Oceanic heat pulses fueling moisture transport towards continental Europe across the mid-Pleistocene transition

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doi: 10.1016/j.quascirev.2017.11.009
Author(s): Bahr, A.; Kaboth, S.; Hodell, D.; Zeeden, C.; Fiebig, J.; Friedrich, O.
Author Affiliation(s): Primary:
Heidelberg University, Institute of Earth Sciences, Heidelberg, Germany
Other:
National Taiwan University, China
University of Cambridge, United Kingdom
Institute of Celestial Mechanics and Ephemeris Calculations, France
University of Frankfurt, Germany
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, Vol.179, p.48-58. Publisher: Elsevier, International. ISSN: 0277-3791
Note: In English. 91 refs.; illus., incl. sketch map
Summary: The mid-Pleistocene Transition (MPT; approx. 1.2-0.7 Ma), is characterized by growing Northern Hemisphere ice sheets and the shift from a 41 kyr to a 100 kyr glacial-interglacial cyclicity. Concomitant to the growth of large ice sheets, atmospheric and oceanic circulation pattern have changed. One key feature of the North Atlantic is the wind-driven Subtropical Gyre, a major provider of heat and moisture for continental Europe. Here, we investigate changes in the strength and spatial configuration of the Subtropical Gyre during the MPT and its impact on the continental moisture balance. To reconstruct Subtropical Gyre dynamics, we conducted paired δ18O and Mg/Ca analyses on the deep-dwelling foraminifera Globorotalia inflata from Iberian Margin Site U1385 yielding thermocline temperature (Ttherm) variability between 1400 and 500 ka at the eastern boundary of the Subtropical Gyre. Long-term trends of Ttherm at Site U1385 oppose the North Atlantic climatic evolution of progressively intensified glacials during the MPT. Particularly, glacials MIS 20 and 18 were marked by warm thermocline waters off Iberia. We infer that a southward shift of the (sub)polar front displaced the source region of thermocline waters within the Subtropical Gyre from high to mid-latitudes. In addition, a strong Mediterranean Outflow Water production during the MPT caused the advection of warm waters to Iberia. Humid conditions during MIS 20 and 18 in SE Europe indicate that atmospheric moisture derived from this warm water might have been advected deep into continental Europe and contributed to enhanced growth of Alpine glaciers.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Alkaline earth metals; Atlantic Ocean; Calcium; Cenozoic; Chemostratigraphy; Chronostratigraphy; Climate forcing; Cores; Expedition 306; Expedition 339; Expeditions 303/306; Foraminifera; IODP Site U1313; IODP Site U1385; Integrated Ocean Drilling Program; Invertebrates; Isotope ratios; Isotopes; Lithostratigraphy; Magnesium; Marine sediments; Metals; Mg/Ca; Microfossils; Mid-Atlantic Ridge; Middle Pleistocene; North Atlantic; O-18/O-16; Ocean circulation; Orbital forcing; Oxygen; Paleo-oceanography; Paleotemperature; Pleistocene; Protists; Quaternary; Reconstruction; Sediments; Stable isotopes; Thermocline
Coordinates: N373417 N373417 W0100719 W0100720
N410000 N410000 W0325700 W0325700
Record ID: 2018053588
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands