The Stratigraphy and Paleoenvironments of the Ringerike Group (Late Silurian), Southern Norway

N. Davies
Birmingham University, School of Earth Sciences, Birmingham, UK

The Ringerike Group in southern Norway has previously been described as a 120 Dm thick Late Silurian (Ludlow) succession of fluvially deposited siltstone and sandstone red beds that were conformably deposited subsequent to the deposition of the Cambro-Silurian carbonates of the Oslo Region. Preliminary fieldwork in the area suggests that the number of lithofacies and the paleoenvironments that they represent are more complex than previously thought.

The Ringerike sediments were deposited in a foreland basin ahead of the Caledonian orogenic belt, and generally represent a major marine regressive sequence. Sedimentary logging of the facies suggests that the littoral influence within the red beds is more apparent than hitherto recognized, and that the marine regression was a net result of a continually fluctuating sea level for the duration of the deposition of the Ringerike Group.A number of calcareous sandstones have been identified throughout the succession which contain sedimentary structures that suggest they may represent marine-derived storm deposits. Microfossils from these calcarenites pose a number of biostratigraphic questions.

Ongoing fieldwork in the Ringerike Group type area, as well as in other previously undescribed localities in southern Norway, will allow a sequential suite of related paleoenvironments to be described which will eventually be constrained through the use of magnetostratigraphic and biostratigraphic techniques. The completed study will ultimately further the understanding of a set of linked paleoenvironmental facies associations and the way in which their stratigraphic relationship represents basin infill within a classic foreland setting.

AAPG Search and Discovery Article #90902©2001 AAPG Foundation Grants-in-Aid