A nonmarine record of eccentricity forcing through the Upper Triassic of southwest England and its correlation with the Newark Basin astronomically calibrated geomagnetic polarity time scale from the North America

David B. Kemp*, Angela L. Coe

*Corresponding author for this work

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The Late Triassic was a time of major environmental change, yet the precise chronology of events is poorly constrained owing to the nonmarine nature of most preserved Upper Triassic strata and the difficulty in correlating sections. St. Audrie's Bay, southwest England, has been the focus of many studies on this interval of time and is one of the proposed sections for the base Jurassic global stratotype section and point (GSSP). In this study, lacustrine deposits exposed at St. Audrie's Bay have been used to construct a floating astronomical time scale for ∼3.7 m.y. of the Late Triassic based on the recognition of ∼100 k.y. eccentricity cycles in rock color. In addition, we have correlated this time scale with an existing magnetostratigraphy through the same succession and produced an astronomically calibrated record of geomagnetic polarity. Using a novel statistical procedure, we have determined the correlation between this succession and the Late Triassic geomagnetic polarity time scale of the Newark Basin, North America, on which the current (2004) geological time scale is based. Our results show unequivocally that the studied St. Audrie's Bay succession represents part of the Norian and we demonstrate for the first time that cyclostratigraphy can be used in the correlation of Mesozoic strata between North America and Europe.

Original languageEnglish
Pages (from-to)991-994
Number of pages4
JournalGeology
Volume35
Issue number11
DOIs
Publication statusPublished - 1 Nov 2007

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Keywords

  • Cyclostratigraphy
  • Newark Basin
  • Norian
  • St. Audrie's Bay
  • Stratigraphic correlation
  • Time scale
  • Triassic

ASJC Scopus subject areas

  • Geology

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