Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications

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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 you...

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Autores principales: Kay, R.F., Madden, R.H., Vucetich, M.G., Carlini, A.A., Mazzoni, M.M., Re, G.H., Heizler, M., Sandeman, H.
Formato: Artículo publishedVersion
Lenguaje:Inglés
Publicado: 1999
Materias:
Eocene
Mammalian evolution
Paleontology
South America
age determination
analytic method
article
chronology
cold climate
mammal
physical anthropology
priority journal
wildlife
Invertebrata
Mammalia
Vertebrata
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00278424_v96_n23_p13235_Kay
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling paperaa:paper_00278424_v96_n23_p13235_Kay2023-06-12T16:45:21Z Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications Proc. Natl. Acad. Sci. U. S. A. 1999;96(23):13235-13240 Kay, R.F. Madden, R.H. Vucetich, M.G. Carlini, A.A. Mazzoni, M.M. Re, G.H. Heizler, M. Sandeman, H. Eocene Mammalian evolution Paleontology South America age determination analytic method article chronology cold climate mammal physical anthropology priority journal South America wildlife Invertebrata Mammalia Vertebrata 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. Fil:Re, G.H. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 1999 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion application/pdf eng info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00278424_v96_n23_p13235_Kay
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
language Inglés
orig_language_str_mv eng
topic Eocene
Mammalian evolution
Paleontology
South America
age determination
analytic method
article
chronology
cold climate
mammal
physical anthropology
priority journal
South America
wildlife
Invertebrata
Mammalia
Vertebrata
spellingShingle Eocene
Mammalian evolution
Paleontology
South America
age determination
analytic method
article
chronology
cold climate
mammal
physical anthropology
priority journal
South America
wildlife
Invertebrata
Mammalia
Vertebrata
Kay, R.F.
Madden, R.H.
Vucetich, M.G.
Carlini, A.A.
Mazzoni, M.M.
Re, G.H.
Heizler, M.
Sandeman, H.
Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
topic_facet Eocene
Mammalian evolution
Paleontology
South America
age determination
analytic method
article
chronology
cold climate
mammal
physical anthropology
priority journal
South America
wildlife
Invertebrata
Mammalia
Vertebrata
description 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.
format Artículo
Artículo
publishedVersion
author Kay, R.F.
Madden, R.H.
Vucetich, M.G.
Carlini, A.A.
Mazzoni, M.M.
Re, G.H.
Heizler, M.
Sandeman, H.
author_facet Kay, R.F.
Madden, R.H.
Vucetich, M.G.
Carlini, A.A.
Mazzoni, M.M.
Re, G.H.
Heizler, M.
Sandeman, H.
author_sort Kay, R.F.
title Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
title_short Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
title_full Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
title_fullStr Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
title_full_unstemmed Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
title_sort revised geochronology of the casamayoran south american land mammal age: climatic and biotic implications
publishDate 1999
url http://hdl.handle.net/20.500.12110/paper_00278424_v96_n23_p13235_Kay
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