Evolutionary Anthropology Faculty Database
Evolutionary Anthropology
Arts & Sciences
Duke University

 HOME > Arts & Sciences > BAA > Faculty    Search Help Login pdf version printable version 
Evaluations

Publications [#240780] of Richard F. Kay

search PubMed.

Refereed Publications

  1. Kay, RF; Madden, RH; Vucetich, MG; Carlini, AA; Mazzoni, MM; Re, GH; Heizler, M; Sandeman, H, Revised geochronology of the Casamayoran South American Land Mammal Age: climatic and biotic implications., Proceedings of the National Academy of Sciences of the United States of America, vol. 96 no. 23 (November, 1999), pp. 13235-13240, ISSN 0027-8424 [10557304], [doi]
    (last updated on 2024/03/27)

    Abstract:
    Isotopic age determinations (40Ar/39Ar) and associated magnetic polarity stratigraphy for Casamayoran age fauna at Gran Barranca (Chubut, Argentina) indicate that the Barrancan "subage" of the Casamayoran South American Land Mammal "Age" is late Eocene, 18 to 20 million years younger than hitherto supposed. Correlations of the radioisotopically dated magnetic polarity stratigraphy at Gran Barranca with the Cenozoic geomagnetic polarity time scale indicate that Barrancan faunal levels at the Gran Barranca date to within the magnetochronologic interval from 35.34 to 36.62 megannums (Ma) or 35. 69 to 37.60 Ma. This age revision constrains the timing of an adaptive shift in mammalian herbivores toward hypsodonty. Specifically, the appearance of large numbers of hypsodont taxa in South America occurred sometime between 36 and 32 Ma (late Eocene-early Oligocene), at approximately the same time that other biotic and geologic evidence has suggested the Southern high latitudes experienced climatic cooling associated with Antarctic glaciation.


Duke University * Arts & Sciences * BAA * Faculty All * Postdoc Staff * Non-PHD Staff * Staff * Grads * Reload * Login