Magmatic Volatiles, Unraveling the Reservoirs and Processes of the Volcanism in the Antarctic Peninsula

Over the last 60 years of funded research, the Antarctic Peninsula and surrounded ridges have been extensively investigated providing important information on the origin of the magmatism, and the composition, structure, temperature and evolution of the lithospheric and asthenospheric mantle. Diverse hypotheses have been proposed for the origin of the magmatism in the Antarctic Peninsula, from flux melting of the mantle wedge during devolatilization of the subducted Phoenix plate, to adiabatic decompression melting of a carbonated and hydrous asthenosphere, to melting of a volatile-rich metasomatized subcontinental lithospheric mantle. All proposed hypotheses invoke the role of volatiles. Surprisingly, data on the volatile contents of basalts and mantle from this region are non-existent. This is a glaring omission from the geochemical data set given the important role volatile elements play in the generation and composition of magmas and their sources. The focus of our research is to examine the regional variations in volatile contents in geochemically well-characterized Pliocene-recent basalt samples along a transect from the Phoenix-Antarctic ridge to James Ross Island(through the South Shetland Islands, Bransfield Strait and the Antarctic Peninsula). The goal is to understand 1) the processes responsible for the generation of chemically diverse basalts in close spatial and temporal proximity within the Antarctic Peninsula and 2) the nature (lithology, composition and temperature) of the heterogeneous mantle source beneath the region .