摘要:

During late Precambrian to Mesozoic time an overall northward migration of the locus of east Australian orogeny was complemented by an overall southward migration of the locus of initial rifting in western Australia. Related shifts in dextral and/or compressive strain occurred along a trans‐Australia zone of relative crustal mobility. Palaeomagnetic data show that this overallanticlockwisemigration of compressive and tensional tectonic regimes about the continent corresponded to apparent overallclockwiserotation upon the globe by Palaeozoic Australia. We propose that the pattern of Australia's tectonism during late Precambrian to Mesozoic time accords with the episodic application in eastern Australia of major continent‐ward‐directed compressive forces. Such forces, moreover, were directed generally palaeowestward, and relative northward migration of the locus of stress application arose by Australia's apparent clockwise rotation upon the globe.

ISSN:0016-7614    

DOI:10.1080/00167617808729011

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Maps of the southwest Pacific area at 90, 60, 53, 83, 29, 21, and 10 m.y. are accompanied by brief descriptions of the data and palaeogeographic developments in each major area within the region. There are four stages in. the regional palaeogeographic development:I.I (80–60 m.y.): Tasman Basin and New Caledonia Trough formed; II (60–53 m.y.): Coral Sea Basin formed;II.III (53–21 m.y.): A great Melanesian marginal sea formed, bounded by Cainozoic island arcs;III.IV (21 m.y. to present): Much of northern part of Melanesian marginal sea consumed during retrograde motion of island arcs.

ISSN:0016-7614    

DOI:10.1080/00167617808729012

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Much of South Australia, western New South Wales, and Tasmania was affected by the Late Cambrian‐Early Ordovician Delamerian Orogeny. Areas of the former shelf margin exhibit molasse‐type conglomerates overlying a major late Middle to Late Cambrian unconformity (Jukesian Movement in Tasmania or Mootwingee Movement in western N.S.W.). In continental platform areas to the north the effects of the orogeny were less intense with, in the Georgina Basin for instance, only dis‐conformable relationships, and the overlying deposits consisting of fine elastics and carbonates. Regression accompanied this first phase of tectonic upheaval and was followed by a period of ‘late Tremadoc’ transgression of the sea into several embayment areas of the continental platform. This short‐lived transgression was succeeded by ‘early Arenig’ regression which appears to be related to a second, less intense Delamerian orogenic phase. Expression of this phase ranges from unconformity in west Tasmania (Haulage and Lynchford Movements) to disconformity in the Georgina Basin (Kelly Creek Movement).

ISSN:0016-7614    

DOI:10.1080/00167617808729013

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The stratigraphic nomenclature for the Lamington Volcanics in the southern part of the Tweed Shield Volcano is revised. An alkaline formation (the Kyogle Basalt) containing discontinuous rhyolitic‐agglomerate (the Homeleigh Agglomerate Member) and rhyolite flow (the Georgica Rhyolite Member) horizons is the basal unit of the volcanic succession. The Kyogle Basalt thins eastward where it is overlain by a subalkaline sequence comprising the Lismore Basalt, Nimbin Rhyolite, and Blue Knob Basalt respectively. The Lismore Basalt is composed predominantly of tholeiitic andesite with minor icelandite and sporadic flows of mildly alkaline rocks; tholeiitic andesites predominate in the Blue Knob Basalt. The Nimbin Rhyolite consists of rhyolite flows, and a relatively minor pyroclastic component (principally lapilli tuff).

ISSN:0016-7614    

DOI:10.1080/00167617808729014

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Thick rhyolite sheets occur within the middle Palaeozoic cauldron subsidence complexes in Victoria. Well‐preserved eutaxitic and vitroclastic textures in the basal regions of the Rubicon, Jemba, and Ryans Creek rhyolites provide evidence of an ash‐flow origin. Subsequent recrystallization during cooling has masked these primary textures towards the central and upper parts of the rhyolitic sheets. All three rhyolites show dense welding throughout and the major zonation observed is in the degree of granophyric recrystallization.

ISSN:0016-7614    

DOI:10.1080/00167617808729015

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The structural deformation which produced more than 80 Jura‐type folds each of an axial length exceeding 1 km, in the Redbank Area, N.T., involved only a 360‐to 400‐m thick blanket of sediments. This thin skin of sediments and volcanic rocks, belonging to the Lower Proterozoic Tawallah Group, consists from bottom to top of the Wollogorang Formation, Gold Creek Volcanics, and Pungalina beds. Folding did not involve the underlying Settlement Creek Volcanics or Aquarium Formation. It is postulated that the cause of this detachment and shearing off along the bottom of the thin blanket of sediments is the infiltration of carbonated, K‐rich hydrothermal fluids under high pressure. This occurred during a period of igneous activity related to a postulated deep‐seated alkaline magma thought to be responsible for the many breccia pipes in the area. Thus the folds result from a décollement triggered by high fluid pressure, and from the accompanying gravity gliding and gravitational induced deformation of the thin skin of sediments along a gentle slope.

ISSN:0016-7614    

DOI:10.1080/00167617808729016

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Two lithofacies maps of the Lachlan Fold Belt, one for the Ordovician and one for the Silurian, are illustrated. Both maps indicate shorelines in western New South Wales, Victoria and Tasmania.

ISSN:0016-7614    

DOI:10.1080/00167617808729017

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167617808729018

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167617808729019

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167617808729020

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor