title: New sedimentary evidence reveals a unique history of C4biomass in continental East Asia since the early Miocene.
abstract: Pyrogenic carbon (PyC) and n-alkane data from sediments in the northern South China Sea reveal variations in material from C4plants in East Asia over the last ~19 Ma. These data indicate the likely presence of C4taxa during the earliest part of the record analysed, with C4species also prominent during the mid and late Miocene and especially the mid Quaternary. Notably the two records diverge after the mid Quaternary, when PyC data indicate a reduced contribution of C4taxa to biomass burning, whereas plant-derived n-alkanes indicate a greater abundance of C4plants. This divergence likely reflects differences in the predominant source areas of organic materials accumulating at the coring site, with PyC representing a larger source area that includes material transported in the atmosphere from more temperate (relatively cooler and drier) parts of East Asia. Variations in the relative abundances of C3and C4taxa appear to be linked to a combination of environmental factors that have varied temporally and geographically and that are unique to East Asia. A major expansion of C4biomass in warmer subtropical parts of eastern Asia from ~1 Ma and particularly from ~0.4 Ma is later than other parts of the world.
authors.affiliation: Key Laboratory of Surficial Geochemistry (Ministry of Education), School of Earth Sciences and Engineering, Nanjing University, Nanjing, China. zhoubinok@nju.edu.cn.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.affiliation: College of Science and engineering and Centre for Tropical environmental and Sustainability Science, James Cook University, Cairns, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Bird
authors.affiliation: School of Resource, Environment and Earth Science, Yunnan University, Chenggong District, Kunming, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and limnology, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Enlou
authors.initials: E
authors.lastname: Zhang
authors.affiliation: College of Science and engineering and Centre for Tropical environmental and Sustainability Science, James Cook University, Cairns, Australia.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Wurster
authors.affiliation: CAS Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Luhua
authors.initials: L
authors.lastname: Xie
authors.affiliation: Department of Geography, National University of Singapore, Singapore, Singapore.
authors.forename: David
authors.initials: D
authors.lastname: Taylor