Palynology of some tertiary deposits from New South Wales
Date
1975
Authors
Owen, Judith Annette
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Abstract
Microfloras from freshwater sediments from three localities in
New South Wales - Nerriga, Kiandra, and Cadia, have been studied and
compared with previously described Tertiary assemblages. Samples
for palynological study were taken from sections with a K-Ar dated
basalt to give independerit age control. For two localities, Kiandra
and Cadia (dated as early and middle Miocene, respectively) there is
good agreement betw2an the microfloral and radiometric ages. At
Nerriga, this dating is less precise; the age indicated by the
microflora is early Eocene, whereas the K-Ar age on the basalts
indicate late Eocene.
All three microfloral suites could be compared to those
described from the Gippsland and Otway Basins, and could therefore
be related to zones described from these sequences. Many characteristic
species from these south coast assemblages (e.g. some species
of Proteacidites) are absent, however. Suites from all three localities suggest a rainforest vegetation,
and can be considered part of the widespread Tertiary Cinnamomum
flora. This flora consists of Nothofagus of all three types (brassi,
menziesii, and fusca), various gymnosperms, and a diversity of
angiosperms and pteridophytes. Whether this was a pan-Australian
flora remains to be assessed, as data become available from areas
outside of southeastern Australia. Elements of this flora are also
found in Tertiary deposits of other southern regions - New Zealand,
Antarctica, Kerguelen, southern South America, and Ninetyeast Ridge. Most fossil taxa can be related to living groups with a
temperate distribution, although some tropical elements are present.
The assemblage indicates a higher rainfall in these areas in the
Tertiary than at present. Indications of warmer temperatures are
uncertain from the microfloras, although palaeotemperature data
indicate warmer temperatures at least in the Paleogene.
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