Journal and Proceedings of
The Royal Society of New South Wales
Volume 111 Parts 3 and 4 [Issued 20th December, 1978]
CONTENTS
| AUTHORS & TITLES | PAGES |
| King, D.S., Proper Motions in the Region of the Galactic Cluster NGC 2516 | 61-64 |
| Morgan, T.L., Precise Observations of Minor Planets at Sydney Observatory During 1977 | 65-70 |
| Robertson, W.H., The Minor Planets [Presidential Address, 1978] |
71-75 |
| Ly, Cheng K., Late Quaternary Deposits of the Newcastle-Port Stephens Area as Revealed by Grain Size and Scanning electron Microscopy | 77-88 |
| Korsch, Russell J., Region-Scale Thermal Metamorphism Overprinting Low-Grade Regional Metamorphism, Coffs Harbour Block, Northern New South Wales | 89-96 |
| Korsch, Russell J., The Use of Inflection Surfaces in Descriptions of Folds | 97-100 |
| Korsch, R.J., Archer, N.R. and McConachy, G.W., The Demon Fault | 101-106 |
| Loughnan, F.C. and Evans, P.R., The Permian and Mesozoic of the Merriwa-Binnaway-Ballimore Area, New South Wales | 107-119 |
| Powell, Christopher McA., Gilfillan, Malcom A. and Henry, Neville M., Early East-Southeast Trending Folds in the Sofala Volcanics, New South Wales | 121-128 |
| Bamber, R.K., Clarke, M.F. and Jamieson, Peter, An Unusual Specimen of Fossil Wood | 129-132 |
v. 111 pts 3-4, pp.61-64
Proper Motions in the Region of the Galactic Cluster NGC 2516
D.S. King
Abstract. Relative proper motions of stars in the region of the galactic cluster NGC 2516 based on plates taken with the 33 cm astrograph, are determined with the aim of identifying stars which are non-members. The relative proper motions have an average standard error of 0".07/century and reveal 19 likely non-members and 100 likely members.
v. 111 pts 3-4, pp.64-70
Precise Observations of Minor Planets at Sydney Observatory During 1977
T.L. Morgan
Abstract. Positions of 2 Pallas, 3 Juno, 11 Parthenope, 18 Melpomene, 39 Laetitia, 148 Gallia and 704 Interamnia obtained with the 33 cm camera are given.
v. 111 pts 3-4, pp. 71-75
The Minor Planets
[Presidential Address, 1978]
W.H. Robertson
Abstract. The discovery and observation of minor planets is summarised and a review given of our present knowledge of their orbits, masses diameters and surface properties.
v. 111 pts 3-4, pp. 77-88
Late Quaternary Deposits of the Newcastle-Port Stephens Area as Revealed by Grain Size and Scanning electron Microscopy
Cheng K. Ly
Abstract. Modern sediments of the Newcastle-Port Stephens area were examined by grain-size analysis and scanning electron microscopy to determine the characteristic differences. Sands from the nearshore marine, beach and frontal ridge, transgressive dune, and river environments are differentiated by their grain size characteristics and surface texture of quartz grains. The differences obtained in the modern environments were applied to the older Quaternary deposits of the area in order to reconstrct their depositional environments. Each Holocene of Pleistocene sequence is composed of relict deposits of nearshore marine, beach, frontal ridge and river sands.
v. 111 pts 3-4, pp.89-96
Region-Scale Thermal Metamorphism Overprinting Low-Grade Regional Metamorphism, Coffs Harbour Block, Northern New South Wales
Russell J. Korsch
Abstract. Two regional metamorphic events are recognised in the rocks of the Coffs Harbour Block in northeastern New South Wales. The first event (M1) is a progressive low-grade regional event with metamorphic recrystallisation increasing southwards towards the Bellinger Fault. In the southern part of the block M1 has been overprinted by a static thermal event (M2). Four metamorphic zones are recognised. Zones I and II contain rocks affected by M1 only, whereas Zones III and IV contain rocks affected by both M1 and M2. The sequence of facies produced by M1 is indicative of low-pressure II facies series, whereas the M2 facies belongs to the low-pressure I facies series. M1 is considered to be part of paired metamorphic belts recognised in New England. M2 is post-tectonic and possibly related to the intrusion of post tectonic batholiths.
