李明,
赵俊香,
张世民
中国地震局地壳应力研究所, 地壳动力学重点实验室, 北京 100085
基金项目: 国家自然科学基金项目（批准号：41802226）与中国地震局地壳应力研究所中央级公益性科研院所基本科研业务专项项目（批准号：ZDJ2018-03）共同资助
详细信息
作者简介: 姜大伟, 男, 29岁, 助理研究员, 构造地质研究, E-mail:jiangdawei12@163.com
中图分类号: P931.2;P546 收稿日期:2018-09-20
修回日期:2018-12-26
刊出日期:2019-03-30
Distinguishing the Qingyijiang River's morphologic surfaces by grading analysis method
Jiang Dawei,Li Ming,
Zhao Junxiang,
Zhang Shimin
Key Laboratory of Crustal Dynamics, Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085
MSC: P931.2;P546
--> Received Date: 20 September 2018
Revised Date: 26 December 2018
Publish Date: 30 March 2019
摘要
摘要:通过河流阶地的变形特征来分析区域构造活动已得到广泛应用，但同级阶地的对比方法仍存在很多问题，尤其是在缺少标志地层、风化严重的地区。文章通过横穿青藏高原东缘龙门山南段的青衣江河流地貌研究，探讨了粒度分析在阶地、冲积扇面等河流地貌面对比研究中的应用。研究结果表明：河流沉积物中砾石之间基质砂的粒度，很好地区分了同一地区的不同级阶地，粒度呈现出规律的渐变特征；另外，在不同河谷的同级河流地貌面之间存在较大差别，主要与河谷的大小规模相关。这表明，基质粒度的变化反映了河流沉积物随年龄增加而风化程度变大的规律；另一方面，从新到老的河流沉积物剖面中基质的颜色有明显的渐变特征，可以应用于野外初步识别地貌面。这些成果为河流地貌面的对比研究提供了新的简便、可行的方法。
关键词: 青衣江/
河流地貌/
粒度曲线/
门塞尔颜色/
沉积物对比
Abstract:The deformation of river terraces has been applied on the research of the active tectonics widely. Generally, terraces were distinguished by depositional characteristic and the weathering degree. However, quantitative method of the terraces' recognition which are formed in the same period of geological time are still unsolved. In this study, grading analysis were applied in the recognizing of Qingyijang River terraces and fluvial fans in the region of Longmen Shan, east edge of Tibetan Plateau. Qingyijiang River runs through the south range of Longmen Shan and formed multiple levels of terraces and ancient alluvial fans. These geomorphological surfaces are suitable for sedimentary research. In this research, it is indicated that terraces formed in different geological time can be recognized by the grain size of sediments in some specific conditions. It is important that the samples are collected from the fluvial sand that filling the interspace between the gravels. And the grading results showed that the matrix sand in older terrace has finer grain size, which may indicate the deeper degree of weathering. More information can also be interpreted from the grading plat form of the sand samples, such as the multiple graining indexes. Furthermore, the color of terraces in different level also has a regular variation in the tonality. These results provide convenient and reasonable methods in distinguishing the geomophological surfaces.
Key words:Qingyijiang River/
river geomorphology/
grain size curve/
Munsell Soil Color/
contrast of sediments
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