Compaction-driven melt segregation in migmatites

TitleCompaction-driven melt segregation in migmatites
Publication TypeJournal Article
Year of Publication2015
AuthorsRF Weinberg, E Veveakis, and K Regenauer-Lieb
Start Page471
Pagination471 - 474
Date Published04/2015

A common and puzzling feature of migmatite terranes is the presence of synkinematic leucosomes oriented perpendicular to the maximum principal compressive stress axis, σ , particularly leucosomes oriented parallel to the axial plane of folds. These are parallel to planes of compaction, but experiments predict that leucosomes should form in dilational bands oriented instead at small angles to σ . This discrepancy suggests that our understanding of melt extraction is incomplete. We propose that leucosomes at high angles to σ are results of ductile compaction instabilities that arise in compressive environments as a result of compaction of porous media with nonlinear rheology and interstitial fluids. These instabilities form at high angles to σ and their spacing can be regular, controlled by the compaction length. 1 1 1 1

Short TitleGeology