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Submarine depositional terraces in the Tyrrhenian Sea as a proxy for paleo-sea level reconstruction: Problems and perspective.

Authors :
Casalbore, D.
Falese, F.
Martorelli, E.
Romagnoli, C.
Chiocci, F.L.
Source :
Quaternary International. Apr2020, Vol. 544, p1-11. 11p.
Publication Year :
2020

Abstract

In the last decade, a great effort was made to determine relative sea level changes along the Mediterranean coastlines through the integration of geophysical modelling and direct measuring of paleo-shoreline related to Late-Holocene and the Last Interglacial events. In this paper, we show the potential use and limitations of additional marine geomorphic markers of past and deeper sea levels. These markers are submarine depositional terraces (SDTs), i.e., deposits formed by a set of small prograding sedimentary wedges, having a terraced shape and found at variable shallow-water depths (mainly the first −150 m) on continental and insular shelves in the Tyrrhenian Sea. The shallowest terraces (near-shore) have their edges at depths of −10/−30 m, compatible with the present-day, local storm-wave base level. Their formation has been associated to present-day/highstand environmental conditions, and as such they can be used to interpret the genesis of deeper terraces formed during earlier sea levels on the middle and outer shelf. Mid-shelf terraces have their edges at variable depths between −40 and −90 m and likely formed during the last sea level rise. They show a patchy distribution and a large variability in their internal structure, so that they are not suitable for correlations at regional scale. Shelf-edge terraces have their edges at depths mainly comprised between −120 and −170 m, compatible or deeper than the sea-level depth reached during the Last Glacial Maximum (LGM). They show an overall similar prograding internal structure and have a remarkable lateral continuity, thus representing a good proxy of sea level position at ≈20 ka. However, the edge's depth of SDTs is not a direct measurement of paleo sea level at that time, since their depth depends on a complex interplay of different factors, such as storm-wave base level and its variation in response to coastal physiography, as well as the occurrence of later erosive-depositional processes. Depending on the geophysical and mapping methods used to determine their depth, the associated error range can also differ. Based on the analysis of these complexities and a wide range of settings from the Italian Seas, a rough estimate of these error ranges is discussed to determine the potential use and the limitations of the SDTs to assess the vertical mobility of an area. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
10406182
Volume :
544
Database :
Academic Search Index
Journal :
Quaternary International
Publication Type :
Academic Journal
Accession number :
143683030
Full Text :
https://doi.org/10.1016/j.quaint.2016.07.051