ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    湖南湘西古夷平面发育及古环境演化研究

    Sedimentary Characteristics and Paleoenvironment Evolution of Paleoplanation in Xiangxi Hunan

    • 摘要: 湖南湘西地区断裂和褶皱构造较发育,经历了多次构造运动的改造、大面积断块抬升与大规模的剥蚀夷平作用,发育形成了两级夷平面,十分有利于夷平面演化的研究。笔者在对湘西地区若干岩溶红色风化壳剖面进行了广泛野外调查的基础上,选取了湘西州两个典型剖面进行了古风化壳粒度、磁化率和孢粉的综合研究,从地貌学、表生地球化学和土壤学、孢粉学的角度探讨湘西地区岩溶风化壳的形成时代与夷平面演化的关系。研究结果表明:研究区内夷平面发育时期应该在中更新世至中新世阶段,在进入古近纪后,总体上长期处于相对稳定状态;贾坝剖面沉积环境相对于洛塔剖面略微干燥或凉润,夷平作用较发育,沉积时期虽有明显的气候波动变化,但两个剖面沉积环境整体湿润,期间伴随的干燥波动幅度较小。

       

      Abstract: The Xiangxi fault and fold structures in Hunan Province are well-developed, which have undergone multiple tectonic movements, large-scale fault block uplift, and large-scale erosion and leveling, forming two levels of planation planes, which is very conducive to the study of planation plane evolution. On the basis of extensive field investigations on several karst red weathering crust profiles in the western Hunan region, the author selected two typical profiles in Xiangxi Prefecture to conduct a comprehensive study on the particle size, magnetic susceptibility, and spore pollen of ancient weathering crust. From the perspectives of geomorphology, epigeochemistry, soil science, and spore pollen, this study explores the relationship between the formation age of karst weathering crust in the western Hunan region and the evolution of the planation plane. The research results indicate that the development period of the planation plane in the study area should be from the Middle Pleistocene to the Middle Miocene, and after entering the Paleogene, it is generally in a relatively stable state for a long time; The sedimentary environment of the Jiaba section is slightly dry or cool and moist compared to the Luota section, with more developed planation. Although there were significant climate fluctuations during the sedimentation period, the overall sedimentary environment of the two sections was moist, and the accompanying dry fluctuations were relatively small.

       

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