Provenance of Triassic strata in the Cordilleran miogeocline, western Canada

Gerald M. Ross, George E Gehrels, P. Jonathan Patchett

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Siliciclastic strata of Triassic age that are exposed in the Rocky Mountains have been sampled for isotopic studies in order to determine their provenance. Sm-Nd analyses of whole rock shale and sandstone samples from northeast British Columbia and the Bow Corridor of western Alberta are isotopically homogeneous with εNd values of -6.7 to -10.5 at the time of deposition. These values are part of a distinct isotopic provenance signature that characterizes the Devonian through Jurassic of the miogeocline of western Canada and thus the sources of Triassic sediments are part of a larger provenance signature within the miogeocline. These isotopic data do not support sediment derivation from the exposed Canadian Shield and our present working model is that most of the sediment is detrital material reworked from the Innuitian (Ellesmerian) clastic wedge. No evidence has been found in the Nd data to suggest that magmatic arc rocks of Triassic age to the west of the miogeocline (e.g., Quesnellia) made any contribution to the sediment record. U-Pb geochronology of detrital zircons from Triassic sandstones in the Pine Pass and Kananaskis areas are dominated by Precambrian grains with only a few Silurian grains. Comparison with detrital zircons dated from the Devonian Ellesmerian clastic wedge of Arctic Canada show a similar pattern and strengthen the contention that sedimentary strata of the western miogeocline were derived from reworking of Innuitian clastic strata which must have been formerly more widespread and covered the Canadian Shield.

Original languageEnglish (US)
Pages (from-to)461-473
Number of pages13
JournalBulletin of Canadian Petroleum Geology
Volume45
Issue number4
StatePublished - 1997

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provenance
Sediments
Triassic
Zircon
Sandstone
sediment
shield
zircon
Rocks
sandstone
Geochronology
Shale
reworking
geochronology
rock
Silurian
Precambrian
shale
Jurassic
mountain

ASJC Scopus subject areas

  • Earth and Planetary Sciences (miscellaneous)
  • Energy Engineering and Power Technology

Cite this

Provenance of Triassic strata in the Cordilleran miogeocline, western Canada. / Ross, Gerald M.; Gehrels, George E; Patchett, P. Jonathan.

In: Bulletin of Canadian Petroleum Geology, Vol. 45, No. 4, 1997, p. 461-473.

Research output: Contribution to journalArticle

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