摘要:

A complete system to obtain ratios of stable isotopes of certain elements (carbon and oxygen from carbonates, sulfur from sulfides and sulfates) is described. The chemical preparations necessary to convert the geological samples to a suitable gas (CO2or SO2) are discussed. The isotopic measurements are performed with a modified Micromass 602C mass spectrometer. The computer programs used for corrections and calculations are also discussed. Stress is laid on those parts of the above procedures where we have modified earlier methods. The system has been in continuous use for about four years. A survey of geological projects partly based on results obtained with this system is given in the last section.

ISSN:0016-786X    

DOI:10.1080/11035898209455241

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A volcanic conglomerate from the province of Östergötland is described. The conglomerate is intraformational in postorogenic Svecokarelian porphyries. In the vicinity of the conglomerate and the volcanics occurs a medium- to coarse-grained, partly foliated granite with rather large quartz crystals. This granite is considered to be the basement of the volcanic conglomerate. The prevolcanic granite is supposed to have weathered to give arkosic material, now appearing as medium- to coarse-grained granite. This material also constitutes the matrix and some of the granitic pebbles of the conglomerate. Other pebbles are finegrained and medium-grained granites and different types of volcanic rocks. The prevolcanic granite and the vulcanism are followed by postvolcanic, complex plutonic intrusions and a hypabyssal activity, which completes a possible postorogenic model. Svecokarelian rocks, postorogenic volcanics and subvolcanics constitute roof pendants of the postorogenic granites.

ISSN:0016-786X    

DOI:10.1080/11035898209455242

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898209455243

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The Late Weichselian shore displacement at Hunneberg has been established on the basis of stratigraphical investigations of 15 lakes situated between 129 m a.s.l. and 91 m a.s.l. The isolation of the lakes has been determined by diatom analysis, and dated by14C and pollen analysis. The regression gradient between 12200 B.P. and 11000 B.P. has been calculated to be about 1.0 m/100 years, and between 11000 B.P. and 10300 B.P. to be about 3.3 m/100 years. An even more rapid increase of the gradient is indicated to have started at about 10200 B.P. Possible causes for the shore displacement at Hunneberg are discussed.

ISSN:0016-786X    

DOI:10.1080/11035898209455244

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898209455245

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A ripple-marked grainstone bed in the upper Hemse Beds is described externally and internally. Most of the ripple-mark crests are flat, and some are concave. The entire surface is covered by traces, most of which are biogenic. It is concluded that the ripple train was generated by oscillatory wave action, and that the flat and concave crests were caused by penecontemporaneous erosion. A reconstruction of the original ripple form is made and the mean grain size is estimated. A graph is constructed which enables an interpretation of the set of ripple-marks in terms of wave conditions and absolute water depth. It is concluded that the ripples were formed by waves with a period of about 11 s and a near-bottom water-particle orbital diameter of about 0.9 m, at a water depth of about 10 m or less.

ISSN:0016-786X    

DOI:10.1080/11035898209455246

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Sediment filled fissures are common within Middle and Upper Ordovician carbonate mounds in the Siljan district, Dalarna, central Sweden. The fossil content of a fissure in the Upper Ordovician Boda Limestone at Solberga indicates at late Ashgill (Hirnantian) and Llandovery age. The Ashgill fillings consist mainly of carbonates and mudstoncs, whereas the Llandovery sediments are black graptolitic shales. Seven species of Bryozoa occur commonly. These species also occur in the Öjle Myr Beds and are consequently of late Ashgill age. Three new species,Phaenopora wimani, Stictoporella siljanensisandFistulipora gustaviare described.

ISSN:0016-786X    

DOI:10.1080/11035898209455247

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Geological and geophysical mapping reveal prominent Precambrian faults in the Borås area of south-western Sweden. No difference of altitudes exists at present between upfaulted and downfaulted areas, as peneplanation subsequently occurred. The maps suggest the faults to be approximately vertical with slips of several thousand meters. They have a preferred NNE—SSW- orientation, which is a characteristic feature of lineaments in south-western Sweden. The development from fracture to lineament is due to subsequent Tertiary (and probably also Cretaceous) erosion. In areas which suffered less erosion during these periods, even major faults are but little reflected in the topography. It is suggested that the same type of faults contributed to the development of the Lake Vättern depression. Riphean-Vendian sediments were there protected from erosion by downfaulting in late Precambrian time. The general orientation of faults and rock lineation of this area is NNE—SSW. Postcambrian, probably Permian, faulting of NNE—SSW orientation has occurred as well, judging by several indications. Thus it would seem that the Precambrian faulting, which affected the Vättern area, was to a great extent overprinted, while a set of NNE—SSW Precambrian faults is preserved in the Borås area.

ISSN:0016-786X    

DOI:10.1080/11035898209455248

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The building of a very quiet non-magnetic house can raise special problems in Precambrian areas and in the cold climate of northern Sweden. The special precautions taken in the construction of a non-magnetic house belonging to the University of Luleå have resulted in a laboratory for high-precision rock magnetic and palaeomagnetic work. The mean total field in the house one metre above the floor is 52011 ±3 nT and the maximum variation inside is 12 nT. The geographical, position is the mountain Rånekölen, latitude 65.8°N, longitude 22.3°EGr, about 30 km north of Luleå.

ISSN:0016-786X    

DOI:10.1080/11035898209455249

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The recent report-in this journal by A. Holmqvist (1980: Ordovician gastropods from Vardofjället, Swedish Lapland, and the dating of Caledonian serpentinite conglomerates.Geologiska Föreningens i Stockholm Förhandlingar 102, 493–497) of a newly discovered fossil locality in the Köli of Vardofjället, Swedish Lapland is discussed. Whilst the find of five, poorly preserved gastropods is important, the assignment of this material to the long-ranging superfamily Macluritacea severely restricts its use and significance. Any stratigraphical conclusions based upon such material are misleading.

ISSN:0016-786X    

DOI:10.1080/11035898209455250

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor