Geoscience and the Sibyls sanctuaries locations
February 2006, CIESM News

There were many Sibyls in the ancient world. Sibyls were seeresses who prophesised at certain holy sites under the divine influence of a deity. Among the most renowned is the Delphic Sibyl, also known as Phytia or Herophile, the priestess of the Apollonian Oracle at Delphi. Pausanias, a Greek traveller and geographer of the 2 nd Century AD, and other sources attributed the prophetic inspiration of the oracle to a magical chasm in the earth, a vapour that rose from it, and a spring. By inhaling “the breath of the god Apollo” (according to other sources she received advice from Gaia, the goddess personifying the Earth) the Sibyl entered a state of trance and gained the oracular power. Recently, the scientific explanation for the Sibyl’s behaviour has been found: the ruins of Delphi lie over the juncture of two faults that transfer psychoactive hydrocarbon gases through a spring. These findings follow exactly the ancient descriptions and led the scientists to other excavations of important religious sites of the ancient world in southwest Turkey, where they also detected intoxicating gases.

In an article published in Science*, this is given as one example of how today ancient sources and myths are taken into account by geoscientists providing valuable hints for the environmental setting and natural processes. In order to properly assess the environmental evolution, various parameters and different time and spatial scales have to be considered. Geological processes and short-term, catastrophic events, such as earthquakes and volcanic eruptions, might have left reliable traces in legends and myths, as documented in a paper by Tim Wyatt (among others) in the CIESM Monograph No. 24.

Another ancient Sibyl sanctuary was located within the area of the Campi Flegrei ("burning fields") or Phlegrean Fields, an active volcanic complex including parts of the seabed near the coastal town of Pozzuoli.   The Cumaean Sibyl was the priestess presiding over the Apollonian Oracle at Cumae (a Greek colony near Naples), who pronounced her predictions in a cavern cut out of the volcanic stone. She became a symbol of the myth, because she brought the famous sibylline books to the ancient Rome, a collection of sacred verses, which were consulted in moments of religious and political crisis.

In the center of the Phlegrean Fields caldera, a Roman market place has been built near the shoreline in Pozzuoli. In a study, published in this month’s issue of Geology, it is shown that the importance of these ruins lies in the possibility to link sea-level change and Earth deformation with volcanic activity. A French-Italian geoarcheological team used radiocarbon dated bioindicators on Roman remains and reconstructed relative sea-level changes. Their new data describe a complex history of ground deformation, i.e. large-scale uplift and submersion, and correlated sea-level records. Uplift, for example, means that sites previously underwater were raised and were then under aerial conditions. Ground uplift and subsidence, not always followed by eruptive activity, and a reconstruction of the past and repeated cycles of deformation have important implications for evaluating the volcanic hazard.

More information on geoarchaeology, geochronology and myths in the Mediterranean, in CIESM Monograph No. 24, entitled “Human records of recent geological evolution in the Mediterranean Basin – historical and archaeological evidence”. Like all CIESM Monographs it can be downloaded from this site.