Strontium isotope profiles across K/T boundary sequences in Denmark and Antarctica

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• 作者：McArthur ; J.M. ; Thirlwall ; M.F. ; Engkilde ; M. ; Zinsmeister ; W.J. ; Howarth ; R.J.
• 关键词：K-T boundary ; Sr-87/Sr-86 ; Antarctica ; Denmark
• 刊名：Earth and Planetary Science Letters
• 出版年：1998
• 期刊代码：18_0012821x
• 类别：ph
• 出版时间：July, 1998
• 卷：160
• 期：1-2
• 页码：179-192
• 文件大小：807 K

摘要

Strontium isotope profiles, derived from minimally altered samples, across marine K/T boundary sequences exposed at Kjølby Gaard and Nye Kløv, Denmark, and on Seymour Island, Antarctica, show neither the boundary excursions, nor the boundary spikes, in ⁸⁷Sr/⁸⁶Sr that have been reported for K/T boundary sequences from elsewhere. Nor do our data conform to modelled predictions of the Sr isotopic response of the oceans to a positive spike in ⁸⁷Sr/⁸⁶Sr at the terminal Cretaceous. Boundary values for ⁸⁷Sr/⁸⁶Sr (with 95%confidence intervals) are 0.707828±3 in Denmark and 0.707832±7 in Antarctica. Our data suggest that ⁸⁷Sr/⁸⁶Sr stopped increasing and started decreasing at least 90 ka before the K/T boundary.