(Appendix A) Oxygen and carbon isotope results of detrital carbonate grains of Heinrich layers from HU90-013-028 and IODP Sites 303-U1302/U1303/U1308 in the North Atlantic Ocean

• Main Authors: Hodell, David A, Curtis, Jason H
• Format: Dataset
• Language: English
• Published: PANGAEA 2008
• Subjects: 303-U1302D; 303-U1303B; 303-U1308B; 303-U1308C; 303-U1308E; Comment; DEPTH; sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Exp303; HU90-013-028; HUD90/13; Hudson; Identification; Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP; Joides Resolution; Labrador slope; Mass spectrometer Finnigan MAT 252; North Atlantic Climate 1; PC; Piston corer; Sample code/label; δ13C; δ18O; Canada; Labrador Sea; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.762947; https://doi.org/10.1594/PANGAEA.762947

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 (1sigma; n = 166), reflecting values of dolomitic limestone derived from source areas in northeastern Canada. The d18O 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 d18O 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 d18O also decreases during H3 and H6 but only attains values of - 1ppm, indicating either a greater proportion of biogenic-to-detrital carbonate or a different source. Because the d18O of detrital carbonate is ~ 9 ppm lower than foraminifer carbonate, any fine-grained detrital carbonate not removed from the inner test chambers will lower foraminifer d18O. We conclude bulk carbonate d18O 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.