Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications
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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1999
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00278424_v96_n23_p13235_Kay http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00278424_v96_n23_p13235_Kay_oai |
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I28-R145-paper_00278424_v96_n23_p13235_Kay_oai2020-10-19 Kay, R.F. Madden, R.H. Vucetich, M.G. Carlini, A.A. Mazzoni, M.M. Re, G.H. Heizler, M. Sandeman, H. 1999 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. application/pdf http://hdl.handle.net/20.500.12110/paper_00278424_v96_n23_p13235_Kay info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar Proc. Natl. Acad. Sci. U. S. A. 1999;96(23):13235-13240 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 Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00278424_v96_n23_p13235_Kay_oai |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-145 |
| collection |
Repositorio Digital de la Universidad de Buenos Aires (UBA) |
| 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 http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00278424_v96_n23_p13235_Kay_oai |
| work_keys_str_mv |
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