Geology of the Barkerville Deposit
Terry Harbort, Chief Geoscientist, Barkerville Gold Mines
Since 1858, the Cariboo Gold Belt of south-central British Columbia has produced approximately 3.2 million ounces of gold from alluvial production and 1.3 million ounces from lode gold mines and remains today, one of Canada’s last great underexplored gold districts. Barkerville Gold Mines’ properties encompass 182,222 hectares of mineral rights in the Cariboo Gold Belt across an area that is 67 kilometres long and 25 kilometres wide.
New mapping of the Cariboo Gold Belt conducted by BGM has defined a systematic marine transgressive sequence from fine carbonaceous mudstones --> sandstone --> calcareous sandstone --> calcareous siltstone --> limestone separated by clear transition zones. Identification of these facies is key to understanding the mineralization on a local and district scale and unravel the complex folding and faulting history. Detailed structural mapping on surface, underground and utilizing systematically oriented core has helped BGM to identify evidence a previously unrecognized late deformation and clearly define kinematic controls on vein mineralization.
Mineralization is exhibited in numerous styles:
1. Fault brecciated lensoidal veins sub-parallel to lithology hosted in meta-carbonaceous mudstone
2. Vertical NE trending extensional veins dominantly hosted by meta-sandstone units
3. A conjugate set of moderately dipping ENE trending shear veins hosted in meta-sandstone units
4. Gold bearing sulphide replacement mineralization hosted in fold hinges of meta-calcareous sandstone units
5. Gold bearing sulphide replacement mineralization hosted in calcareous siltstone units bounded by fault structures
Mineralization in the replacement styles consists of dominantly pyrite with lesser arsenopyrite. Vein mineralization is dominantly quartz hosted with pyrite and minor to trace galena, sphalerite, chalcopyrite, sheelite, argentite and cosalite. Cosalite appears to have an association with the occurrence of visible gold. Alteration varies from intense silica with pyrite to silica-sericite and then distal sericite-Fe carbonate. BGM interprets a unified metallogenic model for all styles of mineralization supporting a late orogenic collapse model for gold deposition.
Speaker: Terry Harbort
Dr. Harbort is a professional economic geologist with 24 years of multi-continent experience in mineral exploration. His extensive post-graduate experience focusing on applied structural geology of ore deposits makes Mr. Harbort a specialist in mapping and interpretation of ore geometries and ore controls covering various types of geological environments with direct applications to mineral economics from target generation, target definition and evaluation, and project management. Terry is a recognized senior member of the discovery team of the La Colosa and Gramalote deposits for AngloGold Ashanti Ltd. where over a 9 year period he held positions of Senior Geologist and Chief Structural Geologist for the Americas. In 2010, Terry was a founder and is Vice President -Exploration of Talisker Exploration Services Inc. an exploration management company providing international exploration consulting in M & A and exploration strategy, project evaluation, target generation and exploration program design and implementation for Osisko Gold Royalties and related companies.