Anatomy of Heinrich Layer 1 and its role in the last deglaciation

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doi: 10.1002/2016PA003028
Author(s): Hodell, David A.; Nicholl, Joseph A.; Bontognali, Tomaso R. R.; Danino, Steffan; Dorador, Javier; Dowdeswell, Julian A.; Einsle, Joshua; Kuhlmann, Holger; Martrat, Belen; Mleneck-Vautravers, Maryline J.; Rodríguez-Tovar, Francisco Javier; Röhl, Ursula
Author Affiliation(s): Primary:
University of Cambridge, Godwin Laboratory for Palaeoclimate Research, Cambridge, United Kingdom
Other:
Eidgenössische Technische Hochschule Zürich, rich, Switzerland
Universidad de Granada, Spain
University of Bremen, Germany
Spanish Council for Scientific Research, Spain
Volume Title: Paleoceanography
Source: Paleoceanography, 32(3), p.284-303. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 113 refs.; illus., incl. 1 table, sketch map
Summary: X-ray fluorescence (XRF) core scanning and X-ray computed tomography data were measured every 1 mm to study the structure of Heinrich Event 1 during the last deglaciation at International Ocean Discovery Program Site U1308. Heinrich Layer 1 comprises two distinct layers of ice-rafted detritus (IRD), which are rich in detrital carbonate (DC) and poor in foraminifera. Each DC layer consists of poorly sorted, coarse-grained clasts of IRD embedded in a dense, fine-grained matrix of glacial rock flour that is partially cemented. The radiocarbon ages of foraminifera at the base of the two layers indicate a difference of 1400 14C years, suggesting that they are two distinct events, but the calendar ages depend upon assumptions made for surface reservoir ages. The double peak indicates at least two distinct stages of discharge of the ice streams that drained the Laurentide Ice Sheet through Hudson Strait during HE1 or, alternatively, the discharge of two independent ice streams containing detrital carbonate. Heinrich Event 1.1 was the larger of the two events and began at ∼16.2 ka (15.5-17.1 ka) when the polar North Atlantic was already cold and Atlantic Meridional Overturning Circulation (AMOC) weakened. The younger peak (H1.2) at ∼15.1 ka (14.3 to 15.9 ka) was a weaker event than H1.1 that was accompanied by minor cooling. Our results support a complex history for Heinrich Stadial 1 (HS1) with reduction in AMOC during the early part (∼20-16.2 ka) possibly driven by melting of European ice sheets, whereas the Laurentide Ice Sheet assumed a greater role during the latter half (∼16.2-14.7 ka). Abstract Copyright (2017), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 02 Geochemistry; 03 Geochronology; 24 Surficial Geology, Quaternary Geology; Absolute age; Assemblages; Atlantic Ocean; Biogenic structures; Bioturbation; C-14; Carbon; Cenozoic; Computed tomography data; Deglaciation; Expedition 303; Expeditions 303/306; Foraminifera; Heinrich Layer 1; Heinrich events; IODP Site U1308; Ice sheets; Integrated Ocean Drilling Program; Invertebrata; Isotope ratios; Isotopes; Manganese; Metals; Microfossils; Mid-Atlantic Ridge; North Atlantic; Northeast Atlantic; O-18/O-16; Oxygen; Paleoclimatology; Planktonic taxa; Pleistocene; Protista; Quaternary; Radioactive isotopes; Sedimentary structures; Spectra; Stable isotopes; Upper Pleistocene; X-ray data; X-ray diffraction data; X-ray fluorescence spectra
Coordinates: N495300 N495300 W0241400 W0241400
Record ID: 2017048287
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom