Storm-surge Sandstones and the Deposition of Interbedded Limestone: Late Precambrian, Southern Norway

Abstract

In the Late Precambrian Biri Formation of southern Norway, graded sandstones are intercalated with thin-bedded micrites and flakestones. The sandstones, interpreted as storm-surge deposits, commonly show parallel lamination passing up into cross lamination and they have offshore-directed current ripples on their upper surfaces. The thin-bedded micrites,initially looking like tidal flat or lagoonal deposits,are locally disrupted into intraclast horizons, and intraclasts occur within sandstone beds. The occurrence of the storm sandstones indicates a subtidal, below wave-base shelf depositional environment for the micrites. The intraclasts are thought to form by storm disruption of surficial micrite layers which were lithified on the seafloor. Thick flakestone units in the sequence are probably storm-channel fills.