2. Centre for Palynology and Palaeoecology, School of Geography and Environmental Science, Monash University, Victoria 3800, Australia.
3. Department of Earth Sciences, 204 Heroy Geology Laboratory, Syracuse University, New York 13244, USA
A fission-track dated discontinuous palynological record from
Pejark Marsh, a volcanic maar near Terang in the southeastern Western
plains of Victoria, shows evidence of the nature of vegetation
dynamics in the region from the Early to Mid Pleistocene period.
Represented amongst the minor pollen taxa, of predominantly
rainforest affinity, are some that are now regionally extinct. The
determination of which taxa were reworked from the underlying
Oligo-Miocene Gellibrand Marl and which were coeval with the Early
Pleistocene pollen record proved difficult and a number of
occurrences are still uncertain. Overall the major pollen taxa
recorded are similar to those that have dominated the vegetation of
the region during the late Quaternary, with evidence of variation
from forest during the warm and moist interglacials to dry steppe and
open woodland during glacial periods. However, this variability is
subdued in the basal part of the sequence, while the upper part shows
marked oscillations. It is likely that extinctions and the increase
in the strength of vegetation cycles are due to the development of
increased climatic variability, particularly increased aridity during
glacial periods, in the Middle to Late Pleistocene. Overall, the
Early Pleistocene pollen record of Pejark Marsh represents an
extension of the vegetation history of the Western Plains to form
part of a developing regional Quaternary biostratigraphy.