Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling
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...
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ftconicet:oai:ri.conicet.gov.ar:11336/77538 2023-10-09T21:47:16+02:00 Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling Khon, Matthew J. Stromberg, Caroline Madden, Richard H. Dunn, Regan E. Evans, Samantha Palacios, Alma Carlini, Alfredo Armando application/pdf http://hdl.handle.net/11336/77538 eng eng Elsevier Science info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0031018215002928 info:eu-repo/semantics/altIdentifier/doi/10.1016/j.palaeo.2015.05.028 http://hdl.handle.net/11336/77538 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 0031-0182 CONICET Digital CONICET info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ Atmospheric Co2 Dust Hypsodonty Notoungulate Precipitation Stable Isotopes https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 info:eu-repo/semantics/article info:ar-repo/semantics/artículo info:eu-repo/semantics/publishedVersion ftconicet https://doi.org/10.1016/j.palaeo.2015.05.028 2023-09-24T20:26:09Z 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. Fil: Khon, Matthew J. Boise State University; Estados Unidos ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas) Antarctic Southern Ocean The Antarctic Patagonia Palaeogeography, Palaeoclimatology, Palaeoecology 435 24 37 |
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Open Polar |
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CONICET Digital (Consejo Nacional de Investigaciones Científicas y Técnicas) |
op_collection_id |
ftconicet |
language |
English |
topic |
Atmospheric Co2 Dust Hypsodonty Notoungulate Precipitation Stable Isotopes https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
spellingShingle |
Atmospheric Co2 Dust Hypsodonty Notoungulate Precipitation Stable Isotopes https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 Khon, Matthew J. Stromberg, Caroline Madden, Richard H. Dunn, Regan E. Evans, Samantha Palacios, Alma Carlini, Alfredo Armando Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling |
topic_facet |
Atmospheric Co2 Dust Hypsodonty Notoungulate Precipitation Stable Isotopes https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
description |
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. Fil: Khon, Matthew J. Boise State University; Estados Unidos ... |
format |
Article in Journal/Newspaper |
author |
Khon, Matthew J. Stromberg, Caroline Madden, Richard H. Dunn, Regan E. Evans, Samantha Palacios, Alma Carlini, Alfredo Armando |
author_facet |
Khon, Matthew J. Stromberg, Caroline Madden, Richard H. Dunn, Regan E. Evans, Samantha Palacios, Alma Carlini, Alfredo Armando |
author_sort |
Khon, Matthew J. |
title |
Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling |
title_short |
Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling |
title_full |
Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling |
title_fullStr |
Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling |
title_full_unstemmed |
Quasi-static Eocene-Oligocene climate in Patagonia promotes slow faunal evolution and mid-Cenozoic global cooling |
title_sort |
quasi-static eocene-oligocene climate in patagonia promotes slow faunal evolution and mid-cenozoic global cooling |
publisher |
Elsevier Science |
url |
http://hdl.handle.net/11336/77538 |
geographic |
Antarctic Southern Ocean The Antarctic Patagonia |
geographic_facet |
Antarctic Southern Ocean The Antarctic Patagonia |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0031018215002928 info:eu-repo/semantics/altIdentifier/doi/10.1016/j.palaeo.2015.05.028 http://hdl.handle.net/11336/77538 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 0031-0182 CONICET Digital CONICET |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar/ |
op_doi |
https://doi.org/10.1016/j.palaeo.2015.05.028 |
container_title |
Palaeogeography, Palaeoclimatology, Palaeoecology |
container_volume |
435 |
container_start_page |
24 |
op_container_end_page |
37 |
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1779310268207071232 |