CGRG Bibliography of Canadian Geomorphology
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Author : Cummings, D.I.; Arnott, R.W.C.; and Hart, B.S.
Date : 2006.
Title : Tidal signatures in a shelf-margin delta.
Publication : Geology
Issue : 34(4):
Page(s) : 249-252.
Abstract
Based on its anomalous thickness (150 m) and stratigraphic position above continental-slope mudstone, an upward-coarsening succession consisting in part of tidal rhythmites in the Glenelg Field, offshore Nova Scotia, Canada, is interpreted to be a strongly tide-influenced shelf-margin-delta deposit. A large, funnel-shaped erosional shelf-edge invagination is observed where the paleoshelf edge is resolved in three-dimensional seismic data adjacent to Glenelg. We propose that the delta at Glenelg prograded into a similar shelf-edge invagination within which tidal currents were amplified and wave energy was attenuated. Given that funnel-shaped invaginations (e.g., slope canyon heads, slump scars, fluvially incised knickmarks) are relatively common along modern shelf edges, and that fluvio-deltaic systems should be focused into these topographic lows during regression across the shelf, it seems likely that shelf-edge invaginations play an important but underappreciated role in mediating terrigenous clastic sedimentation during sea-level lowstands.
Bibliography of Canadian Geomorphology