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. 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. Though all the volcanic rocks in the study area indicate subduction-related magmatism (eg 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 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