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<p>The tectonic character of the Indian Peninsular Shield is in a state of dichotomy among various researchers. Although the landscape is a very ancient surface, an outcome of prolonged denudation, various topographic disequilibrium conditions at different areas in the shield repeatedly question the notion of long-term tectonic stability. One of the important sub-units of the shield is the Chhotanagpur Granite-Gneiss Complex in the north. It is a plateau formed by solidification of lava flows, and no noticeable tectonic movement is observed during the Holocene. However, many of the rivers draining this plateau display numerous characteristics of topographic disequilibrium conditions. One such river is the Barakar River, which flows through the Indian states of Jharkhand and West Bengal. Apart from high-level surfaces, this river is elongated and closely resembles a river flowing through a rift valley. The present study has been carried out in the Barakar River Basin to identify various evidence of topographic disequilibrium. Further analysis involved checking whether there is any spatial arrangement in such conditions of disequilibrium and associating their occurrence with litho-structure and tectonics. For this purpose, the SRTM–DEM-derived longitudinal profiles were extracted for the Barakar River and its major tributaries. The reason for extracting the long profiles is the fact that these profiles represent the long-term morphological adjustment of the rivers to varying conditions of litho-structure and tectonics. DEM analysis reveals that the concave-up profile associated with river systems under tectonic stability is missing. Furthermore, the above-grade conditions and over-steepened lower segments of many of the tributaries reveal that the evolutionary phase of drainage development has not been completed yet. A number of steep segments are noticed with no relation to the lithologic boundaries, implying tectonic control. However, the results derived for the Barakar River do not resemble actively uplifting areas such as the Himalayas. The marked resemblance to the rivers of the Deccan and Mysore Plateau implies that there is no evidence in the Barakar River Basin, wherein the tectonic upheaval is geologically recent.</p>

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Identifying topographic disequilibrium conditions and their lithological and tectonic implications in a rifted river basin of Eastern India: Insights from DEM-derived longitudinal profiles and their derivatives

  • 期刊论文

  • 发表日期：

    2025年1月24日

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  • Souvik Das,
  • Subha Roy,
  • Jaya Chatterjee,
  • Md Hasanur Jaman,
  • Somasis Sengupta

摘要

The tectonic character of the Indian Peninsular Shield is in a state of dichotomy among various researchers. Although the landscape is a very ancient surface, an outcome of prolonged denudation, various topographic disequilibrium conditions at different areas in the shield repeatedly question the notion of long-term tectonic stability. One of the important sub-units of the shield is the Chhotanagpur Granite-Gneiss Complex in the north. It is a plateau formed by solidification of lava flows, and no noticeable tectonic movement is observed during the Holocene. However, many of the rivers draining this plateau display numerous characteristics of topographic disequilibrium conditions. One such river is the Barakar River, which flows through the Indian states of Jharkhand and West Bengal. Apart from high-level surfaces, this river is elongated and closely resembles a river flowing through a rift valley. The present study has been carried out in the Barakar River Basin to identify various evidence of topographic disequilibrium. Further analysis involved checking whether there is any spatial arrangement in such conditions of disequilibrium and associating their occurrence with litho-structure and tectonics. For this purpose, the SRTM–DEM-derived longitudinal profiles were extracted for the Barakar River and its major tributaries. The reason for extracting the long profiles is the fact that these profiles represent the long-term morphological adjustment of the rivers to varying conditions of litho-structure and tectonics. DEM analysis reveals that the concave-up profile associated with river systems under tectonic stability is missing. Furthermore, the above-grade conditions and over-steepened lower segments of many of the tributaries reveal that the evolutionary phase of drainage development has not been completed yet. A number of steep segments are noticed with no relation to the lithologic boundaries, implying tectonic control. However, the results derived for the Barakar River do not resemble actively uplifting areas such as the Himalayas. The marked resemblance to the rivers of the Deccan and Mysore Plateau implies that there is no evidence in the Barakar River Basin, wherein the tectonic upheaval is geologically recent.