U-Pb geochronology of late Cretaceous and early Tertiary plutons in the northern Coast Mountains Batholith

G. E. Gehrels, W. C. McClelland, S. D. Samson, P. J. Patchett, D. A. Brew

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

U-Pb geochronologic studies demonstrate that steeply dipping, sheetlike tonalitic plutons along the western margin of the northern Coast Mountains Batholith were emplaced between ~83 and ~57 (perhaps ~55) Ma. Less elongate tonalitic-granodioritic bodies in central portions of the batholith yield ages of 59-58 Ma, coeval with younger phases of the tonalitic sheets. Large granite-granodiorite bodies in central and eastern portions of the batholith were emplaced at 51-48 Ma. Trends in ages suggest that the tonalitic bodies generally become younger southeastward and that, at the latitude of Juneau, plutonism migrated northeastward across the batholith at ~0.9 km/Ma. Old zircons, combined with evolved Nd isotopic signatures for most plutons, record assimilation of continental crustal or supracrustal rocks during the generation and (or) ascent of the plutons. -from Authors

Original languageEnglish (US)
Pages (from-to)899-911
Number of pages13
JournalCanadian Journal of Earth Sciences
Volume28
Issue number6
DOIs
StatePublished - Jan 1 1991

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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