Upper Triassic depositional environments at Lunnom, northwest Scania

Abstract: The mid-Rhaetic sequence at Lunnom, with coal and kaolinitic clays, indicates partly deltaic environments affected by alluvial processes during humid conditions. Of special interest is a thin bed of sandstone with coarse, angular quartz grains. The bed occurs mainly as a covering sheet on top of a heterolithic sequence in the eastern parts of the pit, while it is recognized as isolated dunes inside the heterolithes in the western parts. Lithic trends suggest a palaeotransport direction from southeast towards northwest from continentally influenced source areas. The observed occurence of the bed indicate repeated high energy events. The evental deposition may be explained by crevassing, or due to sediment transport from a nearby alluvial fan, into areas with differentiated subsidence.