Multimethod radiometric age for a bentonite near the top of the Baculites reesidei zone of southwestern Saskatchewan (Campanian- Maastrichtian stage boundary?)

H. Baadsgaard; J. F. Lerbekmo; J. R. Wijbrans; C. C. Swisher; M. Fanning

doi:10.1139/e93-063

Multimethod radiometric age for a bentonite near the top of the Baculites reesidei zone of southwestern Saskatchewan (Campanian- Maastrichtian stage boundary?)

H. Baadsgaard, J. F. Lerbekmo, J. R. Wijbrans, C. C. Swisher, M. Fanning

Research output: Contribution to journal › Article › peer-review

22 Scopus citations

Abstract

A 15 cm thick bentonite at the top of the Baculites reesidei Zone in Cruikshank Coulee north of Herbert in southwestern Saskatchewan yielded biotite, sanidine, plagioclase, and zircon. Rb-Sr analyses give a mineral isochron with an age of 72.5 ± 0.2 Ma (±2σ). U-Pb analyses of zircon produced concordant ²⁰⁶Pb/²³⁸U and ²⁰⁷Pb/²³⁵U ages of 72.4 ± 0.4 Ma (±2σ) and 72.6 ± 0.4 Ma (±2σ), respectively. Laser ⁴⁰Ar/³⁹Ar dating of sanidine and biotite revealed ages of 72.5 ± 0.2 Ma (± SE) and 72.6 ± 0.2 Ma (±SE), respectively. If the Campanian-Maastrichtian stage boundary is near the top of the Baculites reesidei Zone, then the overall average age of 72.5 ± 0.4 Ma dates the stage boundary. -Authors

Original language	American English
Pages (from-to)	769-775
Number of pages	7
Journal	Canadian Journal of Earth Sciences
Volume	30
Issue number	4
DOIs	https://doi.org/10.1139/e93-063
State	Published - 1993
Externally published	Yes

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General Earth and Planetary Sciences

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@article{75902c1ff9954d6a8cc4b0d55c1b6b30,

title = "Multimethod radiometric age for a bentonite near the top of the Baculites reesidei zone of southwestern Saskatchewan (Campanian- Maastrichtian stage boundary?)",

abstract = "A 15 cm thick bentonite at the top of the Baculites reesidei Zone in Cruikshank Coulee north of Herbert in southwestern Saskatchewan yielded biotite, sanidine, plagioclase, and zircon. Rb-Sr analyses give a mineral isochron with an age of 72.5 ± 0.2 Ma (±2σ). U-Pb analyses of zircon produced concordant 206Pb/238U and 207Pb/235U ages of 72.4 ± 0.4 Ma (±2σ) and 72.6 ± 0.4 Ma (±2σ), respectively. Laser 40Ar/39Ar dating of sanidine and biotite revealed ages of 72.5 ± 0.2 Ma (± SE) and 72.6 ± 0.2 Ma (±SE), respectively. If the Campanian-Maastrichtian stage boundary is near the top of the Baculites reesidei Zone, then the overall average age of 72.5 ± 0.4 Ma dates the stage boundary. -Authors",

author = "H. Baadsgaard and Lerbekmo, {J. F.} and Wijbrans, {J. R.} and Swisher, {C. C.} and M. Fanning",

year = "1993",

doi = "10.1139/e93-063",

language = "American English",

volume = "30",

pages = "769--775",

journal = "Canadian Journal of Earth Sciences",

issn = "0008-4077",

publisher = "National Research Council of Canada",

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T1 - Multimethod radiometric age for a bentonite near the top of the Baculites reesidei zone of southwestern Saskatchewan (Campanian- Maastrichtian stage boundary?)

AU - Baadsgaard, H.

AU - Lerbekmo, J. F.

AU - Wijbrans, J. R.

AU - Swisher, C. C.

AU - Fanning, M.

PY - 1993

Y1 - 1993

N2 - A 15 cm thick bentonite at the top of the Baculites reesidei Zone in Cruikshank Coulee north of Herbert in southwestern Saskatchewan yielded biotite, sanidine, plagioclase, and zircon. Rb-Sr analyses give a mineral isochron with an age of 72.5 ± 0.2 Ma (±2σ). U-Pb analyses of zircon produced concordant 206Pb/238U and 207Pb/235U ages of 72.4 ± 0.4 Ma (±2σ) and 72.6 ± 0.4 Ma (±2σ), respectively. Laser 40Ar/39Ar dating of sanidine and biotite revealed ages of 72.5 ± 0.2 Ma (± SE) and 72.6 ± 0.2 Ma (±SE), respectively. If the Campanian-Maastrichtian stage boundary is near the top of the Baculites reesidei Zone, then the overall average age of 72.5 ± 0.4 Ma dates the stage boundary. -Authors

AB - A 15 cm thick bentonite at the top of the Baculites reesidei Zone in Cruikshank Coulee north of Herbert in southwestern Saskatchewan yielded biotite, sanidine, plagioclase, and zircon. Rb-Sr analyses give a mineral isochron with an age of 72.5 ± 0.2 Ma (±2σ). U-Pb analyses of zircon produced concordant 206Pb/238U and 207Pb/235U ages of 72.4 ± 0.4 Ma (±2σ) and 72.6 ± 0.4 Ma (±2σ), respectively. Laser 40Ar/39Ar dating of sanidine and biotite revealed ages of 72.5 ± 0.2 Ma (± SE) and 72.6 ± 0.2 Ma (±SE), respectively. If the Campanian-Maastrichtian stage boundary is near the top of the Baculites reesidei Zone, then the overall average age of 72.5 ± 0.4 Ma dates the stage boundary. -Authors

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DO - 10.1139/e93-063

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SN - 0008-4077

VL - 30

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EP - 775

JO - Canadian Journal of Earth Sciences

JF - Canadian Journal of Earth Sciences

IS - 4

ER -

Multimethod radiometric age for a bentonite near the top of the Baculites reesidei zone of southwestern Saskatchewan (Campanian- Maastrichtian stage boundary?)

Abstract

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