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High-latitude application of sup 87 Sr/ sup 86 Sr: Correlation of Nuwok beds on North Slope, Alaska, to standard Oligocene chronostratigraphy

Journal Article · · Geology; (USA)
 [1];  [2]
  1. Geological Survey of Canada, Calgery, Alberta (Canada)
  2. Columbia Univ., Palisades, NY (USA)

Strontium isotope ratios ({sup 87}Sr/{sup 86}Sr) calculated from three samples of benthic forminifers and one mallusc indicate an age range from 23.8 to 27.0 Ma for the Nuwok Member of the Sagavanirktok Formation, eastern North Slope, Alaska. Previous correlations derived paleontologically (foraminifers, ostracodes, and molluscs) for the Nuwok beds have differed greatly (Oligocene to Pliocene), but strontium isotope ratios substantiate the late Oligocene age determined from benthic foraminifers. The results constitute an important test case, illustrating the effectiveness of the strontium isotope method in correlating high-latitude carbonate samples to the standard Oligocene chronostratigraphy. In addition, a sample from the Kugmallit sequence in the Beaufort Sea Edlok N-56 well provided a strontium isotope age estimate of 30.7 Ma. The Edlok sample was paleontologically correlated to just below the early/late Oligocene boundary (30.0 Ma).

OSTI ID:
6357532
Journal Information:
Geology; (USA), Journal Name: Geology; (USA) Vol. 18:5; ISSN GLGYB; ISSN 0091-7613
Country of Publication:
United States
Language:
English