LDEO Earth Science Colloquium presents:
Volcanism at Convergent Margins: Sources, Volumes, Diapirs?
with Dr. Charles Langmuir, Principal Investigator, Higgins Professor of Geochemistry, Director of Mineralogical and Geological Museum at Harvard University
The geochemistry of convergent margin stratovolcanoes is extremely diverse. A single model, SWHETS (Slab melts, Wedge HEterogeneity, and Thermal Structure), which builds upon much previous work that was not previously integrated, quantitatively accounts for the average compositions of global arcs. Model outcomes include the sediment contribution to the source increasing with subducting sediment thickness, and the ocean crust melt contribution increasing with the slab thermal parameter. The results require melting of the uppermost ~2 km of the slab, a constraint on thermal models of subduction zones. The model also yields crustal production rates of ~47 km³/km/Ma, in agreement with earlier seismic estimates. Remarkably, the source region is ~ 5 km thick, providing strict limitations on porous flow through the wedge.
Host: Dr. Terry Plank, Arthur D. Storke Memorial Professor, Geochemistry, LDEO
The Earth Science Colloquium Series, sponsored by Lamont-Doherty Earth Observatory and Columbia University Department of Earth and Environmental Sciences (DEES), provides a lively forum for discussing a wide variety of topics within the Earth sciences and related fields. Colloquia are attended by the full range of scientific and technical staff at LDEO. Colloquium attendance is required of all pre-orals DEES graduate students.
