『Abstract
The purpose of this paper is to present a complete stratigraphic
framework for the modern Simeto River delta (eastern Sicily, Italy)
by the description of its geomorphology and sedimentology, which
allow an analysis of its recent evolution.
The Simeto River delta represents an asymmetric wave-influenced
delta which developed during the Holocene by prograding into the
Catania Gulf.
This delta represents a good example of a Mediterranean-type
system, characterized by a micro-tidal regime and moderate wave
energy; the peculiar distribution of sedimentary facies both in
the subaerial and in the subaqueous sectors is interpreted as
the response of the system to the intimate interaction of geological
and, in recent times, anthropogenic coastal activity.
The integration of a large amount of historical data allows the
definition of prograding and retrograding pattern within the delta
and the cyclical shifting of the river mouth over the last two
centuries. A hypothetical model is proposed to explain this phenomenon,
and it is suggested that this may be a characteristic of several
Mediterranean-type deltas.
Progradation of the delta ended during the early-middle XIX Century
after which it began to retreat. The retreat of the coastline
accelerated after the 1950s when owing to the construction of
embankments on the delta plain and, since 1970s, increasing diversion
of water resources in the upper part of the Simeto River drainage
basin, the sediment input of the river to the Ionian Sea sharply
decreased. This caused a dramatic change of the deltaic morphology
and significant coastal land loss.
The morphological and sedimentary features of the Simeto River
fully reflect the processes of its adaptation to the persistence
of coastal human activity within an active geological setting.
Keywords: Simeto River delta; Morpho-sedimentary evolution; Anthropogenic
influences』
1. Introduction
2. Geological framework of the Simeto River
3. Wind and oceanographic setting
4. Methodology
5. Results
5.1. Morphology and sediment distribution on the subaerial
Simeto delta plain
5.1.1. Sediment distribution on the subaerial delta
5.1.1.1. Abandoned delta plain
5.1.1.2. Active delta plain
5.1.2. Sedimentary facies associations of the Simeto delta plain
5.1.2.1. Marine facies association
5.1.2.2. Alluvial facies association
6. Bathymetry and sediment distribution of the subaqueous delta
6.1. Description of deltaic bathymetry
6.2. Sediment distribution on the Simeto River subaqueous delta
7. Sedimentary and dynamic processes of the Simeto delta system
7.1. Marine influences at the mouth
8. Delta evolution and human-induced changes
8.1. Historical migrations of the Simeto River mouth
8.2. Recent human-induced modifications
9. Discussion and conclusions
Acknowledgements
References