Oxygen and carbon isotopes of detrital carbonate in North Atlantic Heinrich events

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doi: 10.1016/j.margeo.2008.09.010
Author(s): Hodell, David A.; Curtis, Jason H.
Author Affiliation(s): Primary:
University of Florida, Department of Geological Sciences, Gainesville, FL, United States
Volume Title: Marine Geology
Source: Marine Geology, 256(1-4), p.30-35. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. Supplemental information/data is available in the online version of this article. 33 refs.; illus., incl. sketch map
Summary: We report oxygen and carbon isotope results of detrital carbonate grains from Heinrich layers at three sites in the North Atlantic located along a transect from the Labrador Sea to the eastern North Atlantic. Oxygen isotopic values of individual detrital carbonate grains from six Heinrich layers at all sites average -5.6 ppm± 1.5 ppm (1σ; n = 166), reflecting values of dolomitic limestone derived from source areas in northeastern Canada. The δ18O of bulk carbonate at Integrated Ocean Drilling Program (IODP) Site U1308 (re-occupation of Deep Sea Drilling Project (DSDP) Site 609) in the eastern North Atlantic records the proportion of detrital to biogenic carbonate and δ18O decreases to -5 ppm during Heinrich (H) events 1, 2, 4 and 5 relative to a background value of ∼1 to 2 ppm for biogenic carbonate. Bulk δ18O also decreases during H3 and H6 but only attains values of -1 ppm, indicating either a greater proportion of biogenic-to-detrital carbonate or a different source. Because the δ18O of detrital carbonate is ∼9 ppmlower than foraminifer carbonate, any fine-grained detrital carbonate not removed from the inner test chambers will lower foraminifer δ18O. We conclude bulk carbonate δ18O is a sensitive proxy for detrital carbonate and may be useful for identifying Heinrich layers in cores within and near the margins of the North Atlantic ice-rafted detritus (IRD) belt. Abstract Copyright (2008) Elsevier, B.V.
Year of Publication: 2008
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 02 Geochemistry; 24 Surficial Geology, Quaternary Geology; Anomalinidae; Atlantic Ocean; Biostratigraphy; C-13/C-12; Carbon; Carbonate sediments; Cassidulinacea; Cenozoic; Cibicidoides; Detritus; Expedition 303; Expedition 306; Expeditions 303/306; Foraminifera; Geochemistry; Globigerinacea; Grains; Heinrich events; IODP Site U1302; IODP Site U1303; IODP Site U1308; Ice rafting; Integrated Ocean Drilling Program; Invertebrata; Isotope ratios; Isotopes; Labrador Sea; Marine sediments; Microfossils; Mid-Atlantic Ridge; Neogloboquadrina; Neogloboquadrina pachyderma; North Atlantic; Northeast Atlantic; Northwest Atlantic; O-18/O-16; Oxygen; Protista; Provenance; Quaternary; Rotaliina; Sediments; Stable isotopes
Coordinates: N501000 N501000 W0453800 W0453800
N501200 N501200 W0454100 W0454100
N495300 N495300 W0241400 W0241400
N590000 N600000 W0580000 W0590000
Record ID: 2009022767
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands