 Much of the record of this deformation has been overridden by Tertiary age structures and the zone of Cretaceous dextral thrust faulting appears to have been widespread.It was also during this period when massive amounts of molten granite intruded highly deformed ocean rocks and assorted fragments from pre-existing island arcs, largely remnants of the Bridge River Ocean.This molten granite burned the old oceanic sediments into a glittering medium-grade metamorphic rock called schist.