• 地貌 •

### 青藏高原东北缘马衔山夷平面特征指标的提取与分析

1. 1. 兰州大学资源环境学院 西部环境教育部重点实验室,兰州 730000
2. 南京师范大学地理科学学院,南京 210023
• 收稿日期:2015-11-08 修回日期:2015-12-06 出版日期:2016-03-25 发布日期:2016-03-25
• 作者简介:

作者简介:马振华(1990-), 男, 山东沂源人, 硕士, 主要研究方向为地貌演化及GIS在地貌学中的应用.E-mail: mazhh2013@lzu.edu.cn

• 基金资助:
国家自然科学基金项目(41330745, 41272128);国家重点基础研究发展计划项目(973)(2013CB956403)

### Extraction and analysis of Maxianshan planation surfaces in northeastern margin of the Tibetan Plateau

Zhenhua MA1(), Xiaomiao LI1, Benhong GUO1, Hao YU1, Xiyan YE1, Chunhui SONG1, Jijun LI1,2

1. 1. MOE Key Laboratory of Western China's Environmental Systems & College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China
2. College of Geography Science, Nanjing Normal University, Nanjing 210023, China
• Received:2015-11-08 Revised:2015-12-06 Published:2016-03-25 Online:2016-03-25
• Supported by:
National Natural Science Foundation of China, No.41330745, No.41272128;Major State Basic Research Development Program, No.2013CB956403

Abstract:

Planation surfaces not only play a major role in revealing the geomorphological evolution, but also shed lights on the regional tectonic activities, especially in the fields of Tibetan Plateau uplift. Before we explain their tectonic significance, the critical step is to quantitatively or semi-quantitatively obtain the exact features of planation surfaces, such as their distribution, altitude and area. Till now, much progress has been achieved in extracting the planation surface characters via computer image processing and visual interpretation, but there is still some subjective and random when we choose the index of slope and elevation to extract the information of planation surfaces. Two extensive planation surfaces (the Summit and the Main surface) remain in the inner part of the Tibetan Plateau and its surrounding region. For example, in the Maxianshan mountains of NE Tibetan Plateau, two planation surfaces are identified as the Summit and Main surfaces of Tibet. Some typical periglacial landforms can be observed on the Summit surface, and the Main surface is characterized by the undulating flat topography and several monadnocks and covered by the red clay of 40 m in thickness and loess of 30 m in thickness. In addition, the weathered regolith of granite rocks reaches 3 m thick in some regions. Hence, the Maxianshan mountains are the ideal area for studies on the planation surface. In detail, ridge and valley profiles present the "S"-shaped curve based on our observation, and they are explained by the exponential model which can transform to the mean change point model. In order to obtain the exact altitude and slope parameters of Maxianshan planation surfaces, we chose the mean change point theory and the minimum error method to extract them. Our results show that the best slope parameter of both planation surfaces is 12°. Its reliability is also demonstrated by contrasting the results between our method, visual interpretation and field validation. Subsequently, the distribution and area of planation surfaces were extracted and analyzed. Statistical analyses suggest that the Summit surface covers a total area of about 6.4 km2, with an average elevation of 3559 m and the Main surface has a total area of about 15.5 km2, with an average elevation of 2771 m. Furthermore, we evaluate the deformation characters of the planation surfaces after integration of the slope profiles, slope aspect distribution and regional geology data. The conclusion supports that the deformation of Maxianshan planation surfaces is controlled by regional faults.