Fridbjørg Biskopstø1, John R. Underhill1
(1) The University of Edinburgh, Edinburgh, United Kingdom
ABSTRACT: Development of Paleogene Dendritic Drainage Patterns: The Sedimentary Response to Plume-Related Uplift in the North Atlantic
Interpretation of closely-spaced, three-dimensional seismic data has revealed the occurrence of a spectacular, dendritic palaeo-drainage pattern in Paleogene sediments of the Moray Group in the Faroe-Shetland Basin, West of Britain. The valley network was incised into a Late Paleocene, progradational deltaic complex ascribed to the Flett Formation and was primarily infilled and capped by transgressive, tuffaceous fine-grained clastics of the Early Eocene, Balder Formation. The drainage system can be mapped over an area in excess of 700sq km and consists of numerous low sinuosity channels each of which were fed by a pattern of outward-bifurcating tributaries. Individual valleys obtain a maximum vertical relief of around 100m and widths of between 3 and 5km. Similarity between their dominant NNE-directed drainage patterns and the underlying Mesozoic basin structure suggests that the latter retained an influence on Early Cenozoic (post-rift) sediment dispersal. The record of shallowing, incision and fill is coincident with upward-shoaling and fluvial downcutting in the Dornoch Formation of the North Sea. The regional evidence for incision and valley fill provides important documentary evidence for the sedimentary response to basin uplift related to mantle plume development and igneous underplating.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado