Glaciation of Frenchmans Cap-National Park

Mapping of glacial landforms of the Frenchmans
Cap National Park shows that an independent
system of cirque and valley glaciers accumulated
upon and caused considerable modification of this
area during the last Pleistocene glaciation. Clearest
evidence of the sequence of advance and retreat
is seen in the Vera Valley where, during the maximum
phase, the ice reached the Vera Creek gorge
and overspilled a series of diffluence passes further
upstream. The history of subsequent retreat can
be traced with reference to the post-maximum
moraines.
Some detailed work on the morphology of the
lake basins makes possible a classification of lakes
which shows clearly the nature of the glaciation
and the influence of lithology. Careful consideration
of the aspect, morphology, and elevation of
the cirques in which many of these lakes occur
provides interesting comment upon the factors
governing accumulation and ablation in the maritime
mountain environment of glacial and lateglacial
times.
Radiocarbon assay of leaf fragments in rock-flour
below peat in a bedrock depression on the lip of
one of the high discrete cirques gives a minimum
age of 8720 ±220 years B.P. for the final deglaciation
of the Frenchmans Cap area in particular and
the western Tasmanian mountains in generaL
The present study is discussed with reference to
some of the chronological problems of the last
glruciation. The possibility of a sequence of glacials
and interglacials is recognized. As the Pleistocene
climate changes of the southern hemisphere form
the broad context of the present study attention is
drawn to analogies in the New Zealand sequence.