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A mineralogic approach to estimating the volume of dissolution, alteration, and unaltered residue from weathering of different provenance lithotypes
  • William Andrew Heins,
  • Latisha A Brengman
William Andrew Heins
Getech Group plc

Corresponding Author:[email protected]

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Latisha A Brengman
University of Minnesota-Duluth, Department of Earth and Environmental Sciences University of Minnesota-Duluth
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Abstract

Evaluation of the approximate magnitude of the gross discrepancy between the volume of sediment produced on the hinterland and the volume deposited in the basin, over long time and length scales, is required to make source-to-sink sediment mass-balance calculations more accurate so that multiple sources for a single widespread stratigraphic unit, or bypass of the unit, might be more easily detected.
This paper outlines a method to characterize the sources of sediments, or provenance lithotypes, according to their relative ability to produce dissolved ions, clay minerals, and unaltered residue at different levels of weathering. Estimating the relative proportion of the hinterland that is dissolved supports mass-balance analysis comparing hinterland denudation with basinal deposition, whereas estimating the relative proportion of clay (both original clay, eroded from mudstone, for example, as well as newly created clay produced by weathering of feldspar) supports potential identification of multiple sediment sources. The method is illustrated with a practical example from the Bohemian Massif and documented with an Excel workbook.
This is a mineralogical approach based on mineral inventories of weathering profiles. Even if the prediction is necessarily uncertain because the mineralogical representation of the PLs are gross abstractions, the modelled transformation processes are crude cartoons, and the extent of transformation under different environmental conditions is wild speculation based on sparse examples, quantitative provenance analysis will be more accurate and more precise than it would be if dissolution and alteration were not explicitly accounted. There is ample opportunity for the community to improve the procedure!
24 Aug 2023Submitted to ESS Open Archive
24 Aug 2023Published in ESS Open Archive