Magnetic properties of deep-sea sediments off Southwest Greenland; evidence for major differences between the last two deglaciations

Online Access: Get full text
doi: 10.1130/0091-7613(1995)023<0241:MPODSS>2.3.CO;2
Author(s): Stoner, Joseph S.; Channell, James E. T.; Hillaire-Marcel, Claude
Author Affiliation(s): Primary:
Université du Québec à Montréal, Centre de Recherche en Géochemie Isotopique et en Géochronologie (GEOTOP), Montreal, QC, Canada
University of Florida, Gainesville, FL, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 23(3), p.241-244. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 20 refs.; illus., incl. sketch map
Summary: High-resolution rock magnetic data, atomic mass spectroscopy 14C dates, δ18O, and grain-size analyses from a piston core (HU90-013-013) located off southwest Greenland provide a record of the last two deglaciations. During Termination I, a well-defined interval having high volumetric magnetic susceptibility (k) and a low ratio of anhysteretic susceptibility to volumetric magnetic susceptibility (kARM/k) postdates the Younger Dryas and the δ18O change marking the stage 2/1 boundary and correlates with sedimentological and geomorphological evidence for Greenland ice-sheet retreat from the coastline to the continental interior. During Termination II, a very similar magnetic signal coincides with the δ18O shift marking the stage 6/5 glacial-interglacial transition and continues throughout substage 5e. We suggest that this magnetic signal, during both Termination I and Termination II, marks continental meltwater-carried detritus from Greenland. If so, the synchronous changes in magnetic and oxygen isotopic records at Termination II indicate very early and rapid deglaciation of Greenland, in contrast to the relatively late deglaciation observed for Termination I. Distinct fluctuations in k and kARM/k occur below the onset of the δ18O change at Termination I (where they occur at ∼16 900 yr B.P.) and at Termination II. These fluctuations are interpreted as due to sudden influxes of detritus into the basin caused by unpinning of ice from the continental shelf at the inception of deglaciation.
Year of Publication: 1995
Research Program: ODP Ocean Drilling Program
Key Words: 03 Geochronology; 07 Marine Geology and Oceanography; 24 Surficial Geology, Quaternary Geology; Absolute age; Arctic region; Atlantic Ocean; C-14; Carbon; Cenozoic; Cores; Dates; Deep-sea environment; Deglaciation; Detrital sedimentation; Foraminifera; Glacial geology; Glacial sedimentation; Glaciation; Glaciomarine sedimentation; Globigerinacea; Grain size; Greenland; Holocene; Interglacial environment; Invertebrata; Isotope ratios; Isotopes; Labrador Sea; Leg 105; Lower Holocene; Magnetic hysteresis; Magnetic properties; Marine environment; Marine sedimentation; Marine sediments; Microfossils; Neogloboquadrina; Neogloboquadrina pachyderma; North Atlantic; O-18/O-16; ODP Site 646; Ocean Drilling Program; Oxygen; Paleomagnetism; Planktonic taxa; Pleistocene; Protista; Quaternary; Radioactive isotopes; Rotaliina; Sedimentation; Sediments; Stable isotopes; Textures; Upper Pleistocene; West Greenland
Coordinates: N581300 N581300 W0482200 W0482200
Record ID: 1995029700
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States