EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evolution of chemical weathering processes and CO2 sequestration in the glaciated basins of Western Himalayas

Kalyan biswal, Naveen kumar, Mohd soheb, and Ramanathan al
Kalyan biswal et al.

Understanding of chemical weathering process involved in ionic elution helps in distinguishing the CO2 sequestration rate at the different micro-climatic setup of Himalayan catchments. In the present study, we have selected three glaciated basins from two different climatic zones of Western Himalayas (Lato and Phutse from the cold-arid zone of Ladakh and Chhota Shigri from the monsoon-arid zone of Himachal Pradesh, India) for determining various solute sources, CO2 sequestration rate and its control over melt-water quality. Solute sourcing models used in this work shows major cations like Ca2+  and Mg2+ are from crustal rock-weathering while Na+ and K+ sourced out from the sea-salt origin. However, major anions like SO42- (> 85%) were derived from the crustal origin and HCO3- mostly derived from atmospheric sources (39% to 45 %) in all catchments except HCO3- contribution from carbonation dissolution and silicate weathering is ~29% and ~16% for Ladakh catchments compared to ~9 % and ~29% in Chhota Shigri respectively. The solute model also reveals that the contribution of sulphate oxidative mediated carbonate dissolution (SOCD) in HCO3- flux is relatively higher in Chhota Shigri (~16%) than others (~9%). It is also observed that catchment like Chhota Shigri having a combined network of channelized and distributed drainage patterns with lower specific discharge, more glacierized area, low pH, high pCO2, Low molar ratio [Ca2+ + Mg2+]/[ Na+ + K+], high SMF (~ 0.4), low CO2 carbonate/CO2 silicate ratio (~1.3) show relatively more sulphide oxidative and silicate weathered products than other catchments. Conversely, presence of excess non-glaciated areas in Stok and Phutse having well-channelized subsurface discharge with high CO2 carbonate/CO2 silicate ratio (~10 to ~5) show enhanced carbonation via atmospheric CO2 (CAC) and carbonate dissolution with high annual CO2 sequestration. Thus, varying subglacial drainage system, specific discharge pattern and reactive rock-types with distinct hydro-micro-climatic set up alters the chemical weathering mechanism in these catchments and control meltwater quality.

How to cite: biswal, K., kumar, N., soheb, M., and al, R.: Evolution of chemical weathering processes and CO2 sequestration in the glaciated basins of Western Himalayas, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15282,, 2021.

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