Ocean ventilation and sedimentation since the glacial maximum at 3 km in the western North Atlantic

摘要: [1] Stable isotope, sedimentological, and radiocarbon data from cores at ∼3 km water depth on the Blake Ridge, western subtropical North Atlantic, reveal history of deep ventilation since last glacial maximum (LGM). Bulk sediment accumulation rates varied locally by a factor 2 under influence bottom currents in this drift environment, but sand flux, mostly foraminifera, was nearly identical given time. This suggests that rain rate foraminifera (mostly planktonic) constant, transport negligible, current-controlled differences clay silt drive bulk accumulation. In two cores, flux peaks benthic Cibicidoides Uvigerina peregrina occurred during Younger Dryas (YD) cold event, 18.2, 19.6, 21.1, 25.0, 28.1 ka. Radiocarbon measurements those show age waters ∼1000 years YD, for older events it as great 2000 years. These results contrast with Holocene ventilation, which ∼500 700 1500 ∼7100 before present, respectively.