T250 Geologic Timescale—Current Status, Future Enhancement, and Applications (Posters)

Wednesday, 7 November 2012
9:00 AM - 6:00 PM
Hall B

A COMPOSITE 87SR/86SR CURVE FOR PHANEROZOIC SEAWATER AND LOOK-UP TABLE FOR DERIVATION OF NUMERICAL AGE

Paper number: T250-13
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

Since Wickman proposed using 87Sr/86Sr of marine precipitates as a method of dating, numerous workers have attempted to define the way that the 87Sr/86Sr of marine Sr has varied through geological time. Building on this work, we present a composite curve of marine- 87Sr/86Sr through the Phanerozoic, based on 4119 literature data for 87Sr/86Sr, plotted against the latest numerical timescale of Gradstein et al. (2012). The curve is fitted to data using the LOWESS regression smoother of Cleveland (1979) and Cleveland et al. (1992). An accompanying table converts the 87Sr/86Sr values to numerical ages. A comparison is drawn with previous composite curves of marine 87Sr/86Sr through time and some of the details of the new fitted curve are discussed in terms of the way it may be reflecting geological events.

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