Lower Cambrian sandstone erratics and geophysical indications of sedimentary rock in the Stockholm area, Sweden

Abstract

Just north of Stockholm a trending till fan has yielded a number of Lower Cambrian erratics of coarse‐grained, immature, feldspar‐rich sandstones with graded‐ and cross‐bedding, and siltstones with wave ripples, Skolithos, and Planolites. The contact between the siltstone and the sandstone has been found in one erratic boulder. The siltstone seems to be intercalated in the sandstone. The Early Cambrian age, probably within the Holmia kjerulfi Assemblage‐zone, is indicated by tubes and shells of Torellella laevigata, Torellella sp., and a hyolithid. The erratics are devoid of microfossils. A reddish, very fine‐grained sandstone occur as pebbles in the sandstone erratics, indicating the once existence of Middle Riphean sandstone in the investigated area. The Lower Cambrian sandstone is suggested to have been deposited in a coastal area influenced by tectonic block movements. Glacial striae, the orientation of the boulder fan, and geophysical evidences indicate an in situ occurrence of Lower Cambrian sandstone north to northeast of the Tranholmen Island, probably in the Stora Värtan Bay north of Stockholm City.

Hagenfeldt, S.E. & Söderberg, P., 1994: Lower Cambrian sandstone erratics and geophysical indications of sedimentary rock in the Stockholm area, Sweden. GFF, Vol. 116 (Pt. 3, September), pp. 185–190. Stockholm. ISSN 1103–5897.

Keywords:

• Shelly fossils
• trace fossils
• sedimentary rock
• erratics
• geophysics
• Cambrian
• Stockholm Archipelago
• Stockholm
• Sweden