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Seasonal controls of meltwater runoff chemistry and chemical weathering at Urumqi Glacier No.1 in central Asia
Author(s) -
Li Xiangying,
Ding Yongjian,
Han Tianding,
Kang Shichang,
Yu Zhongbo,
Jing Zhefan
Publication year - 2019
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.13555
Subject(s) - weathering , meltwater , denudation , surface runoff , glacier , snowmelt , glacial period , hydrology (agriculture) , geology , silicate , environmental chemistry , snow , environmental science , geochemistry , chemistry , geomorphology , ecology , paleontology , geotechnical engineering , organic chemistry , biology , tectonics
Temporal variation of runoff chemistry and its seasonal controls relating to chemical weathering processes and drainage system evolution were examined at Urumqi Glacier No.1 in Xinjiang, China, over a full melt season. The dominant ions in meltwater runoff are HCO 3 − , Ca 2+ , and SO 4 2− ; and Fe, Sr, and Al are dominant elements. Concentrations of major ions and some elements show periodic variations with seasons and negatively correlate with discharge, whereas other elements (e.g., Al, Ni, Cu, Zn, Cd, and Pb) show a random change, providing insights into the hydrological and physicochemical controls. HCO 3 − and Ca 2+ are primarily derived from calcite, SO 4 2− and Fe mainly come from pyrite, and Sr and Al principally originate from silicate. Hydrochemical fluxes of solutes exhibit strong seasonality but are positively related to discharge, suggesting an increasing release of solutes during higher flow conditions. Solute yields, cation denudation rate, and chemical weathering intensity observed at Urumqi Glacier No.1 are higher than those at most basins worldwide. This suggests that chemical weathering in central Asia may be stronger than at other glacial basins with similar specific discharge. Concentrations of some elements (e.g., Fe, Al, As, Pb, and Zn) are close to or exceed the guidelines for drinking water standards in meltwater‐fed rivers. These rivers may face future challenges of water quality degradation, and relationships between changing flow and water quality conditions should be established soon, given that development of channelized flow is expected to be earlier over a melt season in a warming climate.