Wed 17th July @ noon, Rm 312.222

Abstract:

The Western Branch of the East African Rift System is known to have a thick lithosphere and sparse, alkaline volcanism associated with a metasomatized mantle source. Recent work investigating the relationship between Western Branch metasomatized mantle xenoliths and associated lavas has suggested that these metasomes are a significant factor in the evolution of the rift. Hydrous/carbonated fluids or silicate melts are potent metasomatic agents, however gaining insight into the source of a metasomatic agent proves challenging. Twenty-four silica-understaturated potassic lavas from the Virunga province in the Western Branch yield potential insight into metasomatic processes within their olivine hosted melt inclusions. These data are used in concert with B isotope analyses of associated metasomatized mantle xenoliths in an attempt to distinguish the driver of metasomatism in the area. Elevated volatile concentrations, anomalously negative B isotope ratios, and trace element evidence suggest two plausible sources of metasomatic agents – fluids evolved during paleo-subduction, and fluid exsolved from the melting of a mantle plume entraining old subducted material. These scenarios have implications for the long-term storage of volatiles within the lithosphere and may suggest prior metasomatism is a factor in driving rifting.

Short bio:

Born in Michigan, B.S. in Geology from Michigan State University in 2010, PhD in Geology from the University of Michigan 2015, Assistant Professor at the University of Puerto Rico. Other than playing around with rocks I enjoy making instruments out of kitchen utensils.