THE NEOGENE ELEVATION OF SOUTHERN TIBET AS DETERMINED BY FOLIAR PHYSIOGNOMY
The leaf material, deposited in lacustrine waterlain tuffaceous silts, possesses taphonomic characteristics that suggest rapid burial, minimal pre-depositional transport and no species-dependant preferential preservation. Palaeoaltitude data were derived using leaf physiognomic analysis (CLAMP) combined with enthalpy fields derived from coupled ocean/atmosphere modelling for the mid Miocene and validated by CLAMP analysis of coeval sea-level floras. Altitudes derived from two CLAMP datasets (PHYSG3ar and PHYSG3br) suggest no significant change in altitude.
These data imply that the elevation of the southern plateau has remained unchanged over the past 15 Myrs. The results, coupled with other geological indicators also suggest a strongly diachronous nature of plateau uplift, thereby precluding simple links between local elevation histories and intensification of the monsoon system.