Mineralogy of Marbles produced by metamorphism of Listvenites of Upper Proterozoic Anarak Ophiolite

In the upper Proterozoic Anarak ophiolite, the marbles are present and havr excellent exposures in different areas. Their best exposure is in southern slope of Chah-Gorbeh mountain (Chah-Mahdi valley). In the field, marbles have massive and dike like exposures. Petrographic studies and geochemistry of minerals show that marbles consist of carbonate (calcite), garnet (andradite), clinopyroxene (diopside and magnesian-augite), amphibole (tremolite), serpentine, chlorite, epidote, chromian spinel, magnetite and chromian-magnetite, that are alteration products of chromian spinel. Field and microscopic studies show that the marbles have been produced by regional metamorphism of old listvenites at different phases of metamorphism. The protoliths of these metamorphosed listvenites were ultrabasic dikes and intrusions, and mantle peridotites. Presence of serpentine, relic chromian spinel, magnetite and chromian magnetite that have changed to garnet, supports this interpretation. Therefore, the marbles of Anarak ophiolite, are productions of regional metamorphism of old listvenites.