• journal_title：Bollettino della Societa Geologica Italiana
• Contributor：Laura Buzzi ; Laura Gaggero ; Giacomo Oggiano
• Publisher：The Electrochemical Society
• Date：2008-
• Format：text/html
• Language：en
• journal_abbrev：Bollettino della Societa Geologica Italiana
• issn：2038-1719
• volume：127
• issue：3
• firstpage：683
• section：Structural geology

The main volcanic rhyolitic event in NW Sardinia (Nurra) and Permo-Triassic successions outcrop between Punta Capparoni and Cala Viola, where they attain the maximum thickness (>300 m), northwards undergo sudden reduction. In particular at Mt. Santa Giusta, the "Autunian" succession was not deposited, and the thickness of the Permo-Triassic red beds decreases to few metres above the ignimbrite that rests directly on the basement. New ⁵⁰ Ar- ³⁹ Ar step heating technique on biotite separates gives 291.5+ or -1.5 Ma for this event; this age is considerably older than existing radiometric data. The corresponding Lower Sakmarian age and the field relationships with the Permo-Triassic successions Nurra to the S, allow to assess that north of Porto Ferro the Nurra basement was a structural high bounded by E-W trending faults since the Late Carboniferous-Lower Permian, and that the same faults that controlled the post-collisional Variscan extension Also controlled the development of Mid Permian and Lower Triassic successions.