Terrane Map Description(see Figure 3)
The data has been compiled by J.O. Wheeler, A.J. Brookfield, H. Gabrielse, J.W. H. Monger, H.W. Tipper, and G.J. Woodsworth from Terrane Map of the Canadian Cordillera, Geological Survey of Canada, Open File 1894, 1988.
"Terranes are bodies of rock, each preserving a geological record different from those of neighboring terranes (Monger and Berg, 1984). Plutonic and metamorphic rocks and mineral deposits may be integral parts of terranes. Terrane boundaries are important faults, although in places these may be concealed by younger cover rocks or intrusions. Paleontological and paleomagnetic data suggest that some currently juxtaposed terranes were originally separated by distances of up to thousands of kilometres." (DNAG, Chapter 2)
Terranes are categorized according to their relationship to ancestral North America. Tectonic assemblages and plutonic suites which make up each terrane are listed using symbols and names from Tectonic Assemblage Map of the Canadian Cordillera and adjacent parts of the United States of America, compiled by J.O. Wheeler and P. McFeely, Geological Survey of Canada, Open File 1565, 1987. |
Legend
MIOGEOCLINE
CRATON
NA |
Ancestral North America |
Middle Proterozoic to Carboniferous passive and offshelf continental margin sediments, Devonian to Carboniferous clastic wedges, Pennsylvanian to Jurassic passive continental margin prism, and Permian clastics.
mPCM Cap Mountain, mPM Mackenzie, mPMu Muskwa, mPPW Purcell-Wernecke, uPW Windermere, uPWR Rapitan, uPPI Pinguicula, PCG Gog, PCH Hyland, mCr rift assemblage, CDR Rocky Mountains, DMB Besa River, DME Earn, DMI Imperial, DCR Rundle, CM Mattson, CL Lisburne, CPO Outer, PPI Ishbel, PJ Jungle Creek, TRJS Spray River, JKp Parsons
plutonic rocks: MPgH Hellroaring Creek, MPdM Moyie, LPqD Deserters, LPdM Macdonald, LPdR Rackla, LPdT Thundercloud, Sy Bearpaw Ridge.
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TERRANES: geological record, except for displaced continental margin, differs from that of Ancestral North America.
NORTH AMERICAN BASEMENT?
MO |
Monashee |
Craton-related metasedimentary rocks overlying basement paragneiss and orthogneiss of Early Proterozoic age.
lPM Monashee Complex
plutonic rocks: EPnMo Monashee, LPYC Mt. Copeland
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MO? |
Monashee - inferred IPnV Vaseaux Gneiss |
DISPLACED CONTINENTAL MARGIN: stratigraphic record similar to that of adjacent Ancestral North America.
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Upper Proterozoic and lower Paleozoic miogeoclinal sedimentary, volcanic and granitic rocks unconformably overlain by Lower Carboniferous to Triassic continental margin deposits and displaced along the Kaltag Fault.
uPN Neruokpuk, PCHA Hyland, CDRA Rocky Mountains, DMIA Imperial, CMA Mattson, CLA Lisburne, PTRS Sadlerochit, JKPA Parsons
plutonic rocks: DMqA Ammerman, DMqF Fitton, DMqOC Old Crow, DMqSH Schaeffer, DMqSe Sedgwick.
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CA |
Cassiar |
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Upper Proterozoic to Upper Triassic passive continental margin sediments displaced along the Tintina and Northern Rocky Mountain Trench transcurrent faults. |
uPWC Windermere, PCGC Gog, CDRC Rocky Mountains, DMRC Rundle, DMEC Earn, TRJSC Spray River plutonic rocks: EPnT Tochieka |
SUBTERRANE |
CAC |
Cariboo |
Upper Proterozoic to Upper Triassic displaced offshelf passive continental margin sediments without characteristic platformal Upper Silurian (?) to Upper Devonian carbonate and sandstone
uPWCA Windermere, PCGCA Gog, CDRCA Rocky Mountains, DMECA Earn, PPICA Ishbel, TRSCA Spray River |
NS |
Nisling |
|
Metamorphosed Proterozoic to lower Paleozoic (?) passive continental margin assemblage and partly metamorphosed carbonaceous and siliceous offshelf sediments.
