The development and evolution of landform based on neotectonic movement: The Sancha river catchment in the southwestern China

Abstract

Neotectonics has changed the coupled process of endogenic and exogenic geological dynamics, which mold the modern landform. Geomorphologic analysis is essential for identifying and understanding the tectonic activity and indicates the responsive mechanism of the landform to tectonic activity. At first, this research reconstructed the twisted Shanpen period planation surface, computed the valley floor width-to-height ratio of Sancha river and extracted the cross sections marking the river terraces to analyze the characteristics of the neotectonics. And then, the relation between neotectonic movement and landform development was analyzed by dividing the landform types. At last, the spatial variation of landform evolution was analyzed by extracting the Hypsometric Integral of sub-catchments. The Sancha river catchment's neotectonic movement presents the tilt-lift of earth's crust from NW to SE, which is characterized by the posthumous activity of Yanshan tectonic deformation. The spatial distribution of river terraces indicates that Sancha river catchment has experienced at least four intermittent uplifts and the fault blocks at both the sides of Liuzhi-Zhijin basement fault have differentially uplifted since the late Pleistocene. As the resurgence of Liuzhi-Zhijin basement fault, the Sancha river catchment was broken into two relative independent landform units. The spatial variations of the landform types near the Sancha river and the sub-catchments' landform evolution are characterized by periodic replacement. The styles of geological structure have controlled the development of landform far away from the Sancha River and influenced the landform evolution. The posthumous activities of the secondary structure have resulted in the spatial variation of sub-catchments' landform evolution, which presents periodic replacement with local exceptions. The present study suggests that spatial variations of the development and evolution of modern landform of Sancha River catchment owe their genesis to the interplay between the hydrodynamic force and tectonic activity in the neotectonic period. Likewise, the application of geomorphic indicators also provides a new way to assess the regional crustal stability.

Ecological Environment Restoration and Economic Transformation in Karst Landscape Areas—Take Guizhou Province as an Example

“…It's main ecological service functions include water conservation, biodiversity protection and soil conservation. The soil layer in this area is shallow and discontinuous , with poor water and fertilzer retention capacit and poor vegetation habitat conditions (Wu et al, 2021) [4], there are few species of suitable plants, simple community structure, and low stability of ecosystem resilience (Wang et al, 2002) [5]. Due to the joint influence of natural conditions and human activities, the zonal native vegetation has evolved from evergreen broadleaf forests and mixed evergreen deciduous broadleaf forests to shrub communities and grass communities, which directly affects the biodiversity of the region (Zhong et al, 2018;Li et al, 2023;Zhong et al, 2023) [6].Guizhou Province is located in a karst region, the distribution area of carbonate rocks accounts for about 80% of the province, and the thickness accounts for 50% to 70% of the total stratum thickness.…”

New evidence from heavy minerals and detrital zircons in Quaternary fluvial sediments for the evolution of the upper Yangtze River, South China

“…Most of the high-elevation landforms related to the plateau were distributed east of the main Himalayan collision zone, where the crustal volume increased more than 2 × 10 7 km 3 in Cenozoic times (Clark et al, 2005). The crustal deformation and thickening in the southeastern Tibetan Plateau had a significant effect on large fluvial systems, landforms, and climate in East Asia (Brookfield, 1998;Zhong et al, 2018;McRivette et al, 2019;Li et al, 2020;Xiang et al, 2020;Li et al, 2022). Thus, research of river evolution can reveal the processes and degree of effect of the Tibetan Plateau tectonic activity on East Asia and its surrounding regions, and help us better understand the significance of the Tibetan Plateau uplift.…”