Cretaceous climate variations indicated by palynoflora in South China

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We compiled the Cretaceous sporopollen fossil data from 19 locations of six provinces in South China, reviewed the affinities of spore and pollen genera by examining and assessing these fossils with published data, and associated them with the sporomorph eco-groups (SEG) model and vegetation type. Seven palynofloral assemblages (PA1–PA7) were identified. PA1 (Berriasian–Valanginian) and PA2 (Hauterivian–Barremian) mainly include Cheirolepidiaceae (∼60–80%), Cycadophytes (∼10%), and Lygodiaceae (∼10%), indicating warm and dry climate; PA3 (Aptian) and PA4 (Albian) represent warm, semi-arid to semi-humid climate with vegetation composed of Araucariaceae (∼10%), Cheirolepidiaceae (∼40–60%), Cycadophytes (∼10%), and Lygodiaceae (∼10%); PA5 (Cenomanian–Turonian) and PA6 (Coniacian–Santonian) imply a hot, semi-humid to humid climate with the vegetation taxa of Lygodiaceae (∼20–40%), Cheirolepidiaceae (∼20–50%), Ephedraceae (∼5–8%), and Araucariaceae (∼10%); and PA7 (Campanian–Maastrichtian) indicates a relatively cool and dry climate evidenced by the vegetation composition of Cheirolepidiaceae (∼30–40%), Pteridaceae (∼10%), Ephedraceae (∼5–8%), and Ulmaceae (∼30–40%). Our SEG analysis reveals three climatic evolution phases: the Berriasian–Barremian warm-dry phase, the Aptian–Santonian warm-wet phase, and the Campanian–Maastrichtian cool-dry phase. The climatic variation pattern is compatible with that indicated by fossil stomatal pCO2 values and the pCO2 simulation of GEOCARB II and III models, providing independent climatic proxies of the region and contributing to better understanding of the global Cretaceous climatic changes.