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TitleU-Pb dating of granites with inherited zircon: conventional and ion microprobe results from two Paleozoic plutons, Canadian Appalachians
AuthorRoddick, J C; Bevier, M L
SourceChemical Geology (Isotope Geoscience Section) vol. 119, issue 1-4, 1995 p. 307-329,
Alt SeriesGeological Survey of Canada, Contribution Series 42793
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf
ProvinceNew Brunswick
AreaMiramichi Highlands
Lat/Long WENS -66.0000 -65.0000 48.0000 47.0000
Subjectsgeochronology; general geology; uranium lead dates; uranium lead dating; granites; zircon; microscopic analysis; geochronometry; Gander Zone
Illustrationsgeological sketch maps; tables; photographs; Concordia diagrams
ProgramCanada-New Brunswick Mineral Development Agreement, 1984-1989
Released1995 01 01
AbstractTwo Paleozoic granites from the Gander Zone, New Brunswick, contain inherited zircon. U-Pb dating of these granites by three different methods (multi-gram and s e-grain conventional techniques and ion microprobe) highlights the strengths and weaknesses of each technique. Zircon morphology determined by optical microscopy of sectioned grains is shown to be a useful but not totally reliable technique for distinguishing magmatic and inherited zircons a&scattered electron imaging with an electron microprobe can clarify the compositional zoning in zircons. Conventional analyses of carefully selected single grains and multi-grain fractions provide the most precise magmatic ages whereas ion microprobe dating is the most effective technique for defining populations of inherited grains. The magmatic ages of the Meridian Brook and Pabineau Falls granites are 472.3 +/- 4.0 and 397.2+/- 1.9 respectively. Ages of inherited zircon range from 480 to 1850 Ma in the Meridian Brook granite and 435 to 1750 Ma in the Pabineau Falls granite.

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