摘要:

Norfolk and Philip Islands on the Norfolk Ridge linking New Caledonia and New Zealand are deeply weathered erosional remnants of volcanoes consisting of olivine basalt lavas and tuff. Both volcanoes were active in the late Pliocene. The subaerial portion of the Norfolk volcano was constructed during several volcanic episodes from about 3.05 m.y. to about 2.3 m.y. ago. Both were built when relative sea level stood at about its present level, indicating that the Norfolk Ridge has been very stable at this latitude for the past 3 m.y.

ISSN:0016-7614    

DOI:10.1080/14400957308527916

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The basalts of Norfolk Island were erupted in three main episodes from 3.0 to 2.3 m.y. ago. Both tholeiites and alkali olivine basalts occur, and subordinate, more evolved rocks range into tholeiitic andesites and hawaiites. Chemically the rocks show no regular change in composition with time, over the 0.7 m.y. eruptive period, nor any compositional features peculiar to one period of eruption. They are characterized by high Na2O, moderately high Al2O3, uniform TiO2, and high K/Rb ratios. These chemical features are similar to Pliocene basalts in Northland, New Zealand, and southwest Victoria, but are distinctly different from other basalts in well documented oceanic and continental provinces. The Norfolk Island rocks plot in a unique field on a Ti-Zr-Y diagram. This is possibly attributable to the unique tectonic setting of Norfolk Island, on a ridge 20 km thick, about midway between the Australian continent and the active Tonga-Kermadec trench-arc system.

ISSN:0016-7614    

DOI:10.1080/14400957308527917

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The Finke Group in central Australia was divided into four formations by Wellset al.(1966), and the Santo Sandstone (Wellset al., 1967) is now included in the group as a synonym of the Idracowra Sandstone. The distribution of the latter has been amended following detailed stratigraphic work south of Black Hill Range. The age of the Finke Group is Upper Devonian to ?Lower Carboniferous, based on correlation with the Pertnjara Group.

ISSN:0016-7614    

DOI:10.1080/14400957308527918

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Landscapes in southwestern Australia are associated with variable proportions of a deep mantle of chemical weathering. By recognizing a continuum of landscapes showing a minimal amount of erosional modification of the deep mantle through to surfaces exhibiting intrusive stripping, broad soil-landscape units have been delineated. A descriptive classification of these units is proposed, based on the application of the concept of etch landsurfaces, the central theme of which incorporates both deep chemical weathering and differential stripping of the resultant saprolite.

ISSN:0016-7614    

DOI:10.1080/14400957308527919

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The distribution of remnants of a system of conglomeratic sediments is described in the Harvey district of southwestern Australia. A study of their relationship to the major physiographic elements and to laterite gives rise to certain suggestions regarding landscape development in the southwestern margin of the Western Australian Precambrian Shield.

ISSN:0016-7614    

DOI:10.1080/14400957308527920

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Detailed stratigraphical investigations of Mesozoic sediments in the Dubbo-Binnaway-Wollar region have made it possible to correlate sedimentary rock units and sequences previously described under different names in separate areas. Triassic and Jurassic sediments have been divided into five formations with an interbedded section of volcanics. Two of the formations have been subdivided into members. Rock units have been traced and correlated throughout the region, and a uniform system of nomenclature is proposed. The stratigraphical position of the Triassic-Jurassic time boundary has been established, and an associated disconformity varying in extent of time break and of significance in depositional history is recorded throughout the region.

ISSN:0016-7614    

DOI:10.1080/14400957308527921

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The Koogah Formation, which is the equivalent of the Greta Coal Measures of the lower Hunter Valley, is restricted in outcrop to the area lying immediately to the northeast of Wingen. The unit increases in thickness from 30 to 230 m in an easterly direction and consists for the most part of kaolinite clayrocks that range in texture from fine-grained to coarsely conglomeratic. Residual volcanic textures are characteristic of most of the kaolinite clasts and there seems little doubt that the detritus was derived from weathered zones developed on the Werrie Basalts, and accumulated in an alluvial fan environment. Nevertheless, in parts of the Koogah Formation lithic-quartz sediments that presumably represent fluvial material transported from a geosynclinal source which lay some distance to the north or west are abundant, and in the cores of two boreholes these sediments predominate to the virtual exclusion of the kaolinite clayrocks.

ISSN:0016-7614    

DOI:10.1080/14400957308527922

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The Carribuddy Formation [Upper Ordovician to (?) Lower Devonian] is halite-bearing, dolomitic, and partly red. The low bromine content of the halite accords with the absence of potassium salts in the study area, but the geochemistry is probably complex. The overlying Tandalgoo Red Beds [(?) Lower Devonian] are mainly sandstone, and represent a later influx of clastic material, some of which may have been deposited subaerially.

ISSN:0016-7614    

DOI:10.1080/14400957308527923

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Cenomanian-Turonian and Neogene calcareous sediments with rich foraminiferal faunas are recorded from USNSEltaninCore E54-7, 500 km off the northeast flank of Kerguelen Ridge, southeast Indian Ocean. Surface waters in the vicinity were warm during the Cenomanian-Turonian and sediments accumulated at depths significantly deeper than expected on continental shelves but not in abyssal conditions. The Neogene fauna indicates cold surface waters. The initial break between Broken Ridge and Kerguelen Ridge must be older than late Cenomanian and not early Tertiary. The break probably coincides with early movement between Australia and Antarctica. Twenty-three planktonic foraminiferal species are recorded.

ISSN:0016-7614    

DOI:10.1080/14400957308527924

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

In northern and western Tasmania fossils in the sediments beneath apparently conformable Cambrian-Junee Group contacts show a progressive decrease in age from Mindyallan (early Upper Cambrian) in northern Tasmania to late Upper Cambrian in the Birch Inlet area (south of Macquarie Harbour). This suggests that the fossiliferous Cambrian sediments in these sections are paraconformably overlain by the Junee Group.

ISSN:0016-7614    

DOI:10.1080/14400957308527925

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor