The Mandy Glacier showing area is underlain by Middle Jurassic mafic and intermediate rocks of the Salmon River formation, Hazelton Group (Assessment Report 30131). Quartz with magnetite, pyrrhotite and chalcopyrite is reported to occur (Geology Map - Newmont Exploration). The host rock was not specified.
See Cumberland (104B 011) for details of the Corey property which encompasses this showing.