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河南省侏罗—白垩纪沉积相与古地理研究
Study on Jurassic-cretaceous Sedimentary Facies and Paleogeography in Henan Province
【作者】 钟明洋;
【导师】 胡斌;
【作者基本信息】 河南理工大学 , 地质资源与地质工程, 2010, 硕士
【摘要】 河南省中生代侏罗-白垩纪时期,受印支运动后期及燕山运动的影响,沉积了近30余山间坳陷、断陷(坳)小盆地,为全面开展全省侏罗-白垩纪沉积相与古地理研究奠定了基础。本文收集了东部隐伏区侏罗-白垩纪时期沉积的25口钻井资料,实测了包括济源盆地侏罗纪、马市坪晚侏罗-早白垩世、西峡盆地晚白垩世地层等露头较好的7条剖面;较详细地收集了大量野外一手资料,并采集了大量的岩石和化石样品,尤其是遗迹化石。通过室内对岩样进行显微镜下观测和粒度分析,结合沉积学和遗迹学知识,得出河南省侏罗-白垩纪时期,主要为陆相沉积体系,局部为火山岩建造。研究区陆相沉积主要包括冲积扇、辫状河、曲流河及滨浅湖等4种沉积相,河漫湖泊、湖泊三角洲、深湖浊流及扇三角洲等4种沉积亚相,并建立了冲积扇-河流-湖泊体系沉积模式。在济源盆地早侏罗世和西峡盆地晚白垩世地层中,详细描述及鉴定了14属21种遗迹化石。根据遗迹化石产状特征,及其与沉积物、沉积环境间的相互关系,在济源盆地中建立了代表湖泊浊流环境的鞍腰遗迹群落;在西峡盆地中建立了代表河流环境的Beaconites-Palaeophycus遗迹组构和代表湖泊环境的Beaconites- Taenidium遗迹组构。以构造控盆思想为指导,遵循“点-线-面”编图原则,比较全面地恢复了研究区的构造、岩相古地理面貌,研究认为:早-中侏罗世时期,以淅川-桐柏-新县-商城为界,呈现南为山地,北为高地或平原的格局,以河湖相沉积为主;晚侏罗-早白垩世时期,盆地呈狭窄长条状展布,表现明显的走滑拉分盆地的性质,开始出现火山岩沉积;晚白垩世时期,盆地分布在豫西南地区,主要受断裂控制,表现为断陷、走滑性质,沉积以冲积体系为主。本次研究充分反映了研究区沉积体系的时空演化特征,从而为油气、煤等矿产资源勘探提供了较为可靠的理论依据。
【Abstract】 During the Jurassic-Cretaceous period, effected by the later stage of Indosinian orogeny and Yanshan movement, there are more than 30 of small intermountain depressions (fault) basins in Henan Province; it laid the foundation for fully studying the Jurassic-Cretaceous sedimentary facies and paleogeography. This paper has collected 25 drilling data of deposits in Jurassic-Cretaceous strata of concealed areas in the eastern Henan, measured 7 sections including outcrops of Jurassic in Jiyuan Basin, Upper Jurassic-Lower Cretaceous in mashiping Basin, Upper Cretaceous in Xixia Basin. Lots of first-hand field information has been collected in detail, including a large number of rock and fossil samples, especially trace fossils.After the rock samples observation under a microscope and particle size analysis in laboratory,and combined with knowledges of sedimentology and ichnology, it is clear that there mainly were continental sedimentary system,locally construction of the volcanic rock in Jurassic-Cretaceous period in Henan Province. Continental deposits in the study area have 4 kinds of sedimentary facies including alluvial fan, braided stream, meandering stream, shallow lake;and 4 kinds of sedimentary sub-facies including flood lakes, lake delta, deep lake turbidite and fan delta, and establish a depositional model of alluvial fan -fluvial -lacustrine system.14 genera and 21 species of trace fossils are described and identified in detail in the Early Jurassic strata in Jiyuan basin and Late Cretaceous strata in Xixia Basin. According to the occurrence features of trace fossils, and its relationship with sediments and sedimentary environment, the Anyao ichnocoenosis represented lake turbidite environment is established in Jiyuan basin; and the Beaconites-Palaeophycus ichnofabric generated in the fluvial environment and the Beaconites-Taenidium ichnofabric occurred in of lake environment are established in Xixia basin.With the thought of Structure-controlled Basin Evolution as the guide, follow the "Point - Line - Area" map compilation principle, a more comprehensive study to restore the tectonic, lithofacies palaeogeography has been finished in the area.During the Early - Middle Jurassic period, take Xichuan - Tongbai - XinXian - Shangcheng for the sector, the mountains in the South, highlands or plains in the north, mainly were fluvial and lacustrine facies; During the Late Jurassic - Early Cretaceous, the basin was a shape of narrow strip distribution, showing characteristics of significant strike-slip pull-apart basin, and the volcanic deposits began to appear; During the Late Cretaceous period, the basin, dominated by the alluvial deposits, was located in southwest Henan, mainly controlled by faults, and had the characteristics of fault and strike-slip.This study reflects the characteristics of space-time evolution of sedimentary systems in the study area, and provide a more reliable theoretical basis for the exploration of oil and gas, coal and other mineral resources.
【Key words】 Henan province; Jurassic Period; Cretaceous Period; sedimentary facies; trace fossils; paleogeography;