藏北依布茶卡东康托组重新厘定
发布时间：2019-04-30 08:51
【摘要】：羌塘地块内发育大面积的陆相红色地层,主要为山间河湖相沉积以及少量磨拉石建造。前人对这些红层的研究程度一直较低,但它们却是记录羌塘地体乃至整个青藏高原新生代的隆升过程的最好载体。位于南羌塘北缘的荣玛地区,发育了大套红色河湖相地层,前人一致将它们统一划归为渐新世—中新世康托组。但现有区域资料显示区内应该发育有晚白垩世陆相红色碎屑岩地层。本文通过实测剖面,并从沉积学、岩相学、同位素年代学和构造变形等多方面分析测区新生代盆地演化和构造活动,并对红层重矿物、物源区构造背景、古流向、沉积相进行探讨,最后利用红层构造变形样式的区别,辅助加以约束地层时代。沉积学研究显示,区内红色地层主要为冲积扇—滨浅湖—湖泊扇三角洲—辫状河相地层;Dickinson砂岩碎屑成分三角图解显示红层物源区构造背景主要为再旋回造山带;古流向研究结果指示了沉积盆地周缘造山带不同阶段差异隆升的特征;重矿物分析得到不同红层物源区距离和母岩类型的差异;砂岩碎屑锆石U-Pb测年结果证实了区内存在白垩纪地层的可能;地层构造变形的研究则较为准确的将区内红层划分为两个构造层次。最后从依布茶卡湖东的原康托组中分解出上白垩统阿布山组(~105Ma),充实了研究区地层单元。
[Abstract]:A large area of continental red strata is developed in Qiangtang block, mainly intermountain fluvial-lacustrine deposits and a small amount of grinding rock formation. Previous studies on these red beds have been low, but they are the best carriers to record the Cenozoic uplift process of the Qiangtang terrane and even the entire Qinghai-Tibet Plateau. Located in the northern margin of southern Qiangtang, a large set of red fluvial and lacustrine facies strata have been developed in the Rongma area, which were unanimously classified into the Oligocene-Miocene Kangtuo formation. However, the available regional data indicate that there should be red clastic strata of late Cretaceous continental facies in the area. In this paper, the evolution and tectonic activity of Cenozoic basin in the survey area are analyzed from the aspects of sedimentary, lithofacies, isotope chronology and tectonic deformation, and the heavy minerals in red bed, the tectonic background of provenance area, and the paleo-direction are analyzed through the measured sections. The sedimentary facies is discussed, and finally, the difference of the deformation pattern of red bed structure is used to restrain the stratigraphic age. Sedimentological studies show that the red strata in the area are mainly alluvial fan-shoreline shallow lake-lacustrine fan delta-braided river facies strata, and the triangle diagram of the clastic composition of Dickinson sandstone shows that the tectonic setting of the red bed provenance area is mainly the recirculation orogenic belt. The results of paleo-flow study indicate the characteristics of different stages of uplift in the orogenic belts around the sedimentary basin, and the differences in the distance between the source areas of different red beds and the types of parent rocks from the analysis of heavy minerals. The results of U-Pb dating of sandstone clastic zircon confirm the possibility of Cretaceous strata in the area, and the study of stratigraphic structural deformation accurately divides the red strata into two tectonic levels. Finally, the Upper Cretaceous Abu Shan formation (~ 105Ma) is decomposed from the Yuankangtuo formation in the east of Ibuchaka Lake, which enriches the stratigraphic unit of the study area.
【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】：P535
本文编号：2468654
[Abstract]:A large area of continental red strata is developed in Qiangtang block, mainly intermountain fluvial-lacustrine deposits and a small amount of grinding rock formation. Previous studies on these red beds have been low, but they are the best carriers to record the Cenozoic uplift process of the Qiangtang terrane and even the entire Qinghai-Tibet Plateau. Located in the northern margin of southern Qiangtang, a large set of red fluvial and lacustrine facies strata have been developed in the Rongma area, which were unanimously classified into the Oligocene-Miocene Kangtuo formation. However, the available regional data indicate that there should be red clastic strata of late Cretaceous continental facies in the area. In this paper, the evolution and tectonic activity of Cenozoic basin in the survey area are analyzed from the aspects of sedimentary, lithofacies, isotope chronology and tectonic deformation, and the heavy minerals in red bed, the tectonic background of provenance area, and the paleo-direction are analyzed through the measured sections. The sedimentary facies is discussed, and finally, the difference of the deformation pattern of red bed structure is used to restrain the stratigraphic age. Sedimentological studies show that the red strata in the area are mainly alluvial fan-shoreline shallow lake-lacustrine fan delta-braided river facies strata, and the triangle diagram of the clastic composition of Dickinson sandstone shows that the tectonic setting of the red bed provenance area is mainly the recirculation orogenic belt. The results of paleo-flow study indicate the characteristics of different stages of uplift in the orogenic belts around the sedimentary basin, and the differences in the distance between the source areas of different red beds and the types of parent rocks from the analysis of heavy minerals. The results of U-Pb dating of sandstone clastic zircon confirm the possibility of Cretaceous strata in the area, and the study of stratigraphic structural deformation accurately divides the red strata into two tectonic levels. Finally, the Upper Cretaceous Abu Shan formation (~ 105Ma) is decomposed from the Yuankangtuo formation in the east of Ibuchaka Lake, which enriches the stratigraphic unit of the study area.
【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】：P535
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