Quantitative results of IRD, microfossil, and isotopic analyses of Pleistocene sediments from Hole 919A in the western Irminger Basin, East Greenland margin

Author(s): St. John, Kristen; Flower, Benjamin; Rowe, Callie
Author Affiliation(s): Primary:
Appalachian State University, Department of Geology, Boone, NC, United States
Other:
University of South Florida, United States
Volume Title: Geological Society of America, 2001 annual meeting
Source: Abstracts with Programs - Geological Society of America, 33(6), p.20; Geological Society of America, 2001 annual meeting, Boston, MA, Nov. 1-10, 2001. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Hole 919A in the western Irminger Basin yielded a continuous section (100% core recovery) of Pleistocene sediments, which had high rates of deposition (6-35 cm/k.y.) and suitable materials for isotopic analyses. These conditions make 919A ideal for high resolution paleoclimatic and paleoceanographic study of the southeast Greenland margin. Oxygen and carbon isotope data on Neogloboquadrina pachyderma from 919A provide isotope stratigraphy and paleoenvironmental records of Irminger Basin surface waters. Correlation with deep Pacific records indicates that the 919A isotope records are controlled primarily by global influences. A census of the lithic, biogenic, and volcanic components of the >150 micrometer size fraction from each sample provide further proxy data for evaluating fluctuating glacial-interglacial climates on the east Greenland margin. Samples were taken every 20 cm from 0 to 94 meters composite depth (mcd; 0 to 610 ka). Sample resolution is 1.3 k.y. 500 grains were identified and counted in each sample. Results of the preliminary analysis of the counted dataset indicate: 1) Major source areas for IRD included central East Greenland redbeds, based on the abundance of hematite stained quartz, 2) IRD deposition had a 100 k.y. cyclic and saw-toothed pattern, suggesting repeated episodes of gradual ice build-up followed by rapid drawdown, and 3) warm water microfossil assemblages often occurred concurrently with rapid transitions from high to low % IRD.
Year of Publication: 2001
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 24 Surficial Geology, Quaternary Geology; Arctic region; Atlantic Ocean; Biochemistry; C-13/C-12; Carbon; Cenozoic; Continental margin; Continental margin sedimentation; Correlation; East Greenland; Foraminifera; Geochemistry; Glacial environment; Glaciomarine environment; Globigerinacea; Greenland; High-resolution methods; Ice rafting; Ice-rafted debris; Interglacial environment; Invertebrata; Irminger Basin; Isotope ratios; Isotopes; Leg 152; Marine environment; Marine sediments; Microfossils; Neogloboquadrina; Neogloboquadrina pachyderma; North Atlantic; O-18/O-16; ODP Site 919; Ocean Drilling Program; Oxygen; Paleo-oceanography; Paleoclimatology; Paleoecology; Pleistocene; Protista; Quaternary; Rotaliina; Sedimentation; Sedimentation rates; Sediments; Stable isotopes
Coordinates: N624012 N624012 W0372737 W0372737
Record ID: 2002011058
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