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Published online December 1, 2023

Copyright © International Union of Geological Sciences.

Characteristics of relative tectonic activity in the Longchuan River Basin, central Yunnan: Evidence from digital elevation model-based geomorphological analysis

Zhichao Cao1, Lidong Zhu2*, Wenguang Yang2, Yongsheng Yuan3, Wanneng Wang3, Tengxiao Ma2

1 School of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China
2 Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu 610059, China
3 Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming 650111, China

Correspondence to:*E-mail: zhuld@cdut.edu.cn

Received: July 5, 2023; Revised: October 23, 2023; Accepted: October 23, 2023

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Longchuan River basin lies within the China Sichuan-Yunnan rhomboid block. The NS-trending Yuanmou-Lvzhi River Fault (YLF), NW-trending Chuxiong-Nanhua Fault (CNF) and Shiyang-Huoshaotun Fault (HSF) are found within the basin. The nature of the faults is complex, and the tectonic activity distribution characteristics require further clarification. By extraction from a digital elevation model, the measured longitudinal profile and the geomorphic indices of the Longchuan River, basin showed a stream-length gradient index (SL) of 49–650, hypsometric integral (HI) of 0.27–0.58, drainage basin asymmetry factor (AF) of 3.29–27.47, basin shape index (BS) of 0.87–2.75, valley floor width-to-height ratio (VF) of 0.06–5.40, and evaluation of relative tectonic activity (Iat) of 1.6–2.6. Results showed that river morphology and geomorphological indices in the Longchuan River basin were influenced by tectonic activity, bedrock lithology, climatic conditions, and development time, with tectonic activity playing a dominant role. The relative tectonic activity of the Longchuan River basin was zoned, with a gradual increase in relative tectonic activity from the south to the north. That the slip fault zone primarily controls the tectonic deformation of the Longchuan River basin in central Yunnan and the dynamics of the central Yunnan massif are consistent with the “rigid block lateral extrusion” 1model.