CHIRP subbottom profiles performed on the Ionian Calabrian margin, southern Italy, allow the recognition of an irregular seabed topography. It shows both concave-up and concave-down profiles in any dip section and a local stepped geometry, with gradients between 1° and > 20°. The steeper slopes are interpreted as relicts of palaeo-coastal cliffs generated by wave action during the post-LGM relative sea-level rise. In particular, the formation of a slope locally exposed between ca. 75 and 100 m water depth is inferred to be related to the melt-water pulse (MWP) 1A (14.3 - 14.0 ka BP), whose depth range corresponds closely with that of this slope, assuming no subsidence or uplift. A transgressive model for high-gradient settings and stepped sea-level rise is proposed. Coastal cliffs develop and retreat due to wave erosion during phases of slow relative sea-level rise. During phases of very high rate of relative sea-level rise, coinciding with melt-water pulses, cliffs tend to be overstepped, drowned and not completely eroded. The present model may be effective in reconstructing stepped sea-level rises and the evolution of shelf areas during Late Quaternary time.
Post-LGM features along the Ionian Calabrian margin (southern Italy)
Zecchin M.;Ceramicola S.;Gordini E.;Deponte M.;
2011-01-01
Abstract
CHIRP subbottom profiles performed on the Ionian Calabrian margin, southern Italy, allow the recognition of an irregular seabed topography. It shows both concave-up and concave-down profiles in any dip section and a local stepped geometry, with gradients between 1° and > 20°. The steeper slopes are interpreted as relicts of palaeo-coastal cliffs generated by wave action during the post-LGM relative sea-level rise. In particular, the formation of a slope locally exposed between ca. 75 and 100 m water depth is inferred to be related to the melt-water pulse (MWP) 1A (14.3 - 14.0 ka BP), whose depth range corresponds closely with that of this slope, assuming no subsidence or uplift. A transgressive model for high-gradient settings and stepped sea-level rise is proposed. Coastal cliffs develop and retreat due to wave erosion during phases of slow relative sea-level rise. During phases of very high rate of relative sea-level rise, coinciding with melt-water pulses, cliffs tend to be overstepped, drowned and not completely eroded. The present model may be effective in reconstructing stepped sea-level rises and the evolution of shelf areas during Late Quaternary time.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
