The Paleocene-Eocene transition in the southern Tethys (Tunisia): climaticand environmental fluctuations

This study, based on a multidisciplinary approach including micropaleontolo gy, sedimentology, mineralogy and geochemistry, evaluates the Paleocene-Eoc ene transition in Tunisia. At Foum Selja, sediment deposition occurred in t he shallow, restricted Gafsa Basin influenced by the adjacent Saharan platf orm. During the early Paleocene this area experienced a warm and humid clim ate that changed to warm but arid climatic conditions during the Paleocene- Eocene transition. At Elles the sediment deposition in the EI Kef Basin occ urred in an open marine environment connected to the Tethys. During the lat e Paleocene, the Tethyan region was submitted to a seasonal warm climate ch anging to a warm and humid climate across the P/E transition and becoming s easonal/arid in the early Eocene. From Africa to northern Europe, kaolinite , a strong marker of warmth and humidity disappeared diachronously suggesti ng a latitudinal shift in the source area of this mineral and consequently in the climatic zones, from lower to higher latitudes. The P/E transition o bserved at Elles corresponds to a 2.7 m thick clay layer and is marked by a drastic decrease in carbonate sedimentation, a negative delta(13)C excursi on of 1.3 parts per thousand and increased detrital input. The presence of a condensed interval, the accumulation of phosphate deposits after the P/E event, which obliterate the original isotopic signal and strong dissolution of the planktic fauna and flora in these phosphatic layers, all are criter ia that prevent the Elles section to be a potential GSSP candidate for the P/E boundary.