v. 111 pts 3-4, pp.97-100
The Use of Inflection Surfaces in Descriptions of Folds
Russell J. Korsch
Abstract. The form of inflections surfaces for both fold trains and fold stacks are developed for theoretical fold profiles. The fold train inflection surfaces for symmetrical folds are always normal to the axial surfaces. For asymmetrical folds the above conditions need not apply. Inflection surfaces for field examples of mesoscopic folds are compared with the theoretical models.
v. 111 pts 3-4, pp. 101-106
The Demon Fault
R.J. Korsch, N.R. Archer and G.W. McConachy
Abstract. The Demon Fault is a major north-south trending ancient fault extending for over 200 km in length in the New England mobile belt in northeastern New South Wales. The most impressive feature is the consistent linearity. Previous authors have invoked strike-slip movements ranging from 30 km to 200 km, but it is possible conclusively to prove movements of the order of 17 km in a dextral sense. The Demon Fault is a fracture zone which has existed for a long period of time but along which there has been relatively little movement. It has possibly controlled sedimentation patterns and the emplacement of plutons.
v. 111 pts 3-4, pp. 107-119
F.C. Loughan and P.R. Evans
The Permian and Mesozoic of the Merriwa-Binnaway-Ballimore Area, New South Wales
Abstract. In the Merriwa-Binaway-Ballimore area a succession of essentially horizontal fluvial strata, ranging in age from the Late Permian to Middle Jurassic, forms a thin veneer draped over the structural high of Carboniferous granite and Middle Palaeozoic geosynclinal rocks that separates the northwestern Sydney Basin from the Coonamble Embayment of the Surat Basin. Subdivision of these strata has been possible by use of two key units; the Wollar Sandstone of mainly Triassic age, and the Ukebung Formation, which over most of the area forms the base of the Jurassic succession. The Ukebung Formation is of particular interest in that it comprises dominantly kaolinitic clayrock or flint clays that form the principal source of refractory kaolinite in Australia. Coal occurs in the Upper Permian Dunedoo Formation and is also associated with the kaolinite clayrocks of the Ukebung Formation but at present it appears to be of little commercial value. From examination of microfloral assemblages, the Ukebung Formation is of Toarcian (Late Early Jurassic) age whereas the youngest Triassic strata in the area, those of the Wallingarah Formation, were laid down in the Early Anisian (Early Middle Triassic). A hiatus in sedimentation of about 30 m.y., therefore, preceded deposition of the Ukebung Formation.
v. 111 pts 3-4, pp. 121
Christopher McA. Powell, Malcom A. Gilfillan and Neville Henry
Early East-Southeast Trending Folds in the Sofala Volcanics, New South Wales
Abstract. A regional interference-fold pattern has been discovered in the Ordovician Sofala Volcanics by tracing out mappable chert bands. The interference pattern results from superposition of meridionally-trending folds on an early east-southeast trending set of structures. The early folds are restricted to the Sofala Volcanics whereas the meridional folds affect all pre-Upper Carboniferous rocks in the region. The geometry of the early folds is determined in part by restoring the folded unconformity at the base of the Upper Devonian Lambie Group to the horizontal. The early folds were possibly formed in the latest Ordovician and/or Early Silurian, before the Lower Silurian Tanwarra Shale was deposited.
v. 111 pts 3-4, pp. 129-132
An Unusual Specimen of Fossil Wood
R.K. Bamber, M.F. Clarke and Peter Jamieson
Abstract. An unusual fossil wood from the South coast of New South Wales is described. Although siliceous, it was extremely friable. The fossil was composed almost entirely of long filaments which were shown microscopically to be siliceous replicas of the lumina and pit chambers of longitudinal tracheids. It was identified as Araucarioxylon.
The process of silicification in relation to the anatomy of the fossil is discussed.