ABSTRACT
Unusual platinum-group mineral (PGM) assemblages from two distinct chromitites from the Kraubath massif, Austria, have been investigated. Chromitite type 1 is massive podiform, occurs as schlieren. Chromite is characterised by a Cr# [100*(Cr/(Cr+Al)] of 81-86. Chondrite-normalised platinum-group element (PGE) pattern is negatively sloped, similar to ophiolitic chromitite from the mantle section. 21 different PGM forming single grains as well as complex polyphase assemblages are dominated by laurite. The chromitite type 2 occurs as a layer at a stratigraphically higher level than chromitite type 1. Chromite has Cr# between 73 and 77. The chromitite type 2 displays a positively sloped PGE pattern with 15 different noble metal minerals identified. Sperrylite is most abundant. Phenomena such as stratiform appearance, positively sloped PGE pattern, dominance of Pd-Pt-rich minerals, and relatively low-temperature PGM assemblages, indicate that chromitite type 2 was formed above the mantle section, most likely within the transition zone of the ophiolite.
