Stanford University
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Wen Song, UT Austin, Clathrate-Rich Sediments: Compositional Buffering of Local Phase Behavior

When:
Thursday, Jan 30, 2020 12:00 PM
Where:
Mitchell Building, Rm 350/372
Sponsor:
Geophysics Department

GEOPHYSICS DEPARTMENT SEMINAR

Wen Song

University of Texas at Austin

On the Dynamics of Clathrate-Rich Sediments: Compositional Buffering of Local Phase Behavior

Date: Thursday, January 30th 2020

Location:  Mitchell 350/372

Time:  12:00 pm - 1:15 pm

Host:  Tiziana Vanorio




Clathrates are an ubiquitous resource for energy and CO2 storage, but also pose an important geohazard with potential for catastrophic release of methane to the atmosphere and ability to trigger landslides and earthquakes with warming. The mechanisms at which the hydrates form and dissociate in porous sediments, and the fate of the related fluids and sediments that underlie the earth hazards, however, are not understood. In this talk, we probe the hydrate formation and dissociation processes in sediments, and investigate the feedback between phase change, flow, and local salinity. We show, using functionalized microfluidics and optical microscopy, the pore-occupancy of hydrates and its discrepancy between sand- and silt-rich sediments, and map the rate-controlling mechanics of diffusive transport and phase change. We leverage microRaman spectroscopy to provide the first visual observation of a long-debated hypothesis that a negative feedback exists between phase phenomena and local salinity whereby melting-induced salt dilution buffers subsequent melting as a result of the altered local fluid composition.

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