Late Proterozoic (Vendian) to Early Cambrian sedimentation in the Hedmark Group, south-western part of the Sparagmite Region, southern Norway

Abstract

Field studies of the allochthonous Ekre Shale and Vangsås Formation (uppermost Hedmark Group) were undertaken in order to develop a sedimentary model for the final stages of infilling of the Hedmark rift basin. The Ekre Shale accumulated as a prodeltaic deposit following a quick eustatic sea-level rise caused by the Vardal Sandstone Member of the Vangsås Formation, which in its lower and middle parts represents a transition from a fan-deltaic to a braid-plain environment. Towards the top, the Vardal Sandstone Member is dominated by high-energy (wave-dominated) shallow-marine deposits, and a widening of the basin is documented. The Ringsaker Quartzite Member of the Vangsås Formation reflects the mature stages in this shallow-marine (epicontinental) sedimentation phase. Proximal (south) to distal (north) relationships can be demonstrated throughout the sequence.