Aeolian n-alkane isotopic evidence from North Pacific for a Late Miocene decline of C4 plant in the arid Asian interior

A Late Miocene Terrestrial Temperature History for the Northeastern Tibetan Plateau's Period of Tectonic Expansion

“…Paleoenvironmental data for the Mid to Late Miocene from the Xining Basin and adjacent areas. (a) C 4 contributions derived using the carbon isotopes of n ‐alkanes from Ocean Drilling Program Site 1208 in the North Pacific (Jia et al, ). (b) δD values of n ‐alkanes from the eastern Qaidam Basin (Zhuang et al, ).…”

“…In ecosystemic terms, the expansion of C 4 plants (Shen et al, ) and the consequent turnovers in mammalian faunas (Y. Wang & Deng, ) occurred later than the Miocene. Nonetheless, it is notable that eolian n ‐alkanes from ODP sites 1208 and 886 in the North Pacific suggest a decline in C 4 plants (Figure a) connected with regional drops in temperature and the uplift of the northern TP between ~12 and 8 Ma (Jia et al, ). In addition, the establishment of monsoonal upwelling in the western Arabian Sea during the ~11‐ to 10‐Ma period can be linked to the outward expansion of the TP (Zhuang et al, ), suggesting that a broader impact was caused by the tectonic uplift, which occurred during the Late Miocene.…”

Late-Miocene palaeoecological evolution of the Tianshui Basin, NE Tibetan Plateau: Evidence from stable organic carbon isotope record

“…It was thought that the C 4 pants have occurred in Pakistan, Kenya, North America, and Asia's interior much earlier than 8 Ma (Morgan et al, 1994;Koch, 2003, 2004;Jia et al, 2012). However, stable carbon isotope measurements on carbonate and organic matter in the Chinese Loess Plateau (CLP), NW China suggest that C 4 plants began to expand at about 4 Ma (Ding and Yang, 2000).…”

Regional-scale variability in the spread of grasslands in the late Miocene

“…For example,Cotton et al (2014) found significant differences in regional C 4 abundance between late Miocene-mid-Pliocene sites at different elevations in northern Argentina. In Asia,Jia et al (2012) andSingh et al (2013) found evidence for ~20% C 4 3-6 Ma prior to previous estimates of C 4 expansion in the Tibetan Plateau region, although studies for the same region byLeier et al (2009), Martin et al (2011), Charreau et al (2012, andZhang et al (2012) found no such evidence. In Inner Mongolia,Zhang et al (2009) found little evidence for C 4 pre-8 Ma, and mixed C 3 -C 4 post-8 Ma.…”

“…For A horizon samples from lower paleosol, the error range is averaged from all three samples. Jia et al (2012) 50-15 -11 to -2 0% C3-Carbonate Leier et al (2009) …”