April 14, 2016
Science Team Meeting
The 36th MESSENGER Science Team Meeting* (STM36) will be led by Larry Nittler on April 12-14, 2016, at the Carnegie Institution for Science headquarters in downtown Washington, D.C.
The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) mission to orbit Mercury following three flybys of that planet is a scientific investigation of the planet Mercury. Understanding Mercury, and the forces that have shaped it is fundamental to understanding the terrestrial planets and their evolution. The orbital phase used the flyby data as an initial guide to perform a focused scientific investigation of this enigmatic world. Former DTM Director Sean Solomon is the Principal Investigator of the MESSENGER Mission. DTM Staff Scientist Larry Nittler is the Deputy Principal Investigator.
*This is a closed meeting on campus for invited participants only.
April 7, 2016
Merle Tuve Lecture
Jacqueline E. Dixon
Jacqueline E. Dixon, professor of geological oceanography at the University of South Florida and DTM Merle A. Tuve Fellow, will give her Merle Tuve Lecture titled, "Light Stable Isotopic Compositions of Enriched Mantle Sources: Resolving the Dehydration Paradox", at 11 a.m. on Thursday, 7 April 2016, in the Greenewalt Lecture Hall.
Dixon received her Ph.D. in geochemistry from California Institute of Technology in 1992. Her research interests focus on the role of H2O and CO2 in the generation and evolution of basaltic magmas with an emphasis on submarine volcanoes.
Abstract: One of the remaining puzzles in mantle geochemistry is the origin and evolution of volatile components. In particular, the “dehydration paradox” refers to the following conundrum. The enriched “prevalent mantle” (PREMA) component found in many mantle plumes requires involvement of a mostly dehydrated slab component to explain the trace element ratios and radiogenic isotopic compositions of PREMA-type oceanic basalts, but a fully hydrated slab component to explain the stable isotopic compositions. I will present new volatile concentration and hydrogen, lithium, and boron isotopic compositions for PREMA- and EM-type oceanic basaltic glasses bearing on this issue. I use these and other published data to develop a comprehensive model for the volatile element, trace element and isotopic compositions of most basaltic melts that resolves the dehydration paradox. This model also accounts for the thermal parameters of slabs in controlling compositions of subduction-derived components in mantle reservoirs.
Coffee, tea, and a continental breakfast will be served before the lecture at 10:30 a.m.