Geology of the Chilanko Forks and Southern Clusko River Map Areas (NTS 093C/01 & 09 south)
BCMEMPR Open File 2009-6
By M. Mihalynuk, E.A Orovan, J.P. Larocque, T. Bachiu and J. Wardle
View Open File 2009-6 Map (PDF, 20.9 MB)
In an area extending from Kamloops northward to Smithers, and from the Coast Mountains eastward to the Rocky Mountain Trench, infestation by Mountain Pine Beetle was essentially continuous in 2004. We refer to this area as the Beetle Impacted Zone (BIZ). It is predicted that only ~10% of the already diminished 2006 volume of pine will be left standing by 2016 (Eng et al., 2006). Anticipating an economic downturn in the forestry sector within the BIZ by 2015, the Provincial Government is supporting economic diversification throughout the region. Geological mapping and related studies in the Chilanko Forks area are part of that provincial effort.
Accelerated timber harvest and overburden disturbance, needle loss, and forest fires, create unprecedented opportunities to find never-before-seen outcrops of prospective rocks within the BIZ.
The Clusko - Chezacut - Chilanko Forks areas were targeted for revision mapping because of relatively good logging road access and a historical lack of mineral exploration that we believed to be unwarranted. This viewpoint was validated with 2007 mapping in the Chezacut area, and supported by results from 2008 mapping in the Clusko River - Chilanko Forks area. Geological mapping demonstrated that rock exposures are more extensive than previously recognized, and that the economically uninteresting Chilcotin basalt cover is less extensive. Both observations provide incentive for future mineral exploration in the area.
Open File 2009-6 presents geological data collected in 2008, plus an interpretation of the geology that is expected beneath areas of thick glacial and alluvial cover. It provides a 1:50 000 scale geological map context for new mineral occurrences that were encountered during the course of mapping the area, and which were reported in Mihalynuk et al. (2009)1 with geochemical analyses available from Larocque and Mihalynuk (2009)2.
Eng, M., Fall, A., Hughes, J., Shore, T.L., Riel, B., Walton, A. and Hall, P. (2006): Provincial-level projection of the current mountain pine beetle out break: Up date of the projection of non-recovered losses for the reference management scenario based on the 2005 Provincial Aerial Overview of Forest Health and revisions to “the model” (BCMPB.v3); B.C. Ministry of Forests, <www.for.gov.bc.ca/hre/bcmpb/BCMPB.v3.BeetleProjection.Update.pdf>, 7 pages, [October 15, 2006]
1 Mihalynuk, M.G., Orovan, E.A., Friedman, R.M., Larocque, J. and Bachiu, T. (2009): Geology, Geochronology and Mineralization of the Chilanko Forks to Southern Clusko River Area, West-Central British Columbia (NTS 093C/01, 08, 09S); in Geological Fieldwork 2008, B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 2009-1
2Larocque, J.P. and Mihalynuk, M.G. (2009): Analytical Results from Investigations in the Chilanko Forks and Clusko River Areas (NTS 93C/01, 09S) within the Beetle Impacted Zone 2008; B.C. Ministry of Energy, Mines and Petroleum Resources, Geofile 2009-1
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