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TitleGeology and Mineral Deposits of Nootka Sound map area Vancouver Island, British Columbia
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorMuller, J E; Cameron, B E B; Northcote, K E
SourceGeological Survey of Canada, Paper 80-16, 1981, 53 pages, (Open Access)
MapsPublication contains 1 map
Map Info.geological, 1:250,000
Mediapaper; on-line; digital
RelatedThis publication contains Muller, J E; (1981). Geology, Nootka Sound, British Columbia, Geological Survey of Canada, "A" Series Map no. 1537A
File formatpdf
ProvinceBritish Columbia
NTS92E/08; 92E/09; 92E/10; 92E/14; 92E/15; 92E/16
AreaNooka Sound; Vancouver Island
Lat/Long WENS-127.5000 -126.0000 50.0000 49.0000
Subjectsmineralogy; stratigraphy; lithology; glaciers; nomenclature
Illustrationscharts; diagrams
Released1981 01 01; 2013 11 19
AbstractThe map area encompasses glacially sculptured mountains bordering Nootka Sound and adjacent inlets on the west coast of Vancouver Island, the principal part of the Insular Belt of the Canadian Cordillera. It is underlain by mainly volcanic and crystalline rocks and by minor sedimentary rocks. The Sicker Croup includes volcanics and clastic and carbonate sediments of low metamorphic grade; the few fossils found indicate a late Paleozoic age. The Vancouver Croup (redefined) is composed of three formations: a thick sequence of pillowed to layered basalts (Karmutsen), overlain by Upper Triassic, Karnian to Norian carbonates (Quatsino) and carbonate-clastic sediments (Parson Bay). North of the map area pelites with Ladinian fossils, intruded by diabase sills, form the base of the group. The relationship suggests that a Paleozoic volcanic arc was rifted, engulfed and covered by oceanic basalt, whereon in Late Triassic time carbonate-clastic shelf deposits were laid down. The Bonanza Croup (redefined) consists of Lower Jurassic intermediate volcanic rocks and Pliensbachian clastic sediments. The Westcoast Complex is composed of basic gneiss, agmatite and amphibolite, probably derived from the pre-Jurassic rocks. Island Intrusions are Early Jurassic batholiths which range in composition from quartz diorite to granite (new IUCS definition). The three groups of Jurassic plutonic and volcanic rocks are considered to be successive stages and products of the same plutonic-volcanic process. The Upper Jurassic lowermost Cretaceous Kyuquot Croup (new) includes three formations: Kapoose (new), Callovian to Portlandian; One Tree, Berriasian to lower Valanginian; and Longarm, Valanginian to Barremian (only in Alert Bay map area). The group represents an eastward transgressive clastic wedge, deposited in shelf seas that invaded the eroded Early Jurassic plutonic­volcanic complex. The Pacific Rim Complex is approximately coeval and represents off-shelf clastic, cherty and volcanic rocks, commonly deformed into melange, probably as a result of underthrusting of the Pacific Plate beneath the North American Plate. Catface Intrusions (new name) are small, early Tertiary stocks and sills of fine-grained, K-feldspar poor, granitoid rocks and porphyries. The Carmanah Croup (redefined) of Tertiary clastic sediments is composed of a basal conglomerate, the Escalante Formation, Narizian; the main component Hesquiat Formation (redefined), Refugian to early Zemorrian, or late Eocene to early Oligocene; and the Sooke Formation, late Zemorrian? or late Oligocene? (mainly in Victoria map area). The beds were laid down mainly in deep water on the continental slope (?), partly in quiet water and partly in turbulent submarine channels. The structure of the region is generally a southwest dipping homocline of early Mesozoic rocks, disrupted by Jurassic batholiths. Steep to vertical major faults domina to the structural pattern. They are broadly categorized in sets of northerly and westerly faults of probable early Mesozoic origin, and late Mesozoic to Tertiary northwesterly and north-easterly faults.