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TitleBedrock geological framework, Queen Charlotte Islands, British Columbia
AuthorHaggart, J W; Wagner, C L
SourceGeological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Abstracts Volume vol. 28, 2003, 1 pages
Alt SeriesEarth Sciences Sector, Contribution Series 20100199
MeetingGAC-MAC-SEG 2003 Annual General Meeting; Vancouver; CA; May 25-28, 2003
Mediapaper; CD-ROM
ProvinceBritish Columbia
NTS103B; 103C/16; 103F; 103J/04; 103K/01; 103K/02; 103K/03; 103K/04
AreaQueen Charlotte Islands; Haida Gwaii
Lat/Long WENS-133.5000 -131.0000 54.2500 52.0000
Subjectsstratigraphy; structural geology; bedrock geology; sedimentary rocks; igneous rocks; volcanic rocks; Karmutsen Formation; Paleozoic; Permian; Carboniferous; Mesozoic; Triassic
AbstractThe first comprehensive geological map of Queen Charlotte Islands (QCI) was published in 1880, based on the pioneering explorations of G.M. Dawson. The British Columbia Geological Survey Branch, under A. Sutherland Brown, undertook an islands-wide mapping effort in the 1960s and the first detailed modern geological map of the islands, at 1:125K-scale, was released in 1968. This map emphasized paleontological data in differentiating lithologically-similar stratigraphic units, and also presented the first geochronological data. In late 1980s, the Geological Survey of Canada initiated a bedrock mapping program of QCI in support of a comprehensive analysis of hydrocarbon potential of the adjacent offshore region. Numerous geologists and assistants participated in this effort and a suite of nine 1:50K-scale maps has been produced.
The maps cover an area encompassing 24 complete or partial 1:50K National Topographic System (NTS) mapsheets. Cartographic work was performed digitally in Arc/Info using the GEMS interface system developed by Geological Survey of Canada. The maps include base data (National Topographic Database contours, lakes, and rivers) in addition to the geology units, structure information, MINFILE localities, geochronology localities, and a common legend. Only geology units found on an individual map sheet are coloured on that sheet's legend. All maps are in Universal Transverse Mercator (UTM) projection, in either Zone 8 or Zone 9 as the islands are situated at a UTM zone boundary. A UTM 1 kilometre grid has been printed on the maps for user convenience.
The suite of maps covers all geologically-complex areas of the islands. Oldest rocks known are Carboniferous-Permian calcareous and chert-rich sedimentary strata and volcanic rocks; similar-age plutonic rocks are known locally. The bulk of southern QCI consists of Triassic flood basalt of the Karmutsen Formation, intruded by Middle-Late Jurassic and Tertiary plutons. The central islands are characterized by a stratigraphically-complex and relatively complete succession of Upper Triassic (Norian) through Upper Cretaceous (Campanian) strata; supporting paleontological data indicate that every stage within this time interval is represented in the succession. The northern third of QCI consists of volcanic rocks and minor sedimentary strata of the Masset Formation, overlying Mesozoic stratigraphy along the northwest coast of Graham Island; these strata are onshore equivalents of the thick Tertiary succession preserved in the offshore. A variety of structural regimes are reflected in the maps: principal are various episodes of Late Jurassic and Cretaceous block faulting and compression. Map relationships and outcrop kinematic studies suggest that lateral displacement along strike-slip faults is minimal.