Rare Element Resources
Bear Lodge Project
Canadian NI 43-101 Technical Report
October 9
th
, 2014
10135-200-46 - Rev. 0
7-2
Figure 7.1 - Geologic Setting and General Geology of Bear Lodge Mountains
(Modified from Karner, 1981)
7.3 District Geology
Surface rock exposures are limited, so considerable information was gleaned from
float samples and trenches. Bedrock outcrop exposure is less than 5%, and extensive
soil cover obscures details of the underlying rocks, structures, and alteration patterns.
The Bear Lodge mining district is located in the Bear Lodge Mountains, near the
western end of the northern Black Hills intrusive belt (Figure 7.1). The Tertiary
alkaline intrusive belt consists of a series of intrusive centers that trends about N75°W
and extends from Bear Butte in South Dakota, through the Bear Lodge Mountains, to
Devil’s Tower and the Missouri Buttes in northeastern Wyoming. There is a tendency
for the alkaline igneous rocks to be silica
‐
saturated in the eastern part of the belt and
silica
‐
undersaturated in the western part of the belt. The Bear Lodge alkaline
‐
igneous
complex consists of a central elongated core overlain by older Paleozoic and
Mesozoic sediments in the southern half of the range, and by post- intrusion Tertiary
