Distribution of lithic fragments and the planktic foraminifera Neogloboquadrina pachyderma in quaternary sediments of DSDP Hole 94-609 (Table 2)

• Main Authors: Broecker, Wallace S, Bond, Gerard C, Klas, Mieczyslawa, Clark, Elizabeth, McManus, Jerry F
• Format: Dataset
• Language: English
• Published: PANGAEA 1992
• Subjects: 94-609; Counting >150 µm fraction; Deep Sea Drilling Project; DEPTH; sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Foraminifera; per unit sediment mass; Glomar Challenger; Leg94; Lithic grains; Neogloboquadrina pachyderma sinistral; North Atlantic/FLANK; Sample code/label; Size fraction > 0.063 mm; sand; Ice Sheet; Neogloboquadrina pachyderma; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.667086; https://doi.org/10.1594/PANGAEA.667086

As first noted by Heinrich, 1988, glacial age sediments in the eastern part of the northern Atlantic contain layers with unusually high ratios of ice-rafted lithic fragments to foraminifera shells. He estimated that these layers are spaced at intervals of roughly 10000 years. In this paper we present detailed information documenting the existence of the upper five of these layers in ODP core 609 from 50°N and 24 °W. Their ages are respectively 15000 radiocarbon years, 20000 radiocarbon years, 27000 radiocarbon years, about 40000 years, and about 50000 years. We also note that the high lithic fragment to foram ratio is the result of a near absence of shells in these layers. Although we are not of one mind regarding the origin of these layers, we lean toward an explanation that the Heinrich layers are debris released during the melting of massive influxes of icebergs into the northern Atlantic. These sudden inputs may be the result of surges along the eastern margin of the Laurentide ice sheet.