Crustal recycling

[2] The ultimate fate of crustal material is key to understanding geochemical cycling, as well as persistent heterogeneities in the mantle, upwelling and myriad effects on magma composition, melting, plate tectonics, mantle dynamics and heat flow.

The current understanding of the structure of the deep Earth is informed mostly by inference from direct and indirect measurements of mantle properties using seismology, petrology, isotope geochemistry and seismic tomography techniques.

[11] The shape of the subduction zone was also key in whether the geometry of the slab could overcome the phase transition boundary.

Additional work completed by Spasojevic et al.[15] showed that local minima in the geoid could be accounted for by the processes that occur in and around slab graveyards, as indicated in their models.

It can then be compared to known crustal and mantle isotopic compositions, as well as that of chondrites, which are understood to represent original material from the formation of the Solar System in a largely unaltered state.

[19][20] The work done on carbonatites by Walter et al.[18] and others[4] further develops the magmas at depth as being derived from dewatering slab material.