Corundum-bearing amphibolites from the metamorphic basement of the Krivaja-Konjuh ultramafic massif (Dinaride Ophiolite Zone, Bosnia)

Corundum-bearing amphibolites are part of the metamorphic basement of the Krivaja-Konjuh ultramafic massif in the Dinaride Ophiolite Zone in Bosnia. Pinkish corundum occurs as porphyroblasts and together with edenitic-pargasitic hornblende and anorthite within the amphibolites. Based on major and trace element contents, the protoliths of the corundum-bearing amphibolites were tholeiitic gabbro cumulates. Geothermobarometric estimations on the corundum-bearing amphibolites yielded preliminary P-T conditions of 620-830degreesC and 6-10 kbar for amphibole and plagioclase inclusions inside corundum and 4.5-8 kbar for the main metamorphic assemblage. These estimates are thought to reflect the metamorphic conditions achieved during the Late Jurassic obduction of the Krivaja-Konjuh ultramafic massif onto ophiolite melange. This study documents the mineralogy, petrology and geochemistry of these unusual corundum-bearing ophiolite-related edenite-pargasitic amphibolites.