Glacial water mass geometry and the distribution of δ13C of ΣCO2 in the western Atlantic Ocean

摘要: [1] Oxygen and carbon isotopic data were produced on the benthic foraminiferal taxa Cibicidoides Planulina from 25 new piston cores, gravity multicores Brazil margin. The cores span water depths about 400 to 3000 m intersect major masses in this region. These fill a critical gap South Atlantic Ocean provide motivation for updating classic glacial western δ13C transect of Duplessy et al. (1988). distribution ΣCO2 requires presence three distinct Ocean: shallow (∼1000 m), southern source mass with an end-member value 0.3–0.5‰ VPDB, middepth (∼1500 northern 1.5‰, deep (>2000 less than −0.2‰, perhaps as low −0.9‰ values observed sector Southern (Ninnemann Charles, 2002). origins are supported by meridional gradients δ18O. A revised section documents positions among these intermediate masses. large property strong vertical mixing can only be maintained vigorous overturning circulation.