Preview

PDF (Whole thesis) whole_GoedeAlbe...pdf | Download (10MB) Available under University of Tasmania Standard License. | Preview

Abstract

The study is concerned with the parametric description
of a selected size class of the gravel bedload, collected from a
number of sample points, of the Tambo River in Eastern Victoria.
Lithological composition of the samples is investigated and
related to the lithological nature of the basin. Measurements
of form, sphericity and roundness are made for samples of the two
most abundant lithological types - rhyodacite and sandstone.
Changes in mean values of these parameters between stations are
related to operative processes, some of which can be characterized
by the physical and lithological characteristics of the basin.
kdetailed description is presented of the physical
environment of the catchment. Consideration is given to sampling
procedures and, the selection of suitable parameters to describe
pebble morphometry. It can be shown that Wadell and Maximum
Projection sphericity are partial expressions of form. R-mode
factor analysis is used to compare the relative merits of four
measures of roundness, on the basis of which the Kuenen and Kaiser
measures.are used for further work. Subsequently the Kuenen
roundness method is shown to be the most suitable for the purpose
of this study. The quantitative relationships between the lithological
nature of the basin and the composition of gravel samples are
investigated using methods of analysis first introduced by
Tricart in France in 1959 but apparently not previously applied
in the English speaking world.
The description of the mean form of a sample requires two
parameters but values of chi-square can be used as a single
parameter measuring the magnitude of change in form between two
sampling stations. Changes in form, sphericity and roundness
can be related to four basic processes: abrasion, shape sorting,
dilution and breakage. In the case of form and sphericity it is
shown that all four can be expressed in quantitative form.
Changes in mean roundness of sandstone pebbles show a
marked trend with respect to distance downstream, but no such
tendency can be observed in the case of Thyodacite particles.
Mean Kuenen roundness of samples can be replaced, with very little
loss of information, by abrasion and breakage indices devised by
the writer.
Matrices of correlation coefficients are used to
investigate relationships between variables both within and between
samples and in the latter case also between the two dominant
lithologies. They assist in reaching a better understanding of the
nature of inter-relationships. Finally, a multiple correlation and regression model is
employed to assess quantitatively the relative importance of
different processes in producing change in form and sphericity
between samples. In the case of rhyodacite highly significant
multiple correlations are obtained and it is found that nearly all
change can be explained in terms of processes and variations in
mean sample size. In the case of sandstone the technique is
less successful but even here changes in form at least have a
significant multiple correlation with parameters representing
processes and sample size.

Item Type:	Thesis - Unspecified
Authors/Creators:	Goede, A
Keywords:	Petrology
Copyright Holders:	The Author
Copyright Information:	Copyright 1972 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 (M.Sc.) - University of Tasmania, 1973. Bibliography: l. 174-180
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page