2.2.3. Senonian Limestones

This formation corresponds to thick pelagic strata (1 to 3 m) intercalated with calciturbidites, comprising limestones with fragments of globotruncanids and rudists and fine-grained breccia intervals with limestones and rudist fragments within calcareous cement containing pelagic fauna. Calciturbidites are usually alternated with sub-lithographic pelagic limestones and cherts [34,35]. Overall, this formation corresponds to a period of basinal sedimentation, with significant variations of its lithological characteristics and sedimentary facies from the external (western) to the internal (eastern) parts of the Ionian basin. In the external sub-basin, they have been described as "clastic limestones" [75] containing floatstones, rudstones and rare grainstones and packstones with a micritic matrix, biomicritic intercalations, and rare cherty nodules. In the middle sub-basin, these carbonates are characterized as microclastic, bioclastic or polygenic microbreccias with a micritic matrix (wackestone, packstones), intercalated with (bio)micrites. In the internal sub-basin, the Senonian Limestones are massive, thick bedded microbrecias to breccias containing rudists and coral fragments, with only local appearance of thin-bedded or nodular chert [65,66,76].
