The Portfjeld Formation (?Early Cambrian) of eastern North Greenland

Abstract

The Portfjeld Formation (Jepsen, 1971) was mapped (map 1) during the 1978 field season across the so-called Hagen Fjord Arch (Dawes, 1976), through portions of the South Peary Land - Vildtland Basin and the Hagen Fjord - Danmark Fjord Basin (fig. 6). The beds are flat lying or dip gently to the north on the western side of the area, with gentle dips to the east along Danmark Fjord. The Portfjeld Formation is characterized by well bedded, grey or buff coloured dolomites which form prominent cliffs above the Inuiteq Sø Formation, the Morænesø Formation and its lateral equivalents, or the Fyns Sø Formation. A typical Portfjeld Formation succession is summarized in fig. 7 by the section measured to the west of Øvre Midsommersø (section 7, fig. 6). This section includes several good marker horizons which have been noted previously by several authors (Jepsen, 1971; Haller, 1971; Troelsen, 1949, 1956). These marker beds and the horizons in between are described briefly here.