摘要:

A middle Wenlock (lower Silurian) graptolite fauna is described from the deep well Maglarp 1, in southwest Scania. The investigated material originates from the Maglarp 1 core No. 2, 1,951–1,956 m below kelly bushing (1,947–1,952 m below ground level). The core samples comprise dark grey shale with graptolites intercalated with at least 9 beds of presumably volcanic origin, viz. six sandstone beds, partly consisting of highly altered tuffaceous material, and three thin bentonite beds. The following graptolite forms are present:Pristiograptussp.,Monograptus flemingi, Monograptus priodon?, Monograptus capillaceous, Cyrtograptus rigidus rigidus, andCyrtograptus rigidus cautleyensis.The graptolite assemblage indicates therigidusZone in the Sheinwoodian, lower Silurian. For the first time, the presence in Sweden of this graptolite fauna is reported from a region outside the Röstånga area in Scania. The graptolite fauna is described, and the stratigraphical significance of the core material is discussed and compared with corresponding strata from regions outside Scania.

ISSN:0016-786X    

DOI:10.1080/11035898609453739

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Clastic dikes (dykes) consisting of diamicton and sand were observed in a diamicton bed and in an underlying bed of gravel at a site in the province of Skåne, southern Sweden. In the diamicton bed, a clastic sill made up of laminated sand and gravel also occurs. Features resembling the observed dikes, but made up of only diamicton have been named till wedges. The dikes dip 45–90° and are parallel to each other in the horizontal plane. The largest dikes are 0.8–2.5 m wide and at least 4.0–5.5 m deep. The dikes and the sill were formed beneath an active glacier which fractured the bed. The dikes became infilled with drift from above. Although the dikes and the sill may have been produced when the glacier bed was unfrozen, it seems more likely that they were formed when frozen-bed conditions prevailed.

ISSN:0016-786X    

DOI:10.1080/11035898609453740

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Late Weichselian sediments from two lake basins in southeast Sweden, dated with pollen and radiocarbon in an earlier investigation, have been analysed with respect to their paleomagnetic records. The directional changes of the absolute declination from the two basins are very similar. A strong and quite long-lasting westerly declination maximum during the Allerød Chronozone does gradually turn over to a less strong easterly maximum of short duration around 10,200 B.P. After that another westerly peak seem to follow. The inclination record is reliable from only one site and the filtered curve indicates eight peaks. These geomagnetic records are regarded as good reflections of the secular variations in south Sweden during the Allerød and Younger Dryas Chronozones.

ISSN:0016-786X    

DOI:10.1080/11035898609453741

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898609453742

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

At St. Vika in south central Sweden, a pegmatite has conformably intruded an early Proterozoic, Svecokarelian limestone. Isoclinal folds F1 along N-S axes and subsequent crossfolds F2caused the present structures. Zircons separated from the pegmatite have an age of 1854 ± 5 Ma (2sd), which is considered to reflect the time of intrusion of the pegmatite and consequently the maximum age of the deformation. The Rb-Sr whole rock age of the pegmatite is 1777 ± 24 Ma (2 sd). The closure of the Rb-Sr whole rock system reflects the cessation of the Svecokarelian late-kinematic actitvity and a time when the bedrock had cooled below the threshold for87Sr migration.

ISSN:0016-786X    

DOI:10.1080/11035898609453743

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

U-Pb zircon dating of a synorogenic Svecokarelian tonalite from Eksjö in Småland, southern Sweden, yields upper and lower intercepts with concordia of 1754 ± 10 Ma and —120 ± 102 Ma, respectively. The U-Pb isotopic systems in the zircons have apparently been reset during an earlier phase of deformation and slight migmatization, affecting the investigated area, and by later postorogenic intrusions.

ISSN:0016-786X    

DOI:10.1080/11035898609453744

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Additional material is described and the knowledge we have on the olenellids of the Baltic (or Balto-Scandian) Faunal Province is summarized. Olenellid classification is discussed. New species areHolmia inusitataandKjerulfia schwarzbachi.TheHolmia inusitataZone formally replaces the informalHolmian.sp. zone.

ISSN:0016-786X    

DOI:10.1080/11035898609453745

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Radiometric dating of some young granites of Jungfrun-Götemar type, southeastern Sweden, gives a Rb-Sr whole-rock age of 1350 ± 11 Ma which is in accordance with earlier obtained values. A U-Pb concordia age from zircons is rejected since the zircons carry cores and consequently yield a mixed age. However, a discordia line with an upper intercept of 1400 Ma, the time of intrusion for the Jungfrun and Götemar granites, may be drawn assuming that the zircons were completely reset at the time of intrusion. A Rb-Sr mineral isochron for a post-Svecokarelian Småland dike porphyry yields an age of 1419 ± 14 Ma. This age was reset, probably at the time of intrusion of the younger granites.

ISSN:0016-786X    

DOI:10.1080/11035898609453746

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035898609453747

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Traces of microscopic filaments of the cyanophytic algaGirvanellahave been found in the inferred regressive Lower Ordovician limestone sequence at Hälludden, N. Öland. The algae and their mode of occurrence, as aggregates or as encrustations, are described. Their vertical range is discussed in relation to water depth and water energy. A correlation between the presence ofGirvanellaand limited water depth is demonstrated. The distribution ofGirvanellathus supports the idea of a shallowing in theA. expansuszone in the upper part of the section. An observed association between sponge spiculae and encrusting blue-green algae, is discussed briefly.

ISSN:0016-786X    

DOI:10.1080/11035898609453748

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor