Mantle heterogeneities produced by open-system melting and melt/rock reactions in Patagonian extra-Andean backarc mantle (Paso de Indios, Argentina)

Mantle flow, melting, and dehydration of the Iceland mantle plume

Recent studies have shown that the extraction of water from the mantle due to partial melting beneath mid-ocean ridges may increase the viscosity of the residuum by 2–3 orders of magnitude. We examine this rheological effect on mantle flow and melting of a ridge-centered mantle plume using three-dimensional numerical models. Results indicate that the viscosity increase associated with dehydrati...

Shear - Velocity Heterogeneities in the Upper Mantle

Long-period surface waves are used to map lateral heterogeneities of velocity and anisotropy in the upper mantle. The dispersion curves are expanded in spherical harmonics up to degree 6 and inverted to find the depth structure. The data are corrected for the effect of surface layers and both Love and Rayleigh waves are used. Shear wave velocity and shear polarization anisotropy can be resolved...

Isentropic Melting Processes in the Mantle

Batch melting of ascending mantle can be approximated as an isentropic process, since on the time scale of melting heat flow into or out of source regions will typically be negligible and the process is slow enough to be close to reversible. Similarly, fractional fusion can be idealized as a series of incremental isentropic melting steps, although the entropy of the residue decreases in each st...

Initiation of the Andean orogeny by lower mantle subduction

Melting in the Deep Lunar Mantle

Introduction: Whereas previous experimental studies [1,2,3] and interpretation of Apollo seismic experiments [4,5] are permissive for garnet in the deep lunar mantle, interpretations of Lu-Hf isotopic systematics [6] and trace element data [7] seem to require garnet in the source of selected mare basalts. Understanding the mineralogy of the deep lunar mantle is critical to our further interpret...