Increased seasonality during the intensification of Northern Hemisphere glaciation at the Pliocene-Pleistocene boundary ∼2.6 Ma

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doi: 10.1016/j.quascirev.2015.10.010
Author(s): Hennissen, Jan A. I.; Head, Martin J.; de Schepper, Stijn; Groeneveld, Jeroen
Author Affiliation(s): Primary:
University of Toronto, Department of Earth Sciences, Toronto, ON, Canada
Bjerknes Centre for Climate Research, Norway
University of Bremen, Germany
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, Vol.129, p.321-332. Publisher: Elsevier, International. ISSN: 0277-3791
Note: In English. 117 refs.; illus., incl. 2 tables, sketch map
Summary: Near the Pliocene-Pleistocene (Neogene-Quaternary) boundary during Marine Isotope Stage (MIS) 104 at around 2.6 Ma, the intensification of Northern Hemisphere glaciation (iNHG) was marked by a southward shift of the North Atlantic Current and Arctic Front and a concurrent drop in sea surface temperature (SST) in the mid-latitudes of the North Atlantic. Here we evaluate two Mg/Ca-based sea-surface temperature reconstructions for the 2.78-2.52 Ma interval using the planktonic foraminifera Globigerina bulloides and Globigerinoides ruber (white) sensu stricto as the biotic carriers (SSTbul and SSTrub), and a reconstruction based on the alkenone saturation index (SSTalk). The Mg/Ca-based SST estimates begin to diverge from one another significantly during MIS G3 (∼2.66 Ma), culminating during MIS 104 (∼2.60 Ma), and remaining distinctly different for the remaining 80 kyr of the studied interval. The magnitude of this divergence (ΔSSTrub-bul) is caused mainly by a decrease in SSTbul, with SSTrub remaining relatively constant. We attribute this difference to a drop in SST during the early-spring blooming season of G. bulloides that was less pronounced during the late-summer blooming season of G. ruber. Using ΔSSTrub-bul as a seasonality indicator, we show that seasonality increased significantly owing to a drop in early spring temperatures from MIS 104 onwards, and peaked during glacial episodes. Maximum seasonality occurred during MIS 104 in coincidence with a major expansion of the circum-Atlantic ice sheets, particularly the North American ice sheet. This expansion appears to have had a critical influence on global climate and especially seasonality.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Cenozoic; Climate forcing; Expedition 306; Expeditions 303/306; Foraminifera; Glacial geology; Glaciation; IODP Site U1313; Ice sheets; Integrated Ocean Drilling Program; Invertebrata; Microfossils; Mid-Atlantic Ridge; Neogene; North Atlantic; North Pacific; Northern Hemisphere; Orbital forcing; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleotemperature; Pleistocene; Pliocene; Protista; Quaternary; Sea-surface temperature; Seasonal variations; Tertiary
Coordinates: N410000 N410000 W0325700 W0325700
Record ID: 2016091795
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands