The Ranch limestone occurrence is located on an east-facing slope, west of Steele Creek and south-southwest of the south end of Bonanza Lake.

The area is underlain by basaltic volcanic rocks of the Upper Triassic Karmutsen Formation (Vancouver Group), which are overlayed by limestone, marble and calcareous sedimentary rocks of the Upper Triassic Quatsino Formation (Vancouver Group) and limestone, slate, siltstone and argillite of the Middle to Upper Triassic Parson Bay Formation (Bonanza Group), respectively. To the west the sedimentary and volcanic units have been intruded by granodioritic rocks of the Upper Jurassic Nimpkish Batholith, which is a part of the Jurassic Island Plutonic Suite.

Locally, bands of white crystalline (Quatsino) limestone up to 1000 metres in length and varying from 0 to 250 metres in width are exposed. Near the contacts with intrusive rocks the limestone has been recrystallized and bleached into white calcite marble. Minor zones of skarn are also reported along the intrusive contacts.

Work History

In 1992 and 1994, Industrial Filler Ltd. completed a program of geological mapping on the area as the Ranch property. In 1998, Omya Inc. collected eight samples (R-98-1 through -8) of limestone from the occurrence area yielding from 93.41 to 98.93 per cent calcium carbonate, 0.44 to 5.95 per cent magnesium carbonate and 0.06 to 0.21 ferric oxide (Assessment Report 25903).