Coastline modifications in Sardinia starting from archaeological data: a progress report

摘要

This paper uses a combination of archaeological, geomorphologic and radiometric data from the coast of Sardinia, in Italy, to purpose a reconstruction of the sea-level and coastal changes during the recent period in the whole island. The archaeological remains have been used as one of indicators to interpret the recent movements, uplift or subsidence, long the coastal tracts of the island; the evidences are represented by quarries, megalithic buildings, submerged towns, roman villas, the latter by harbor structures, Medieval testifies and other ruins like the wrecks for a long span. In summary, the comparison between the geomorphologic evolution, archaeological indicators and radiometric data suggests a different sea-level uplifting corresponding to the different Pleistocenic evolution in some places of the island; in some cases there is an evident correspondence between the submerged remains and the presence of the grabens that characterizing the geological structure of the Sardinia. The submerged archaeological indicators are intended to identify the level of the sea, in most situation, they indicate the presence of a sea level lower than their base subject to the tidal range at the time which can be only be approximate. However, the presence of a single type of indicator does not know the precise level of the sea; in the same way it is very difficult to distinguish between eustatic and tectonic components. The combination and correlation between different data at the regional level is the only possibility to have an interpretative hypothesis for movements. Unfortunately it is rare to have all three indicators in one place. The results are given in recognition of areas of greatest subsidence, evidenced by some ancient cities, with the more stable areas and those that behave differently showing that even in historic and protohistoric Sardinia, while considered a stable land, suffer a continuous weak lifting or subsidence comforted by archaeological data showing that, at the same time, the progression of the phenomenon is different.