Location:

St Peter Port gabbro

he St Peter Port gabbro is a small layered intrusion of hornblende gabbro and bojite (calcium plagioclase - hornblende rock). Very locally, small magnetite and sulphide-rich segregations occur within it.

Major Minerals:

Magnetite, ilmenite, pyrite

Minor Minerals:

Pyrrhotite, chalcopyrite, haematite, TiO₂, minerals

Trace Minerals:

Include sphalerite-secondary limonite, native copper

Textures:

Magnetite contains oxidation-exsolution lamellae of ilmenite and round chalcopyrite inclusions. Pyrrhotite has altered to pyrite, marcasite and secondary magnetite intergrowths. Secondary magnetite has oxidized to haematite (martitization)