I terrazzi marini dell'Isola di Salina (Isole Eolie, Tirreno meridionale): un'ipotesi di datazione

Abstract

The volcanic history of Salina (Aeolian archipelago, Southern Tyrrhenian Sea) can be divided into two different periods marked in time by a marine ingression. The first period lasted from 0.5 m.y. B.P. to 127,000 y. B.P. and it is represented by some ancient volcanoes (Rivi, Corvo and Capo) at present deeply dissected by marine erosion and covered by younger products. The second period is characterized by the evolution of Monte dei Porri and Pollara and lasted from 67,000 to 13,000 y B.P. During the whole history of Salina the main activity was of the strombolian type with a limited deposition of pyroclastic materials. From a structural point of view the island develops along two well defined trends marked by clear morpho-volcanic evidences: a) an E-W direction recognizable in the general orientation of the northern coast; b) a N-S direction marked by the orientation of the western and eastern segments of the coast. Ancient shorelines remains are represented on Salina by: a conglomeratic level of Tyrrhenian age interbedded between the lavas of the first cycle and the pyroclastic deposits of the second cycle, the marine terraces located at different heights on the slopes of the island which are the subject of the present study. The terraces occur as fossil abrasion platforms on which many paleontological specimens were collected. The fauna is typical of a littoral environment characterized by hard ground. It was possible to define a preliminary chronology of the 3 orders of terraces by dating the eroded bedrock and the data obtained were compared to data from the island of Lipari. The terrace at 45+54 m a.s.l. (2nd order) of Salina can be correlated to the platform at 45+65 m a.s.l. (3rd order) of Lipari and dated about 30,000 y. B.P.; the shoreline at 120+150 m a.s.l. on Salina can be related to the terrace at 96+108 m a.s.l. of Lipari with an age of about 40,000 y B.P.