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Isotopic geochemistry of Panama rivers

Russell S. Harmon·Gerhard Worner·Michael J. Pribil·Zoltan Kern·Istvan Forizs·W. Berry Lyons·Christopher B. Gardner·Steven T. Goldsmith
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Abstract

River water samples collected from 78 watersheds rivers along a 500-km transect across a Late Cretaceous-Tertiary andesitic volcanic arc terrane in west-central Panama provide a synoptic overview of riverine geochemistry, chemical denudation, and CO 2 consumption in the tropics. D/H and 18 O/ 16 O relationships indicate that bedrock dissolution of andesitic arc crust in Panama is driven by water-rock interaction with meteoric precipitation as it passes through the critical zone, with no evidence of a geothermal or hydrothermal input. Sr-isotope relationships suggest a geochemical evolution for Panama riverine waters that involves mixing of bedrock pore water with water having 87 Sr/ 86 Sr ratios between 0.7037-0.7043 and relatively high Sr-contents with waters of low Sr content that enriched in radiogenic Sr that are diluted by infiltrating rainfall to variable extents.

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Russell S. Harmon, Gerhard Worner, Michael J. Pribil, Zoltan Kern, Istvan Forizs, W. Berry Lyons, Christopher B. Gardner, Steven T. Goldsmith. 2015. Isotopic geochemistry of Panama rivers. https://doi.org/10.1016/j.proeps.2015.07.026

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