PCN Nisling, CDN Nasina |
PC |
Porcupine |
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Continental margin sediments comprising upper Proterozoic clastics overlain by Paleozoic carbonates and clastics intruded by Devonian syenodiorite, and bounded by the Yukon and Kaltag faults.
PCHP Hyland, CDRP Rocky Mountains, CLP Lisburne, CPOP Outer, PJP Jungle Creek, TRJSP Spray River, JKpp Parsons
plutonic rocks: DMYDL Dave Lord
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PERICRATONIC: no record of significant displacement but rocks differ in stratigraphic or structural characteristics from the ancient continental margin.
KO |
Kootenay |
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Intensely deformed, variably metamorphosed and poorly dated Proterozoic to Triassic, siliceous clastic sediments, subordinate volcanics, and limestone, locally intruded by Ordovician, Devonian, and Mississippian granitoid plutons. Some of the deformed lowest Paleozoic rocks appear to be stratigraphically related to ancestral North American whereas the younger, less deformed rocks do not.
PPzEK Eagle Bay, CMK Milford
plutonic rocks: OSnL Little Shuswap Lake, DMqF Mt. Fowler, DMqC Clachnacuddain.
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SUBTERRANES
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KO? |
Kootenay - inferred |
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Proterozoic continental margin sediments and basement gneiss separated from North American strata by the Purcell and Esplanade thrust faults
lPM Malton, uPW Windermere
plutonic rocks: EPnM Malton, LPgH Hugh Allan, DyI Ice River
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KOB |
Barkerville |
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Proterozoic and Paleozoic strata which are thrust bounded with and may be a facies equivalent of the Cariboo Subterrane
PPzEK Eagle Bay
plutonic rocks: DMqQ Quesnel Lake
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KON |
Nisutlin |
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Metamorphosed and intensely cataclastized sedimentary, volcanic and intrusive rocks of Late Proterozoic, Paleozoic and possibly early Mesozoic ages
PTRNK Nisutlin
plutonic rocks: DMgS Simpson Range Suite, EpqSC Sulphur Creek
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PG |
Pelly Gneiss |
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Muscovite-biotite granite and leucogranite augen gneiss and biotite quartz monzonite orthogneiss of S-type affinity; in part fault bounded. Pelly Gneiss is in fault contact with Nisutlin Subterrane and in an unknown relationship with the Nisling Terrance. It may be included with the Nisutlin Subterrane if correlated by age with the Simpson Range Suite although Pelly Gneiss is compositionally different.
DMgM Mink Creek Suite |
ACCRETED TERRANES: represent oceanic or island arc lithologies, generally of unknown Paleogeographic origin, which are clearly allochthons with respect to miogeoclinal strata. These are grouped into the Intermontane and Insular superterranes.
INTERMONTANE SUPERTERRANE: terranes amalgamated by latest Triassic time and accreted to Ancestral North America in the Jurassic.
SM |
Slide Mountain |
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Oceanic marginal basin volcanics and sediments of Devonian to Late Triassic age which are basement to Quesnellia in southern B.C.. Included are chert, argillite, sandstone, conglomerate, mafic intrusions, basalt, alpine-type ultramafic rocks, carbonate rocks and local occurrences of blueschist and eclogite. In northern B.C. Permian fusulinids are not found in coeval, co-latitudinal cratonal rocks suggesting terrane movement from the south.
DTRS Slide Mountain
plutonic rocks: DTRuo oceanic ultramafics, DTRd, EPtF and EMtF Four Mile.
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DY |
Dorsey |
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Carboniferous marginal basin chert and clastics with similar lithology to Slide Mountain Terrane but lacking ultramafics, containing less volcanics and including important conglomeratic units. The terrane may represent a facies of either Quesnel or Slide Mountain terrane.
CD Dorsey |
QN |
Quesnel |
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Upper Triassic and Lower Jurassic arc volcanics, volcaniclastics and comagmatic intrusive rocks overlain by Jurassic arc-derived clastics. Triassic and Jurassic faunas differ from those in coeval, co-latitudinal cratonal rocks.
