The Smalfjord Formation in the Varangerfjorden area of northern Norway was deposited as valley fill during an interglacial period of the Varangerian (Marinoan) glaciation. The paleovalley was initially cut by glacial erosion and braided rivers. Subsequent marine transgression due to glacial eustasy entered through the fjord valley mouth located to the present WNW and advanced across an irregular valley floor. As the initial transgression slowed down, the shallow fjord acted as a normal storm-dominated estuary and was filled by a prograding bay-head delta and flood-tidal delta prograding from opposite ends of the paleovalley. The final stage of fjord fill was completed by tidal sandflats and braided-river deposits. The latter was due to isostatic rebound in the hinterland. Renewed transgression resulted in a return to marine conditions in the succeeding Nyborg Formation, which spilled out of the paleovalley onto the surrounding areas.
The Late Neoproterozoic Smalfjord Formation of the Varanger Peninsula in northern Norway: a shallow fjord deposit