A 13 200 year history of century to millennial-scale paleoenvironmental change magnetically recorded in the Palmer Deep, western Antarctic Peninsula

Author(s): Brachfeld, Stefanie A.; Banerjee, Subir K.; Guyodo, Yohan; Acton, Gary D.
Author Affiliation(s): Primary:
Ohio State University, Byrd Polar Research Center, Columbus, OH, United States
Other:
University of Minnesota, United States
University of Florida, United States
Texas A&M University, United States
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 194(3-4), p.311-326. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. 50 refs.; illus., incl. sketch map
Summary: A 13200-yr record of magnetic parameters from the Palmer Deep, western Antarctic Peninsula, records a sequence of five distinct shifts in glacimarine sedimentation coupled with century-scale variations in paleoproductivity. The five major shifts are manifested as abrupt, order of magnitude changes in low-field magnetic susceptibility, accompanied by changes in magnetic particle size and mineralogy. The Late Holocene (3.4-0 ka), the Early Holocene (11.5-9 ka), and the Last Glacial Maximum (prior to 13.2 ka) are intervals of strong low-field magnetic susceptibility and are characterized by multi-domain (MD) magnetite. MD magnetite is associated with zones of abundant gravel grains and is interpreted here as an indicator of material transported as ice-rafted debris. Deglaciation (13.2-11.5 ka) and the Middle Holocene (9-3.4 ka) were times of enhanced productivity. The Middle Holocene marks the onset of century-scale productivity cycles seen in high-field magnetic susceptibility, which is responding to variations in biogenic silica. Deglaciation and the Middle Holocene interval contain pseudo-single domain magnetite and titanomagnetite, respectively. These observations are surprising given the abundance of coarse MD magnetite available in local source rocks. The magnetic mineral assemblage in the Deglaciation interval, however, can be explained by density sorting in meltwater plumes. During the Middle Holocene, the magnetic mineral assemblage suggests the reduction or cessation of locally derived terrigenous sediment, and by inference, the reduction or cessation of iceberg generation. The Early Holocene-Middle Holocene shift in terrigenous sedimentation may be responding in part to sea level, which controls the position of the grounding line. The Palmer Deep Late Holocene interval coincides with the Neoglacial period, a time of glacier re-advances worldwide. Abstract Copyright (2002) Elsevier, B.V.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Antarctic Ocean; Antarctic Peninsula; Antarctica; Biogenic processes; C-14; Carbon; Cenozoic; Chronology; Climate change; Cores; Dates; Deglaciation; Glacial environment; Glacial geology; Glacial sedimentation; Glaciation; Glaciomarine environment; Glaciomarine sedimentation; High-resolution methods; Holocene; Ice movement; Ice rafting; Ice-rafted debris; Isotopes; Leg 178; Magnetic domains; Magnetic minerals; Magnetic susceptibility; Marine environment; Marine sedimentation; Marine sediments; Mineral assemblages; Multidomains; Neoglacial; ODP Site 1098; Ocean Drilling Program; Paleo-oceanography; Paleoclimatology; Paleoecology; Paleoenvironment; Paleomagnetism; Palmer Deep; Productivity; Quaternary; Radioactive isotopes; Sea-level changes; Secular variations; Sedimentation; Sediments; Terrigenous materials; Turbidite; Upper Quaternary
Coordinates: S645143 S645143 W0641228 W0641228
Record ID: 2002017322
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands