Articles | Volume 9, issue 4
Clim. Past, 9, 1911–1920, 2013
Clim. Past, 9, 1911–1920, 2013

Research article 14 Aug 2013

Research article | 14 Aug 2013

Post-Pliocene establishment of the present monsoonal climate in SW China: evidence from the late Pliocene Longmen megaflora

T. Su1,3, F. M. B. Jacques1, R. A. Spicer4,5, Y.-S. Liu6, Y.-J. Huang2, Y.-W. Xing7, and Z.-K. Zhou1,2 T. Su et al.
  • 1Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China
  • 2Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, China
  • 3State Key Laboratory of Paleobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology, the Chinese Academy of Sciences, Nanjing 210008, China
  • 4Department of Earth and Environmental Sciences, Centre for Earth, Planetary, Space and Astronomical Research, The Open University, Milton Keynes, MK7 6AA, UK
  • 5Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • 6Department of Biological Sciences, P.O. Box 70703, East Tennessee State University, Johnson City, Tennessee 37614-1710, USA
  • 7Institute of Systematic Botany, University of Zürich, Zürich, 8008, Switzerland

Abstract. The paleoclimate of the late Pliocene Longmen flora from Yongping County located at the southeastern boundary of the Qinghai-Tibet Plateau was reconstructed using two leaf-physiognomy-based methods, i.e., leaf margin analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP), to understand the paleoclimate condition and geographical pattern of monsoonal climate in southwestern China during the late Pliocene. The mean annual temperatures (MATs) estimated by LMA and CLAMP are 17.4 ± 3.3 °C and 17.4 ± 1.3 °C, respectively, compared with 15.9 °C at present. Meanwhile, the growing season precipitation (GSP) estimated by CLAMP is 1735.5 ± 217.7 mm in the Longmen flora, compared with 986.9 mm nowadays. The calculated monsoon intensity index (MSI) of the Longmen flora is significantly lower than that of today. These results appear consistent with previous studies on the late Pliocene floras in western Yunnan based on the coexistence approach (CA), and further suggest that there was a slightly warmer and much wetter climate during the late Pliocene than the present climate in western Yunnan. We conclude that the significant change of the monsoonal climate might have been resulted from the continuous uplift of mountains in western Yunnan, as well as the intensification of the eastern Asian winter monsoon, both occurring concurrently in the post-Pliocene period.