Serpentinization of peridotites in Logatchev Massif, 14.75°N Mid- Atlantic Ridge

1568-1578Ultramafic and gabbroic rocks sampled from the Mid-Atlantic Ridge exposed on a detachment fault at the Logatchev Massif south of the Fifty-Twenty Fracture Zone (15°20’NFZ) are serpentinized peridotites, soapstone and altered gabbros. Based on the detail petrological and mineralogical studies of serpentinized peridotite and gabbro samples, in conjunction with already existing mineralogical and isotopic data, we proposed a model of serpentinization at different depths beneath the 15°20’NFZ and to provide a framework for the serpentinization of many abyssal peridotites in slow-spreading environments. At the main stage of serpentinization model, there is possibly a transition zone of serpentine formation from antigorite to lizardite and chrysotile, leading lizardite to be dominant in serpentinized abyssal peridotites. Present model, also propose that the initial depth of serpentinization should be much deeper than Moho