摘要:

Urban Hiärne was a pioneer in Swedish geology. His achievements included both theoretical and practical endeavours in a variety of professions. As part of his endeavours as an empirical mineralogist, he presented theories about the lower regions of the earth. His famous illustration of the subterranean world (see the cover illustration of this journal) reveals his relations to contemporary geologists and philosophers.

ISSN:0016-786X    

DOI:10.1080/11035898609454721

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

At a meeting with the Council of the Geological Society of Sweden on March 14, 1986, Dr. Hermann Jaeger, Berlin, and Professor Charles H. Holland, Dublin, were elected Honorary Corresponding Members of the Society.

ISSN:0016-786X    

DOI:10.1080/11035898609454722

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Orientations of the orthocone nautiloids on twenty-three bedding planes in Arenig and Llanvirn (Ordovician) limestones on Öland are analyzed. Nine bedding planes display a bipolar orientation indicating very shallow water. The other fourteen have polymodal orientations, although uniform distributions are rejected statistically. Clusters of orthocones with abnormal distributions are very common on Oland. Experimental data suggest that the clusters are reflecting irregularities on the sea bottom, the so calledneighbour effect.The distribution on either side of the flow direction is probably a combination of the neighbour effect and the particle rotation between conch and sediment. The currents in the Ordovician sea around Öland flowed south and may have paralleled the depth contours. The closest land at that time was probably to the west.

ISSN:0016-786X    

DOI:10.1080/11035898609454723

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In the Lower Ordovician of N. Öland, Sweden, several beds contain ooids. Five localities have been examined, Hälludden, Hagudden, Byrum, Horns Udde, and Gillberga. The chemical and mineralogical composition of the ooids differ between beds and between localities. At Hälludden and Horns Udde, the ooids are mainly composed of francolite, with nuclei of glauconite or skeletal grains, whereas at Hagudden both phosphatic and chamositic ooids occur. At Byrum, several beds of chamositic ooids have been discovered, but also one thin bed containing both hematitic and geothitic ooids. At Gillberga, only scattered phosphatic ooids have been found. Most ooids contain two or more mineral fractions, including calcite. This paper describes their mineralogy, ultrastructure, size variation and distribution in the sections. The origin of the ooids is also discussed. It is suggested that the francolite ooids are primary, and that the ferriferous ooids might have a polygenetic origin.

ISSN:0016-786X    

DOI:10.1080/11035898609454724

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The rugose corals from the Upper Ordovician glacial erratic boulders containing the Hulterstad Fauna are described and illustrated. The following species are recorded:Rectigrewingkia anthelion(Dybowski, 1873),Streptelasmacf.primum(Wedekind, 1927) andStreptelasma medioseptatumn.sp. The taxonomy and ontogeny of these species and genera are discussed.

ISSN:0016-786X    

DOI:10.1080/11035898609454725

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898609454726

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The disseminated copper ore deposit at Aitik in northern Sweden has been studied by means of sulphur and strontium isotopes. The δ34S values are around zero relative to CDT for all sulphides (pyrite, chalcopyrite, pyrrhotite) and about + 10% for barite, indicating that the ore body is homogeneous with respect to sulphur isotopes. The sulphur isotope data indicate a temperature of formation around 500 °C and a magmatic hydrothermal origin of the Aitik ore. The strontium isotope data of barite show an increase in87Sr/86Sr from the center of the ore body (0.7045) towards the hanging wall (0.7160) and the footwall (0.7069). This increase is possibly due to the contribution of radiogenic Sr from the bedrock. The lowest Sr values, together with the spread in values across the ore, support the hypothesis of a primary hydrothermal origin for the ore.

ISSN:0016-786X    

DOI:10.1080/11035898609454727

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898609454728

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The results of Rb-Sr datings of two reddish to reddish grey microcline-rich granites, the Segmon and Gösta granites, from the Gneiss Complex of south-western Sweden are presented. The granites have previously been dated with the U-Pb method on zircons. The Rb-Sr age of the Segmon granite is 1250 Ma, which is identical with the zircon age. The initial87Sr/86Sr-ratio is 0.7107. The Rb-Sr isotopic system of the Gösta granite is profoundly disturbed. The best-fit reference line (MSWD = 3.1) corresponds to an age of 1423 Ma, which is 154 Ma less than the zircon age. The Rb-Sr date has probably no geological significance. These data fit the general pattern of Rb-Sr isotopic characteristics of the ensialically formed granitoids in the Gneiss Complex. According to this pattern, rocks older than c. 1250 Ma frequently have disturbed systems whereas younger rocks often yield primary isochrons.

ISSN:0016-786X    

DOI:10.1080/11035898609454729

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898609454730

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor