Volcanic forces are either intrusive or extrusive
forces. Intrusive forces are found within the
lithosphere and produce such features as
batholiths, dykes, and sills. The deep-seated, major
intrusions – batholiths and stocks – result from
plutonic processes, while the minor, nearersurface
intrusions such as dykes and sills, which
occur as independent bodies or as offshoots from
plutonic intrusions, result from hypabyssal
processes. Extrusive forces occur at the very top
of the lithosphere and lead to exhalations,
eruptions, and explosions of materials through
volcanic vents, all of which are the result of
volcanic processes.