Late Proterozoic vase-shaped microfossils from the Visingsö Beds, Sweden

Abstract

Vase-shaped microfossils occur abundantly in phosphate nodules from near-shore, marine shales and siltstones of the Late Proterozoic (Late Riphean to Early Vendian) Visingsö Beds in southern Sweden. These fossils are not recovered in acid-resistant residues and are only detectable in thin-section. They are regarded as morphologically comparable to vase-shaped microfossils from Upper Proterozoic rocks of the Chuar Group in Arizona, Eleonore Bay Group in East Greenland, Jacadigo Group of Mato Grosso (Brazil), the Murdama Group of Saudi Arabia, and the Akademikerbreen and Roaldtoppen groups of Ny Friesland and Nordaustlandet (Svalbard). The microfossils are tentatively interpreted as remains of loricate, heterotrophic protists which functioned as predators in the near-shore planktic ecosystem, feeding upon bacteria, algae, and other protists. From available data it is concluded that these microfossils may be biostratigraphically significant as indicators of the uppermost Proterozoic (Upper Riphean and Lower Vendian).