The Caribou Fraction showing is located on the shore of Alice Arm of Observatory Inlet, 600 metres southwest of Alice Arm.

The area is underlain by Middle to Upper Jurassic Hazelton Group sediments. The sediments dip moderately to steeply southwest and northeast as a result of being deformed into closely spaced northwest-trending folds.

The showing consists of a quartz vein, up to 0.30 metre wide, which dips 60 degrees southeast and is hosted in argillite. It appears barren of mineralization, however, it has been reported to contain very small shoots of silver ore (Geological Survey of Canada Memoir 175, page 57).

In 1916, the Caribou Fraction group of three claims were owned by G.R. Naden et al. A 21-metre tunnel runs 320 degrees azimuth from near the water on a quartz vein dipping 60 degrees to the southeast. Farther south, 453 kilograms of high-grade ore was mined from a stringer near the water; production statistics not available.

In 2017 an airborne magnetometer survey and geological interpretation were completed for Granby Gold Ltd. on their Tidewater property, north of Alice Arm. The Caribou Fraction area showed a low magnetic response (Assessment Report 36830).