摘要:

A simulated sedimentary system, capable of being controlled and monitored for a considerable length of time without undue disturbance, has been assembled and applied to specific problems of the genesis of stratiform Pb‐Zn ore deposits. Results have been obtained relevant to: (i) the concentration of Pb and Zn from brines to underlying sediments; (ii) the behaviour of microorganisms in metal‐rich, highly saline environments; (iii) the precipitation diagenesis of calcium and magnesium carbonates; and (iv) the diagenesis of organic matter.

ISSN:0016-7614    

DOI:10.1080/00167617508728882

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Precambrian high‐grade metamorphic rocks (granulite facies, transitional granulite to amphibolite facies, and amphibolite facies) from the Amata area, Mus‐grave Ranges, central Australia, display contrasting weighted average K/Rb ratios (628, 310, and 203 respectively). This pattern of higher K/Rb ratios in medium to high‐pressure granulite facies rocks than in amphibolite facies rocks is in keeping with patterns found elsewhere in areas of metamorphosed Precambrian continental crust. The weighted average values are strongly influenced by the predominantly quartzo‐feldspathic (acidic to sub‐acidic) nature of the three metamorphic terrains. The ratios therefore reflect extensive control exerted by host‐rock mineralogy on the distribution of K and Rb.

ISSN:0016-7614    

DOI:10.1080/00167617508728883

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

A spinner magnetometer has been used to determine the fabric of susceptibility anisotropy within the Moruya Granite. Magnet foliation planes are generally parallel to the granite contact and dip away from the centre of the intrusion.

ISSN:0016-7614    

DOI:10.1080/00167617508728884

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The volcanic rocks recorded from the Edel No. 1 well are probably Mesozoic in age and consist of a variety of trachytes, nosean phonolites, and ‘lamprophyres’. They can be thought of as a mixture of variable amounts of alkali feldspar, pyroxene, biotite, hornblende, and minor nosean. Chemically they are all undersaturated with respect to SiO2.

ISSN:0016-7614    

DOI:10.1080/00167617508728885

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The Jurassic dolerites around Hobart were probably emplaced during four or five injection periods. Each period has produced a series of interlinked stepped sheets with the overall form of an axially flattened cone. Feeders were dyke‐like, although some were pipes or wedges from dykes. Dislocation by fracturing was followed by hydrostatic intrusion. Controls were imposed on the intrusion by roof load, magma pressure, and barrier formations. Early injections are believed to have been intruded low in the rock column, later ones at high levels.

ISSN:0016-7614    

DOI:10.1080/00167617508728886

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Small bodies of intrusive olivine‐bearing cumulate rocks from part of the Tom‐kinson Ranges in central Australia are correlated as one suite on the basis of consistent relative age relationships. The group has gradational chemical and petro‐logical properties between different members and has been termed the picrite suite after its most abundant member. It comprises dunites, picrites, olivine mesogabbros, olivine leucogabbros, and leucogabbros. Rare doleritic chilled margins are observed. Many of the bodies contain high‐pressure characteristics indicative of a lower crustal origin.

ISSN:0016-7614    

DOI:10.1080/00167617508728887

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Ten ore types, of three genetic types, are recognized in the mine: those formed by the recrystallization of ore layers rich in carbonates and sulphides, those formed by the diffusion of Ca, Mn, and Fe from ore layers into adjacent weakly mineralized siliceous rocks, and those ore layer rocks modified by the loss of Ca, Mn, and Fe. Some constituents moved at least tens of metres. The method of transport probably was by diffusion through, and/or transport by, a gas phase which was being expelled as the system dehydrated, decarbonated, and desulphidized during metamorphism. Most of the ‘metasomatic interaction’ between ore lodes and wall rocks occurred early in the history of the area, but some occurred after earliest metamorphic foliation, had formed, and resulted in the formation of ‘epigenetic’ vein‐like bodies of lode rock ('droppers'). Chemically similar but quantitatively minor migration took place during the high‐grade metamorphism and subsequent retrograde metamorphic events.

ISSN:0016-7614    

DOI:10.1080/00167617508728888

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The separation of the Lord Howe Rise and New Zealand from Australia and the separation of Antarctica from Australia are distinct continental splitting events and Mesozoic‐Cainozoic tectonics of southeastern Australia can be correlated with stages of these events. Burke & Dewey's (1973) suggestion that a triple junction initiated opening of the Tasman Sea appears correct, but the Lower Cretaceous Strzelecki Basin, rather than the overlying Gippsland Basin, is identified as a ‘failed arm’ (aulacogen). The Port Phillip Sunkland may be a failed arm of the rift system which separated Australia and Antarctica. Post‐rifting fault and basin development of the area is in accordance with the crustal flow hypothesis of Bott (1971).

ISSN:0016-7614    

DOI:10.1080/00167617508728889

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

Field relations from a small area in the Maubisse region of Portuguese Timor fail to support the hypothesis of southward overthrusting of Permian rocks (Audley‐Charles, 1965) or the postulate that the Maubisse Formation represents a mid‐Tethys island group (Audley‐Charleset al.,1972).

ISSN:0016-7614    

DOI:10.1080/00167617508728890

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor

摘要:

The Yeoval porphyry copper prospect lies in a complex of dioritic rocks which form part of the eastern margin of the Yeoval Batholith in central‐western New South Wales. Rocks of the batholith are mainly granite and adamellite whose age is about 370 m.y. The diorite complex, (411 m.y.) is composed of rocks ranging from granodiorite to gabbro and pyroxenite.

ISSN:0016-7614    

DOI:10.1080/00167617508728891

出版商:Taylor & Francis Group    

年代:1975

数据来源: Taylor