Sensitivity of
Clinoform Geometry to Geological Processes Operating on the Continental Shelf
and Slope
Kertznus, Vanessa1, Ben
Kneller1, Mason Dykstra2 (1) University of Aberdeen,
Aberdeen, United Kingdom (2) University of California, Santa Barbara, CA
Conventional 3D seismic reflection data
acquired by BG on the Ebro continental margin (northwestern Mediterranean),
together with wire-line log data from previously drilled wells, allow us to
present a morphological analysis of the Plio-Pleistocene shelf-to-slope
depositional system of the Ebro, by examining the geomorphic response of
clinoform slopes to changing sedimentary and geological conditions.
The seismic data displays a complex
pattern of highly prograding and aggrading clinoforms with variable geometry.
Two major periods characterize the evolution of this post-Messinian margin in
terms of clinoform geometry and slope morphology. Following the Messinian
salinity crisis, the first period is characterized by dominantly oblique
clinoforms developed as the new Pliocene margin prograded. Rapid progradation
resulted in the filling of the underlying Messinian topographic lows. During
this period the continental slope is highly incised by closely spaced submarine
canyons. The second period is characterized by highly progradational and
aggradational, dominantly sigmoidal, and progressively steeper clinoforms, and
by an increase in the shelf-to-basin relief. The degree of incision of the
continental slope decreases, however submarine canyons are wider and incise
deeper.
Mapping of the stratigraphy and
quantification of the slope curvature throughout the succession, reveal both
along-strike and vertical variations in the morphology and curvature of the
continental-margin clinoforms, as the depocenters migrated towards the
southwest. Documentation of these morphologies is essential for understanding
mechanisms of progradation and sediment distribution, and the interplay between
proximity to the sediment source, rate of sediment supply, shelf-to-basin
relief, character of oceanographic regime, and sea-level change.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California