Environmental history of quartz sand grains from the Lower and Middle Pleistocene of Norfolk, England

Abstract

Criteria aresuggested for the distinction of glacial, glacio-fluvial, dune, beach, and deeper-water or estuarine environments on the basis of electron-microscopic examination of surface textures of quartz sand grains. In favourable circumstances a sequence of events representing a succession of environments may be recorded on a single sand grain or group of grains. Textures resulting from chemical action are also recognized. Application of the technique to the Lower and Middle Pleistocene (Norwich Crag to North Sea Drift) deposits of Norfolk, England, has confirmed the origin of deposits previously interpreted on the basis of their contained faunas and general sedimentary characteristics, and has provided new evidence on the origin of others. On the basis of these studies it is concluded that the Norwich Crag is of littoral and sublittoral origin with occasional incorporation of dune sand, that the quartz–quartzite–flint gravels of the upper part of the Norwich Crag Series s.l., the Weybourne Crag, and the Estuarine Bed of the Cromer Forest Bed Series each show initial glacial and sometimes glacio-fluvial action, followed by turbulent (beach) or less turbulent (estuarine or deeper-water) action, and that the Norwich Brickearth and Cromer Till both appear to have incorporated large quantities of mainly marine sand into relatively stoneless till, probably near the margins of an ice-sheet.