Work History

First noted by the GSC in 1971 and later studied extensively by mineralogists and gem collectors.

This occurrence lies within a large area withdrawn from staking in July, 1978 pending creation of a National Wilderness Park, settlement of native land claims, and development of a management plan for the Porcupine Caribou Herd.

Capsule Geology

Thick deposits of siderite and phosphatic ironstone occur in shale within the Rapid Creek Formation, part of a flyschoid clastic wedge of Early Cretaceous age. The sequence consists of three units of cyclically interbedded siderite, mudstone and shale separated by two grey montmorillonite shale units.

A spectacular suite of approximately thirty unusual phosphate minerals, including ten new species, are present as epigenetic fracture fillings (veins) and lesser concentrations in vugs, bedding plane partings and fillings in fault breccia. Calcium-rich phosphate minerals occur in phosphatic mudstone, barium-rich minerals in conglomeratic slump deposits, sodium-rich minerals with phosphatic sandstone and iron-magnesium rich minerals with sideritic sandstone. Phosphate mineralization at this location is largely confined to recrystallized spherulitic replacements of ammonites and pelecypods and oblate concretionary phosphate nodules. The main minerals are pyrite, wolfeite, satterlyite, maricite, vivianite-baricite and varulite.