Variation of clay mineral input in the Parece Vela Basin since the last 2.1 Ma and the response to the mid-Pleistocene climate transition

The composition and morphology of clay minerals collected from Core PV090102 in the Parece Vela Basin over the last 2.1 Ma were analyzed. Results show that the clays are mainly composed of illite (48% on average) and smectite (34%), and chlorite (13%) and kaolinite (6%). The illite crystallinity (0.29°Δ2θ) indicates that illite is mainly derived from cold and dry terrestrial regions; and the illite chemical index (0.32) implies that illite is rich in Fe-Mg and has experienced strong physical weathering. The clay mineral assemblage and morphological characteristics reflect that smectite is mainly derived from surrounding volcanic islands, while illite, chlorite, and kaolinite from Asian dust. The mass accumulation rates (MARs) of illite, chlorite, and kaolinite in Core PV090102 increased during mid-Pleistocene, which is consistent with the increase of MARs of eolian dust quartz in the Parece Vela Basin and Asia continent, suggesting that the MARs of illite, chlorite, and kaolinite in the Parece Vela Basin responded to the aridification in Asia during the mid-Pleistocene. Therefore, the MARs of illite, chlorite, and kaolinite in the Parece Vela Basin can be used to trace the paleoclimate change of Asian continent. In addition, variation of smectite MARs in Core PV090102 since the Quaternary is very consistent with the trend of volcanic material MARs in this core, and thus the variation can be used as a proxy of volcanic material input into the West Philippine Sea.