Isotope Ratio – Discharge Relationships of Solutes Derived From Weathering Reactions

Details

Ressource 1Download: 84469-isotope-ratio-discharge-relationships-of-solutes-derived-from-weathering-reactions.pdf (3557.71 [Ko])
State: Public
Version: Final published version
License: CC BY-NC-ND 4.0
Serval ID
serval:BIB_36D32040CB02
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Isotope Ratio – Discharge Relationships of Solutes Derived From Weathering Reactions
Journal
American Journal of Science
Author(s)
Druhan Jennifer L., Benettin Paolo
ISSN
1945-452X
0002-9599
Publication state
Published
Issued date
15/08/2023
Peer-reviewed
Oui
Volume
323
Number
5
Language
english
Abstract
To date, the vast majority of studies seeking to link discharge to solute concentrations have been based on representations of fluid age distributions in watersheds that are time-invariant. As increasingly detailed spatial and temporal datasets become available for weathering-derived riverine solute concentrations, the capacity to link this mass flux to transient routing of reactive fluids through Critical Zone environments is vital to quantitative interpretation. Relationships between fluid age distributions and the stable isotope ratios of these geogenic solutes are even less developed, yet these signatures are vital to parsing the suite of water-rock-life interactions that create concentration-discharge relationships. Here we offer the first merging of a hydrological model featuring time-variant fluid age distributions with a geochemical model for isotopically fractionating weathering reactions. Using SiO2(aq) and the corresponding silicon isotope ratio δ30Si as an example, we show that the stable isotope signatures of riverine solutes produced by weathering reactions reflect a component of the fluid age distribution that is unique to the corresponding solute concentrations. This distinct sensitivity is the result of a stronger link between isotope ratios and the age distribution parameters describing a given watershed. This novel modeling framework is used to provide a quantitative basis for the interpretation of SiO2(aq) and δ30Si in six low-order streams spread across a diversity of climates, geologies, and ecosystems. To our knowledge, this is the first forward and process-based model to describe the isotopic signatures of solutes derived from weathering reactions in watersheds subject to time-varying discharge.
Keywords
Chemical weathering, stable isotope fractionation, StorAge Selection functions
Web of science
Open Access
Yes
Create date
21/11/2023 17:09
Last modification date
10/02/2024 7:15
Usage data