HR: 15:25h
AN: PP53A-08    [Abstracts]
TI: Holocene ENSO Reconstructions from Molecular Rain Gauges
AU: * Sachs, J P
EM: jsachs@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Zhang, Z
EM: zhaohui@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Smittenberg, R
EM: smitten@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Saenger, C
EM: csaenger@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Pahnke, K
EM: kpahnke@MIT.EDU
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 United States
AU: Koutavas, A
EM: athan@ldeo.columbia.edu
AF: Department of Earth and Environmental Science, Columbia University Lamont-Doherty Earth Observatory 61 Rt 9W, Palisades, NY 10964 United States
AB: The response ENSO to the mean climate state is poorly understood. Paleoclimate records of ENSO variability under different climate boundary conditions are needed to validate models but remain few and far between. Most existing records are from single cores or locations, are constructed from a single paleo-environmental proxy, and span a short time interval. In light of this paucity of data we are constructing a continuous history of ENSO-related rainfall anomalies, spanning the Holocene, from a wide diversity of settings across the equatorial Pacific, using a multitude of biomarker and molecular isotopic (D/H, 13C/12C) measurements. During 2004-2005 we collected sediment cores from equatorial lakes, bogs, hypersaline basins, and marine sediments in Palau (western Pacific), Kiribati and the Galapagos (central Pacific), and the Panama Basin (eastern Pacific). Each location was specifically targeted for its centrality in one of three zones of anomalous ENSO-related rainfall. Each water body cored was targeted for its sensitivity to rainfall variations. Many of the cores have sediment accumulation rates, derived from Pb-210 and C-14, that exceed 1 m/kyr, permitting decadal resolution. Here we report on our findings to date. Biomarker and molecular D/H records of drought in Palau, high lake levels in the Galapagos, and diminished Andean runoff to the Panama Basin indicate a late Holocene increase in El Nino frequency and/or intensity.
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 1055 Organic and biogenic geochemistry
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
DE: 4522 ENSO (4922)
DE: 4914 Continental climate records
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005