Instead , a zone of breccia or cataclasite is formed , with the rock milled and broken into random fragments .
Within depths less than 5 km , dynamic metamorphism is not often produced because the confining pressure is too low to produce frictional heat .
A zone of breccia or cataclasite is formed , with the rock milled and broken into random fragments .
Within depths less than 5 km , dynamic metamorphism is not often produced because the confining pressure is too low to produce frictional heat .