Krissek, Lawrence et al. (2008): Coarse fraction abundances and the Plio-Pleistocene record of iceberg-rafting at IODP Sites 1305 and 1308, North Atlantic Ocean

Leg/Site/Hole:
IODP 303
IODP 303 U1305
IODP 303 U1308
Identifier:
2012-019100
georefid

Creator:
Krissek, Lawrence
Ohio State University, School of Earth Sciences, Columbus, OH, United States
author

Haack, Margaret
Northern Illinois University, United States
author

Leitner, P.
author

Stoll, A.
author

Krissek, P.
author

Calhoun, J. P.
author

Baumgartner, L.
author

Blake, D.
author

Guleff, E.
author

Identification:
Coarse fraction abundances and the Plio-Pleistocene record of iceberg-rafting at IODP Sites 1305 and 1308, North Atlantic Ocean
2008
In: Anonymous, Geological Society of America, 2008 annual meeting
Geological Society of America (GSA), Boulder, CO, United States
40
6
501
Plio-Pleistocene orbital- and suborbital-scale climatic variability in the North Atlantic was investigated during IODP Expedition 303, which cored Sites 1305 (southwestern Eirik Drift, 3459 mbsl) and 1308 (reoccupation of DSDP Site 609, central North Atlantic, 3871 mbsl). Sediments from Sites 1305 and 1308 were sampled with an average time spacing of approximately 3 ky, and analyzed for coarse fraction abundance (CFA; weight % of the 150 mu m-2 mm fraction) by sieving. Present data are the total CFA, including both biogenic particles (predominantly foraminifers) and terrigenous grains (interpreted as iceberg-rafted debris, or IRD). IRD grains have a significantly higher weight per grain, however, so IRD variations are interpreted to drive major variations in total CFA. The Site 1305 record extends to approximately 1 Ma, and contains six to seven major CFA peaks in the interval 0-700 ka. CFAs do not appear to correlate directly with marine isotope stages (MIS); e.g., both MIS 6 and MIS 11 have relatively low CFAs. However, larger CFA peaks tend to occur near transitions from an interglacial to a glacial. In the interval 700 ka-1.0 Ma, CFAs vary more frequently, recording local response to the mid-Pleistocene transition. The Site 1308 record extends to approximately 1.8 Ma. CFAs vary quasi-cyclically at a period of approximately 100-150 k.y. to approximately 950 ka, and CFA maxima tend to occur during MIS-defined glacials; however, not every glacial is marked by a CFA maximum, and a few maxima occur within interglacials or near stage transitions. CFA variations are more rapid before approximately 950 ka. Future work will define more clearly the roles of global vs. local controls on iceberg-rafting by: extracting the IRD signal from the CFAs; defining iceberg sources from IRD composition; and evaluating the IRD signals within the oxygen isotope stratigraphy developed for each site.
English
Coverage:Geographic coordinates:
North:57.2900
West:-48.3200East: -24.1400
South:49.5300

Stratigraphy; Atlantic Ocean; Cenozoic; cores; Eirik Drift; Expedition 303; Expeditions 303/306; glacial environment; glacial geology; grain size; ice rafting; icebergs; Integrated Ocean Drilling Program; interglacial environment; IODP Site U1305; IODP Site U1308; isotope ratios; isotopes; Mid-Atlantic Ridge; Neogene; North Atlantic; Northeast Atlantic; Northwest Atlantic; O-18/O-16; oxygen; Pleistocene; Pliocene; Quaternary; sampling; sediments; stable isotopes; Tertiary;

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