CSM Rock Collection

Gabbro

Gabbro is the plutonic equivalent of basalt. The group is here taken to include norite (orthopyroxene-bearing gabbro) and other products of differentiation from basaltic magma. Basalt and gabbro are the dominant products of magmatism at tectonic spreading zones and form most of the oceanic floor. They are additionally found in continental rift zones and areas affected by mantle hot spots.