摘要:

Tabular steeply dipping cassiterite‐bearing lodes in the Mount Wells region are hosted by lower greenschist fades metasediment of the Pine Creek Geosyncline within the contact aureole of late orogenic granitoids. The latter are predominantly I‐type, but S‐type phases are developed near the sediment‐granitoid contact.

ISSN:0812-0099    

DOI:10.1080/08120099308728094

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Biotite from granite and gneiss in the southwestern part of the Yilgarn Craton near Perth has been dated by the Rb‐Sr technique at about 430–500 Ma in a belt at the western edge of the craton. The belt widens southward from 30 km near Perth to 55 km east of Harvey. The eastern boundary of the belt passes along the east margin of the Saddleback greenstone belt. A transition zone 15–40 km wide separates the belt of young dates from an eastern chronological plateau where biotite dates, mainly 2300–2600 Ma, are marginally younger than regional Rb‐Sr whole rock dates which average about 2550 Ma. In contrast to biotite dates, whole rock dates greater than 2500 Ma persist to the western edge of the craton. The 430–500 Ma dates probably represent resetting during uplift in the Early Palaeozoic.

ISSN:0812-0099    

DOI:10.1080/08120099308728095

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The township of Bajool, situated 30 km south of Rockhampton, Queensland, experienced two minor earthquakes, each of Richter magnitude 2.9 on 10 June 1991. The foci were located 7 km north of Bajool, at a depth of less than 10 km. The felt intensity in Bajool was generally IV‐V, with minor damage occurring to several houses. There were several foreshocks and four aftershocks. The events may represent reactivation of a thrust fault, close to its junction with an inferred transform fault, the Fitzroy River Fault. These events demonstrate that the quiescence of central Queensland is apparent only, and that the recently installed University of Central Queensland Regional Network will provide a useful contribution to the understanding of earthquakes occurring along a passive continental margin.

ISSN:0812-0099    

DOI:10.1080/08120099308728096

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Zircon, concentrated from basaltic terrains in northeastern New South Wales and southeastern Queensland, reveals some unexpectedly young fission track peaks. Between 2 to 13 Ma in age, these peaks are younger than known Tertiary basaltic ages from these regions which match older fission track peaks. Analysis of the fission track data suggests that the young dates are probably not reset ages due to recent heating events such as bush fires, but more likely mark thermal resetting by later volcanic eruptions.

ISSN:0812-0099    

DOI:10.1080/08120099308728097

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Canning Basin contains several Mississippi Valley‐type Zn‐Pb sulphide prospects and deposits in Devonian carbonate reef complexes on the northern edge of the Fitzroy Trough, and in Ordovician and Silurian marine sequences on the northern margin of the Willara Sub‐basin. This study uses the ionic composition and 5D, δ18O, δ34S,87Sr/86Sr isotopic data on present‐day deep formation waters to determine their origin and possible relationship to the Zn‐Pb mineralizing palaeofluids.

ISSN:0812-0099    

DOI:10.1080/08120099308728098

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Skarns are developed over two temperature‐time intervals in calcite limestone adjacent to the southern extension of the Glenrock Granodiorite, a pluton of the Marulan Batholith, Southern Highlands, New South Wales. The initial volumetrically‐dominant prograde phase of skarn formation produced a suite comprising bimetasomatic skarn, including pyroxene endoskarn, potassic endoskarn and wollastonite‐bearing exoskarn, together with mineralogically‐zoned vein skarn, massive garnet‐pyroxene skarn and calcite‐vesuvianite skarn. Retrograde replacement is manifested by the development of hydrous silicate minerals, carbonate and cross‐cutting sulphide veinlets.

ISSN:0812-0099    

DOI:10.1080/08120099308728099

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The results of the Soviet geological mapping program in the Prince Charles Mountains (Australian Antarctic Territory) are presented as the first major publication of the Soviet mapping program from 1983 and 1991. Except for a map of Else Platform, the maps published in this paper represent all maps completed by the 28th to 35th Soviet Antarctic Expeditions in the Prince Charles Mountains. The maps cover four suggested tectonic provinces, the Beaver Belt, Lambert Province, Fisher Belt and Ruker Terrane. The four terranes show a continuous increase in metamorphic grade from south to north. The Ruker Terrane is of a greenschist and lower amphibolite facies metamorphic grade, the Lambert Province consists of retrogressively metamorphosed Beaver Belt granulite and prograde metamorphosed greenschist of the Ruker Terrane and the Beaver Belt consists of high grade granulite. The Fisher Belt is a greenstone belt which is interpreted to be thrust later against the Lambert Province. Rock‐types of all four terranes as shown on the maps are discussed and an up‐to‐date summary of the work completed by the Soviet Antarctic Expeditions in the Prince Charles Mountains is given.

ISSN:0812-0099    

DOI:10.1080/08120099308728100

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor