 Quaternary climatic reconstructions of the Tibetan Plateau area are mostly based on pollen analysis, while Mesozoic climatic reconstructions are done by analyzing benthic foraminifera from paleo-oceanic basins.Little study has focused on the Tertiary period, at which the South Asian monsoon is thought to have initiated.Further studies on Tertiary carbon isotope composition of paleosols could be carried out to examine the shift in C3/ C4 vegetation ratio.