The Jabal Al Akhdar anticline, Northeast Libya. Upper Cretaceous to Tertiary Tectonic Evolution, Influence on the East Mediterranean Ridge and Relation to the Sirt Basin

Stavros Arsenikos, Nicolas Chamot-Rooke, Dominique Frizon de Lamotte, and Christian Blanpied

The Cyrenaica promontory (northeast Libya) is dominated by the presence of the Jabal Al Akhdar regional anticline. The onshore part of this ENE-WSW trending structure, reaches a maximum elevation of about 800m and involves primarily Upper Cretaceous, Eocene and Oligocene sedimentary rocks. We present here industrial seismic profiles crossing the offshore domain and illustrating the northeast prolongation of the anticline up to the East Mediterranean Ridge subduction zone. Well calibration allows us to precise the timing of the main tectonic events. As in the onshore domain, Oligocene sediments underline a major unconformity sealing a main folding event. Growth strata of Late Ypresian to Priabonian age indicate a protracted folding during the Middle-Late Eocene. At depth, there are some arguments to consider an older Upper Cretaceous folding event. The Jabal Al Akhdar anticline is also indicated by a pronounced re-entrant of the East Mediterranean Ridge front, showing that it forms a kind of buttress interfering with this propagating tectonic front. On this basis, we will address different questions including: (1) the role of the heritage in the location, orientation and general shape of the Jabal Al Akhdar anticline; (2) the relationships of this prominent structure with the adjacent Sirt basin, which developed synchronously at right angle.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013