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This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: B26420.1v1 121/11-12/1475    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Corrado, S. Articles by Grasso, M. GeoRef GeoRef Citation

Structural evolution of the sedimentary accretionary wedge of the alpine system in Eastern Sicily: Thermal and thermochronological constraints

Sveva Corrado^1,, Luca Aldega¹, Maria Laura Balestrieri², Rosanna Maniscalco³ and Mario Grasso³

¹ Dipartimento di Scienze Geologiche, Università "Roma Tre," Largo San Leonardo Murialdo 1, 00146 Roma, Italy
² C.N.R., Istituto di Geoscienze e Georisorse, Sezione Firenze, Via La Pira 53, 50121 Firenze, Italy
³ Dipartimento di Scienze Geologiche, Università di Catania, Corso Italia 55, 95129 Catania, Italy

Correspondence: E-mail: corrado{at}uniroma3.it

Temperature-dependent clay-mineral assemblages, vitrinite reflectance, and apatite fission-track data have been used to investigate levels of diagenesis and time of exhumation of the double-verging Sicilide-Antisicilide accretion-ary wedge in Eastern Sicily. The integration of organic and inorganic thermal indicators allowed us to distinguish parts of the accre-tionary wedge with different thermal signature and evolution. We recognize a warmer core made up of the Mount Soro and Troina units and two colder rims (Antisicilide and far-traveled Sicilide units). The Antisicilide unit was thrust back toward the hinterland, and the far-traveled Sicilide units were gravity-driven toward the Hyblean Plateau.

In detail, the highest percentages of vitrinite reflectance (VR_o) values (0.60%–0.96%) and percentages of illite layers in illite-smectite (I-S; 60%–85%) are found in the Mount Soro and Troina units. Apatite fission-track data, together with the paleotemperature estimates from vitrinite-reflectance data and clay-mineral–based geothermometers, indicate that fission tracks were partially to totally annealed during wedge accretion and that the subsequent exhumation occurred mainly in Burdigalian times.

Low VR_o values (0.35%–0.50%) and percentages of illite layers in I-S (30%–60%) occur in early thrust-top deposits (Reitano Flysch) that unconformably overlie the Sicilide Complex, as well as the far-traveled Sicilide and Antisicilide units. Apatite fission-track data for the Antisicilide unit confirm low paleo-temperature values. Thus the far-traveled Sicilide and Antisicilide units were probably at higher structural levels in the original accretionary prism and were remobilized since late Aquitanian–Burdigalian times.