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A study of late quaternary environment and man from four sites in Southeastern Tasmania.

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Sigleo, Wayne Richard (1978) A study of late quaternary environment and man from four sites in Southeastern Tasmania. PhD thesis, University of Tasmania.

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Abstract

A study of the geomorphic and stratigraphic relations of selected
sandsheets, lunettes and associated landforms in southeastern Tasmania
revealed a complex sequence of aeolian, slope and alluvial deposits including
buried soils that were developed during the late Quaternary period.
In addition, several of the aeolian deposits contained evidence of Aboriginal
occupation, and provided information on the antiquity of Man in southeastern
Tasmania and his role in locally modifying the landscape.
At least two major phases of aeolian activity are recorded from
the late Quaternary period, each related to relatively cold, and seasonally
arid conditions that occurred during and/or immediately following episodes
of periglacial activity in the lowlands of Tasmania. The age of the initial
phase of deflation is yet to-be determined; however, aeolian activity
could have occurred during either the Penultimate Glaciation or an early
stadial of the Last Glacial Stage. The aeolian sediments of this phase
unconformably overlie still older alluvial fan and lacustrine deposits.
These were formed during cold climatic conditions when geomorphic processes
causing slope instability and alluviation of small catchments operated with
greater intensity than during warmer and moister intervals. Reduced precipitation
was more than counter-balanced by reduced evaporation to
maintain high lake levels in the Midlands. Truncated paleosols on the
older sandsheets and dunes indicate that a period of climatic warming of
unknown duration and intensity occurred between the two major colder and
drier episodes.
Renewed deflation, resulting in the accumulation of younger
sandsheets and lunettes, occurred during the later part of the Last
Glacial Stage, and was broadly synchronous with a second period of fan
deposition and high lake levels. An approximate age for this phase of
aeolian activity is indicated by a radiocarbon date of 15,740 BP from a
sand dune at Malcolms Hut. Pollen evidence from lake sediments in the
Midlands suggests a considerably colder climate throughout much of this
period. Archeological material from the base of a sandsheet in the lower
Derwent Valley demonstrates the presence of Aboriginal Man in southeastern
Tasmania by at least the later part of the Last Glacial Stage. Towards
the end of the Last Glacial Stage, increased summer temperatures and
evaporation rates resulted in intermittent or seasonal drying of the lake
basins in the Midlands and clay dune formation.
This later phase of aeolian activity was followed by soil
development on the various sandsheets and lunettes, and weathering
occurred during the general climatic amelioration beginning at the end
of the Last Glacial Stage. Relative land surface stability continued
during the Holocene until profile truncation occurred locally through
Aboriginal occupation, and the site-intensive activities of Man were
responsible for the generation of secondary, anthropogenic coversand
deposits at some of the sites. Radiocarbon dates indicate the profile
truncation caused by Aboriginal occupation occurred by at least 5,800 BP
in the lower Derwent Valley and by 4,800 BP in the Midlands. European
land use and quarrying activities after 1803 resulted in the disturbance
of the Aboriginal occupation units and initiated the deposition of tertiary
aeolian deposits.
A reasonable framework exists for correlation of the major late
Quaternary events in southeastern Tasmania presented in this study with
similar sequences recorded from adjacent parts of the Australian mainland.

Item Type: Thesis (PhD)
Keywords: Geology, Stratigraphic, Landforms, Prehistoric peoples
Copyright Holders: The Author
Copyright Information:

Copyright 1978 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Thesis (Ph.D.)--University of Tasmania, 1979. Bibliography: l. 285-297

Date Deposited: 03 Feb 2015 03:21
Last Modified: 11 Mar 2016 05:56
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