MORB-type vs. BARB-type ophiolites of the Dinarides: geologic and geochemical data

The Dinaridic Alpine ophiolites can be divided into two groups: 1) those of the Jurassic Dinaride Ophiolite Zone (DOZ) and 2) those of the Cretaceous-Early Paleogene (?) Sava-Vardar Zone (SVZ). However, geologically and petrologically they have so far been treated as a whole, and their geotectonic setting has not been reliably established. We have investigated ophiolite terranes from both regions in order to determine their tectonic setting. Our comparison is based on trace element data and characteristic elemental ratios correlated with ophiolite settings in recent oceans. We show that the DOZ tectonite peridotites are enriched in LREE and have high Ti/V ratios (up to 23), whereas the SVZ mantle rocks are LREE-depleted and have low Ti/V ratios (1-4). The DOZ cumulate gabbros and peridotites are characterized by increased Ni content and high Ba/Sr ratio, positive Eu anomalies and lower Cr# of spinels, comparable with MORB cumulates. The SVZ cumulates do not show a positive Eu anomaly and are characterized...