Wave-Dominated Gilbert-Type Gravel Deltas in the Hinterland of the Gulf of Taranto (Pleistocene, Southern Italy)
- Albina Colella3 and
- David B. Prior4
Published Online: 2 APR 2009
Copyright © 1990 The International Association of Sedimentologists
How to Cite
Massari, F. and Parea, G. C. (1990) Wave-Dominated Gilbert-Type Gravel Deltas in the Hinterland of the Gulf of Taranto (Pleistocene, Southern Italy), in Coarse-Grained Deltas (eds A. Colella and D. B. Prior), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303858.ch18
Universita della Calabria, Italy
Atlantic Geoscience Center, Nova Scotia, Canada
- Published Online: 2 APR 2009
- Published Print: 19 OCT 1990
Print ISBN: 9780632028948
Online ISBN: 9781444303858
- sand-gravel deltas, developing in Gulf of Taranto;
- fluvial-dominated types;
- wave-influenced Gilbert-type bodies;
- coarse-grained marine progradational sequences, developing duringPleistocene;
- Gilbert-type deltaic bodies, occurring in basin of Bradano river;
- gravity-dominated foresets;
- upslope-dipping stratification;
- slope-apron systems
A number of Gilbert-type gravel and sand—gravel deltas developed in the hinterland of the Gulf of Taranto during the Pleistocene. Progradation took place in broad erosional depressions interpreted as drowned valleys cut during a previous relative lowstand of base level. The resulting confined bodies may represent constrained lowstand deltas.
Topsets mostly consist of beach deposits, suggesting that deltas experienced high nearshore wave power. Erosional surfaces commonly interrupt the continuity between topsets and foresets and result in alternating sigmoid and oblique offlap; this is regarded as the expression of constructional and destructional phases in delta growth, related to small fluctuations of relative base level or to the shifting of stream mouth(s).
Purely gravitative processes initiated by slumping or sliding apparently played only a minor role on the delta front. Instead, the commonly observed merging of wave-worked topsets into foreset beds and the textural characters of the latter suggest that sediment dispersal on to the foreset slope was frequently initiated in the nearshore area by storm-induced, high-density surging flows which were subsequently driven by gravity down the foreset slope. Some segments of the foreset are characterized by diffusely stratified gravel and sands with antidune-like bedforms and scour-filling backset beds, the latter thought to reflect development of chutes and pools, with sedimentation related to upstream-migrating hydraulic jumps. A line source rather than a single or multiple point source(s) is thought to have been active, leading to the formation of a debris apron on a channel-deficient foreset slope. Ubiquitous scour-filling backset beds at the toe are thought to record hydraulic jumps which accompanied the flow deceleration at the slope break.
Changes in the geometry and internal organization of the deltaic bodies, as recognized in sections parallel and transverse to the direction of progradation, show that a continuum exists from gravel-beach sequences of increasing ramp height to Gilbert-type bodies.