摘要:

Three extensive areas of intense scapolitization have been found in the Cloncurry district of north-western Queensland, centring on the Dugald River lead prospects, the old Duchess copper mine, and the Trekelano copper mine. At Dugald River the scapolite rocks occur over an area of more than 50 square miles, while at Duchess they outcrop over more than 30 square miles. They lie within the narrow, 150-mile long, north-south belt of Argylla gneisses and schists mapped by Honman, and may be co-extensive throughout this belt.

ISSN:0016-7614    

DOI:10.1080/14400955308527845

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

Large outcrop areas in the Canning Desert and the Fitzroy Valley of northwestern Australia consist of marine Jurassic and Upper Triassic rocks, not of Permian as formerly believed. On present knowledge, outcrops of the Triassic formations are restricted to parts of the Fitzroy and Bonaparte Gulf Basins, whereas the distribution of Jurassic (Kimmeridgian to Tithonian) rocks provides evidence for a major marine invasion that affected the Canning Desert area and may have advanced into the centre of the Australian continent and beyond. The late Jurassic transgression did not enter the Fitzroy Basin area.

ISSN:0016-7614    

DOI:10.1080/14400955308527846

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

Linear, planar and composite flow structures are discussed and classified with regard to the stereographic pattern of apparent lineations produced by their constituent fabric elements in random exposure planes. For simple structures it is shown that apparent lineations statistically coincide with either the true projection of a linear structure or the intersection of a planar structure, independent of the habit of their fabric elements. Combined and complex structures are differentiated and examples of the latter, expressed by either linear or planar fabric elements, are given from the Kosciusko batholith. It is pointed out how the different structural components may be identified and resolved in a semi-statistical manner on the Schmidt net.

ISSN:0016-7614    

DOI:10.1080/14400955308527847

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

The rheidity of a substance is defined as that property which determines whether it will behave as a fluid or solid for a particular experiment. It may be measured for given conditions of temperature, pressure, and shear stress, by that time for which the shear must be maintained for the deformation by viscous flow to exceed by one thousand times the elastic deformation. When loads are maintained for longer than the rheidity, the substance deforms as a fluid, and the elastic terms of the deformation equation may be neglected as insignificant. The rheidity of ice, salt, gypsum and serpentine are respectively of the order of a fortnight, a year, ten years and ten thousand years. Glaciers, salt domes, gypsum extrusions, and post-magmatic re-intrusion of serpentine are examples of rheid behaviour. Geological and astronomical evidence indicates that the rheidity of the mantle of the earth varies from tens of thousands of years at the top to hundreds of years at the base. Since tectonic loads are maintained from ten thousand to ten million years, the mantle of the earth behaves as a fluid for all geotectonic phenomena. The rheidity of the crust varies from 105to 109years, and hence the crust behaves as a solid for many tectonic processes. Geosynclinal materials and orogenic zones have, in general, shorter rheidities. and many fluid phenomena occur. Crystalline schists undergo rheid folding in the cores of orogens. Rheid folding, in spite of its appearance of extreme complexity, obeys simple geometrical laws, the understanding of which allows the complexly attenuated and contorted folds to be projected and extrapolated from fragmentary data. The universal contortion of the Archaean gneisses, which is usually regarded as evidence of intense shortening, does not necessarily imply much shortening or intense diastrophism.

ISSN:0016-7614    

DOI:10.1080/14400955308527848

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

The lithology and primary structural features of the Ordovician rocks of Victoria, and also of many of the Silurian rocks, are explicable according to the hypothesis of turbidity currents, but it is necessary to account for the preservation of a very complete succession of graptolite-bearing horizons in these rocks. It is suggested that the graptolites which are fossilized within graded beds, occurring towards the top in their silty or clayey portions, represent communities killed by fine suspended detritus in the upper parts of turbidity currents. Each graded bed is thus taken to represent a very small portion of time, and the duration of the diastems on major bedding planes is, correspondingly, much greater. A review of sedimentation and vulcanicity within the Victorian geosynclinal zone in the lower Palaeozoic is given.

ISSN:0016-7614    

DOI:10.1080/14400955308527849

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor