Diastrophic processes
Traditionally, tectonic (or geotectonic) forces
divide into two groups: (1) diastrophic forces and
(2) volcanic and plutonic forces. Diastrophic
forces lead to the folding, faulting, uplift, and
subsidence of the lithosphere. Volcanic forces
lead to the extrusion of magma on to the
Earth’s surface as lava and to minor intrusions
(e.g. dykes and sills) into other rocks. Plutonic
forces, which originate deep in the Earth,
produce major intrusions (plutons) and associated
veins