Deep distributary channels and giant bedforms in the Upper Carboniferous of the Central Pennines, northern England

Authors

  • PETER J. McCABE

    1. Department of Geology, The University, Keele, Staffordshire ST5 5BG
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      Department of Geology, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.


ABSTRACT

Channels, with maximum depths of over 40 m, have been cut into the top of a coarsening upward sequence, in the Upper Carboniferous of northern England. The channels are interpreted as deep, distributaries cut into delta slope deposits.

Giant cross-bed sets, up to 40 m thick, are the major channel infilling facies. Internal erosion surfaces occur within the giant cross-beds and some are draped by micaceous, silty sandstone. Previously interpreted as deltaic sedimentation units, the cross-beds are now thought to have been produced mainly by side attached, alternate bars and the drapes are interpreted as low stage deposits.

Cosets of medium scale cross-beds overlie the giant cross-beds. These are thought to be deposits of dunes and smaller bars on top of the transverse bars and in the shallower parts of the distributary. The giant cross-beds are commonly underlain by unlaminated sandstone but may be underlain by undulatory bedding. The latter was apparently produced by ridges, parallel to the current, spaced between 9 and 23 m apart.

The north of England appears to have had a major river by present day standards, for at least part of the upper Carboniferous.

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