摘要:

The author compares the young Pre-Cambrian rocks of the Red Sea area. On the basis of paleontological and radioactive age-determinations he comes to the conclusion that in this area the rocks belong to the youngest consolidated rim (abt. 600 m.y.) of the old African cratonic shield (abt. 3 000 m.y.), equal to the Riphean (Schatsky). Two geosynclines or two parts of one geosyncline with plenty of basic volcanics, pillow lavas and serpentines have been mapped by Glen Brown in western Saudi Arabia (250 km length) and by the Geological Survey of Egypt in the central part of the Eastern Desert (100 km length). In Saudi Arabia the young Pre-Cambrian section is over 20 km thick and in the central part of the Eastern Desert of Egypt about 12 km. There is a change in facies from submarine ophiolites in the trough to partly subaerial volcanics on the block-faulted rim of the trough. The sedimentary section is mainly pelitic and psammatic. Limestone (marble) is rare or absent. The tectonic trends are probably influenced by older highs. In the northern part of the area the general trend is often across the Gulf of Suez. In the central and southern part of the Red Sea a strike roughly N—S predominates, but some E—W trends occur too, as in Hadramaut, Eritrea and Eastern Somaliland.

ISSN:0016-786X    

DOI:10.1080/11035896109449592

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

摘要:

At Håkantorp in the County of Örebro in Central Sweden a strongly metamorphosed and folded Archean serie of supracrustal rocks contains small skarn iron ores. In a few ore-bodies uraninite disseminations occur along shear zones. The precipitation of uraninite is caused by the reducing action of the ferrous iron content in tremolite and magnetite on acid uranium-bearing ore solutions. Geological and mineralogical evidence as well as age determinations indicate that the mineralization is connected with the end of the palingenic phase which drew the Svecofennian orogeny to a close.

ISSN:0016-786X    

DOI:10.1080/11035896109449593

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035896109449594

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

摘要:

A brief presentation of the isotopic composition of carbon in the graphite-bearing iron ores associated with limestone in the Norberg mining district, central Sweden.

ISSN:0016-786X    

DOI:10.1080/11035896109449595

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

摘要:

Sandstone and quartzite with fluorspar cement

ISSN:0016-786X    

DOI:10.1080/11035896109449596

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035896109449597

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

摘要:

Title: Geology and the radioactive waste. A congress report

ISSN:0016-786X    

DOI:10.1080/11035896109449598

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

摘要:

The Border Zone of the Caledonian Mountains in Southernmost Swedish Lapland

ISSN:0016-786X    

DOI:10.1080/11035896109449599

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

摘要:

In a recent paper the New Zealandish geologist A. Steiner has made a redefinition of ignimbrite as a descriptive non-genetic term meaning an acid volcanic rock showing gradational, vitroclastic-like textures and characterized by the presence of two contrasting glasses, which are usually devitrified. In indicating the significance of liquid immiscibility in forming of ignimbrites he emphasizes that according to the widespread occurrence of ignimbrites liquid immiscibility is an important phenomenon of igneous petrogenesis.

ISSN:0016-786X    

DOI:10.1080/11035896109449600

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035896109449601

出版商:Taylor & Francis Group    

年代:1961

数据来源: Taylor