Ammonitico Rosso (Zaress formation) of the Tunisian Dorsale

The Upper Jurassic biostratigraphy, so far limited to the J. Zaress, is ext ended to the ranges of the Tunisian Dorsale. The AR facies (Fm Zaress) begi ns as early as the Middle/Upper Callovian and ranges up into the Lower Kimm eridgian (Planula Zone). Above, the grey limestones and overlying beds (Res sas Fm) span the rest of the Kimmeridgian and the Tithonian. Compared to th e north-south axis, the Ammonitico Rosso facies develops earlier in the Dor sale on starving shoals while AR of J. El Haouareb are slope deposits fed f rom the north-south axis heights, where Callovian and Oxfordian are reduced or absent. ((C) Academie des sciences / Elsevier, Paris.).