Sr-Nd Isotopic mapping and HFS element ratios of volcanic rocks from the Northern Fossa Magna - Two mantle sources beneath the Fossa Magna region -

Abstract

Neogene to Quaternary volcanic rocks distributed in the Fossa Magna region. They show geochemical and isotopic lateral variations suggesting deferent component of mantle sources. The low Nd isotopic group is distributed in marginal part of the Fossa Magna, while the high Nd isotopic group central part. The former group is lower in Zr/Nb and Hf/Nb ratios than the latter, which indicates E-MORB-like and MORB-like source. The volcanic rocks of high Nd isotopic group would be derived from the MORB like source which upwelled asthenospheric material were erupted.