TY  - JOUR
AU  - Musy, S.
AU  - Purtschert, R.
PY  - 2023//
TI  - Reviewing 39Ar and 37Ar underground production in shallow depths with implications for groundwater dating
JO  - Science of The Total Environment
SP  - 163868
VL  - 884
KW  - Subsurface production
KW  - Argon-39
KW  - Argon-37
KW  - Muons
KW  - Isotope hydrology
KW  - Tracers
N2  - Argon-37 (37Ar) and Argon-39 (39Ar) are used for groundwater dating on timescales from weeks to centuries. For both isotopes, the quantification of underground sources is essential to accurately infer water residence times from sampled dissolved activities. Subsurface production resulting from interactions with neutrons from the natural radioactivity in rocks and with primary cosmogenic neutrons has been known for a long time. More recently, the capture of slow negative muons and reactions with muon-induced neutrons were documented for 39Ar subsurface production in the context of underground particle detectors (e.g. for Dark Matter research). However, the contribution from these particles was never considered for groundwater dating applications. Here, we reevaluate the importance of all potential depth-related production channels at depth ranges relevant for 39Ar groundwater dating [0 − 200 meters below the surface (m.b.s)]. The production of radioargon by muon-induced processes is considered in this depth range for the first time. The uncertainty on the total depth-dependent production rate is estimated with Monte Carlo simulations assuming a uniform distribution of the parameter uncertainties. This work aims to provide a comprehensive framework for interpreting 39Ar activities in terms of groundwater residence times and for exposure age dating of rocks. The production of 37Ar is also addressed since this isotope is relevant as a proxy for 39Ar production, for the timing of river-groundwater exchanges, and in the context of on-site inspections (OSI) within the verification framework of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). In this perspective, we provide an interactive web-based application for the calculation of 37Ar and 39Ar production rates in rocks.
SN  - 0048-9697
UR  - https://www.sciencedirect.com/science/article/pii/S0048969723024890
N1  - exported from refbase (http://www.uhydro.de/base/show.php?record=217), last updated on Fri, 26 Jan 2024 14:06:49 +0100
ID  - Musy+Purtschert2023
ER  -