serpentinite:
Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth’s mantle. The mineral alteration is particularly important at the sea floor at tectonic plate boundaries. [Wikipedia]
Noticed in “Life could exist up to 10 kilometres beneath the sea floor,” Chelsea Whyte, NewScientist (15 April 2017):
The heat and stress causes some of the material on the subducting plate to become a buoyant mineral called serpentinite that rises and erupts out of mud volcanoes.
Examining the serpentinite in their samples, the team found chemicals usually produced by life, including amino acids and hydrocarbons.
