Pleistocene carbonate dissolution fluctuations in the eastern equatorial Pacific on glacial timescales: Evidence from ODP Hole 1241

This study presents a record of dissolution from the eastern equatorial Pacific (EEP) that extends to 2.1 Ma, based on sediments from Ocean Drilling Program (ODP) Site 1241. A new benthic oxygen isotope record was developed in order to provide the stratigraphic framework for the Pleistocene section of the core. The isotope record extends back to 2.1 Ma, covering MIS 1–80, and has a sampling resolution of 2 kyr from 0 to 360 kyr and 5 kyr from 360 to 2100 kyr. Dissolution at ODP Site 1241 is characterized through the use of percent coarse fraction (%CF) and shell fragmentation records. These records indicate that %CF in the EEP is recording a dissolution signal dominated by the 41-kyr and 100-kyr climate cycles, and that preservation maxima lag glacial maxima by 9–14 kyr at the major orbital periods. The dissolution signals observed in the ODP Site 1241 record can be correlated across the Pacific and likely record the response to basinwide changes in carbonate chemistry. The dissolution fluctuations and δ13C signal observed at ODP Site 1241 are consistent with both the Shackleton, 1977 and Toggweiler et al., 2006 hypotheses that explain changes in the global carbon cycle during glacial–interglacial transitions.

Research highlights
► CaCO3 dissolution signal at ODP 1241 dominated by major orbital periods.
► CaCO3 preservation maxima lag glacial maxima by 9–14 kyr at major orbital periods.
► % coarse fraction records dissolution signal in the eastern equatorial Pacific.
► Dissolution fluctuations can be correlated in cores across the Pacific.