TRJN Nicola, JHA Hall
plutonic rocks: LTRup Polaris Suite, EJgG Guichon Suite, EJYCM Copper Mountain Suite
SUBTERRANES: basement to Quesnellia |
QNH |
Harper Ranch
Upper Devonian to Triassic arc clastics, volcanics and carbonate. |
DTRH Harper Ranch
QNO |
Okanagan |
|
Carboniferous to Permian oceanic volcanics and sediments.
OTRS Shoemaker, CPA Anarchist |
CC |
Cache Creek |
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Mississippian to Upper Triassic oceanic volcanics and sediments, Upper Triassic island arc volcanics and local accretionary prism melange. Included are radiolarian chert, argillite and basalt, shallow water carbonate and alpine-type ultramafics. The terrane is bounded on the east by the Teslin and Pinchi faults. Permian fusulinid and coral faunas of Tethyan affinity are not found in coeval, co-latitudinal cratonal rocks suggesting an exotic origin.
MTRC Cache Creek, TRKU Kutcho
plutonic rocks: DTRuo oceanic ultramafics
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ST |
Stikine |
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Devonian to Permian arc volcanics and platform carbonates form the basement to Stikinia. They are overlain by Triassic and Lower Jurassic arc volcanics, volcaniclastics, and arc-derived clastics, which are intruded by comagmatic plutonic rocks. Permian, Triassic and Jurassic faunas differ from co-latitudinal cratonal rocks indicating northward terrane displacement.
DPA Asitka, TRS Stuhini, TRL Lewes River, JH Hazelton, JT Takwahoni plutonic rocks: LTRup Polaris Suite, LTRdS Stikine Suite, TRJgK Klotassin Suite, EJqB Black Lake, EJqCM Copper Mountain Suite, EJq unnamed plutons in Coast Mountains, EJqL Long Lake Suite, EJqT Topley Suite, MJdgT Three Sisters Suite. |
WM |
Windy McKinley |
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Devonian oceanic sediments and volcanics; Cretaceous blocks
DKWR White River |
TERRANES OF THE COAST BELT
TU |
Taku |
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Variably metamorphosed upper Paleozoic and Triassic basalt, local acid volcanics, carbonate, pelite and Permian crinoidal limestone. Jurassic to Cretaceous metamorphosed sediments and volcanics are similar to the Gambier (Gravina-Nutzotin) Assemblage. The stratigraphic base of the terrane is unknown and relationships with other terranes are obscured by intrusions and metamorphism.
PKT Taku |
CD |
Cadwallader |
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Upper Triassic island arc clastics and volcanics (regarded in part by some workers as Stikinia) overlain by Jurassic arc clastics and volcanics, and Jura-Cretaceous easterly derived continental margin clastic wedge of shale and siltstone in Tyaughton Trough.
TRC Cadwallader, JL Ladner, JKR Relay Mountain |
MT |
Methow |
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Upper Triassic basalt overlain by Lower Jurassic arc clastics and volcanics, and Jurassic and Cretaceous easterly derived clastic wedges shed from Quesnellia
JL Ladner, JKR Relay Mountain, KS Skeena |
BR |
Bridge River |
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Accretionary prism and oceanic crust of Permian to Middle Jurassic age disrupted and variably metamorphosed radiolarian chert, argillite, basalt, alpine-type ultramafics and minor carbonate and diorite.
PJB Bridge River |
HA |
Harrison |
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Jurassic island arc volcanics and clastics. Carbonate clasts in Toarcian conglomerate contain Permian fossils similar to those in the Chilliwack Terrane
JHL Harrison Lake |
CK |
Chilliwack |
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Devonian to Permian arc volcanics and clastics overlain by Upper Triassic to Lower Jurassic arc clastics. Permian fusilinid faunas resemble those in Quesnellia and Stikinia. The Yellow Aster may in part by basement to the Chilliwack Terrane.
DPCH Chilliwack, TRJC Cultus
plutonic rocks: PPnV Vedder, COnY Yellow Aster.
|
SH |
Shuksan |
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Upper Triassic and Lower Jurassic oceanic crust and sediments metamorphosed to greenschist and blueschist and Jurassic near arc oceanic marginal basin crust and sediments |
TRJSE Settler, JS Shuksan |
INSULAR SUPERTERRANE: terranes amalgamated by Late Jurassic to earliest Cretaceous time and accreted to continental margin in the Cretaceous.
