Patterns of CaCO₃ deposition in the eastern tropical Pacific Ocean for the last 150 Kyr: Evidence for a southeast Pacific depositional spike during marine isotope stage (MIS) 2

We constructed biogenic mass accumulation rate (MAR) time series for eastern Pacific core transects across the equator at ∼105° and ∼85°W and along the equator from 80° to 140°W. We used empirical orthogonal function (EOF) analysis to extract spatially coherent patterns of CaCO₃ deposition for the last 150 kyr. EOF mode 1 (51% variance) is a CaCO₃ MAR spike centered in marine oxygen isotope stage 2 (MIS 2) found under the South Equatorial Current. EOF mode 2 (19% of variance) is high north of the equator. EOF mode 3 (9% of variance) is an east-west mode centered along the North Equatorial Counter Current. The MIS 2 CaCO₃ spike is the largest event in the eastern Pacific for the last 150 kyr: CaCO₃ MARs are 2-3 times higher at 18 ka than elsewhere in the record, including MIS 6. It is caused by high CaCO₃ production rather than minimal dissolution. EOF 2, while it resembles deep water flow patterns, nevertheless, shows coherence to C_org deposition and is probably also driven by CaCO₃ production.