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January Meeting: Mudrocks (shales, mudstones) at the Scale of Grains and Pores: Current Understanding – Kitty Milliken

Come join the FCGS to kick off 2024 with our first talk of the year!

Location: Fort Lewis College campus, Sitter Family Hall, Rm 710


5:30 to 6:30 pm: Happy Hour with Appetizers, Salads, Cookies, and Pizza

6:30 to 8:00: Business, Talk, and Raffle

Talk Abstract: 

The fine-grained sediments and rocks that constitute most of the sedimentary record have received tremendous research attention in the past decade. This talk reviews some of the technologies that have supported these advances and summarizes current knowledge of the pore-scale processes that drive the evolution of bulk rock properties of mud in the subsurface. Electron microbeam instrumentation has been central to improving our understanding of fine-grained sediment.  In particular, improvements in resolution offered by field-emission electron guns and advances in sample preparation by various ion-milling techniques have allowed researchers to see tiny grains and pores in unprecedented detail. Grain assemblages in mudrocks vary across a compositional range greater than the ranges seen in sandstones and limestones. As in these less abundant lithologies, the initial compositions in muds have significant implications for the evolution mudrock properties in the subsurface.  It is now clear that the principal diagenetic processes of sandstones and limestones, compaction and cementation, also operate in mudrocks. Compaction is the most important cause of pore loss and cementation is the key control on the evolution of mechanical properties. Quantification of compaction and cementation is central in the quest to refine a predictive understanding of the evolution of mudrock properties in the subsurface.

Speaker Bio:

Kitty L. Milliken is a Senior Research Scientist at the Bureau of Economic Geology, University of Texas at Austin. She received a B.A. in geology (1975) from Vanderbilt University and M.A. (1977) and Ph.D. (1985) degrees from UT Austin. Her research focuses on diagenesis of siliciclastic sediments and the evolution of rock properties in the subsurface. She has authored and co-authored over 120 peer-reviewed papers and also digital resources for teaching sedimentary petrography. Her current work is focused on the application of electron microbeam imaging and analysis to interpret chemical and mechanical histories of mudrocks.