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dc.contributor.author
Khon, Matthew J.  
dc.contributor.author
Stromberg, Caroline  
dc.contributor.author
Madden, Richard H.  
dc.contributor.author
Dunn, Regan E.  
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Evans, Samantha  
dc.contributor.author
Palacios, Alma  
dc.contributor.author
Carlini, Alfredo Armando  
dc.date.available
2019-06-03T17:03:19Z  
dc.date.issued
2015-10  
dc.identifier.citation
Khon, Matthew J.; Stromberg, Caroline; Madden, Richard H.; Dunn, Regan E.; Evans, Samantha; et al.; Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling; Elsevier Science; Palaeogeography, Palaeoclimatology, Palaeoecology; 435; 10-2015; 24-37  
dc.identifier.issn
0031-0182  
dc.identifier.uri
http://hdl.handle.net/11336/77538  
dc.description.abstract
New local/regional climatic data were compared with floral and faunal records from central Patagonia to investigate how faunas evolve in the context of local and global climates. Oxygen isotope compositions of mammal fossils between c. 43 and 21Ma suggest a nearly constant mean annual temperature of 16±3°C, consistent with leaf physiognomic and sea surface studies that imply temperatures of 16-18°C. Carbon isotopes in tooth enamel track atmospheric δ13C, but with a positive deviation at 27.2Ma, and a strong negative deviation at 21Ma. Combined with paleosol characteristics and reconstructed Leaf Area Indices (rLAIs), these trends suggest aridification from 45Ma (c. 1200mm/yr) to 43Ma (c. 450mm/yr), quasi-constant MAP until at least 31Ma, and an increase to ~800mm/yr by 21Ma. Comparable MAP through most of the sequence is consistent with relatively constant floral compositions, rLAI, and leaf physiognomy. Abundance of palms reflects relatively dry-adapted lineages and greater drought tolerance under higher pCO2. Pedogenic carbonate isotopes imply low pCO2=430±300ppmv at the initiation of the Eocene-Oligocene climatic transition. Arid conditions in Patagonia during the late Eocene through Oligocene provided dust to the Southern Ocean, enhancing productivity of silicifiers, drawdown of atmospheric CO2, and protracted global cooling. As the Antarctic Circumpolar Current formed and Earth cooled, wind speeds increased across Patagonia, providing more dust in a positive climate feedback. High tooth crowns (hypsodonty) and ever-growing teeth (hypselodonty) in notoungulates evolved slowly and progressively over 20Ma after initiation of relatively dry environments through natural selection in response to dust ingestion. A Ratchet evolutionary model may explain protracted evolution of hypsodonty, in which small variations in climate or dust delivery in an otherwise static environment drive small morphological shifts that accumulate slowly over geologic time.  
dc.format
application/pdf  
dc.language.iso
eng  
dc.publisher
Elsevier Science  
dc.rights
info:eu-repo/semantics/openAccess  
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/  
dc.subject
Atmospheric Co2  
dc.subject
Dust  
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Hypsodonty  
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Notoungulate  
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Precipitation  
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Stable Isotopes  
dc.subject.classification
Meteorología y Ciencias Atmosféricas  
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Ciencias de la Tierra y relacionadas con el Medio Ambiente  
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CIENCIAS NATURALES Y EXACTAS  
dc.title
Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling  
dc.type
info:eu-repo/semantics/article  
dc.type
info:ar-repo/semantics/artículo  
dc.type
info:eu-repo/semantics/publishedVersion  
dc.date.updated
2019-05-23T19:00:48Z  
dc.journal.volume
435  
dc.journal.pagination
24-37  
dc.journal.pais
Países Bajos  
dc.journal.ciudad
Amsterdam  
dc.description.fil
Fil: Khon, Matthew J.. Boise State University; Estados Unidos  
dc.description.fil
Fil: Stromberg, Caroline. University of Washington; Estados Unidos  
dc.description.fil
Fil: Madden, Richard H.. University of Chicago; Estados Unidos  
dc.description.fil
Fil: Dunn, Regan E.. University of Washington; Estados Unidos  
dc.description.fil
Fil: Evans, Samantha. Boise State University; Estados Unidos  
dc.description.fil
Fil: Palacios, Alma. Boise State University; Estados Unidos  
dc.description.fil
Fil: Carlini, Alfredo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina  
dc.journal.title
Palaeogeography, Palaeoclimatology, Palaeoecology  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0031018215002928  
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.palaeo.2015.05.028