(1) Statoil, Stavanger, Norway
(2) Wyoming University, Laramie, WY
Abstract: Contrasts betwen upper- and lower-slope channel complexes, Battfjellet Fm., Eocene Spitsbergen
The Eocene Battfjellet Formation on Spitsbergen is dominated by a series of steep, high-amplitude (up to 350m) prograding clinoforms, a few of which are sand prone and develop from rivers and shelf-edge deltas downslope into basin-floor sandbodies. Channel complexes have developed on the slope segment of some of the clinoforms, and of particular interest is the contrast between the architectures of upper slope and lower slope complexes.
The studied lower-slope complex has formed at a paleodepth of ca.250m, and occurs near the base of a 4km-long slope. Three offset-stacked (landwards) sets of channels, each leading back up to a specific shelf-edge configuration, can be mapped. The channels within each set build progressively basinwards. In the oldest set the channels are up to 8m deep and 150m wide, were infilled mainly by sustained high-density turbidity flows, and formed the feeder system for a larger basin-floor fan. In the younger sets the channels, associated with extensive slumped units, are smaller (up to 4m deep), are single storey and slightly sinuous, and are infilled by thin-bedded, ungraded and ripple-laminated sandstones derived from waning, high-density flows. The youngest and most landward set of channels can be traced upslope into by-pass surfaces within a slope-delta complex.
The upper-slope channel complex, visibly occurring just below the shelf edge, forms an erosively-bounded, basinward-expanding sandstone wedge. The constituent channels stack in a markedly progradational architecture, and contain turbidites probably generated by river-fed hyperpycnal flows. This upper-slope complex infills a canyon developed by slump collapse at the shelf edge.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana