| 上扬子地区晚三叠世层序地层格架：扬子地台消亡与上扬子前陆盆地形成的地层学效应 |
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| 引用本文： | 梅冥相.上扬子地区晚三叠世层序地层格架：扬子地台消亡与上扬子前陆盆地形成的地层学效应[J].地质学报,2014,88(10):1944-1969. |
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| 作者姓名： | 梅冥相 |
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| 作者单位： | 中国地质大学地球科学与资源学院,北京,100083 |
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| 基金项目： | 国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 摘 要： | 发生在中、晚三叠世之交的印支运动,在中国南方表现为以下构造事件:1秦岭-大别造山带的形成与隆升,记录了华北板块与华南板块的对接碰撞;2中国南方东南部1300km宽的陆内造山带的强烈作用,以及由此造成的前陆褶皱逆冲带的北西向迁移。在上述构造事件的结果,结束了扬子地台自埃迪卡拉纪以来以作为一个稳定的古地理单元而且大多数时间发育浅水碳酸盐岩的沉积历史。在扬子地台消亡之后形成一个特别的上扬子前陆盆地(或四川前陆盆地),其中堆积了以河流沉积为特征的须家河组及其相关地层。以河流沉积为特征的须家河组及其相关地层,在川西地区覆盖在马鞍塘组台地碳酸盐岩和小塘子组陆棚至滨岸相砂页岩地层之上,向东、向南逐渐超覆尖灭,从而形成了一个特殊的上三叠统层序地层格架,这个特殊的层序地层格架记录了扬子地台的消亡和上扬子前陆盆地的形成和发育过程。就像黔西南地区在中三叠世台地边缘再生的晚三叠世前陆盆地以及该盆地中填充的特别的上三叠统一样,上扬子前陆盆地上三叠统层序地层格架,尤其是河流沉积为特征的须家河组特别的沉积趋势(从相对集中发育煤层的高可容纳空间低能河流沉积、演变到河道砂岩聚合作用为特征的低可容纳空间高能河流沉积的序列,所组成的沉积层序)所组成的冲积构架,以及逐渐从西向东、从北向南的逐渐超覆尖灭的空间分布,不但是了解扬子地台消亡和上扬子前陆盆地形成的重要物质记录,而且代表了前陆盆地充填序列中一种较为特别的河流相层序地层序列。
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| 关 键 词： | 扬子地台消亡 上扬子前陆盆地的形成 晚三叠世层序地层格架 上扬子地区 中国南方 |
| 收稿时间： | 5/6/2013 12:00:00 AM |
| 修稿时间： | 2014/6/18 0:00:00 |
The Sequence Stratigraphic Framework of the Late Triassic in the Upper Yangtze Region, South China: Stratigraphic Forcing for the Death of the Yangtze Platform and the Birth of the Upper Yangtze Foreland Basin |
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| meimingxiang.The Sequence Stratigraphic Framework of the Late Triassic in the Upper Yangtze Region, South China: Stratigraphic Forcing for the Death of the Yangtze Platform and the Birth of the Upper Yangtze Foreland Basin[J].Acta Geologica Sinica,2014,88(10):1944-1969. |
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| Authors: | meimingxiang |
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| Institution: | School of Earth Sciences and Natural Resources, China University of Geosciences, Beijing 100083 |
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| Abstract: | An important tectonic movement occurred at the turn from the middle to the late Triassic, which has been nominated as the Indochina Movement, was express as the following tectonic events in the South-China: 1) the formation and the uplift of the Qinling-Dabie orogenic belt along the northern margin of the South-China, which records the collision with North-China Plate; 2) the strong action of the 1300-km-wide intracontinental orogen in the southestern part of the South-China Plate, which led to the shift of the foreland thrust-fold zone toward the northwest. The result of these tectonic events led to the death of the long-term development history of the Yangzhe platform that formed a stable palaeogeographical element from the Eidacaran to the end of the middle Triassic, and this stable palaeogeographical element is marked by the development of shallow-water carbonates over this vast platform during much of this vast of expense of time. After the death of the Yangtze platform,a particular sedimentary basin, i.e. the upper-Yangtze foreland basin (or the Sichuan foreland basin) was formed in the the late Triassic, in which accumulated the Xujiahe formation that is characteristic of the fluvial deposits and their relative strata. The Xujiahe formation that is characteristic of the fluvial deposits direct covers the shallow-water carbonate rocks of the Maantang Formation and the siliclastic rocks from the shelf to the littoral facies of the Xiaotangzi Formation in the western part of the Sichuan Province, and gradually become thinned or even overlapping pinched out toward both the east and the south; ultimately, a special sequence-stratigraphic framework of the upper Triassic was formed in the study area, and this sequence-stratigraphic framework become an important matter records expressing both the death of the Yangtze platform and the birth of the Upper-Yangtze foreland basin. Like the birth of a special foreland basin of the late Triassic in the platform margin of the middle Triassic in the southwestern part of Guizhou Province and a particular basin-filling succession of the upper Triassic in this basin, the sequence-stratigraphic framework of the upper Triassic in the Upper-Yangtze foreland basin, especially for the alluvial architectures that is marked by the particular depositional trends (the sequence is composed of the succession from the high accommodation system tract (HAST) of the coal-measure strata to the low accommodation system tract (LAST) of the bottom-loading sandstones of the high-energy fluvial system) of the fluvial system of the Xujiahe Formation, and its specially spatial distribution that is marked by the thinning or even pinching-out toward both the east and the south, not only becomes an important record of both the death in Yangtze platform and the birth of the upper-Yangzhe foreland basin but also expresses a particular sequence-stratigraphic succession of the fluvial deposits within the filling succession of the foreland basin. |
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| Keywords: | The death in Yangzte platform the birth of the Schuan foreland basin sequence-stratigraphic framework of the late Triassic the upper-Yangtze region South China |
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