HR: 11:05h
AN: PP52B-04 INVITED     [Abstracts]
TI: Arctic's hydrology during global warming at the Palaeocene-Eocene thermal maximum
AU: * Pagani, M
EM: mark.pagani@yale.edu
AF: Yale University, 210 Whitney Avenue, New Haven, CT 06520 United States
AU: Pedentchouk, N
EM: nikolai.pedentchouk@yale.edu
AF: Yale University, 210 Whitney Avenue, New Haven, CT 06520 United States
AU: Huber, M
EM: huberm@purdue.edu
AF: Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906 United States
AU: Sluijs, A
EM: a.Sluijs@bio.uu.nl
AF: Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AU: Shouten, S
EM: schouten@nioz.nl
AF: Royal Netherlands Institute for Sea Research, PO Box 59, Texel, 1790 AB Netherlands
AU: Brinkhuis, H
EM: h.brinkhuis@bio.uu.nl
AF: Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AU: Sinninghe Damst‚, J S
EM: damste@nioz.nl
AF: Royal Netherlands Institute for Sea Research, PO Box 59, Texel, 1790 AB Netherlands
AU: Dickens, G R
EM: jerry@rice.edu
AF: Rice University, 6100 Main Street, Houston, TX 77005 United States
AB: The Palaeocene-Eocene thermal maximum (PETM) was an interval of rapid global warming ~55 million years ago, superimposed on the sustained warmth of the late Palaeocene and early Eocene. This event is associated with an >2.5‰ negative carbon isotope excursion in both marine and soil carbonates, and organic carbon, as well as a severe shoaling of the ocean calcite compensation depth; indicative of a massive input of ¹³C-depleted carbon. Recently, the Integrated Ocean Drilling Program (IODP) Expedition 302 successfully recovered upper Paleocene to middle Eocene sediments at 88° latitude on the Lomonosov Ridge in the central Arctic Ocean, providing the first opportunity to evaluate the environmental response at the North Pole to global warming during the PETM. Arctic PETM sediments are devoid of primary carbonates commonly employed to assess paleoclimate conditions, but contain abundant organic components. Here we present stable carbon and hydrogen isotope measurements of n-alkanes derived from higher plants and algae. The carbon isotopic excursion of terrestrial plant n-alkanes (-5 to -6‰) is larger than the excursion recorded in marine carbonates. However, the current model that explains these isotopic differences in terms of changes in soil moisture and humidity is inadequate for these Arctic samples given that the Arctic appears near saturation with respect to soil moisture and humidity during late Paleocene-early Eocene. The hydrogen isotopic compositions of n-alkanes suggest that regional precipitation was isotopically enriched during the PETM. Specifically, we observe a 55‰ positive excursion in the D/H composition of Arctic precipitation and argue that this isotopic enrichment was a consequence of reduced rain-out of subtropical water vapor due to a decrease in meridional and vertical temperature gradients. Thus, our data supports an increase in water vapor transport to the Arctic, leading to substantial changes in regional hydrology and surface water salinities as a consequence of global warming.
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 1055 Organic and biogenic geochemistry
DE: 3344 Paleoclimatology (0473, 4900)
DE: 3354 Precipitation (1854)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005