Identifying the origins of the gold first recovered between 1860 and 1863 from areas around Barkerville is necessary to help modern mineral explorers locate new gold deposits. The majority of the gold panned from rivers and streams around BC in the last 150 years has come from orogenic gold deposits, a style of gold mineralization that forms during the collision or subduction of tectonic plates. The structure of the deformed rocks in the ‘eastern Cordilleran gold belt’ is complicated and the grade of the gold is inconsistent. Updated studies were needed to unravel the age of gold mineralization and its relationships to host rocks and their structures, such that the location of potential new deposits can be predicted.
The project was designed to:
- Map and determine the age of gold-related features at Cariboo, Cassiar, and Sheep Creek study areas
- Determine the structural relationship of BC’s ‘eastern Cordilleran gold belt’ to the larger-scale Cordilleran deformation
- Outline a set of exploration considerations to help predict the location of new deposits
- Stimulate on-the-ground exploration activities that could lead to new mineral discoveries.
Earth science information generated in the eastern Cordilleran gold belt project is contributing to mineral exploration activity and investment at the historic gold mining camps around BC, including the Cariboo, Cassiar, and Sheep Creek gold districts. Modern mineral explorers are working to expand the historic gold deposits panned and mined in these areas over 150 years ago. It is thought to be orogenic gold, formed by collision between the North American and Pacific Plates. By mapping rock units and structures at local scales and determining when gold was introduced, earth scientists have generated information to help companies and individual explorers decide where to stake claims and focus their mineral exploration activities. By identifying mineral opportunities, this project provides First Nations, regional districts, governments, communities and the mineral exploration sector with a better understanding of resources in the area leading to more informed land-use and resource management decisions.
Orogenic gold deposits in BC tend to occur in two main tectonic belts; the Bralorne-Pioneer mining camp and the ‘eastern Cordilleran gold belt’, which includes the Cariboo Gold district, Sheep Creek gold camp, and the Cassiar gold district.
- The Cariboo gold district in east-central B.C. is famous for its more than 150-year history of gold discovery and production. Several million ounces of alluvial and lode gold have been mined from the surrounding region, with the majority of gold production came from the Wells-Barkerville camp.
- The Cassiar gold district is located in the Cassiar Mountains of north-central BC, near the settlement of Jade City and a few kilometres southeast of the former asbestos-mining town of Cassiar. The district has produced over 100,000 ounces of alluvial gold in over 140 years of placer gold mining, and at least 350,000 ounces from bedrock sources that have been exploited sporadically since the 1930s.
- The Sheep Creek gold camp is 12 km southeast of the town of Salmo in the Kootenay region of southern BC. The camp is part of the broader Salmo mining district, in which mineral occurrences represent a variety of commodities, deposit styles, and mineralization ages.
How was the data collected?
At field sites across each of the Cariboo, Cassiar, and Sheep Creek study areas, researchers collected information about rock types, structures, veins, and their relationship to gold. They recorded structural data, waypoints, oriented photographs, and field notes on tablets. This digital structural data was compared routinely with analogue compass measurements to ensure accuracy. Two methods were used in the laboratory to help determine the ages of rock and mineral samples collected in the field. At the University of Manitoba 40Ar/39Ar analyses were carried out. U-Pb geochronology was performed at The University of British Columbia.
What was found?
The project identified several features in the rocks that will help guide explorers toward mineralization, particularly predicable geometries of veins that could point toward areas of potential high mineralization. Also, they identified several rock units that are potentially more likely to contain gold mineralization.