Abstract:

The lherzolites have been commonly regarded as mantle residues after low degrees of partial melting. However, melt
refertilization, which refers to transform the refractory harzburgites to fertile lherzolites through adding asthenosphere-derived
basaltic melts, provides a new explanation for the fertile lherzolites. Besides the enrichment in major elements, this process also transforms the enriched characteristics in trace elements and Sr-Nd isotopes of the harzburgites to the depleted characteristics of lherzolites. It is still highly debated as to whether melt refertilization can change the Os isotopic compositions of mantle peridotites, which depend on the ratios of the refertilizing melts, the sulfur saturation of the melt, and the time of refertilization, etc. The melt/rock ratios in the sub-continental lithospheric mantle are commonly low. Therefore, effects of melt refertilization on the Os isotopic compositions of the peridotites are probably limited. In addition to chemical compositions, addition of refertilizing melts changes the physical properties. Melt refertilization would destabilize the lithospheric mantle through increasing the permeability and decreasing the viscosity. Although it can change the chemical-physical properties of the lithospheric mantle, it is unclear whether the melt refertilization process is responsible for lithospheric thinning and craton destruction.

Key words: Melt refertilization, Subcontinental lithospheric mantle (SCLM), Sr-Nd-Os isotope