Open File 2012-08 (also released as GSC Open File 7234)
Bedrock geology of the upper Kutcho Creek area (parts of NTS 104-I/01, 02)
By P. Schiarizza
The upper Kutcho Creek map area is in northern British Columbia, about 100 km east of Dease Lake. It covers about 400 square kilometres and encompasses the transition between the Stikine Ranges of the Cassiar Mountains to the north and the Spatsizi Plateau to the south. Open File 2012-08 presents a 1:40 000-scale geologic map of this area based on fieldwork conducted in 2010 and 2011. The map features new subdivisions of the Permo-Triassic Kutcho assemblage, a heterogeneous package of schists derived from felsic and mafic volcanic and volcaniclastic rocks and associated felsic and mafic intrusions. The Kutcho assemblage hosts the Kutcho Creek Cu-Zn volcanogenic massive sulphide deposit (MINFILE 104I 060), as well as several other VMS prospects and younger vein occurrences. The Kutcho assemblage is in the King Salmon allochthon, a narrow belt of penetratively deformed, greenschist-grade metamorphic rocks that also includes slivers of the late Paleozoic to early Mesozoic Cache Creek Complex, and a Triassic-Jurassic metasedimentary succession, the Whitehorse trough, that unconformably overlies both Kutcho and Cache Creek rocks. The allochthon is bounded to the south by the north-dipping King Salmon thrust fault, and to the north by the Nahlin fault; it is truncated by the northwest-striking Kutcho dextral strike-slip fault near the northeast edge of the map area.
Operating funds for the Kutcho mapping program were provided by the BC Geological Survey, a private-public partnership agreement with Kutcho Copper Corporation, the Geological Survey of Canada (EDGES component of the GEM program) and, in 2010, a partnership agreement with the University of Victoria.
Details and descriptions of the geologic units and structures within this map area can be found in:
Schiarizza, P. (2012): Geology of the Kutcho assemblage between the Kehlechoa and Tucho rivers, northern British Columbia (NTS 104I/01, 02); in Geological Fieldwork 2011, British Columbia Ministry of Energy and Mines, Paper 2012-1, pages 75-98.
Most provincial geoscience data can be easily accessed over the internet in map format at: and through various thematic pages at
BC Geological Survey Publications are available online at
Questions or to update your contact info please contact the BC Geological Survey:
Email: Tel: 250-952-0372 Fax: 250-952-0381
BC Geological Survey
British Columbia Ministry of Energy and Mines
Mines and Mineral Resources Division
Release Notification 2012-10
August 20, 2012