Sediment sorting and focusing in the eastern equatorial Pacific

• We analyzed downcore grain size distribution of the EEP sediment.
• Sorting coefficients and focusing factors within the same core were compared.
• Sediments in the EEP are moderately to well sorted.
• More focused sediments are also better sorted.
• Sediments in the EEP show evidence of lateral sediment redistribution.

The interpretation of sedimentary records in terms of glacial-interglacial changes in particle flux in the eastern equatorial Pacific (EEP) has been controversial. Here, we analyze disaggregated inorganic grain size (DIGS) distributions of three marine sediment cores from this region, focusing on the last 21 ka, to investigate evidence of sediment redistribution on the sea floor. Grain size sorting coefficients show that sediments in the EEP are moderately to well sorted, indicating sediment reworking in this region due to bottom currents. Furthermore, a systematic correlation between focusing factors and sorting coefficients at two sites shows that more focused sediments are also better sorted. We conclude that grain size based sedimentary records are consistent with the 230Th-based evidence of lateral sediment redistribution on the sea floor in the EEP.

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