Onocerane testifies to dry climatic events during the Quaternary in the Tropics. - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Organic Geochemistry Année : 2004

Onocerane testifies to dry climatic events during the Quaternary in the Tropics.

Résumé

An unusual molecular fossil (onocerane I) has been detected for the first time in Quaternary lacustrine sediments (Lagoa do Caçó, NE Brazil). This molecule was initially thought to attest to the former presence of ferns or club mosses. According to possible plant precursors of onocerane-related molecules recorded in the literature and by comparison with palynological results and palaeoclimatic data, we here provide evidence that club mosses and ferns cannot account as sources of onocerane I in this setting. Onocerane I is abundant in the lipid extracts of sediments deposited during the two driest periods recorded in Northern Brazil (Last Glacial Maximum and Younger Dryas). This molecule is therefore suspected to be diagnostic of the development of plants adapted to dry or semi-arid conditions in this region.

Domaines

Géochimie
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Dates et versions

hal-00022457 , version 1 (10-04-2006)

Identifiants

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Jérémy Jacob, Jean-Robert Disnar, Mohammed Boussafir, Marie-Pierre Ledru, Ana Luiza Spadano Albuquerque, et al.. Onocerane testifies to dry climatic events during the Quaternary in the Tropics.. Organic Geochemistry, 2004, 35, pp.289-297. ⟨10.1016/j.orggeochem.2003.11.005⟩. ⟨hal-00022457⟩
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