Experimental constraints on the formation of pegmatite-forming melts by anatexis of amphibolite: A case study from Evje-Iveland, Norway

The Evje-Iveland pegmatite field in Norway contains pegmatites that are known for their rare scandium mineralization. petrogenesis of these has been debated the literature nearly a century. Hypotheses origin pegmatite-forming melt have included either anatexis host amphibolite vapor-absent conditions, wherein is scavenged from amphibolite; or magmatic differentiation, concentrated through processes. In order to test hypothesis was sourced amphibolite, partial melting experiments on performed. These were performed at temperatures ranging 700 1064 °C and pressures between 400 550 MPa piston-cylinder apparatus. solidus determined be approximately 900 500 significantly higher than temperature formation. Partial <40% can produce glasses broadly granitic composition aluminum- sodium-rich; however, they less siliceous pegmatites. also scandium- REE-poor, REE patterns similar leucosomes vein-type migmatites, produced low pressures, but dissimilar results thus inconsistent with or, by extension, other rare-element pegmatites, result direct alone common metamorphic rock such as amphibolites. It proposed formation scandium-rich ultramafic mafic complex, differentiation melt, emplacement into amphibolite. Thus, may represent final stages which preferred model