Ultramafic Hornfelses in Central Iran Ophiolites

There are leucocratic gabbro intrusions in serpentinized mantle peridotites of Central Iran ophiolites (Jandaq, Anarak, Naein and Ashin-Zavar). In contacts of gabbro intrusions and serpentinized mantle peridotites, ultramafic hornfelses are formed by contact metamorphism. These ultramafic hornfelses are different with host mantle peridotite in petrography, texture and mineral chemistry. Two-pyroxene thermometry of hornfelses and intact mantle peridotites that are far from contact metamorphism, present 987 and 1200°C, respectively. To occuring the reaction between the gabbro intrusions and mantle peridotites, the host rock should be serpentinized previously.