OPHIOLITES

Ophiolites are pieces of oceanic crust that have become exposed on land. This can happen at subduction zones where the upper layers of oceanic crust are scraped off the descending slab. Seamounts can be scraped off mostly intact and therefore are exposed on land where we can study them more easily. Ophiolites can give us access to detailed cross-sections of seamounts.

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Studying pillow lavas in the Nicasio Reservoir Terrane, California.

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Cross-section of a seamount based on an ophiolite section.

My work on ophiolites has focused on mapping lava flow morphologies and measuring rock physical properties such as density and porosity. Mapping has shown that pillow lavas at the bottom of seamounts tend to be smaller, more tightly packed, and less porous than pillows at the top. We also see a change from mainly pillow lavas at the bottom to more fractured material at the top. The objective of this work is to understand how volcanostratigraphy reflects changes in magma supply over time.