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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Detalles Bibliográficos
Autor principal:	Ré, Guillermo Héctor
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:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00278424_v96_n23_p13235_Kay 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

id	paper:paper_00278424_v96_n23_p13235_Kay
record_format	dspace
spelling	paper:paper_00278424_v96_n23_p13235_Kay2023-06-08T14:54:37Z Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications Ré, Guillermo Héctor 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 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00278424_v96_n23_p13235_Kay 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)
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 Ré, Guillermo Héctor 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.
author	Ré, Guillermo Héctor
author_facet	Ré, Guillermo Héctor
author_sort	Ré, Guillermo Héctor
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	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00278424_v96_n23_p13235_Kay http://hdl.handle.net/20.500.12110/paper_00278424_v96_n23_p13235_Kay
work_keys_str_mv	AT reguillermohector revisedgeochronologyofthecasamayoransouthamericanlandmammalageclimaticandbioticimplications
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Revised geochronology of the Casamayoran South American Land Mammal Age: Climatic and biotic implications

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