Colloquium:Francis McCubbin

Magmatic volatiles in the inner solar system: Constraints from apatite in planetary materials and apatite-melt partitioning experiments

Francis M. McCubbin

Assistant Research Professor, Institute of Meteoritics and Department of Earth & Planetary Sciences, University of New Mexico

Abstract - Magmatic volatiles like water, C-species, S- species, N-species, and the halides play many important roles in geologic processes on Earth, from magma genesis to climate change. Furthermore, these components are the basis of organic chemistry and they are required for life. However, little is known about the origin, abundances, and roles of magmatic volatiles among the other terrestrial bodies in our Solar System. In the present study, we attempt to gain a first-order understanding of the magmatic volatiles H2O, F, and Cl through analyses and experimental work centered around the calcium-phosphate mineral apatite. The mineral apatite contains F, Cl, and OH as essential structural constituents, and it is ubiquitous in planetary materials. Consequently, we have analyzed apatites from Earth, Moon, Mars, 4-Vesta, and ordinary chondrites to gain a better understanding of the magmatic volatile inventories and distributions within those bodies. Importantly, apatite does not mirror the magmatic volatile load of a fluid or melt from which it formed; therefore, we have conducted petrologic experiments to investigate the partitioning behavior of H2O, F, and Cl between apatite and silicate melts. These experiments will allow one to develop a model to use apatite compositions to infer concentrations in magmatic liquids and source regions.