Li, L.Li, Q.Tian, J.Wang, H.Wang, P.2013-11-282013-11-282013Quaternary Science Reviews: the international multidisciplinary research and review journal, 2013; 78:209-2240277-3791http://hdl.handle.net/2440/81352High resolution records of long chain n-alkane biomarkers from the southern South China Sea reveal tightly response of n-alkane distribution to hydro-climate changes over the past 5Ma, with increasing longer chain n-C<inf>31</inf> alkanes indicating a correlation with drier conditions and increasing shorter chain n-C<inf>27</inf> alkanes with wetter conditions. The variations of the C<inf>31</inf>/C<inf>27</inf> ratio, or the alkane chain length index, imply humid conditions before 2.9Ma, progressively reduced moisture since then and to bigger fluctuations between wet and dry conditions since 1.2Ma. This long term hydro-climate trend is superimposed by glacial dry and interglacial wet patterns over the Plio-Pleistocene glacial cycles. Combined with other proxy records, our results indicate that precipitation over the tropical Asia-Pacific strengthened before the onset of the northern hemisphere glaciation and the mid-Pleistocene climate transition at about 1.2Ma. These dramatic humidity changes over major climate transitions imply a crucial role of tropical hydrology dynamics on global climate change in the late Cenozoic. © 2013 Elsevier Ltd.enCopyright © 2013 Elsevier Ltd.Plio-PleistocenePlant n-alkanesn-Alkane chain lengthsHydro-climateJournal article002013188910.1016/j.quascirev.2013.08.0070003279089000142-s2.0-8488379201317973