摘要:

This paper deals with the contents of certain trace elements in the Grängesberg iron ore, especially the content of tin.

ISSN:0016-786X    

DOI:10.1080/11035897209454196

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A regular banding is preserved in many parts of the potash granite at Nagu in the archipelago of southwestern Finland. The principal differences between the bands involve their grain size and their content of porphyroblasts of micro-cline and garnet, for some bands lack both kinds of porphyroblasts. The micro-cline porphyroblasts lie subparallel to the banding or to the axial plane in those parts of the granite where the banding has been destroyed. The banding is interpreted as a relict sedimentary bedding. It forms concentric folds conformable with the folds in the supracrustal amphibolites within the granite. These folds seem to be survivals from the first folding phase, when the sediments were transformed into gneisses. Later, the gneisses were granitized without appreciable orogenic movements. The chemical composition is unexpectedly constant in all parts of the granite. The formation of garnets in the granite, as well as that of hypersthene in gabbroic layers in the granite, points to an expulsion of water in connection with the granitization.

ISSN:0016-786X    

DOI:10.1080/11035897209454197

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

On the basis of the K-feldspar obliquity the graniroid plutonics in Jämtland can be subdivided into two principal groupings: one comprises rocks of the Svecofennian orogenic-to-early-postorogenic development and the other restricted intrusions of the Ragunda and Sörvik types. In the first group, which includes the Revsund and Rätan granites with associated migmatites, the K-feldspars are close to maximum microcline with obliquities above 0.8. Granitoids belonging to the Ragunda and Sörvik types have K-feldspars which range from mono-clinic through inhomogéneous to triclinic structural states. A large area of low obliquity in the orogenic rocks of northern Jämtland is liable to interpretation as a thermal-influence aureole around the postorogenic intrusions. The effect of rock-blasting on K-feldspar obliquity has been checked in samples obtained from road cuttings.

ISSN:0016-786X    

DOI:10.1080/11035897209454198

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Rb-Sr isotope data arc presented for nine whole-rock samples of perthite granite from Masugnsbyn - and six whole-rock samples of Sjaunjatuottar syenite. The ages and initial Sr87/Sr86ratios of. 1535 ± 30 m.y. and 0.713 ± 0.004 for the perthite granite, and 1565 ± 25 m.y. and 0.710 ± 0.002 for the syenites compare favourably with the “younger” Lina-granite age of 1565 ± 35. m.y. and initial ratio of 0.712 ± 0.003 (Welin et al. 1971). The ages are indistinguishable within the limits of precision of the age measurements. A discussion of the relationship between the various granitic rocks and their connection with the skarn iron ores is given. Analyses of the interlaboratory standards NBS K-feldspar 70 a and GSP-1 are presented in the Appendix.

ISSN:0016-786X    

DOI:10.1080/11035897209454199

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

The Lake Vättern area in Southern Sweden has been studied by gravity methods in an attempt to secure new information about the lake as a “graben” structure. An interpretation of the main anomalies shows different relationships between the “tectonic” near-surface structures and the more deep-seated structures in the crust. Anomalies in precambrian granites and basic bodies outside the main area have also been interpreted to show the complexity of the earth's outer crust in these areas. The result of this investigation is that the graben structure is a very plausible explanation of the gravity anomalies. The Visingsö series is about 400 m thick in the southern part of the area but reaches a thickness of 1000–2000 m in the middle part. The thickness of the granites varies from about 15 km under the “graben” to some kilometres outside this area.

ISSN:0016-786X    

DOI:10.1080/11035897209454200

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

K/Ar dating of alkaline olivine basalts from Skåne has produced Cretaceous ages between 79 million years (m. y.) and 131 m. y. These basalts were previously believed to be of Tertiary age.

ISSN:0016-786X    

DOI:10.1080/11035897209454201

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A lectotype is chosen forClimacograptus scalaris(Hisinger), a species which has not often been successfully identified since its' original definition in Sweden. It is proposed that several subsequently described subspecies should be raised to specific status. The subgenusGlyptograptus (Pseudoglyptograptus) is recognised in Sweden in Törnquist's (1890) specimens ofC. scalaris. G.(Pseudoglyptograptus) is reviewed, and three forms are left under open nomenclature.

ISSN:0016-786X    

DOI:10.1080/11035897209454202

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

A section of the coastal Holocene with predominating clastic deposits and intercalated peat layers is described. The results of sedimentological investigations and the analysis of the micro- and mesofaunas are discussed with regard to the development of the lithofacies and the changes of the salinity. By means of a very large number of14C datings, the reliability of data from Phragmitespeat is checked, on the one hand, and a chronostratigraphic system is given for the investigated area, on the other.

ISSN:0016-786X    

DOI:10.1080/11035897209454203

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

For many years I have been working on the stratigraphy and the trilobite faunas of the Limbata Limestone, a large and hitherto neglected subdivision of the Arenigian limestones of Sweden. The main investigation has been carried out at Lanna, in the South Central part of the Swedish mainland. In the autumn of 1970, I delivered a short manuscript to the “Trìlobite News”, edited by Dr. D. L. Bruton of Oslo, and Dr. V Jaanusson(?) of Stockholm. Without consulting me, my use of the British stratigraphical scheme and of a time-honoured Swedish subdivision, introduced by Moberg, was rejected by the editor. The title of a forth-coming paper of mine: “The Arenigian Limbata Limestone of Sweden” was changed for the East Baltic denomination: “Volkhov Stage (“Limbata” Limestone)”, a concept launched and promoted by Jaanusson. The aim of the present paper is to show that this switching of stratigraphical terms is a result of the editor's ignorance of the stratigraphy of the Swedish strata. Jaanusson's classification can possibly be used for the very small area of the northern part of the island of Öland, but not for the vast mainland of Sweden. The limestones of the latter contain a trilobite fauna which is of Norwegian, and not of East Baltic type. A conspicuous feature is the different vertical distribution in Sweden and the East Baltic district of the species belonging to the subgenusMegistaspis (Megistaspis)Jaanusson, 1956.

ISSN:0016-786X    

DOI:10.1080/11035897209454204

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Rb/Sr whole-rock radiometric dating of 14 porphyries from Småland, southeastern Sweden, yields an age of 1695 ± 20 million years (m. y.) (λ = 1.39 × 10−11y.−1). The initial Sr87/Sr86ratio is 0.7065 ± 0.0012. The relationship between the Småland porphyries may be compared with that between the Dala porphyries, with respect both to relative age and to general appearance. The Småland porphyry age compares favourable with and is well within the limits of error of the age of the sub-Jotnian Dala porphyries 1669 ± 38 m. y. (Welin 1970a). Thus, the postorogenic sub-Jotnian igneous activity occurred, according to this age, in relatively close connection with the Svecofennian orogeny, of which the main tectonic and magmatic activity ceased approximately 1775–1800 m. y. ago. The porphyries and granites probably originated from a palingenic magma formed during the Svecofennian orogeny. Later, during the postorogenic stage, the rise of the magma is explained by the effect of buoyancy (Lundqvist 1968).

ISSN:0016-786X    

DOI:10.1080/11035897209454205

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor