Active tectonics of NE Gujarat (India) by morphometric and morphostructural studies of Vatrak River basin
- 作者：Rachna Raj naveenrachna@gmail.com
- 关键词：Active tectonics ; Morphometric analysis ; Tectonic geomorphology ; Gujarat ; India
- 刊名：Journal of Asian Earth Sciences
- 出版年：2012
- 期刊代码：40_13679120
- 类别：ear
- 出版时间：2 May, 2012
- 卷：50
- 期：Complete
- 页码：66-78
- 文件大小：2443 K
摘要
Landscape owes its shape to the combination of tectonic and climatic forces. Differential displacement of land by tectonic processes changes the elevation of earth鈥檚 surface locally and in turn affects the rate of geomorphic processes which are altitude dependent. The tectonic and geomorphic processes are very tightly coupled and their results are intertwined. To extract the tectonic signal, the numerical modelling of the landscape of the Vatrak River basin, part of which falls in the northern part of the Gujarat Alluvial Plains of western India, has been undertaken applying morphometric and morphostructural approach. The study helped in understanding the role of tectonic elements in the evolution of the basin. Demarcation of geomorphic indicators of active tectonics (which include the analyses of asymmetry factor, valley floor ratio, gradient, basin elongation ratio, long profile and related parameters, pseudo hypsometric integral, drainage basin asymmetry), drainage pattern analysis and azimuthal distribution of stream channels have been performed for each drainage network and associated basin. The morphological field evidence of tectonics combined with the results of morphometric analysis has been used to obtain information about the orientation of tectonic elements and the possible reconstruction of their activity in recent times. The analyses indicate eastward tilting of the drainage systems, strong asymmetry in some reaches, pronounced elongation of certain tributaries, long profiles indicating base level lowering, poor organisation of the hydrographic network, and close alignment between lower order streams and active faults. All these analyses point towards the active tectonism in the area. Data obtained through the statistical analysis of preferred stream orientations confirm that the old tectonic directions markedly influenced the drainage network development of the older order streams, whereas, streams of lower order which preferentially follow the N-S and NE-SW directions suggest that these tectonic trends were active until very recent times.