Séminaire ISTerre

Evolution of the Isthmus of Panama: Biological, Paleoceanographic and Paleoclimatological Implications / ZOOM

jeudi 14 mai 2020 - 11h00
Carlos Jaramillo - Smithsonian Institute, Panama
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Abstract The rise of the Isthmus of Panama was the product of small‐scale geological processes that, nonetheless, had worldwide repercussions. The building of the Panamanian landscape can be summarized in four phases: (i) the emergence of a large, late Eocene island across central Panama and the Azuero Peninsula; (ii) the early Miocene large‐scale generation of terrestrial landscapes in Central America, which connected central Panama with North America; (iii) the full closure of the Central American Seaway (CAS) at 10 Ma, which interrupted the exchange of deep waters between the Caribbean and the Pacific, and generated most of the landscape across the Isthmus (exchange of shallow waters continued until 3.5 Ma, albeit intermittently); and (iv) the persistence of a terrestrial landscape across the Isthmus over the past 3.5 My. Four major events have been linked to the rise of the Isthmus: (i) the onset of thermohaline circulation (TCH); (ii) the onset of northern hemisphere glaciation (NHG); (iii) the birth of the Caribbean Sea; and (iv) the Great American Biotic Interchange (GABI). The available evidence indicates a strong link between the closure of the CAS and the onset of Atlantic meridional overturning circulation (AMOC, a precursor of THC), but at 10.0 rather than 3.5 Ma, as had been assumed. There is no evidence of a connection between the full emergence of the Isthmus at 3.5 Ma and the onset of the NHG. There is, however, strong evidence that the full emergence of the Isthmus at 3.5 Ma changed the oceanography of the Caribbean Sea to its modern conditions, although the role of other variables influencing Pleistocene Caribbean Sea conditions, including the changes in the Pleistocene climate and the cessation of the freshwater flow of several South American rivers into the Caribbean, still needs to be evaluated. The GABI is more complex than is often assumed, and it seems that variables other than a continuous terrestrial Isthmus have controlled the direction, timing and speed of migrations in both directions.

Equipe organisatrice : Grands Séminaires ISTerre

Séminaire uniquement en visio

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Equipe organisatrice : Organisation labo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Mécanique des failles

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Grands Séminaires ISTerre

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Grands Séminaires ISTerre

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Organisation labo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Tectonique active et sismicité

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Cycle sismique et déformations transitoires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Cycle sismique et déformations transitoires

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères

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Equipe organisatrice : Cycle sismique et déformations transitoires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

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