|Abstract: ||In 2005, the National Geological Survey of Italy released the new sheet, 557 Cagliari (1:50.000 scale). A
coastal barrier marine formation at Is Arenas (Cagliari, Sardinia, Italy), containing Strombus bubonius, was
reassigned a Holocene age, in contradiction with extensive literature published over the past century
indicating an MIS 5.5 age. In 2007, spurred by this controversy, a short note was published in Il Quaternario
demonstrating the stratigraphic difficulties in attributing the age of this formation to the
Holocene. Later, another paper signed by numerous Italian geologists was published in Il Quaternario
criticizing the Holocene attribution. The tectonic consequences of assigning a Holocene age to these
deposits are of great significance, as their elevation could only be explained by strong uplift over the past
few thousand years. Such a tectonic setting would imply a radical change in the recent geodynamic
history of Sardinia, which is considered to be among the most stable areas of the Mediterranean basin.
This paper provides further geochronological data for a MIS 5 age for the deposits at Is Arenas. Electron
Spin Resonance (ESR) analyses were performed on 4 fossil shells sampled along the fossil baymouth bar.
The results established an MIS 5 age. The amino acid racemization (AAR) and U-series data that first
determined a correlation with the last interglacial, Tyrrhenian age of this ancient shoreline is reviewed,
with additional documentation provided by the fossil marker S. bubonius|