Marine magnetic anomaly timescales for the Cenozoic and Late Cretaceous: A précis, critique, and synthesis

Abstract

Anomaly timescales for the last 90 million years, derived from marine magnetic profiles and published prior to mid‐1979, are summarized, illustrated for comparison, and critically reviewed. A revised timescale is constructed using calibration points which fix the ages of anomalies 2.3′, 5.5, 24, and 29. An equation is presented for converting K‐Ar dates that is consistent with the recent adoption of new decay and abundance constants. The calibration points used in the revised timescale are so converted, as are the boundary ages of geologic epochs within the range of the timescale.