The Paleocene–Eocene Thermal Maximum (PETM) event during the late Paleocene – early Eocene showed atmospheric CO2 increased to >1000 ppm during just <20 kyr; this led to biological events and significant deviations in δ13C and δ18O. During the Paleocene–Eocene transition, Israel was located at latitudes 20–25° N, within the subtropical region, forming part of the southern Neo-Tethys margins. The exposed Paleogene strata are a promising for PETM research.
The two sampling sites, in Zomet Telalim and Giv'at Rehavam, located about 160 km apart in a general N–S direction in the Negev, southern Israel, on the southern Neo-Tethys margins, were chosen for examination of calcareous nannofossils. Both sections are represented by the Taqiye (grey and brown marls, dark shales) and Mor (limestones, marls, chalks) formations. For biostratigraphy, 38 samples from Tlalim and 53 samples from Rehvam were taken at 0.3–1 m intervals.
In Tlalim section, the lowermost part refers to Zone NP8 (Upper Paleocene). The first occurrence (FO) of Discoaster multiradiatus fixed at 10.0 m points to Zone NP9 (Upper Paleocene). The FO of Rhomboaster bramlettei at 20.45 m indicates Zone NP10 (Lower Eocene) to 26.15 m, where Tribrachiatus contorsus disappears. The lower part of the Mor Fm. (26.15–29.22 m) refers to Zone NP11 (Lower Eocene). The FO of Discoaster lodoensis is fixed at 29.22 m and points to Zone NP12 (Lower Eocene).
The PETM interval (20.45–20.95 m) is conspicuous due to the appearance of Rhomboaster spp., typical for PETM irregular discoasters of the D. araneus group and disappearance of Fasciculithus tympaniformis shortly after the recovery of the Carbon Isotope Excursion.
In Rehvam, the lower part of Taqiye Fm. corresponds to NP8. The FO of D. multiradiatus fixed at 18.79 m points to NP9. The FO of Rh. bramlettei at 24.8 m distinguishes NP10 to 32.46 m, where T. contorsus disappears. The lower part of the Mor Fm. (32.46–42.72 m) refers to NP11. The FO of D. lodoensis at 42.72 m indicates NP12.
The PETM interval (24.32–26.26 m) is also clear due to the appearance of Rhomboaster spp. and irregular discoasters of the D. araneus group, and disappearance of F. tympaniformis.