TY - JOUR
T1 - Coevolution of Weathering Front and Water Table
AU - Wang, Wei
AU - Chen, Po
AU - Dueker, Ken
AU - Zhang, Ye
AU - Lee, En jui
AU - Mu, Dawei
AU - Keifer, Ian
AU - Jiao, Jianying
N1 - Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.
PY - 2021/10/28
Y1 - 2021/10/28
N2 - Water is known to play an essential role in initiating and maintaining subsurface weathering reactions. However, the interaction between the weathering front and the water table is unclear and under intense debate. Here, we present a high-fidelity, 3D image of a variably saturated weathering front beneath a granite terrain in the Laramie Range, Wyoming, constructed using full-3D ambient-noise adjoint tomography and calibrated with data from an extensive drilling and hydraulic well testing effort. The imaged weathering front between saprolite and weathered bedrock is overall shallower than the water table under ridge but deeper than water table under valleys. We propose that downward-advancing weathering front coevolves with water table in a positive cycle that gradually flattens the water table, enhances the rate of groundwater drainage, and exposes underlying bedrock to weathering. As a result, we expect this cycle to become “sluggish” with time as water table gradient decreases.
AB - Water is known to play an essential role in initiating and maintaining subsurface weathering reactions. However, the interaction between the weathering front and the water table is unclear and under intense debate. Here, we present a high-fidelity, 3D image of a variably saturated weathering front beneath a granite terrain in the Laramie Range, Wyoming, constructed using full-3D ambient-noise adjoint tomography and calibrated with data from an extensive drilling and hydraulic well testing effort. The imaged weathering front between saprolite and weathered bedrock is overall shallower than the water table under ridge but deeper than water table under valleys. We propose that downward-advancing weathering front coevolves with water table in a positive cycle that gradually flattens the water table, enhances the rate of groundwater drainage, and exposes underlying bedrock to weathering. As a result, we expect this cycle to become “sluggish” with time as water table gradient decreases.
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U2 - 10.1029/2021GL092916
DO - 10.1029/2021GL092916
M3 - Article
AN - SCOPUS:85118254099
SN - 0094-8276
VL - 48
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 20
M1 - e2021GL092916
ER -