9406109 Furman This is part of long-term research program that integrates field, geochronologic, geochemical, isotopic, petrographic and experimental data on young lavas to determine the dynamics of continental rift volcanism. The Rungwe volcanic province in Tanzania was selected for detailed study because samples for m this area will contribute to understanding both large-scale geodynamic problems and regional tectonic questions. A fundamental objective is to investigate the geochemical consequences of mixing between asthenospheric and lithospheric source melts. A second objective is to document temporal variations in lava geochemistry at individual volcanic centers. All samples analyzed in this study are currently in hand; only fresh samples of young lavas will be used. High quality petrographic, mineralogic and geochemical (including incompatible trace and rare earth element) data will be interpreted in conjunction with available isotopic (Sr, Nd, Pb, O, He) data on the same samples. The investigation at Rungwe will enable both local and regional syntheses of data on the dynamics of asthenosphere-lithosphere interaction in the genesis of continental rift volcanism.