AX |
Alexander |
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Upper Proterozoic to Triassic volcanic and sedimentary rocks in a variety of depositional settings (ocean arc, back arc, platform, rift, trough, offshelf) and comagmatic intrusions.
PCW Wales, OSD Descon, ODD Donjek, ODK Kaskawulsh, OTRA Alexander, DC Cedar Cove, DK Karheen, DPC Cannery, CI Iyoukeen, PH Halleck, PP Pybus, PTRA Alexander, TRH Hyd plutonic rocks: COd in St. Elias, OSg, OSd, Sy and Sum in S.E. Alaska, PPgI Icefield Ranges Suite. |
WR |
Wrangell |
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Silurian to Permian arc volcanics, clastics and platform carbonates form the basement to Wrangellia; they are overlain by Triassic oceanic rift tholeiitic basalt, carbonate and Jurassic arc volcanics, and intruded by comagmatic plutons. Paleomagnetic data suggest displacement from low latitudes.
DPS Sicker, PPS Skolai, TRK Karmutsen, JB Bonanza
plutonic rocks: DgS Saltspring, EJdW, EJnW Westcoast Complex, MJgV Vancouver Island Suite, MJg Chichagof Island
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OUTER TERRANES: Mesozoic and Tertiary accretionary prisms
CG |
Chugach |
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Cretaceous accretionary prism of greywacke, argillite, and melange of Triassic to Lower Cretaceous blocks in a Lower Cretaceous matrix.
KV Valdez
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YA |
Yakutat |
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Upper Cretaceous turbidite and melange of Upper Triassic to Lower Cretaceous blocks in a Cretaceous matrix.
uKY Yakutat, pTM Metchosin, pTC Carmanah, nTY Yakataga |
PR |
Pacific Rim |
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Melange and chert-volcanics assemblage on Upper Triassic calc-alkaline arc volcanics
JKPR Pacific Rim |
CR |
Crescent |
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Pull-apart basin ridge-island Eocene volcanics cut by gabbro and diabase intrusions
pTM Metchosin
plutonic rocks: ETgC Catface Suite
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ROCKS EXCLUDED FROM TERRANE CLASSIFICATION:
METAMORPHIC ASSEMBLAGES
m |
undivided metamorphic assemblages |
PLUTONIC ROCKS
CPC |
All post-terrane accretion intrusives |
POST-TERRANE ACCRETION OVERLAP ASSEMBLAGES HIGHLIGHTED ON MAP:
TRL |
Lewes River (on Cache Creek Terrane) |
JBL |
Bowser Lake (on Stikine Terrane) |
JI |
Inklin (on Cache Creek Terrane) |
JT |
Takwahoni (on Cache Creek Terrane) |
JKG |
Gambier (in Coast Belt) |
POST TERRANE ACCRETION OVERLAP ASSEMBLAGES UNDIFFERENTIATED ON MAP
JKT |
Cratonal overlap: Related to the collision of the Intermontane Superterrane with Ancestral North America, and with subsequent intraplate deformation.
JKK Kootenay, mKB Blairmore, mKS South Fork, uKS Smoky, uKT Trevor, KTB Brazeau, pTMC Moose Channel, pTR Reindeer, nTB Beaufort, nTF Fraser, Q Quaternary |
Terrane overlap: Indicate latest times of assembly of various components of the superterranes and the time of collision between the Insular and Intermontane superterranes.
JKR Relay Mountain, lKL Longarm, KS Skeena, mKS South Fork, uKH Honna, uKM Midnight Peak, uKV Virginian Ridge, uKC Carmacks, KTN Nanaimo, pTA Amphitheatre, pTC Carmanah, pTK Kamloops, pTS Sifton, nTA Alert Bay, nTC Chilcontin, nTF Fraser, nTp Pemberton, nTS Skonun, TQA Anahim, TQE Edziza, TQG Garibaldi, TQW Wrangell, QC Clearwater, Q Quaternary. | |