Alison Shaw:

Postdoctoral Researcher

Carnegie Institution

My research focuses on understanding the role of volatiles (noble gases and major volatiles) in magmatic systems. In particular, I am interested in determining how they are recycled from the Earth's surface back into the mantle, as well as identifying how they can be used as geochemical tracers of various sources (i.e. crust, mantle, sediments, plume) and processes (i.e., degassing, contamination, mixing). I have studied magmatic volatiles from the interior of the Earth in various different types of media including:

1) hydrothermal vent fluids in submarine environments
2) basaltic glasses lavas rapidly quenched as they erupt onto the seafloor
3) fumaroles gases emitted from the craters of active volcanoes
4) thermal springs
5) geothermal wells on the flanks of volcanoes and
6) melt inclusions in mineral phases.

During my graduate studies at Scripps, I participated in expeditions to several volcanically-active regions of the world such as Iceland, Hawaii, the Gulf of California and Central America. A key aspect of my Central America studies was to look at how CO2 is recycled through the Central American subduction zone quantitatively assessing how much carbonate from the subducting plate actually makes it out along the volcanic arc.

As a post-doc at the Carnegie Institution, I will be examining the volatile contents and isotope systematics of olivine-hosted melt inclusions from the Izu-Bonin-Mariana subduction zone system. The IBM system is unique in that the subducting oceanic crust is the oldest in the world, resulting in a relatively cold subduction environment which may influence how volatiles are released from the subducting plate. Melt inclusions are thought to represent primitive melts, and thus offer the exciting possibility of characterizing the composition of sub-arc partial melts. Because these tiny inclusions are trapped during crystal growth and assumed to remain isolated after entrapment, they have the potential of revealing valuable clues regarding how melts evolve and to what extent subduction forcing functions (e.g. slab dip angle, sediment thickness, rate of input) control their composition.