Gabbro

© Craven & Pendle Geological Society

Carrock Fell Gabbro
Gabbro : Carrock Fell, Lake District

Summary :
This is a dark, medium to coarse-grained intrusive rock.  The dark minerals are mainly pyroxene (over 50%) with minor amounts of hornblende or biotite.  The light minerals are usually light grey plagioclase feldspars.  If there are no light crystals at all, the rock is ultramafic.

Some gabbros in the Carrock Fell Complex contain the mineral ilmenite which is a black or dark brown rhombohedral mineral (FeTiO3) and major ore of titanium (although only an accessory in the gabbros case).  The ilmenite is indicative of high temperature segregation.

Recommended site :
Carrock Fell, Lake District