Journal and Proceedings of
The Royal Society of New South Wales
Volume 121 Part 4 [Issued July, 1989]
CONTENTS
| AUTHORS & TITLES | PAGES |
| Sutherland, F.L., Demise of the Dinosaurs and other Denizens – by Cosmic Clout, Volcanic Vapours or other Means [Presidential Address, 1988] |
123-164 |
| Hunter, Robert J., High Frequency Transport Properties of Colloidal Dispersions [Liversidge Lecture, 27th July, 1988] |
165-178 |
| Singh, S.K., Geology of Tillegra Dam Site | 179-184 |
| Theses Abstracts [Opening in a new page] | |
| McNamara, R., Characterisation of Urban Storm Water Run-Off Quality, Jamieson Park, N.S.W. | 185 |
| Yue, Lei, Palaeoecological Studies of the Ordovician Fossil Hill Limestone, Central New South Wales | 187-188 |
Vol 121 Prt 4, pp. 123-164
Demise of the Dinosaurs and other Denizens – by Cosmic Clout, Volcanic Vapours or other Means
F.L. Sutherland
[Presidential Address, 1988]
Abstract. Three of the more dramatic events in natural history – extinction of species, meteoric impacts and volcanic outpourings have come together in a scientific controversy.
Did the dinosaurs die out suddenly? Did other organisms die out with them? A thin layer of sediment found at many places on land and ocean floor marks the boundary of Cretaceous and Tertiary time 65 million years ago. It shows an unusually strong enrichment in heavy metal elements such as iridium. This is claimed to mark a catastrophic event, giving dust clouds that reduced sunlight and blighted vegetation worldwide. The breakdown of food chains is blamed for the suggested demise of both large land animals such as dinosaurs and microscopic marine forms.
One school favours an extraterrestrial impact for the 'catastrophe' marker bed, another violent volcanic discharges from the earth's core. The evidence is conflicting. This paper sorts through these scenarios and seeks a solution. Australian evidence is rarely considered in the balance of the arguments. New concepts on Australia's past volcanism will be discussed, as they seems to suggest vigorous volatile volcanism 65 million years ago.
Vol 121 Prt 4, pp. 165-178
High Frequency Transport Properties of Colloidal Dispersions
Robert J. Hunter
[Liversidge Lecture, 27th July, 1988]
Abstract. Colloidal dispersions occur in a wide range of scientific and technological situations and their proper characterization is an important area of scientific activity. Almost all colloidal systems are composed of particles which carry a net electrical charge on their surfaces, unless special precautions are taken to remove that charge. Indeed, apart from particle size and shape, electrical charge is probably the most important property determining the behaviour in almost all situations.
Both the static (equilibrium) and the kinetic charge are normally determined and the two values used to develop a picture of the charge distribution in the region around each particle. That information can then be used to calculate the electrostatic interactions between the particles and hence, to estimate important aspects of behaviour.
This paper describes some important new techniques for estimating the magnitude of the charge and its distribution in the neighbourhood of the surface. Important new insights are gained from the study of the conductance and interaction of ultrasonic waves and electrical fields at the same frequencies.
Vol 121 Prt 4, pp. 179-184
Geology of Tillegra Dam Site
S.K. Singh
Abstract. Geological investigation of the proposed dam site at Tillegra indicates that the site is suitable for construction of a concrete-faced rock fill dam. Arenites of variable composition are the predominant lithological constituents of the site. The beds are conformable, strike NNW, and dip upstream into the pondage (westerly) with an average angle of 42°. Weathered horizons are present and sometimes may need excavation of more than 10 m during foundation work for the dam. Rock mechanics and petrographic analysis favour the chosen construction mode. Unconfined uniaxial compressive strengths of up to 85 MPa for the arenites, indicates that the foundation is very strong. Most importantly the site does not exhibit any structural anomaly.