Correlation of Late Proterozoic tillites in the North Atlantic region and Europe

Abstract

SummaryWell-established Late Proterozoic tillites are widely distributed in Svalbard, East and North Greenland, the Norwegian and Swedish Caledonides, Scotland, northwestern Ireland, western USSR, the Urals, Newfoundland and the Appalachians. Recent biostratigraphic and geochronometric data have provided the following sequence of glacial events. The earliest evidence of glaciation is represented by tillites in Newfoundland, Scotland and possibly NE Svalbard, and may have taken place in Late Riphean (sensuVidal) or Sturtian (sensuHarland) time, perhapsc.800 Ma ago. A glacial period in Vendian time, the Varangian, centred on 650 Ma was a much more severe climatic event, represented in all the above mentioned areas except Newfoundland. Two Varangian glacial epochs are recorded in Svalbard, East Greenland, northern Norway and possibly western USSR, and although most of the deposits are marine, terrestrial conditions prevailed in some areas with associated periglacial phenomena. The earlier epoch was completed before 650 Ma; the later one occurred within the rangec.650–610 Ma.A tectonic reconstruction of the region places eastern Svalbard adjacent to East Greenland, which has implications for major strike-slip motions in late and post-Caledonian times. A discrete ice-sheet is envisaged, centred on the western USSR (terrestrial tillites) with ice flowing out to the then peripheral area of the northwestern Europe continental margin and to the Urals where shallow platformal glaciomarine sediments accumulated.