摘要:

During the Ordovician and Silurian Periods that part of the Lachlan Geosyncline lying between Yass, N.S.W., and the Victorian border changed from a deep-sea region with basic volcanics, volcanic graywackes, and cherts, to a shallow marine to subaerial platform dominated by acid volcanics, volcaniclastics, mudstones, and limestones. In the course of this development a quartz-graywacke distal flysch body spread throughout the region during the Late Ordovician. This was deformed during the Benambran Orogeny at the end of the Ordovician by gravity tectonics consequent upon the anatexis, metamorphism, folding, and uplift of the Wagga Metamorphic Belt to the west. The region remained deeply submerged after the Benambran Orogeny, and a series of submarine fans comprising a quartz graywacke proximal flysch was developed along its western margin during the late Llandoverian. Distal equivalents may be present, unrecognized, within the Ordovician flysch to the east. Early in the Wenlockian the Quidongan Orogeny, probably due to anatectic collapse of the sedimentary pile, has been recognized. It produced marked unconformities between early and late Silurian strata at Quidong and Canberra. It terminated flysch accumulation, and transformed much of the region into a low-lying land-mass. Marine conditions persisted in some areas, and acid volcanism, beginning near Yass, extended south and east during the remainder of the Wenlockian and Ludlovian. During this time a slight subsidence drowned the eastern half of the area, where late Silurian marine sediments and volcanics with stratiform ore deposits then accumulated, lying unconformably on the deformed Ordovician flysch.

ISSN:0016-7614    

DOI:10.1080/14400957308527903

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Carbonates with volcanic lithic components deposited in a deep-water environment are found on both flanks of the Tomba Anticline, northwest Malaita. Pelagic Foraminifera were used for age determinations, indicating an upper Albian age for the oldest rocks of the Kwai River sections. Senonian, Campanian/Maestrichtian, Paleocene, Eocene, middle and upper Miocene, and Pliocene were also documented by pelagic Foraminifera. It is inferred that there has been uninterrupted deep-water sedimentation from the Albian to the Pliocene in this area.

ISSN:0016-7614    

DOI:10.1080/14400957308527904

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Conventional K-Ar geochronology and the40Ar/39Ar method in which the ratio of radiogenic argon to postassium is determined by measurement of39Ar produced by neutron irradiation are used to document the occurrence of the Upper Carboniferous Kanimblan Orogeny in the D'Aguilar Block and Beenleigh Block of southeastern Queensland.

ISSN:0016-7614    

DOI:10.1080/14400957308527905

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Early Carboniferous sedimentation in the southern part of the New England Belt reflects the gradual filling of the Tamworth Trough and a change from mainly marine to mainly non-marine deposition. Sedimentation was largely controlled by volcanism along the western and southern margins of the trough, but late in the Early Carboniferous uplifts associated with the emergence of the New England Arch combined with the volcanism to influence the configuration of the shoreline.

ISSN:0016-7614    

DOI:10.1080/14400957308527906

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Measurement of the tritium content of water taken from bores along the Murrumbidgee River has yielded information concerning the permeability and flow characteristics of the underground aquifer in the Wagga area of New South Wales. The replenishment of the aquifer in time of high river levels has been established, the effect on the aquifer resulting from heavy pumping in the Wagga area has been studied, and some of the more unusual aquifer structures have been investigated.

ISSN:0016-7614    

DOI:10.1080/14400957308527907

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

The Murrumbidgee Batholith, A.C.T., is an example of a batholith containing abundant metasedimentary xenoliths. It is a composite, intrusive batholith with an outcrop area of 1400 km2and a range in composition from tonalite to leucogranite. Its intrusions can be classified into three natural groups on the basis of textural, modal, and chemical criteria.

ISSN:0016-7614    

DOI:10.1080/14400957308527908

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Ages of eleven volcanoes in the Cape Hoskins area are based on potassium-argon determinations on lava samples, on carbon-14 dates of charcoal from buried soil horizons, on relationships of the volcanoes to one another, and on comparison of the erosional states of the volcanoes with one another and with Hydrographers volcano, east Papua.

ISSN:0016-7614    

DOI:10.1080/14400957308527909

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Finely-banded, stratiform, metal sulphide deposits in carbonaceous shales contain very significant proportions of the world's resources of lead, zinc and copper. The perfect conformability of the sulphide bands suggests that they formed syngenetically.

ISSN:0016-7614    

DOI:10.1080/14400957308527910

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Analyses and interpretation of Rb-Sr data on 17 granite and porphyry pebbles from the White Lake metaconglomerate indicate a maximum possible age for the source rocks of the clasts at 2885 ± 160 m.y. However, we favour a more conservative interpretation of our data as, simply, older than 2670 m.y., and also we caution against the use of these data to support the existence of a pre-Kalgoorlie System granitic basement. The lower limit for the age of the conglomerate is 2550 m.y., imposed by a Rb-Sr age on a biotite from the matrix of the conglomerate. Another control on the minimum age of the metaconglomerate is 2620 ± 20 m.y. imposed by the isochron for the Mungari granite, which is considered as younger than the White Lake metaconglomerate.

ISSN:0016-7614    

DOI:10.1080/14400957308527911

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor

摘要:

Slaty cleavage and overprinting crenulation cleavage(s) have been produced in a single experiment, during essentially homogeneous shortening. The results of several such experiments are described, and their relevance to natural crenulation occurrences is discussed.

ISSN:0016-7614    

DOI:10.1080/14400957308527912

出版商:Taylor & Francis Group    

年代:1973

数据来源: Taylor