Hydroclimate dynamics during the Plio-Pleistocene transition in the northwest Pacific realm

The appraisal of sedimentary archives is key for predicting sea level changes and extreme weather event behavior under varying greenhouse gas levels. Here, we assess the hydroclimate variability of the northwest Pacific realm during the Pliocene-Pleistocene transition by using a continuous record of gamma-ray log data from two bore -holes comprising shallow-marine strata in the Western Foreland Basin, Taiwan. The gamma-ray records provide a high temporally resolved stratigraphic record spanning from-3.15 to-1.95 million years ago. The comparison of the astronomically tuned gamma-ray logs to global sea-level and regional sea-surface temperature re-constructions highlights the impact of high-and low-latitude climate drivers on depositional cycles during the Plio-Pleistocene transition. During the late Pliocene, the interplay between the orbitally paced East Asian Summer Monsoon and tropical cyclones dominates the fluctuation in sediment supplied from Taiwan to our study sites. With the intensification of Northern Hemisphere glaciation from the late Pliocene through the early Pleistocene, sea-level changes were ruled by increasingly pronounced glacial-interglacial cycles, and the sedi-mentary record during this time interval is paced initially by obliquity and later by precession. This study reveals that shallow marine strata can record a more complex history of past hydroclimatie dynamics in the northwest Pacific than recorded in deep sea climate archives.

Automated summary

In this study, the hydroclimate variability of the northwest Pacific during the Pliocene-Pleistocene transition is assessed using gamma-ray log data from shallow-marine strata in the Western Foreland Basin, Taiwan. The comparison of the gamma-ray logs with sea-level and sea-surface temperature reconstructions reveals the influence of climate drivers on sedimentary cycles during this transition. The findings highlight the complex history of past hydroclimate dynamics in the northwest Pacific that can be recorded in shallow marine strata.