Istituto di Geoscienze e Georisorse     
De Vita S., Laurenzi M., Orsi G., Voltaggio M. Application of 40Ar/39Ar and 230Th dating methods to the chronostratigraphy of quaternary basaltic volcanic areas: the Ustica island case history. In: Quaternary International, vol. 47/48 pp. 117 - 127. Elsevier, 1998.
The island of Ustica has been the site of coeval volcanism and transgressive-regressive marine cycles. The volcanic history can be subdivided into five periods of activity according to stratigraphical and compositional data. Basaltic magmas were extruded during most of these periods and only one period was characterized by the emplacement of trachytic rocks. Sea level high-stands generated five orders of marine terraces with related level surfaces at variable elevation and sedimentary deposits. A geochronological study was carried out by means of 40Ar/39Ar and 230Th dating methods on magmatic and marine sedimentary rocks, respectively. The results obtained allow us to give temporal constraints for the geological history of the island. Volcanism took place between about 750 and 130 ka BP. Until about 500 ka BP, Ustica was a seamount with subaqueous eruptions. The sole trachytic explosive eruption occurred about 424 ka BP, after a long period of rest during which the conditions for formation and evolution of a shallow magma chamber were established. The ages of the marine terraces are in very good agreement with those obtained for correlatable level surfaces along the coasts of the southern Tyrrhenian sea. The I-order marine terrace (80-120 m a.s.l.) was created about 350 ka BP, while the III-order terrace (20-30 m a.s.l.), which is the youngest dated, formed around 130 ka BP. According to geomorphological constraints, the IV-(10 m a.s.l.) and V-order terraces (5 m a.s.l.) are correlated with level surfaces dated at 105 and 80 ka BP
URL: http://https://www.journals.elsevier.com/quaternary-international/
Subject Italy
Ustica island
quaternary volcanism
40Ar/39Ar dating
230Th dating

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