Melt production, redistribution and accumulation in mid-crustal source rocks, with implications for crustal-scale melt transfer
Johann FA Diener, Richard W White, Timothy JM Hudson
Lithos | ELSEVIER | Published : 2014
Ascent of granitic melt initiates under suprasolidus conditions in the mid- to lower crust before continuing through subsolidus rocks to higher crustal levels. Whereas migration of melt in suprasolidus rocks can occur in pervasive net-like structures and involve relatively small melt volumes, ascent through the subsolidus crust requires more focused, dyke-like structures and larger volumes to prevent freezing. Migmatites in the Aus granulite terrain, southern Namibia, preserve evidence that large-scale melt redistribution and accumulation occurred in the near-source region under suprasolidus conditions. Melt that was mainly produced in metapelitic rocks utilised pervasive small-scale leucoso..View full abstract
This work is based upon research supported by the National Research Foundation (South Africa) and Bundesministerium fur Bildung und Forschung (Germany) through a Germany-South Africa cooperative research grant. We thank Koos and Anna Bosman for access to their land and their hospitality during field work. Roberto Weinberg and an anonymous reviewer are thanked for comments that helped to clarify the manuscript.