Last glacial-magnitude ice-rafted debris deposition and its provenance in the earliest Pleistocene sub-polar North Atlantic ocean

Author(s): Bailey, Ian; Foster, G. L.; Wilson, P. A.; Jovane, L.; Storey, C.; Becker, J.; Bolton, C. T.
Author Affiliation(s): Primary:
University of Southampton, School of Ocean & Earth Science, Southampton, United Kingdom
University of Portsmouth, United Kingdom
Cardiff University, United Kingdom
Universidad de Oviedo, Spain
Volume Title: AGU 2011 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2011; American Geophysical Union 2011 fall meeting, San Francisco, CA, Dec. 5-9, 2011. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: We present the first spatial reconstruction of ice-rafted debris (IRD) deposition and its provenance in the sub-polar North Atlantic Ocean during the earliest large amplitude Pleistocene glacial, marine isotope stage (MIS) 100 (∼2.52 Ma). Our flux estimates indicate that the magnitude of IRD deposition during MIS 100 was large with maximum inputs (at ∼53 N) comparable to the Last Glacial Maximum (LGM). IRD provenance was determined using laser ablation lead (Pb) isotope analyses of single feldspar grains. We find that the Pb isotope composition (206Pb/204Pb and 207Pb/204Pb) of individual ice-rafted (>150µm) feldspars deposited at DSDP Site 611A, ODP Site 981 and IODP Site U1308 during MIS 100 are very similar to those deposited at the centre of the LGM IRD belt during ambient ice-rafting episodes (Gwiazda et al., 1996a). Based on a comparison to known Pb isotopic composition of potential source regions we propose that abundant iceberg calving sourced from large, multiple circum-North Atlantic Ocean ice-sheets (located on North America, Scandinavia, Greenland and possibly Britain) characterised MIS 100. However, unlike for the LGM, the locus of abundant iceberg melting and IRD deposition may have been situated north of the Last Glacial IRD-belt (∼50 N) due to a reduced glacial meridional sea-surface temperature gradient relative to the late Pleistocene scenario.
Year of Publication: 2011
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Atlantic Ocean; Cenozoic; DSDP Site 611; Dates; Debris; Deep Sea Drilling Project; Expedition 303; Expeditions 303/306; Glacial geology; IODP Site U1308; IPOD; Ice; Ice rafting; Ice sheets; Icebergs; Integrated Ocean Drilling Program; Last glacial maximum; Leg 162; Leg 94; Lower Pleistocene; MIS 100; Mid-Atlantic Ridge; North Atlantic; North Atlantic ice sheets; Northeast Atlantic; ODP Site 981; Ocean Drilling Program; Pb/Pb; Pleistocene; Provenance; Quaternary; Rockall Bank; Sea ice
Coordinates: N495300 N495300 W0241400 W0241400
N552838 N552838 W0143903 W0143903
N525009 N525029 W0301834 W0301906
Record ID: 2018032703
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