青海省南祁连二叠及其沉积相研究
发布时间：2018-08-15 18:25
【摘要】：研究区位于青海省南祁连地区天峻县,隶属于南祁连地块,主要涉及祁连山造山带,属于青藏高原泛华夏大陆秦祁昆构造区。泛华夏古陆块群在晚古生代是介于冈瓦纳大陆与劳亚大陆的陆链,分隔了古特提斯大洋和古亚洲洋,秦祁昆造山带早古生代造山作用受控于原特提斯洋向泛华夏大陆西部陆块群俯冲和消减,属于特提斯构造域的重要组成部分。本文主要对青海省南祁连地区二叠系及其沉积相进行研究。主要涉及二叠系勒门沟组、草地沟组、哈吉尔组、忠什公组、岩石地层、生物地层、年代地层及沉积组合相等方面。勒门沟组由西向东沉积逐渐减薄,至刚察大寺剖面尖灭。草地沟组分布于中祁连山以南,花海于-大柴旦-德令哈-刚察大寺一线以北的广大地域,呈纺锤形展布。草地沟组下部为一套厚层泥晶灰岩夹生物碎屑泥晶灰岩,富含双壳类、腕足类、蜓类及有孔虫化石。忠什公组分布于盆地沉积中心一带,主要出露于忠什公剖面,向东厚度逐渐减薄。总体上,二叠系由西向东灰岩、砾岩沉积逐渐减薄,砂岩沉积逐渐增多,沉降中心可能在忠什公一带。本次研究在草地沟剖面草地沟组底部生物碎屑灰岩中,及莫力克东沟剖面下伏地层哈吉尔组中,发现了蜓类及有孔虫化石15属,牙形石化石2属3种。研究区二叠系砂岩石英含量较高,主要为石英砂岩及长石石英砂岩,分选良好,近次圆状—次棱状,结构成熟度较高。且野外露头上,砂体形态多为透镜状,具有顶平底凸,向两侧尖灭的特点。研究区内原生沉积构造发育,常见平行层理、交错层理、槽状交错层理、浪成交错层理、波痕、泥裂,偶见冲刷充填构造。综合岩性组合特征,沉积构造,野外沉积形态等因素,认为研究区二叠系碎屑岩主要为三角洲沉积。草地沟组底部泥晶灰岩及生物碎屑泥晶灰岩沉积为碳酸盐局限台地沉积相。
[Abstract]:The study area is located in Tianjun County, South Qilian area, Qinghai Province, and belongs to the South Qilian block, which mainly involves the Qilian Mountain orogenic belt and belongs to the Qinghai-Xizang Plateau pan-Chinese continental Qinqi-Kun tectonic area. In the late Paleozoic, the Pan-Cathaysian ancient continental block group was a continental chain between Gondwana and Laoya, separating the Paleotertes Ocean from the Paleo-Asian Ocean. The early Paleozoic orogeny of the Qinqi-Kun orogenic belt is controlled by the subduction and subduction of the primitive Tethys ocean to the western continental block group of Pan-China, which is an important part of the Tethyan tectonic domain. The Permian system and its sedimentary facies in South Qilian area of Qinghai Province are studied in this paper. It mainly involves the Permian Lemengou formation, Caogou formation, Hajier formation, Zhongshigong formation, lithostratigraphy, biostratigraphy, chronostratigraphy and sedimentary assemblages. The Lemengou formation gradually thinned from west to east to the tip of Gangcha Dasi section. The Caogou formation is distributed in the south of the Middle Qilian Mountains, and the Huahai is distributed in a wide area north of the first line of Dachaidan-Delingha-Gangcha Temple, with a spindle-shaped distribution. The lower part of the Caogou formation is a set of thick layer mudstone with bioclastic mudstone, which is rich in bivalves, brachiopods, flies and foraminifera fossils. The Zhongshigong formation is distributed in the sedimentary center of the basin and is mainly exposed to the Zhongshigong section and gradually thinned eastward. On the whole, the Permian limestone is from west to east, the conglomerate deposit is thinning, the sandstone deposit is increasing, and the subsidence center may be in the area of Zhongshi Gong. In this study, 15 genera and 3 species of conodont fossils have been found in 15 genera and 2 genera of conodont fossils in the bottom bioclastic limestone of the grassland gully formation in the Laogou section and in the underlying formation of the Hagil formation in the Molek Donggou section. The content of quartz in Permian sandstone is high, mainly quartz sandstone and feldspar quartz sandstone. In the field outcrop, the sand body is mostly lenticular, which has the characteristics of top and flat bottom convex and pointed out to both sides. In the study area, the primary sedimentary structures are developed, such as parallel bedding, interlaced bedding, trough interlaced bedding, wave interlaced bedding, ripples, mud cracks, and occasionally scour and filling structures. According to the characteristics of lithologic assemblage, sedimentary structure and field sedimentary morphology, it is considered that the Permian clastic rocks in the study area are mainly delta deposits. At the bottom of Caogou formation, mudstone and bioclastic mudstone are deposited into carbonate confined platform sedimentary facies.
【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】：P534.46
本文编号：2185036
[Abstract]:The study area is located in Tianjun County, South Qilian area, Qinghai Province, and belongs to the South Qilian block, which mainly involves the Qilian Mountain orogenic belt and belongs to the Qinghai-Xizang Plateau pan-Chinese continental Qinqi-Kun tectonic area. In the late Paleozoic, the Pan-Cathaysian ancient continental block group was a continental chain between Gondwana and Laoya, separating the Paleotertes Ocean from the Paleo-Asian Ocean. The early Paleozoic orogeny of the Qinqi-Kun orogenic belt is controlled by the subduction and subduction of the primitive Tethys ocean to the western continental block group of Pan-China, which is an important part of the Tethyan tectonic domain. The Permian system and its sedimentary facies in South Qilian area of Qinghai Province are studied in this paper. It mainly involves the Permian Lemengou formation, Caogou formation, Hajier formation, Zhongshigong formation, lithostratigraphy, biostratigraphy, chronostratigraphy and sedimentary assemblages. The Lemengou formation gradually thinned from west to east to the tip of Gangcha Dasi section. The Caogou formation is distributed in the south of the Middle Qilian Mountains, and the Huahai is distributed in a wide area north of the first line of Dachaidan-Delingha-Gangcha Temple, with a spindle-shaped distribution. The lower part of the Caogou formation is a set of thick layer mudstone with bioclastic mudstone, which is rich in bivalves, brachiopods, flies and foraminifera fossils. The Zhongshigong formation is distributed in the sedimentary center of the basin and is mainly exposed to the Zhongshigong section and gradually thinned eastward. On the whole, the Permian limestone is from west to east, the conglomerate deposit is thinning, the sandstone deposit is increasing, and the subsidence center may be in the area of Zhongshi Gong. In this study, 15 genera and 3 species of conodont fossils have been found in 15 genera and 2 genera of conodont fossils in the bottom bioclastic limestone of the grassland gully formation in the Laogou section and in the underlying formation of the Hagil formation in the Molek Donggou section. The content of quartz in Permian sandstone is high, mainly quartz sandstone and feldspar quartz sandstone. In the field outcrop, the sand body is mostly lenticular, which has the characteristics of top and flat bottom convex and pointed out to both sides. In the study area, the primary sedimentary structures are developed, such as parallel bedding, interlaced bedding, trough interlaced bedding, wave interlaced bedding, ripples, mud cracks, and occasionally scour and filling structures. According to the characteristics of lithologic assemblage, sedimentary structure and field sedimentary morphology, it is considered that the Permian clastic rocks in the study area are mainly delta deposits. At the bottom of Caogou formation, mudstone and bioclastic mudstone are deposited into carbonate confined platform sedimentary facies.
【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】：P534.46
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1 姚畅;青海省南祁连二叠及其沉积相研究[D];中国地质大学(北京);2015年
2 罗凯;中祁连北缘托来河地区石炭纪—三叠纪盆地演化研究[D];中国地质大学(北京);2015年
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