T253 Advances in Understanding Processes at or Near the Groundwater–Surface Water Interface

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

EVIDENCE OF DISSOLUTION FROM STABLE CARBON ISOTOPES OF WATER ALONG AN ALTITUDINAL GRADIENT IN THE EASTERN HIMALAYA MOUNTAINS, NEPAL

Paper number: T253-11
Program: Technical Sessions
Time: 12:20 PM – 12:30 PM

Authors

Abstract

Glacier-fed rivers from the Himalaya Mountains transport dissolved inorganic carbon, reflecting the connection between glaciers, chemical weathering, and the global carbon cycle. Measuring the stable carbon isotopes (d13C) in water samples allows the identification of dissolved inorganic carbon sources. In the years 2018 and 2019, we collected water samples (n= 42) along an altitudinal gradient in the upper Dudh Koshi River Basin, Sagarmatha National Park, during the pre-monsoon season in the Eastern Himalayas. This study includes local drinking water sources (surface, spring, and piped/transported water) commonly used along the trekking routes from 2550m to 4950m elevation. d13CVPDB values range from -0.76 to -20.52 ‰, suggesting the influence of dissolution of atmospheric CO2 and microbiological activity, and shallow groundwater from aquifers with active carbonate weathering. Surface and pipe/transported water samples DIC values correspond to carbonate dissolution, whereas spring water samples also indicate a microbiological influence. Our findings pertain to a snapshot of pre-monsoon weather conditions and establish a baseline for future hydro-geochemical studies in the region.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-355248

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