Architecture
and Seismic Geomorphology of Shelf-edge Deltas Along
an Active Tectonic Margin: Eastern Offshore
Maher, Julie A.1, Lesli J. Wood2 (1) The
The South American continental margin,
offshore eastern
Observations show that throughout the
shelf edge, the setting changes visibly from aggradational
to progradational, capped by modern, transgressive flooding deposits. Also, we can distinguish
two clinoform facies across
the shelf edge: horizontal delta topsets cut by
possibly distributary facies
and delta-front clinoforms, varying in steepness.
Southward, deltas prograde into upper-slope minibasins formed by normal faulting, with toe-of-slope turbidites ponding against downslope, counterregional,
accommodation sinks. Alternatively, northward, shelf-edge deltas along the same
margin prograde well onto the upper slope into
accommodation sinks formed by extensional grabens and
growth faults. In addition, their more-point-sourced nature and proximity to
the continental-plate boundary leads to rapid destabilization, resulting in basinward deposition of large mass-transport deposits.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California