The structure of the Aurunci Mountains (southern Lazio): A balanced cross-section and its restoration

This short note presents a short balanced cross section between Gaeta and Campodimele, based on field data from a geologicalstructural map (1:25.000 scale). The investigated area presents some specific topics, which differentiate it from the adjacent northern and southern zones. The structural setting is characterized by a thin-skinned thrusting which involved the whole sedimentary succession (Upper Triassic-Upper Cretaceous). After the structuring of the Apenninic chain, the Plio-Pleistocene extension offsets this sector along NW and subordinated NE trending normal faults. The Aurunci Mountains belong to the southwestern portion of the Lazio-Abruzzi (mesozoic) carbonate platform domain. The sedimentary succession shows the characters of inner shelf environment, with facies ranging from subtidal to supratidal. The lithotypes are mainly laminated dolomitic wackestones and calcareous packstones with benthic assemblages dominated by molluscs, foraminifera and green algae. A number of outcrop of reasonable quality has enabled the construction of one balanced cross-section throughout the Aurunci Mountains, using the line-length method. This has been made up using as main detachment the Triassic dolostones levels and, as secondary ones, the lower portion of the cretaceous succession. Using specific computers software we obtain a value of 6.6 km e.g. (32.8%) of shortening, and a 4.9 km e.g. (26.9%) of extension.