Palynological evidence indicates the paleoclimate evolution in southeast China since late marine isotope stage 5

Abstract

Four coastal cores collected from Fujian province in southeast China revealed new palynological evidence of vegetation, sea level, and climate changes since the late marine isotope stage (MIS) 5. A comparison between modern and fossil pollen assemblages, using scanning electron microscopy and 45 dating samples ensured an accurate interpretation of pollen data. The evergreen Quercus-dominated pollen assemblage indicated that a relatively warm subtropical climate prevailed during the last glaciation, whereas large amounts of Tsuga pollen indicated distinct cooling during early MIS2. Marine dinocysts revealed three transgressional intervals in the Holocene, early MIS3, and late MIS5, which corresponded to a globally sea-level rising. Richer pollen from tropical and subtropical broad-leaved trees and higher sand content in grain-size components confirmed a warm climate during the early MIS1 and early MIS3, and strong river flow associated with heavy precipitation during late MIS5, reflecting the sensitive response of the land climate to high summer insolation. During the early MIS3 period, the reconstructed optimum climate was consistent with the sea surface temperature records in the west Pacific and northern South China Sea and summer monsoon signal from terrestrial records, implying that high summer insolation strongly affected the climate of East Asia.