Channel Complexes Within Pleistocene Clinoforms in the Adriatic Sea
Daniel Minisini and Patrizia Rocchini
Geophysical Studies, Eni E&P Division, San Donato Milanese, Italy
Clinoform architectures vary significantly within the Pleistocene Adriatic units, ranging from progradational to aggradational. In the western side of the basin, clinoforms breaks exhibit steep foreset dips with well developed channel leveed complexes at the toes of 3rd order packages; basinward of the complexes occur well developed basin fan style deposits. In contrast, clinoform architectures on the eastern side of the system appear more progradational, with less dramatic clinoform break angles; basinward of these breaks, seismic attribute analysis suggests that there are a myriad of gully channels and larger channel systems developed, arranged in a more amalgamated fashion.
Successive phases of channels development exhibit how their internal architecture changes from braided- to meandering-dominated, increasing the width of meanders over time. Contemporaneously parallel minor conduits along the slope widen, maintaining low sinuosity. The formed and aggraded meandering belt shows lateral break-overs with adjacent generation of channels, having width similar to conduits within the meandering belt and presenting low sinuosity. These new channels are subparallel to the strike of lower slope and crosscut minor conduits along the slope. Direction and physiographic location of these new channels undermine the lower slope causing sediment instability. Slide headscarps and gullies occur and retrograde, representing an additional source of sediment input. The new channels, subparallel to the strike of the lower slope, gather the sediment of the suite of gullies and headscarps carving the slope.
Channels gathering the sediment from the lower slope deviate when encounter the foreland ramp and converge, forming a braided system. Eventually, retrograding incisions reach the upper slope sector and capture conduits feeding other systems, thus generating new source-to-sink systems.
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