the basin. The sufficient supply of the source, coupled with the increase in the accommodative space, provided good conditions for coal formation. SQ7 was formed, while the supply of the provenance in the northern Simis and Alcati mountains continued unabated. A large amount of material is transported into the basin by the Arrate Mountain in the southern margin of the basin, in addition to the rapid tectonic subsidence, the thickness of sedimentary strata in the southern margin of the basin increases dramatically, and a large number of coal seams are developed. (4) the base-level cycle theory is applied to the study of the law of coal accumulation. It is considered that the shallow lacustrine delta facies environment, which can accommodate the space growth rate and the material supply rate, is favorable to coal-forming, and the coal seam is not developed in the low level system region, and the formation of the high system tract is the best time for the coal development in the late stage.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.11;P534.52

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