Slow dynamics of the Northern Hemisphere glaciation
- 14 December 2005
- journal article
- Published by American Geophysical Union (AGU) in Paleoceanography and Paleoclimatology
- Vol. 20 (4)
Abstract
Unraveling the dynamics of the Northern Hemisphere glaciation (NHG) in the Pliocene is a key step toward a quantitative theory of the climate transition from a greenhouse to an icehouse world. Extracting the ice volume signal from marine oxygen isotope (δ18O) records corrupted with “temperature noise” can be accomplished using statistical time series analysis. We use 45 δ18O records from benthic and planktonic foraminifera and globally distributed sites to reconstruct the dynamics of NHG initiation. We compare δ18O amplitudes with those of temperature proxy records and estimate a global ice volume–related increase of 0.4‰, equivalent to an overall sea level lowering of 43 m. We find the NHG started significantly earlier than previously assumed, as early as 3.6 Ma, and ended at 2.4 Ma. This long‐term increase points to slow, tectonic forcing such as closing of ocean gateways or mountain building as the root cause of the NHG.Keywords
This publication has 96 references indexed in Scilit:
- Early Pliocene climate: A perspective from the western equatorial Atlantic Warm PoolPaleoceanography and Paleoclimatology, 1998
- Oak leaves as biosensors of late neogene and early pleistocene paleoatmospheric CO2 concentrationsMarine Micropaleontology, 1996
- Pliocene climates: the nature of the problemMarine Micropaleontology, 1996
- Mid-Pliocene warmth: stronger greenhouse and stronger conveyorMarine Micropaleontology, 1996
- Modeling of middle Pliocene climate with the NCAR GENESIS general circulation modelMarine Micropaleontology, 1996
- Timescale and paleoceanographic implications of a 3.6 m.y. oxygen isotope record from the northeast Indian Ocean (Ocean Drilling Program Site 758)Paleoceanography and Paleoclimatology, 1995
- Predicting extinctions of some extant planktic foraminiferaMarine Micropaleontology, 1992
- Pliocene-Pleistocene oxygen isotope record Site 586, Ontong Java PlateauMarine Micropaleontology, 1992
- Late Pliocene variation in northern hemisphere ice sheets and North Atlantic deep water circulationPaleoceanography and Paleoclimatology, 1989
- Preliminary estimates for the radiocarbon age of deep water in the glacial oceanPaleoceanography and Paleoclimatology, 1988