Increased dust deposition in the Parece Vela Basin since the mid- Pleistocene inferred from radiogenic Sr and Nd isotopes

Abstract

Abstract Eolian dust deposition is crucial to paleoclimate reconstructions of dust source areas and may have played an important role in the climate during the mid-Pleistocene transition (MPT). Here, we present the radiogenic Sr and Nd isotopic composition and excess barium (Baxs) of a sediment core that was recovered from the Parece Vela Basin (PVB) in the northwestern Pacific. The new record indicates that these detrital sediments are primarily composed of dust from western and central Chinese deserts and volcanic materials from the islands in and around the PVB. A two end-member Sr isotope model was applied to distinguish Asian dust from volcanic materials and to reconstruct the mass accumulation rates (MARs) of dust over the last 2.1 Myr. Starting at ~1.2 Myr, the dust MARs doubled relative to those in the Early Pleistocene, which was coupled with the frequent congruence of minimum eccentricity and low obliquity. We argue that the congruent minimum eccentricity and low obliquity may have triggered the climate change before and during the MPT and resulted in the aridity of East Asia and increased dust input. The coupling of dust MAR, Baxs MAR and atmospheric CO2 concentration and their rapid increase since the MPT strongly suggest that the internal positive feedback of dust input might be another mechanism behind dust input to the PVB since the MPT.