A Cretaceous and Jurassic geochronology.

D. V. Kent, F. M. Gradstein

Research output: Contribution to journalArticlepeer-review

215 Scopus citations


An integrated geomagnetic polarity and geologic time-scale for the Jurassic and Cretaceous periods is presented, based on various methods according to the availability of definitive isotopic ages. An age-calibrated sea-floor-spreading model is used to interpolate the ages of the Kimmeridgian to Barremian, and the Campanian to Maestrichtian stages. Numerical age estimates for the Aptian to Santonian stage boundaries follow published isotopic age determinations. The hypothesis of equal duration of ammonite zones is employed as a vernier to apportion time for the Hettangian to Oxfordian stages. The new scale results in ages of 208 Ma for the base of the Jurassic, 144 Ma for the Jurassic/Cretaceous boundary and 66.5 Ma for the top of the Cretaceous. The integrated biostratigraphic, magnetostratigraphic, and geochronometric record serves as a working hypothesis for geologic correlation of Jurassic and Cretaceous strata. -Authors

Original languageEnglish (US)
Pages (from-to)1419-1427
Number of pages9
JournalGeological Society of America Bulletin
Issue number11
StatePublished - 1985
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geology


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