Large temperature drop across the Eocene-Oligocene transition in central North America

Article Abstract:

A combination of in vivo stable isotope compositions of fossil tooth enamel with diagenetic stable isotope compositions of fossil bone is used to obtain a high-resolution continental temperature record for the Eocene-Oligocene transition (EOT) in central North America. The results have indicated that a decrease in mean annual temperature (MAT), rather than an increase in seasonality or aridity, is the basic cause for the extinctions of gastropods, amphibians and reptiles associated with the EOT.

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The age of the Popigai impact event and its relation to events at the Eocene/Oligocene boundary

Article Abstract:

The ages of several Popigai impact melt rocks were determined using the step heating technique. The results were consistent with a Late Eocene impact age of 35.7 plus or minus 0.2 million years. The age is similar to North american tektites linked with the Chesapeake Bay impact structure in the US. This confirms that there were at least two large impacts during the Late Eocene.

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Cooler winters as a possible cause of mass extinctions at the Eocene/Oligocene boundary

Article Abstract:

Mass extinctions at the Eocene/Oligocene boundary may have been due to cooler winters.

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