Predictive and invertible models of sediment geochemistry from catchment to continental scales

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• Alex Lipp, Imperial College London
• Monday 15 February 2021, 17:00-18:00
• The talk will be held virtually over zoom. The link will be circulated to members via email, while non-members may contact jac293@cam.ac.uk for details.

If you have a question about this talk, please contact James Craig.

Sediments are weathered pieces of rocks that are mixed in rivers (mostly) and transported to basins, becoming sorted along the way. This conceptual understanding of sediment formation has been generally understood for many years, although recent updates to this understanding are still made (e.g. the importance of cation exchange). Here I will show how this conceptual understanding can be represented using quantitative schemes to make predictions about sedimentary geochemistry and improve our understanding of Earth’s surface. First, I demonstrate a statistical method to describe the major-element composition of sediments in terms of the composition of their protolith and how intensely they have been weathered. Applying this method to large compilations of sediment compositions allows us to reconstruct the composition of the Archean continents, and produce a Phanerozoic history of weathering intensity. Second, I show how modern-day river sediments can be reliably predicted using a simple mixture model of their source regions. Finally, I show how this mixing model can be ‘inverted’, allowing higher order river sediments to be ‘unmixed’ to produce geochemical maps of their source regions.

This talk is part of the Sedgwick Club talks series.

This talk is included in these lists:

• Department of Earth Sciences seminars
• Sedgwick Club talks
• The talk will be held virtually over zoom. The link will be circulated to members via email, while non-members may contact jac293@cam.ac.uk for details

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