Petrogenesis of Volcanic Rocks in the Khabr‐Marvast Tectonized Ophiolite: Evidence for Subduction Processes in the South‐Western Margin of Central Iranian Microcontinent

Abstract

Abstract:The Late Cretaceous Khabr–Marvast tectonized ophiolite is located in the middle part of the Nain–Baft ophiolite belt, at the south‐western edge of the central Iranian microcontinent. Although all the volcanic rocks in the study area indicate subduction‐related magmatism (e.g. high LILE (large ion lithophile elements) / HFSE (high field strenght elements) ratios and negative anomalies in Nb and Ta), geological and geochemical data clearly distinguish two distinct groups of volcanic rocks in the tectonized association: (1) group 1 is comprised of hyaloclastic breccias, basaltic pillow lavas, and andesite sheet flows. These rocks represent the Nain–Baft oceanic crust; and (2) group 2 is alkaline lavas from the top section of the ophiolite suite. These lavas show shoshonite affinity, but do not support the propensity of ophiolite.