The proposed study involves the compilation of compositional data from the main oceanic spreading ridges and statistical evaluation of their local and regional variation patterns. Appropriate averaging and data filtering, using carefully selected and justified criteria, with the purpose of extracting the maximum amount of information on mantle source characteristics and melting processes, will be followed by an analysis of multicomponent source mixing. The complex interplay between time-integrated source depletion of the asthenosphere and its re-fertilization by incorporation of various types of detached sub-continental lithosphere and plume-supplied recycled oceanic crust and pelagic sediments will be evaluated in light of the evolution of the individual ridges and ocean basins.
Trønnes: A global compilation and synthesis of the isotopic and elemental compositions of mid-ocean ridge basalts (MORB) and abyssal peridotites
The asthenosphere beneath the global network of spreading ridges is continuously sampled by partial melting, generating MORB. In addition, the residual peridotites from the upper asthenosphere and lithosphere are locally exposed on the ocean floor by rifting-related and fracture zone fault tectonics. Sampling of unaltered zero-age basalts and associated abyssal peridotites along the spreading axes by dredging and drilling is facilitated by shallow bathymetry and sparse sediment cover. The participants on numerous oceanographic expeditions have provided a wealth of systematic along-along axis data sets of major and trace element abundances and isotope compositions. Although many studies have compiled and used such data to investigate aspects of mantle source heterogeneity and origin, as well as melting processes, new and innovative approaches by different individuals may provide additional insights