Final closure of Panama and the onset of Northern Hemisphere glaciation

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doi: 10.1016/j.epsl.2005.06.020
Author(s): Bartoli, G.; Sarnthein, M.; Weinelt, M.; Erlenkeuser, H.; Garbe-Schönberg, D.; Lea, D. W.
Author Affiliation(s): Primary:
Kiel University, Institute for Geosciences, Kiel, Federal Republic of Germany
University of California at Santa Barbara, United States
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 237(1-2), p.33-44. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 64 refs.; illus., incl. 1 table, sketch map
Summary: The Greenland ice sheet is accepted as a key factor controlling the Quaternary "glacial scenario". However, the origin and mechanisms of major Arctic glaciation starting at 3.15 Ma and culminating at 2.74 Ma are still controversial. For this phase of intense cooling Ravelo et al. [1] [A. C. Ravelo, D. H. Andreasen, M. Lyle, A. O. Lyle, M. W. Wara, Regional climate shifts caused by gradual global cooling in the Pliocene epoch. Nature 429 (2004) 263-267.] proposed a complex gradual forcing mechanism. In contrast, our new submillennial-scale paleoceanographic records from the Pliocene North Atlantic suggest a far more precise timing and forcing for the initiation of northern hemisphere glaciation (NHG), since it was linked to a 2-3°C surface water warming during warm stages from 2.95 to 2.82 Ma. These records support previous models [G. H. Haug, R. Tiedemann, Effect of the formation of the Isthmus of Panama on Atlantic Ocean thermohaline circulation, Nature 393 (1998) 673-676. [2]] claiming that the final closure of the Panama Isthmus (3.0-∼2.5 Ma [J. Groeneveld S. Steph, R. Tiedemann, D. Nurnberg, D. Garbe-Schonberg, The final closure of the Central American Seaway, Geology, in prep. [3]]) induced an increased poleward salt and heat transport. Associated strengthening of North Atlantic Thermohaline Circulation and in turn, an intensified moisture supply to northern high latitudes resulted in the build-up of NHG, finally culminating in the great, irreversible "climate crash" at marine isotope stage G6 (2.74 Ma). In summary, there was a two-step threshold mechanism that marked the onset of NHG with glacial-to-interglacial cycles quasi-persistent until today. Abstract Copyright (2005) Elsevier, B.V.
Year of Publication: 2005
Research Program: DSDP Deep Sea Drilling Project
ODP Ocean Drillng Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Albedo; Arctic region; Atlantic Ocean; C-13/C-12; Carbon; Carbon dioxide; Cenozoic; Climate change; Cooling; Currents; DSDP Site 609; Deep Sea Drilling Project; Foraminifera; General circulation models; Glaciation; Greenland; Greenland ice sheet; ICP mass spectra; Ice; Invertebrata; Isotope ratios; Isotopes; Leg 162; Leg 94; Mass spectra; Microfossils; Neogene; North Atlantic; Northern Hemisphere; O-18/O-16; ODP Site 984; Ocean Drilling Project; Ocean circulation; Ocean currents; Oxygen; Paleo-oceanography; Paleoclimatology; Paleotemperature; Panama Strait; Pliocene; Protista; Salinity; Sea ice; Sea-level changes; Sea-surface temperature; Spectra; Stable isotopes; Tertiary; Thermohaline circulation; Upper Pliocene
Coordinates: N612532 N612532 W0240457 W0240457
N495240 N495241 W0241417 W0241418
Record ID: 2006039022
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands