Cambro-Ordovician strata in Ny Friesland, Spitsbergen and their palaeotectonic significance

• Published in: Geological Magazine
• Main Author: Swett, K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1981
• Subjects: Geology; Greenland; Ny Friesland; East Greenland; Newfoundland; North Atlantic; Spitsbergen
• Online Access: http://dx.doi.org/10.1017/s001675680003572x; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S001675680003572X

Summary Field and petrologic investigations of Cambro-Ordovician strata in Ny Friesland, Spitsbergen reveal a stratigraphic, sedimentologic, and diagenetic history for those rocks that bear striking similarities to coeval strata in central East Greenland, northwest Scotland and western Newfoundland. Parallels between these presently widely separated areas include: stratigraphic sequence (including enigmatic gaps), sedimentary structures, faunal assemblages, trace fossils, geochemical anomalies, and diagenetic sequences. It seems inescapable that the Cambro-Ordovician successions in Ny Friesland, central East Greenland, northwest Scotland, and western Newfoundland were developed on a once contiguous shelf on the margin of the lapetus Ocean. A tentative sequential tectono-sedimentological facies model of the ‘North Atlantic Geosyncline’ extending in time from late Proterozoic to the opening of the Atlantic Ocean is proposed to explain the empirical data. Slow closure of the lapetus basin, simultaneously involving transgression of the ‘North American’ plate and subduction of lapetus oceanic crust beneath a Euro-Balto-Scandinavian plate, followed by collision of the two continental plates, in turn followed by reopening along the approximate collision boundary appears to explain the observed relationships. This palaeotectonic/sedimentologic model is subject to further testing. The lithostratigraphic scheme is further refined.