中国东北地区早石炭世岩相古地理特征

发布时间：2018-06-06 13:17

本文选题：中国东北 + 早石炭世　；参考：《中国石油大学(华东)》2015年硕士论文

【摘要】：以中国东北地区11条实测剖面、21条观察剖面和57条收集剖面为研究对象,并针对中国东北地区早石炭世地层划分混乱、沉积环境研究程度较低的问题,通过剖面的岩石组合特征及元素地球化学特征分析,对中国东北地区早石炭世岩相古地理特征进行了研究。本次研究在中国东北地区,共识别出碎屑岩、碳酸盐岩、火山岩和火山碎屑岩四种岩石类型,碎屑岩主要为砾岩、砂岩、粉砂岩、泥岩和页岩等,碳酸盐主要为亮晶灰岩、泥晶灰岩和白云岩等,火山岩主要为玄武岩、安山岩等,火山碎屑岩主要为凝灰岩;沉积构造类型主要有水平层理、平行层理、透镜状层理、交错层理和波状层理等;通过剖面岩石样品的元素地球化学特征分析,对中国东北地区早石炭世的沉积环境进行了研究,结果显示,常量元素具有高Si、Fe,低P、Mn、K、和Na的特点,表明受陆源物质影响较大;微量元素具有高V、Li、Sr、Zr,低Be、Ta、Th、Hf和U的特点,Sr/Ba、Th/U、V/Cr、V/(V+N i)等判别参数说明其为海相还原环境;轻、重稀土元素分异显著,轻稀土较为富集,Ce正异常是稀土元素的特点。根据剖面岩性组合特征、沉积构造,并结合元素地球化学特征,对中国东北地区早石炭世的沉积体系进行了研究,共识别出主要有陆地边缘沉积体系、浅海陆棚沉积体系、台地沉积体系和三角洲沉积体系四种沉积体系,发育的亚相类型有泻湖、后滨、前滨、开阔台地、局限台地、三角洲前缘和扇三角洲。通过野外实测剖面与区域地层资料的结合,选取地层发育相对齐全的剖面,统计地层厚度、砂泥岩厚度,并编制地层厚度图、泥岩厚度图、砂岩厚度图、泥地比图、砂地比图、岩相分类三角图,确定发育北部、南部和东部三个物源体系。依据优势岩相及沉积相的原则,结合剖面相分析,对早石炭世的岩相古地理特征进行了研究,结果显示,中国东北地区早石炭世主体为海相,主要发育三角洲相、碳酸盐岩台地相和浅海相,其中三角洲相主要发育在吉林中部地区和研究区的西部地区,碳酸盐岩台地相主要发育在内蒙古东北部地区,浅海相在研究区广泛发育。
[Abstract]:In this paper, 21 observation sections and 57 collection sections of 11 observed sections in Northeast China are taken as the research objects, and aiming at the problem of the stratigraphic division of the early Carboniferous in Northeast China is chaotic and the study degree of sedimentary environment is relatively low. The characteristics of early Carboniferous lithofacies and paleogeography in northeast China were studied by analyzing the characteristics of rock assemblage and element geochemistry of the section. In this study, four rock types, clastic rock, carbonate rock, volcanic rock and pyroclastic rock, were identified in northeast China. The clastic rocks are mainly conglomerate, sandstone, siltstone, mudstone and shale, while carbonate is mainly lime-rock. The main types of sedimentary structure include horizontal bedding, parallel bedding, lenticular bedding, staggered bedding and wave-like bedding, etc., volcanic rocks are mainly basalt, andesite, pyroclastic rocks are mainly tuff, and sedimentary structural types are mainly horizontal bedding, parallel bedding, lenticular bedding, interlaced bedding and wave-like bedding, etc. The sedimentary environment of the early Carboniferous in northeast China was studied by analyzing the geochemical characteristics of the rock samples in the section. The results showed that the major elements had the characteristics of high Si-Fe, low Pb-MnK, and Na, which indicated that they were greatly influenced by land-based materials. The trace elements have the characteristics of high V Li Li Sr Si Zr, low B E T T T H f and U etc. The discriminant parameters such as Sr / Baer T / U V / V / V / V Ni) indicate that the trace elements are marine reduction environment, and the light and heavy rare earth elements are distinguished significantly, and the positive anomalies of ce enrichment are the characteristics of rare earth elements. According to the characteristics of lithologic assemblage, sedimentary structure and elemental geochemistry, the sedimentary system of early Carboniferous in northeast China is studied. The main sedimentary systems of the early Carboniferous in Northeast China are the terrestrial margin sedimentary system and the shallow sea shelf sedimentary system. There are four sedimentary systems of platform sedimentary system and delta sedimentary system. The subfacies types are lagoon, backshore, foreshore, open platform, limited platform, delta front and fan delta. Based on the combination of the field measured section and the regional stratigraphic data, the relatively complete stratigraphic sections are selected to calculate the formation thickness, sand and mudstone thickness, and to compile the formation thickness map, mudstone thickness map, sandstone thickness map, mud to ground ratio map, sand to ground ratio map. Triangulation of lithofacies to determine the development of the north, south and east of the three provenance systems. According to the principle of dominant lithofacies and sedimentary facies, combined with the analysis of the sectional facies, the lithofacies and paleogeographic characteristics of the early Carboniferous are studied. The results show that the main body of the early Carboniferous in Northeast China is marine facies, and the delta facies is mainly developed. The carbonate platform facies and shallow sea facies, among which the delta facies mainly developed in the central Jilin region and the western part of the study area, the carbonate platform facies mainly developed in the northeast of Inner Mongolia, and the shallow sea facies developed extensively in the study area.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13;P534.45

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