Ravi Kant Prasad , Naman Deep Singh , Sunil Kumar Singh , Vikrant Jain
{"title":"Factors controlling basalt weathering in the Deccan traps: A small catchment perspective","authors":"Ravi Kant Prasad , Naman Deep Singh , Sunil Kumar Singh , Vikrant Jain","doi":"10.1016/j.catena.2024.108566","DOIUrl":null,"url":null,"abstract":"<div><div>Chemical weathering fluxes from small basalt catchments, the Ambika and the Girna in the Deccan Traps, have been compared. The two catchments are characterized by distinct climates: humid in the Ambika and semi-arid in the Girna River. We collected water samples at the sub- catchment scale of these basins and analysed concentrations of major ions and dissolved Sr in them to estimate the weathering rates and to assess their controlling factors. The catchment area, slope and relief of the catchments were derived using Digital Elevation Model (DEM) on ArcGIS platform whereas the Soil and Water Assessment Tool (SWAT) was used to derive the sub-catchment scale runoffs. The SWAT simulated annual discharge shows a nearly three times larger discharge in the Ambika River compared to the Girna River. The various sources, viz., basalt, carbonates, sea-salts and saline alkaline soils (SAS) contributing to major ions in dissolved load, were quantified using inverse modelling approach. The total chemical denudation rates (TCDR*) during monsoon, 1033 ± 512 tons km<sup>−2</sup> y<sup>-1</sup>, is ∼ 12 times higher compared to non-monsoon (82 ± 42 tons km<sup>−2</sup> y<sup>-1</sup>) in the Ambika River, and ∼ 3 times higher in the Girna River (monsoon: 185 ± 155 tons km<sup>−2</sup> y<sup>-1</sup> vs. non-monsoon: 51 ± 25 tons km<sup>−2</sup> y<sup>-1</sup>). Annually, TCDR* is around 6-fold higher in the Ambika River (∼683 tons km<sup>−2</sup> y<sup>-1</sup>) than in the Girna River (∼113 tons km<sup>−2</sup> y<sup>-1</sup>) at their outlets. Basalt (silicate) weathering rates (<em>Bas</em>WR) in the Ambika and the Girna rivers are 88 ± 19 and 12 ± 3 tons km<sup>−2</sup> y<sup>-1</sup>, respectively. The chemical weathering rates in the two adjacent catchments is primarily controlled by rainfall/runoff, while relief plays secondary control. CO<sub>2</sub> consumption rates (CCR) of the Ambika with higher rainfall are much higher ((13 ± 4) × 10<sup>5</sup> mol km<sup>−2</sup> y<sup>-1</sup>) compared to most of the inactive basalt cathchments globally.</div></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":"249 ","pages":"Article 108566"},"PeriodicalIF":5.4000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Catena","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S034181622400763X","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Factors controlling basalt weathering in the Deccan traps: A small catchment perspective
Chemical weathering fluxes from small basalt catchments, the Ambika and the Girna in the Deccan Traps, have been compared. The two catchments are characterized by distinct climates: humid in the Ambika and semi-arid in the Girna River. We collected water samples at the sub- catchment scale of these basins and analysed concentrations of major ions and dissolved Sr in them to estimate the weathering rates and to assess their controlling factors. The catchment area, slope and relief of the catchments were derived using Digital Elevation Model (DEM) on ArcGIS platform whereas the Soil and Water Assessment Tool (SWAT) was used to derive the sub-catchment scale runoffs. The SWAT simulated annual discharge shows a nearly three times larger discharge in the Ambika River compared to the Girna River. The various sources, viz., basalt, carbonates, sea-salts and saline alkaline soils (SAS) contributing to major ions in dissolved load, were quantified using inverse modelling approach. The total chemical denudation rates (TCDR*) during monsoon, 1033 ± 512 tons km−2 y-1, is ∼ 12 times higher compared to non-monsoon (82 ± 42 tons km−2 y-1) in the Ambika River, and ∼ 3 times higher in the Girna River (monsoon: 185 ± 155 tons km−2 y-1 vs. non-monsoon: 51 ± 25 tons km−2 y-1). Annually, TCDR* is around 6-fold higher in the Ambika River (∼683 tons km−2 y-1) than in the Girna River (∼113 tons km−2 y-1) at their outlets. Basalt (silicate) weathering rates (BasWR) in the Ambika and the Girna rivers are 88 ± 19 and 12 ± 3 tons km−2 y-1, respectively. The chemical weathering rates in the two adjacent catchments is primarily controlled by rainfall/runoff, while relief plays secondary control. CO2 consumption rates (CCR) of the Ambika with higher rainfall are much higher ((13 ± 4) × 105 mol km−2 y-1) compared to most of the inactive basalt cathchments globally.
期刊介绍:
Catena publishes papers describing original field and laboratory investigations and reviews on geoecology and landscape evolution with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology. It aims to disseminate new knowledge and foster better understanding of the physical environment, of evolutionary sequences that have resulted in past and current landscapes, and of the natural processes that are likely to determine the fate of our terrestrial environment.
Papers within any one of the above topics are welcome provided they are of sufficiently wide interest and relevance.