摘要:

Two major divisions of the New England Fold Belt, Zone A and Zone B, are separated by the Peel Fault. Deposition in these two zones was probably contemporaneous (Lower Palaeozoic ‐ Lower Permian). Terminal orogenesis in both zones was also contemporaneous (Middle Permian) but whereas in Zone A deformation was only moderate, metamorphism was of burial type, and granitic emplacement was uncommon, in Zone B many rocks were severely deformed and regionally metamorphosed, and both syn‐tectonic and post‐tectonic granites are widespread.

ISSN:0016-7614    

DOI:10.1080/00167617408728840

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The Moon Island Beach Sub‐group is the top sub‐group of the Permian Newcastle Coal Measures. It crops out only along the coast near Newcastle; the geology has been detailed by over 200 bores which have penetrated the section over the northeastern part of the Sydney Basin.

ISSN:0016-7614    

DOI:10.1080/00167617408728841

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The Cambrian Mount Read Volcanics at Queenstown can be subdivided into three major units: (i) a central belt of quartz‐keratophyric lavas, consisting mainly of quartz and feldspar porphyries with lenses of massive potassic lava along the axial zone; (ii) a flanking belt of acid pyroclastic rocks which interfinger with sedimentary sequences of the Dundas Trough to the west and with the central lavas, and which are here termed the Queenstown Pyroclastics; and (iii) an unconformable Late Cambrian sequence of volcanic and sedimentary rocks here defined as the Tyndall Group. Important minor units are quartz‐feldspar porphyry and hornblende‐pyroxene porphyry intrusives and some newly‐discovered granitic bodies.

ISSN:0016-7614    

DOI:10.1080/00167617408728842

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Palaeomagnetic data obtained from studies of rock formations in southeastern Australia are compared with data from the main Australian assemblage. Occurrences and distributions of some of the major serpentine and ultramafic belts in the Tasman Orogenic Zone are interpreted according to current plate theory as marking sites of ancient plate margins. A tectonic model based on the palaeomagnetic data with the aid of geological constraints is proposed. It describes the rotation of a small region in southeastern Australia, relative to the main assemblage, by about 90° since the Middle Silurian and 30° since the Early Devonian. The proposed small plate boundaries may be represented by the Great Serpentine Belt to the east and in part by the less well defined belt of serpentinites which outcrop from Kiandra to Nyngan on the western margin. It seems unlikely that the whole of the western serpentine belt was actively involved with accretion during the Siluro‐Devonian. The northern limit of the plate cannot yet be denned. The significance of other serpentine belts may be assessed by extending palaeomagnetic investigation to include those regions suspected of having an active plate history.

ISSN:0016-7614    

DOI:10.1080/00167617408728843

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

New evidence for the age ofSubinyoites kashmiricus,combined with that ofClaraia stacheiandDiscophicerassp. cf.D. subkyokticum,has called for a revision in age of the Scythian (Lower Triassic) macrofauna from the Kockatea Shale of Beagle Ridge (BMR 10) Bore. The fauna is now regarded as of Scythian (Gries‐bachian to Smithian) age. Combination of this dating with additional palaeontological evidence from the Perth and Carnarvon Basins: (i) indicates that the base of the Kockatea Shale is markedly different in age in Beagle Ridge (BMR No. 10) Bore, Dongara No. 4, and in outcrop at Mount Minchin and Sugarloaf Hill; (ii) suggests that the Lower Triassic sea was most extensive during the Smithian in the Perth Basin; and (iii) confirms that most of the Locker Shale is younger than the Kockatea Shale.

ISSN:0016-7614    

DOI:10.1080/00167617408728844

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Geological sections are still best drawn at natural scale. Sections with vertical exaggerations are rarely drawn correctly, and even when computed carefully give a false notion of the structural features. Many schematic sections which are not drawn to scale and are supposed to explain a proposed new tectonic interpretation give such a distorted and frequently absurd picture of the structural features that they cannot be regarded as valid.

ISSN:0016-7614    

DOI:10.1080/00167617408728845

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The bedrock topography of Broken Bay on the eastern coast of Australia has been investigated by means of a low‐power marine sparker system.

ISSN:0016-7614    

DOI:10.1080/00167617408728846

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167617408728839

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor