Middle Jurassic subduction-related ophiolite fragment in Triassic accretionary complex (Mamu Dagi ophiolite, Northern Turkey)

摘要

The Mamu Dagi ophiolite, ca. 13 km long and 5 km across (Tokat, Sakarya Zone), consists of peridotites, pyroxenites, gabbros, and basalts, which are crosscut by dolerite dykes. These rocks show variable degrees of serpentinization and alteration. Gabbroic rocks consisting of plagioclase + clinopyroxene +/- orthopyroxene +/- olivine +/- amphibole +/- sphene +/- opaque minerals have commonly the ophitic and the cumulate textures. Similar mineral paragenesis is observed in the basalts and the dolerites, which are commonly characterized by the sub-ophitic and the microlitic porphyric textures.