ISSN:0016-786X    

DOI:10.1080/11035897909452574

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Gomphocystites gotlandicusAngelin, 1878 is re-described on the basis of new material from Gotland, Sweden. It differs sufficiently fromGomphocystitess.s. to justify the erection of a new genus,Celticystis. The helmet-shapedCelticystisn.gen. has four circumoral plates forming the mouth frame, whereasGomphocystiteshas seven.Celticystisn.gen. has adambulacral plates in the greater part of the theca and ambulacral flooring plates in the basal portion. The plate distribution inCelticystisn.gen. is more regular than inGomphocystites, from which it is considered to be descended.

ISSN:0016-786X    

DOI:10.1080/11035897909452575

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Additional palaeomagnetic results for the Särna alkaline body of western Sweden confirm the study of Bylund & Patchett (Bylund, G. & Patchett, P. G., 1977: Palaeomagnetism and Rb-Sr isotopic evidence for the age of the Särna alkaline complex, western central Sweden.Lithos 10, 73–79). A combined mean direction (D=201°,I=−23°) from both studies yields a palaeomagnetic pole at 13.6° W, 38.1° S (dp3.9°,dm7.3°) correlating with other European Upper Carboniferous data. Thermomagnetic determinations and petrologic study suggests that pyrrhotite is the predominant mineral responsible for magnetic remanence.

ISSN:0016-786X    

DOI:10.1080/11035897909452576

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

U-Pb isotopic analyses for zircons from an Archaean granitoid gneiss west of the Tjärro supracrustal belt in northern Sweden are presented. Four size fractions showing different degrees of overgrowth on eu- to subhedral zircons are interpreted as reflecting a U-Pb isotopic disturbance during a metamorphic event between 2740 and 2694 Ma ago. Some indication of the primary zircon crystallization is given by the mean diffusion age (2834 ± 40 Ma, 18) of the core-dominated coarser fractions. Subsequent Proterozoic metamorphism, between 1900 and 1750 Ma ago, up to amphibolite facies has caused no significant imprint on the analysed zircons. Together with previous geochronological work, the result indicate the existence of large areas of Archaean crust between the Tjärro belt and the Caledonides.

ISSN:0016-786X    

DOI:10.1080/11035897909452577

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0016-786X    

DOI:10.1080/11035897909452578

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The occurrence ofHauericerascf.pseudogardeniSchlüter in a hardground in the lowermost part of Ignaberga quarry in northern Scania seems to indicate a major Lower Campanian hiatus in the sequence.

ISSN:0016-786X    

DOI:10.1080/11035897909452579

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue

ISSN:0016-786X    

DOI:10.1080/11035897909452563

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor