Lithostratigraphy and U-Pb Geochronology of the Telemark Supracrustals in the Bandak-Sauland Area, Te Le Mark, South Norway
NORWEGIAN JOURNAL OF GEOLOGY Lithostratigraphy and geochronologyof the Telemark supracrustals 119 U-Pb lithostratigraphy and geochronology of the Telemark supracrustals in the Bandak-Sauland area, Telemark, South Norway Kauko Laajoki, Fernando Corfu & Tom Andersen Laajoki, K., Corfu, F. &Andersen, T.: Lithostratigraphy and U-Pb geochronology of the Telemark supracrustals in the Bandak-Sauland area, Te le mark, South Norway. Norsk Geologisk Tidsskrift,Vol. 82, pp. 119-138. Trondheim 2002, ISSN 029-196X. The Mesoproterowic Te lemark supracrustals in southern Norway have been subdivided into four groups: (l) the ca. 1500 Ma volcanic Rjukan group overlain by (2) the quartzite-dominatedSeljord group, itself overlain by (3) the ca. 1160 Ma volcanic-sedimentary Bandak group in the west and by (4) the undated Heddal group in the east. New mapping and U-Pb work provide considerable refinement to this stratigraphy. The Ljosdals vatnet porphyry near the base of the Bandak gro up has an age of 1155 ± 3 Ma age, but it overlies that part of the Seljord gro up, which was folded and eroded before deposition of the Bandak gro up. The Brunkeberg porphyry, which has previously been correlated to the Rjukan gro up, yields an identical age of 1155 ± 2 Ma. It is unconformably overlain by a quartzite, which has also been included into the Seljord group. This group must, therefore, consist of two separate successions separated by a period of folding, here referred to as the Vindeggengro up (older) and the Lifiellgro up (younger). The former represents a thick, fluvial,shallow sea sandstone - intertidal heterolithic sequence, whereas the latter is composed of a relati vely thin and mature beach-shoreline sandstone sequence.
[Show full text]