Sea level fluctuations in the Tyrrhenian period and the presence of Neanderthals in the caves of Circeo and Gaeta: the results of the study provide important indications for the assessment of sea level rise caused by global warming.
The discovery of unexpected variations of the Mediterranean in the Tyrrhenian period (124.000 - 80.000 years ago) constitutes a useful element for the evaluations of the sea level rise following the melting of the ice caused by global warming. This is the result of the studyAnomalous Last Interglacial Tyrrhenian sea levels and Neanderthal settling at Guattari and Moscerini caves (central Italy) conducted by a team of researchers from the National Institute of Geophysics and Volcanology (INGV) in collaboration with the History Department of the Tor Vergata University and the Superintendency of Archaeology, Fine Arts and Landscape for the provinces of FR, LT and RI, just published in Scientific Reports.
"The research”, explains Fabrizio Marra, INGV researcher and co-author of the study, “deals with two apparently very different aspects: the oscillations of the sea level in the Tyrrhenian period and the frequentation by the Neanderthal man of the caves that open on the coast between the promontory of Circeo and Gaeta. In these caves”, continues Marra, “numerous testimonies of human attendance of the Paleolithic were found. Among these, an almost complete Neanderthal skull found in Grotta Guattari is the most important, together with a large quantity of flint tools. Furthermore, the peculiar presence of tools made by Neanderthal man using the valves of a shell, the 'Callista chione' which, known as "fasolaro", is still typical of the beaches of the Lazio coast has emerged".
Precisely thanks to the presence of a series of elements such as shells, holes of "lithodome" organisms that live in holes dug in the cliffs and foreshore furrows engraved in the rock by the tide, these caves provide important indications on the oscillations of the sea level linked to the last two glaciations.
"The Tyrrhenian”, adds the researcher, “it constitutes the interglacial period between the last two glaciations which occurred respectively 160.000 and 20.000 years ago. In this period, after the sea had dropped up to 120 meters below its current level due to the freezing of large masses of water at the poles, its rapid ascent occurred during the glacial termination. Around 125.000 years ago”, continues Marra, “the sea reached and exceeded the current one by about six meters. Two oscillations followed in which the sea level fell again due to the sharp drop in temperatures and then rose again, before "plunging" again by more than a hundred meters during the last ice age.
The study ascertained that during these two temporary ascents, which occurred 100 and 80 thousand years ago, the sea level reached levels close to the current level, unlike what has been estimated up to now through the theoretical calculation of the volumes of ice that formed and they merged at this time".
Because of this, during these interglacial phases, the caves opened onto small beaches which favored the attendance by the Neanderthals. These caves provided them with the possibility of finding the shells they fed on, then using the shells to build small tools.
"The results achieved with this study are also important for the present era. This is because in the assessments of the sea level rise expected following the melting of the ice caused by global warming, this unexpected behavior of the Mediterranean in past eras will necessarily have to be taken into account”, concludes the researcher.
Figure 1 - Through the reconstruction of the surfaces of ancient marine terraces (T) and the review of indicators of paleo-levels of the sea (LdM), the ancient coastlines between Anzio and Gaeta have been reconstructed (a, b, c). Particularly useful for the reconstruction were the beach and dune deposits present inside various caves that open onto the cliffs between Circeo and Gaeta (c). A new dating carried out on a fossil shell in the locality of Quadrato confirmed old datings carried out by paleoanthropologists in Grotta Guattari and Grotta dei Moscerini. These two caves are in fact rich in evidence of the Neanderthal presence in the periods in which the sea level was close to their entrance.
Photo 2 - Images of Grotta Guattari, during the sampling of samples for the chronostratigraphic study by researchers from INGV and the Tor Vergata Department of History.
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