An 85-ka record of climate change in lowland Central America

Hodell, D. A. and Anselmetti, F. S. and Ariztegui, D. and Brenner, M. and Curtis, J. H. and Gilli, A. and Grzesik, D. A. and Guilderson, T. J. and Muller, A. D. and Bush, M. B. and Correa-Metrio, A. and Escobar, J. and Kutterolf, S. (2008) An 85-ka record of climate change in lowland Central America. Quaternary Science Reviews, 27 (11-12). pp. 1152-1165. ISSN 0277-3791 DOI

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Drill cores obtained from Lake Petén Itzá, Petén, Guatemala, contain a not, vert, similar85-kyr record of terrestrial climate from lowland Central America that was used to reconstruct hydrologic changes in the northern Neotropics during the last glaciation. Sediments are composed of alternating clay and gypsum reflecting relatively wet and dry climate conditions, respectively. From not, vert, similar85 to 48 ka, sediments were dominated by carbonate clay indicating moist conditions during Marine Isotope Stages (MIS) 5a, 4, and early 3. The first gypsum layer was deposited at not, vert, similar48 ka, signifying a shift toward drier hydrologic conditions and the onset of wet–dry oscillations. During the latter part of MIS 3, Petén climate varied between wetter conditions during interstadials and drier states during stadials. The pattern of clay–gypsum (wet–dry) oscillations during the latter part of MIS 3 (not, vert, similar48–23 ka) closely resembles the temperature records from Greenland ice cores and North Atlantic marine sediment cores and precipitation proxies from the Cariaco Basin. The most arid periods coincided with Heinrich Events when cold sea surface temperatures prevailed in the North Atlantic, meridional overturning circulation was reduced, and the Intertropical Convergence Zone (ITCZ) was displaced southward. A thick clay unit was deposited from 23 to 18 ka suggesting deposition in a deep lake, and pollen accumulated during the same period indicates vegetation consisted of a temperate pine-oak forest. This finding contradicts previous inferences that climate was arid during the Last Glacial Maximum (LGM) chronozone (21±2 ka). At not, vert, similar18 ka, Petén climate switched from moist to arid conditions and remained dry from 18 to 14.7 ka during the early deglaciation. Moister conditions prevailed during the warmer Bolling–Allerod (14.7–12.8 ka) with the exception of a brief return to dry conditions at not, vert, similar13.8 ka that coincides with the Older Dryas and meltwater pulse 1A. The onset of the Younger Dryas at 12.8 ka marked the return of gypsum and hence dry conditions. The lake continued to precipitate gypsum until not, vert, similar10.3 ka when rainfall increased markedly in the early Holocene.

Item Type: Article
Additional Information: Hodell, David A. Anselmetti, Flavio S. Ariztegui, Daniel Brenner, Mark Curtis, Jason H. Gilli, Adrian Grzesik, Dustin A. Guilderson, Thomas J. Mueller, Andreas D. Bush, Mark B. Correa-Metrio, Alexander Escobar, Jaime Kutterolf, Steffen
Uncontrolled Keywords: NIL AREP
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Quaternary Science Reviews
Volume: 27
Page Range: pp. 1152-1165
Identification Number:
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:02
Last Modified: 23 Jul 2013 10:07

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