Late Quaternary moisture export across Central America and to Greenland: evidence for tropical rainfall variability from Costa Rican stalagmites
| Type | Article | ||||||||
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| Date | 2009-12 | ||||||||
| Language | English | ||||||||
| Author(s) | Lachniet Matthew S.1, Johnson Leah2, Asmerom Yemane2, Burns Stephen J.3, Polyak Victor2, Patterson William P.4, Burt Lindsay1, Azouz April1 | ||||||||
| Affiliation(s) | 1 : Univ Nevada, Dept Geosci, Las Vegas, NV 89154 USA. 2 : Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. 3 : Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA. 4 : Univ Saskatchewan, Dept Geol Sci, Saskatchewan Isotope Lab, Saskatoon, SK S7N 5E2, Canada. |
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| Source | Quaternary Science Reviews (0277-3791) (Pergamon-elsevier Science Ltd), 2009-12 , Vol. 28 , N. 27-28 , P. 3348-3360 | ||||||||
| DOI | 10.1016/j.quascirev.2009.09.018 | ||||||||
| WOS© Times Cited | 28 | ||||||||
| Note | Supplementary information for this manuscript can be downloaded at : http://www.sciencedirect.com/science/article/pii/S0277379109003217 | ||||||||
| Abstract | We present a high-resolution terrestrial archive of Central American rainfall over the period 100-24 and 8.1-6.5 ka, based on delta(18)O time series from U-series dated stalagmites collected from a cave on the Pacific Coast of Costa Rica. Our results indicate substantial delta(18)O variability on millennial to orbital time scales that is interpreted to reflect rainfall variations over the cave site. Correlations with other paleoclimate proxy records suggest that the rainfall variations are forced by sea surface temperatures (SST) in the Atlantic and Pacific Oceans in a fashion analogous to the modern climate cycle. Higher rainfall is associated with periods of a warm tropical North Atlantic Ocean and large SST gradients between the Atlantic and Pacific Oceans. Rainfall variability is likely linked to the intensity and/or latitudinal position of the intertropical convergence zone (ITCZ). Periods of higher rainfall in Costa Rica are also associated with an enhanced sea surface salinity gradient on either side of the isthmus, suggesting greater freshwater export from the Atlantic Basin when the ITCZ is stronger and/or in a more northerly position. Further, wet periods in Central America coincide with high deuterium excess values in Greenland ice, suggesting a direct link between low latitude SSTs, tropical rainfall, and moisture delivery to Greenland. Our results indicate that a stronger tropical hydrological cycle during warm periods and large inter-ocean SST gradients enhanced the delivery of low latitude moisture to Greenland. | ||||||||
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