HR: 17:40h
AN: U12B-06 [PDF]
TI: Analogue or Anomaly? Ocean Drilling Evidence From Marine Isotope Stage 11
AU: * McManus, J F
EM: jmcmanus@whoi.edu
AF: Dept of Geology and Geophysics, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole,
MA 02543 United States
AU: Oppo, D W
EM: doppo@whoi.edu
AF: Dept of Geology and Geophysics, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole,
MA 02543 United States
AU: Cullen, J L
EM: james.cullen@salemstate.edu
AF: Salem State College, Dept. of Geol., Salem, MA 01970 United States
AU: Huybers, P
EM: phuybers@ocean.mit.edu
AF: Program in Atmospheres, Oceans and Climate, MIT, PAOC, Cambridge, MA 02139 United States
AU: Federici, L
EM: lunaf@stanford.edu
AF: Dept of Geology and Geophysics, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole,
MA 02543 United States
AB:
Ocean Drilling makes it possible to recover high quality sedimentary archives from important earlier geologic intervals, such
as Marine Isotope Stage 11 (MIS 11), approximately 400 ky BP. Similar orbital configurations and comparable atmospheric
greenhouse gas concentrations have led to the suggestion that MIS 11 is a suitable, possibly the best, geological analogue
for the natural development of Holocene and future climate. Yet the anomalously strong climate response during MIS 11 in the
absence of strong seasonal insolation changes has long been described as the "the stage 11 problem". Here we review evidence
from a number of widely distributed ODP locations indicating that MIS 11 was not likely to have been a "super interglacial"
interval characterized by both significantly higher sea-level and global temperatures. We discuss the stability and strength
of the meridional overturning circulation as a potential compensator for the limited insolation. We present detailed faunal,
ice-rafting, and isotopic records from North Atlantic ODP Sites 980 (55$\deg$N, 15$\deg$W, 2.2km), 983 (60$\deg$N, 24$\deg$W,
2.0km), and 984 (61$\deg$N, 25$\deg$W, 1.6 km) confirm the relative stability of MIS 11 on millennial timescales, and
document that the transition to the more characteristic instability of the Pleistocene occurred dramatically and abruptly
following the warm interval. In addition, we consider a variety of tuning techniques and apply a new independent dating
approach to deep-sea sediment sequences to show that the regional stable warmth of MIS 11 in the North Atlantic long
outlasted the elapsed portion of the Holocene. Next, we address the question of possibly higher sea levels during MIS 11 with
isotopic evidence from ODP Site 925 (4$\deg$N, 43$\deg$W, 3.0km) in the Tropical Atlantic, ODP Site 1242 (8$\deg$N,
84$\deg$W, 1.4km) in the eastern tropical Pacific, and ODP Site 806 (0$\deg$N, 159$\deg$W, 2.5km) in the western tropical
Pacific. Finally, we discuss possible ways to reconcile the apparently conflicting evidence in existing records of sea-level,
temperature, and variability during MIS 11.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
DE: 3030 Micropaleontology
DE: 4267 Paleoceanography
DE: 4870 Stable isotopes
SC: U
MN: 2003 Fall Meeting