摘要:

In Tasmania shelly fossils are known from Middle and Upper Cambrian sediments of the Dundas Trough, Fossey Mountain Trough, Dial Range Trough, Beaconsfield Trough, Smithton Basin, Adamsfield Trough and from within sediments associated with the Mount Read Volcanics of Western Tasmania. In the Dundas Trough fossils range in age from early Middle Cambrian(Ptychagnostus gibbusZone) to the middle Late Cambrian (pre‐Payntonian A or B). Late Middle Cambrian fossils occur in sediments associated with the Mount Read Volcanics in two places in Western Tasmania. Late Middle Cambrian fossils only are known from the Smithton Basin and the Beaconsfield Trough. Late Middle to early Late Cambrian faunas are known from the Dial Range Trough; the Adamsfield Trough contains middle Middle to middle Late Cambrian fossils. Tasmanian Cambrian faunas show affinities with those of Queensland, China, the northwest Siberian Platform and northern Victoria Land, Antarctica.

ISSN:0016-7614    

DOI:10.1080/00167617908729086

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

During 1976 and 1977, 120 earthquakes occurred in South Australia which were large enough to be recorded by the University of Adelaide seismograph network, and subsequently located. Only four epicentres lie outside the recognised seismic zones of the Adelaide Geosyncline, Eyre Peninsula and the Southeast Zone; only four of the earthquakes had magnitudes (ML) greater than 4. Fault‐plane solutions for three of the events within the Geosyncline suggest a direction of principal stress which is a northeast southwest compression.

ISSN:0016-7614    

DOI:10.1080/00167617908729087

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A practical system of defining deeply weathered rock horizons is proposed, using the concept of a profile, defined as the vertical extent of a weathered rock sequence from the initiating land surface or originating surface down to unweathered parent rock. Advantages inherent in this system lie in the strict stratigraphic approach, its applicability to field mapping, and its broad accordance with accepted principles and concepts of the Australian Code of Stratigraphic Nomenclature. Establishment of a reference (type) section for each profile, with formal registration by a central authority, together with validation through publication, are recommended. Profile names, which carry some genetic implications, are distinguished from lithostrati‐graphic units through the use of distinctive map symbols and inclusion of the word profile within profile names. Three weathered rock units (Morney profile, Canaway profile and Curalle silcrete profile), and one altered rock unit (Haddon silcrete) which is believed to be a product of subsurface silicification, are formally defined. Parent rocks of these profiles (Winton and Eyre Formations) are described to demonstrate the nature of weathering and substantiate the recognition of a particular profile. Combinations of parent rock and weathered profile relationships are given to explain regional continuity of these profiles throughout southwest Queensland.

ISSN:0016-7614    

DOI:10.1080/00167617908729088

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Four Quaternary units occupying a shallow bedrock depression have been delineated from outcrop exposures and auger drilling on Sandon Point Beach, North Bulli, 60 km south of Sydney, N.S.W. In ascending stratigraphic order these units are: a basal muddy sand (2.2+ m) of fluvial origin; a mottled mud (3.5 m) with common iron oxides, representing alluvial deposits with a superimposed soil profile developed during a period of lower sea level; a sandy mud (3.9 m) containing estuarine shell fossils, small tree stumps (including one mangrove) and abundant wood fragments; and, at the top, a pebble layer overlain by beach and dune sands, all partly indurated with iron oxides (2.3 m).14C datingin situtree stumps, shell material and wood fragments from the estuarine sandy mud unit between mean sea level and +1.45 m provided ages ranging from 7520±.150 to 6350±100 years B.P. The age of this unit is supported by a date onin situMyrtaceae root material (7000±150 years B.P.) from a similar study sandy mud unit at Thirroul, some 2 km north of the Bulli site. These dates indicate that sea level reached its present position between 7500 and 6500 years ago and thus record the final stages of the postglacial marine transgression on the southern coast of New South Wales.

ISSN:0016-7614    

DOI:10.1080/00167617908729089

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167617908729090

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Emerged marine erosion terraces and associated terrace deposits showing various degrees of warping are preserved at Cape Range and in the Lake MacLeod‐Cape Cuvier area of Western Australia. Uranium‐series age determinations on corals occurring in the terrace deposits gave the following results: a mean age of 123 000 for the youngest of the terrace deposits (Tantabiddi Member) at Cape Range, which has a maximum elevation of 5.5 m above present sea level (MLWS); mean ages of 123 000 years and 131 000 years for deposits overlying two morphologically distinct marine erosion terraces, with elevations ranging from 3 to 7.4 m and from 9.4 to 10.5 m, respectively, at Cape Cuvier; a mean age of 128 000 years for marine deposits occurring between —0.5 and 1.3 m on the west shore of Lake MacLeod.

ISSN:0016-7614    

DOI:10.1080/00167617908729091

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Groundwater calcretes are a non‐pedogenic form of calcrete occurring in broad fossil drainage systems. In Australia, they only occur north of about latitude 30°S and their formation requires arid conditions with very high potential evaporation as well as the periodic recharge of groundwater systems. They are linear, tabular limestone bodies, averaging about 10 m thick, occurring at or close to the surface and forming gentle mounds. The most extensive are located in the centre of the zone of distribution, where the climatic conditions are optimal, and are of the order of 100 km by 10 km. Some groundwater calcretes are fossil and strongly dissected, others are modern and still in process of formation.

ISSN:0016-7614    

DOI:10.1080/00167617908729092

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

In the Desert Syncline of the southern Georgina Basin there is an Early and Middle Cambrian sequence unconformably overlying late Proterozoic sediments. Stratigraphic drilling and subsequent palaeontological studies have allowed the documentation of the sequence across the Proterozoic‐Cambrian unconformity. Earliest Cambrian green shales are bioturbated and contain distinctive acritarchs. These are overlain, probably unconformably, by sandstone withDiplocraterionburrows, in turn succeeded by archaeocyathan dolostone. Ordian and Templetonian (Middle Cambrian) shales and carbonates unconformably overlie the Early Cambrian sequence. The stratigraphic sequence is very similar to that in the Amadeus Basin and the Adelaide Geosyncline.

ISSN:0016-7614    

DOI:10.1080/00167617908729093

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Calibration of a 200‐cm long, 12‐cm diameter settling tube with quartz spheres and rounded quartz beach sands suggests that the Gibbs equation is suitable for relating settling velocity to quartz sphere diameter.

ISSN:0016-7614    

DOI:10.1080/00167617908729094

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0016-7614    

DOI:10.1080/00167617908729095

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor