Sedex Deposits
Open File 2000-22: Sedimentary Hosted Exhalative Deposits of British Columbia.
* Sedimentary Hosted Exhalative Deposits of British Columbia - 2.6MB in PDF format
Compiled by Nick Massey
Sedimentary hosted exhalative deposits are an important resource in British Columbia primarily for lead, zinc and silver. A hundred years of exploitation from 22 mines has produced over 166,000,000 t of ore (to 1998). This has resulted in the production of over 9,379,000 kg Ag, 1,326 kg Au, 8,557,000 t Pb, 8,478,000 t Zn, 5,150 t Cu and 8,840 t Cd. The bulk of this production has come from one mine, the Sullivan Mine, which accounts for 87% of ore produced. Current exploration interest is focused on finding a replacement for this world class deposit which is due to close in the next few years.
Open File 2000-02 documents 239 sedimentary hosted exhalite occurrences recorded in MINFILE. These include examples from four major deposit model types - clastic sediment-hosted exhalative Zn-Pb-Ag, sedimentary-hosted stratiform barite, carbonate-hosted exhalative Zn-Pb and metasedimentary-hosted Pb-Zn-Ag. They occur in cratonic or pericratonic terranes of the Omenica or Cratonal North American belts.
The 65 occurrences of the clastic sedimentary-hosted deposit type form two main clumps located in southeastern B.C., including the world class Sullivan Mine, and northeastern B.C. The southern group of occurrences are found in rocks of the Middle Proterozoic Purcell Supergroup, while the northern group are hosted in the Devono-Mississippian Earn Group. The latter is also the host to most of the 47occurrences of sedimentary hosted stratiform barite deposit type. Carbonate-hosted (Irish-type) deposits (62 occurrences) are concentrated mostly in Cambrian aged limestones of the Kootenay terrane.
The metasedimentary-hosted deposits (65 occurrences) include Broken Hill or Shushwap type deposits as well as possible metamorphic equivalents of the clastic and carbonate hosted types. They are hosted in Upper Proterozoic to Cambrian aged rocks of the Eagle Bay Assemblage and Monashee Complex.
Copies of Open File 2000-22 can be purchased for $20.00 from
Crown Publications Inc.
New Mineral Deposit Models for the Cordillera
