摘要:

In the present paper the author is treating the questions of the geology of the south-eastern parts of the Swedish Archaean, the relationship of its effusives, gneisses and granites. He thereby attaches his new establishments to the earlier paper published in this journal on the Archean of Western Blekinge, and widens the geological aspects to Eastern Scania and Southern Småland. Principally the genetical relations between the rocks of the area are treated in the first hand, envolving the old interesting problem on the boundary between the gneissose regions of South-Western Sweden and the granites, migmatites and metamorphic sediments of the south-eastern regions. Special attention is hereby drawn to the appearance of supra-crustal material in the horsts of Scania, which by the author is considered an equivalent to the corresponding geological features in the border terrains of the Halen sea district.

ISSN:0016-786X    

DOI:10.1080/11035895909447268

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

Field examinations within the region of Rabinal and Salamå in Central Guatemala have shown that large areas of the crystalline core of the Antillean Cordillera consist of albite gneisses. Within these rocks there exist isolated areas of micro-cline-plagioclase granites. Microscopic examination of the different rocks give evidence that the granite arose through a potash metasomatose of plagioclase-dominated gneissic rocks. It is concluded that the albite gneisses arose through a sodium metasomatose of phyllites and mica schists, and that the granite arose through a potash metasomatose of parts of the albite gneisses. The modes of transformation are discussed, as is also the relationship between feldspatizations within the deeper parts of geosynclines and zonal distribution of ore deposits.

ISSN:0016-786X    

DOI:10.1080/11035895909447269

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

Depth of leaching in weathering profiles of glacial deposits, containing carbonates, may be used for correlation of stratigraphic units, equivalent to substages, if measurements are done in similar material and in soils formed under similar climatic conditions. If great differences in carbonate content of parent material prevent direct comparison of the measured depth of leaching, the original depth of leaching has to be determined by applying a special formula. A comparison between the approximately contemporaneous glacial terrains in Central Latvia and S. W. Ontario suggests that depth of leaching may be applied also for telecorrelation.

ISSN:0016-786X    

DOI:10.1080/11035895909447270

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035895909447271

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

In the Kopparberg county, small sulphide ores containing sphalerite, galena, pyrite, pyrrhotite as well as a gangue of calcite, baryte and fluorite are known around Boda and on the island Sollerön in Lake Siljan. The ore has developed around tectonized zones in Ordovician limestones as disseminations or as hydrothermal veinfillings with alternating layers of ore minerals and gangue. A replacement of matrix by sulphides has also occurred locally in the Obolus conglomerate, the lowest member of the sedimentary formation. The sphalerite shows colloform banding and the colour of the different zones varies from black or dark brown to light yellow. As a rule the dark zones are narrow and have a much higher iron content than the light coloured zones. Important exceptions are some dark black-brown, iron poor narrow zones which have a comparatively high copper content. The formation of the colloform banded sphalerite is discussed and it is assumed that the zinc sulphide has been precipitated as a gel or as cryptocrystalline particles from a neutral or slightly alkaline solution. Because of variations in the iron content of the hydrothermal solutions, the precipitated zinc sulphide may contain more or less iron. Varying Fe/Zn ratio in the solutions may also have changed the original composition of the surface layer of the precipitated zinc sulphide. Etched polished sections show that the zinc sulphide has crystallized as sphalerite. The formation of the ore is connected with the large tectonic deformations of the Paleozoic sedimentary rocks in the Siljan area.

ISSN:0016-786X    

DOI:10.1080/11035895909447272

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

Some aspects of the skarn ore problems in Central Sweden. According to the interpretation of the non-manganiferous skarn-bearing iron ores of Central Sweden that was given by Magnusson and the present writer 15 years ago and has later been repeated (Geijer and Magnusson 1944, 1952 a, 1952 b), this group is not genetically homogeneous. It contains >primary skarn ores>, of pyrometasomatic origin, and more numerous >reaction skarn ores> that were originally formed by sedimentation or by replacement at low or moderate temperatures, and later changed through interior reactions caused by regional heating. This metamorphism, like the development of primary skarn ores, took place during the epoch when the containing leptite formation was folded and invaded by the Earlier group of Svionian granites. Further, the >magnesia metasomatism> that accompanied these events has wrought great chemical changes in many of the earlier formed deposits. In a textbook (Magnusson 1953), however, these views have been presented in a somewhat modified form, the possibility being indicated that the deposits interpreted as such with primary skarn may all be reaction skarn deposits altered by the magnesia metasomatism.

ISSN:0016-786X    

DOI:10.1080/11035895909447273

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

摘要:

A method of coring Quaternary deposits with percussion drillingmachines is described. The Swedish State Power Board and the Swedish Diamond Rock Drilling Co. (Craelius) have constructed and used equipments for sampling cores of soils. No detailed technical descriptions are given. With the equipment, shown in figs 1–3, it is possible to take almost complete cores in all kinds of soil, except for those with especially high boulder and stone contents, for example glacial till with high boulder frequency and extremely coarse glacifluvial deposits. It is an important advance, that representative cores of tills with low or medium boulder frequency can now be obtained. Well over half of Swedens' total area is covered by such types of till.

ISSN:0016-786X    

DOI:10.1080/11035895909447274

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035895909447275

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035895909447276

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035895909447277

出版商:Taylor & Francis Group    

年代:1959

数据来源: Taylor