## 5 Discussion
### The Post-MECO Phase (173-201 m): Partial Recovery of the Pre-Event Conditions  
This phase, which corresponds to the \(\delta^{18}\)O values recovery, shows a recovery in the benthic foraminiferal assemblages marked by an increase in P/B and C/A values that can be ascribed to the end of the dissolution phase (Figure 3). This interval is also characterized by a marked reduction of the E/I and bi-triserial forms and would therefore reflect higher availability of organic matter but likely refractory in origin (Figure 3). The final part of the post-MECO interval (i.e., 181-201 m) exhibits some peculiar feature such as the occurrence of radiolarians with a peak in abundance from 183 to 185.5 m that can suggest a transient increase of eutrophic conditions (e.g., [132]). Interestingly, the benthic foraminiferal assemblages around 188-190 m record the lowest value of P/B, C/A and diversity. In this short interval, the lowest value of bi-triserial forms is associated to relatively high value of E/I. The planktonic foraminiferal assemblages shows a major long-term change as large _Acarinina_ and _Morozovelloides_ do not recover their abundance in this phase that should record the recovery, at least in part, of the pre-event conditions (Figure 5). The results from the Baskil section emphasize that a first abrupt decline in abundance of the large acarininids and morozovellids took place well before their evolutionary extinction level occurred at the Bartonian-Priabonian boundary. Our data confirm other records from Tethyan sections of northern Italy [18; 19] and tropical Atlantic [20]. Although test size-\(\delta^{13}\)C gradients are not available from the Tethyan/Neo-Tethyan successions, the permanent loss of algal photosymbiont-relationship does not appear as the main cause of the permanent reduction in abundance of these groups. On the other hand, the bleaching recorded by [20] revealed to be a transient episode because the symbiotic relationship was recovered after the MECO peak. The causes of this persisting decline in abundance are not yet established, however, a link to the climatic change and paleoceanographic variations that occurred during the MECO or just following it seems implied. The irreversible return towards cooling conditions after the MECO that culminated with the onset of icehouse condition at the Eocene-Oligocene boundary may have played a role, taking in account that both large acarininids and _Morozovoltaides_ were warm-indices. This evidence might explain the decline at the tropical Atlantic and Tethys successions. Possibly local/regional conditions at the Baskil geological setting induced an earlier large acarininids decline in abundance at the MECO beginning. The Baskil section deposited in relatively restricted hemipelagic conditions [33]. The increased sedimentation rates indicate enhanced hydrological cycle in a warmer and more humid climate on land since the beginning of the MECO as it is proved also by increase in smectite/illite ratios, terrigenous elements (e.g., Fe, Ti and Al) [32]. The Neo-Tethys in the middle Eocene was a narrow basin with a complex topography, similar to the Mediterranean Sea [133]. Therefore, the continental runoff delivered significant amounts of light carbon and fresh water [3]. Change in salinity and increase trophism related to freshwater input could have negatively impacted the habitat of the specialized, oligotrophic mixed-layer dwellers, such as large acarininids and _Morozovoltaides_ during the MECO at Baskil. Afterwards, their permanent decline may have been driven by global climatic and paleoceanographic variations. Even though the mixed-layer was deprived of these two groups, the upper water-column appears still stratified during the MECO and afterward. It is possible that the increase of _Subbotin senni_ might be explained, at least in part, with its colonizing the ecological niches released by acarininids. Similar behaviour may have been adopted by _Globigerinathkea_.