摘要:

This paper deals with the palaeotectonic evolution, depositional environment and metallogenetic events in West Tasmania during the Palaeozoic, as revealed by a programme of mineral exploration jointly financed by Rio Tinto Australian Exploration Pty. Ltd. and by Electrolytic Zinc Company of Australasia Ltd.

ISSN:0016-7614    

DOI:10.1080/00167616308728533

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The faunas of the Tulcumba Sandstone and its member, the Rangari Limestone, from the western edge of the Werrie and Belvue synclines of western New England are described. The stratigraphical and palaeontological data are considered to indicate a Tournaisian (Kinderhookian) age.

ISSN:0016-7614    

DOI:10.1080/00167616308728534

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The first open‐sea macrofossils from Australia which can be referred with certainty to the Triassic are described — a linguloid brachiopod, five species of pelecypods belonging to four genera, three species of ammonites belonging to three genera, worms, tracks and burrows. The fauna, which occurs through not less than 1,160 feet of shale regarded as Kockatea Shale, is referred to the Otoceratan, the lowest division of the Lower Triassic (Scythian). The fossils suggest a discontinuity in the Fitzroy Basin, Western Australia, between the Triassic Blina Shale and the underlying Upper Permian rocks. Faunas of the Otoceratan are rare, widespread and closely related, and the Western Australian fauna adds evidence that the lowermost Triassic was a time of widespread equable climate with relatively little tectonic movement.

ISSN:0016-7614    

DOI:10.1080/00167616308728535

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The later history of expanded spherulites (thunder eggs), as disclosed by the minerals found within their central cavities, is interpreted as due to three distinct generations of crystallization.

ISSN:0016-7614    

DOI:10.1080/00167616308728536

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Within the Daly River basin, Northern Territory, three erosion surfaces are described and their relationships to deep weathering are discussed. The Bradshaw surface is the highest and oldest surface recognized. It is of considerable perfection and forms main divides; it is associated with a deep lateritic profile with a strongly silicified horizon forming the lower part of the pallid zone and extending into rocks immediately beneath. The Maranboy surface now forms secondary divides, with related rock‐cut terraces, below the level of the Bradshaw surface. In most areas it was produced by the stripping of the upper, less silicified parts of the Bradshaw pallid zone. The Maranboy surface is associated with a lateritic weathering profile less deep than the Bradshaw profile and mainly developed in the Bradshaw weathering mantle. A younger erosion surface, the Tipperary surface, advanced by the removal of the Maranboy re‐weathered layer exposing the resistant Bradshaw silicified rock which commonly forms a base‐level of denudation. The Tipperary surface consists of broad plains, gently undulating terrain, and dissected headwater valley floors. It is relatively unweathered and carries depositional mantles which are attributed to climatically induced slope instability.

ISSN:0016-7614    

DOI:10.1080/00167616308728537

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The New Zealand succession spans the full length of the Permian, and unlike that of most areas of the world, is almost entirely marine, with faunas ranging from Sakmarian to topmost ("Tatarian") Permian. The Lower Permian is correlated by brachiopods, bivalves and gastropods with faunas of Queensland and New South Wales, and the Upper Permian by brachiopods, an ammonoid, and fusulinids with Tethyan sequences of south and east Asia.

ISSN:0016-7614    

DOI:10.1080/00167616308728538

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

A detailed petrological study has been made of a complete section of the Narrabeen Group exposed in a bore near Helensburgh. The Clifton Sub‐Group is characterised by two major cycles in which thick units of predominantly arenaceous sediments are interspersed with red‐brown claystones. Rock fragments are abundant in the sandstones, particularly near the base of the sub‐group, while siderite is common as a minor constituent. The red‐brown claystones show a marked contrast in composition with the shaly members of the thicker units in that quartz and siderite are absent or sparse and hematite is prevalent. However, the clay mineral contents of the two claystone formations differ. The upper or Bald Hill Claystone contains only kaolinite, whereas inter‐layered clay minerals and illite are present in addition to kaolinite in the lower or Stanwell Park Claystone. Hematite is absent from the upper few feet of the Bald Hill Claystone and kaolinite, partly in the form of vermicular crystals, may comprise the whole sample but elsewhere boehmite or siderite is prevalent. The texture varies from pisolitic to brecciated. The Gosford Formation overlying the Clifton Sub‐Group is composed predominantly of shales which resemble in texture and composition those of the later Wianamatta Group. A brief discussion of the origin of the Narrabeen Group is given.

ISSN:0016-7614    

DOI:10.1080/00167616308728539

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The analysis of the time‐relations between different minerals, between a mineral and some aspect of deformation, and between different aspects of deformation, enables the complex history of some regionally metamorphosed rocks to be recognized. Two separate periods of deformation occurred during the regional metamorphism of Precambrian schists, phyllites, quartzites and amphibolites from Frenchman's Cap, the Mersey‐Forth area and Port Davey, Tasmania.

ISSN:0016-7614    

DOI:10.1080/00167616308728540

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The characteristics of Bedded Cherts and Banded Iron‐Formations are summarised. As, following O'Rourke's work, the latter are considered as not confined to the Precambrian, the only significant difference between the two formations is shown to be the low iron content of Bedded Cherts. This difference it is suggested is due to Bedded Cherts having been deposited in a virtually continuously acid to weakly alkaline environment, whereas Banded Iron‐Formation was precipitated under an alternation of acid and alkaline conditions yielding siliceous and iron‐rich layers respectively. Such chemical precipitation of either Bedded Chert or Banded Iron‐Formation was in some examples of each type of formation rhythmically interrupted by the deposition of clastic sediment.

ISSN:0016-7614    

DOI:10.1080/00167616308728541

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The Cambrian System by definition must include the rocks (in the Caledonian geosyncline of Wales) to which this name was first applied. Its type sequence, however, does not define its boundaries. Evidence on the base of the Cambrian can be found in the Caledonian sedimentary areas of Scandinavia and in the adjoining Baltic region where the Blue Clay contains the oldest known Cambrian fauna. Further east, older rocks of similar character are known and there are references to glauconites over 1,200 million years (m.y.) old in these rocks. The base of the Cambrian cannot be extended down to the base of the sedimentary cover of the shelves surrounding the old shields. “Eocambrian” is probably the oldest defined term suitable for late Precambrian rocks which often resemble the Cambrian lithologically. They may contain a similar microflora, though their fauna which is rare and consists mostly of soft‐bodied animals, is different. There are in many areas tillites in rocks which could be Eocambrian, but their correlation is not yet definitely established. The definition of the base of the Cambrian rests therefore on biostratigraphic evidence and on chronological data (Glaessner, 1963).

ISSN:0016-7614    

DOI:10.1080/00167616308728542

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor