The Structural evolution of the Asinara Island (NW Sardinia, Italy)

Rodolfo Carosi, Anselmo Di Pisa, David Iacopini, Chiara Montomoli, Giacomo Oggiano

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The metamorphic basement of the Asinara island represents a key area of the Sardinia Variscan segment, because it displays an almost complete cross-section through the inner part of the Sardinia Variscan belt, where different tectono-metamorphic complexes have been juxtaposed along narrow belts of high-strain concentration. Detailed field mapping coupled with preliminary studies on the structural and metamorphic features of this small island, allow to draw a better picture of the structural frame issued from the Variscan collision in the inner zone of the belt. Three deformation phases related to crustal thickening in a compressive and transpressive, partitioned tectonic regime, followed by a later phase of extensional deformation have been recognised. In spite of a general HT/LP metamorphic overprint, linked to the post-collisional deformation phases, a relic Barrovian zoneography is still detectable. The Barrovian assemblages are preto syn-kinematic with respect to the D2 deformation phase, and pre-date the third, contractional tectonic event. The HT/LP assemblage indicates a static growth of weakly deformed by the last deformation events. The complex geometry of the fabric associated to the D2 and D3 deformation events suggests an heterogenous deformation history with a monoclinic geometry characterized
by switching of the stretching lineation orientation and a contrasting sense of displacement, probably controlled by a northward partitioned pure shear.
Original languageEnglish
Pages (from-to)309-329
Number of pages21
JournalGeodinamica Acta
Volume17
Issue number5
Publication statusPublished - 2004

Keywords

  • Structural geology
  • Sardinia
  • Variscan orogeny
  • Polyphase deformation

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