Possible evidence for underlying non-linear dynamics in steep-faced glaciodeltaic progradational successions

Steep-faced glaciodeltaic progradational successions are often studied in o rder to reconstruct the behaviour of the glacial feeder system, or changes in the sediment sink. This paper analyses the magnitude and frequency of de positional events associated with steep-faced glacier-fed progradational su ccessions recorded in Scandinavia and Ireland. The successions exhibit depo sitional patterns that may be interpreted as a function of underlying non-l inear dynamics. A number of the sequences display fractal scaling in the fr equency and thickness of foreset units. Other successions demonstrate chaot ic patterns and strong relationships between delta-front angle and bed thic knesses, suggesting that the progradation of such sequences is self-organiz ed, and to an extent occurs independently of forcing by the feeder system t hat provides sediment to the delta front. These patterns of sedimentation a ppear to be a function of the steepness of the delta front and/or the textu ral characteristics of the sediment. This paper provides further evidence f or the simultaneous presence of order and chaos in Earth surface processes and calls into question the extent to which palaeoenvironmental reconstruct ions may be made from steep-faced progradational successions. Copyright (C) 2000 John Wiley & Sons, Ltd.