Leaf trait data of two Miocene floras from eastern China and its palaeoclimate implications

Abstract

The study of Neogene palaeoclimate supports our understanding of effects and consequences of current climate changes. However, many aspects and details of Miocene climate development are still unclear. Fossil leaves are a valuable and rich source of palaeoclimate proxy data. In this contribution, two Miocene leaf assemblages from eastern China, the Toupi flora and the Shengxian flora, were studied with respect to palaeoclimate and leaf economics. Whereas the Shengxian flora is dated to the lower Tortonian, the Toupi flora dates to approximately the border between Burdigalian and Langhian. For palaeoclimate, Climate Leaf Analysis Multivariate Program (CLAMP) was applied. In addition, Leaf Mass per Area (LMA), an essential leaf trait strongly correlated to leaf longevity, was included and was calculated morphometrically. For both sites, the data indicated a principally warm and humid climate, with Mean Annual Temperature (MAT) values between 13 and 17 °C. Also, the LMA indicates evergreen vegetation for both sites, consistent with the identified fossils and palaeoclimate. For Shengxian, however, this study concludes there was a lower temperature in the cooler season. This might possibly indicate a stronger temperature seasonality for this site due to slight climate cooling and East Asian monsoon intensification from the middle to late Miocene.