| Summary: | The Miocene Pietra Leccese formation characterizes the Salentine Peninsula in the southern Italian Apulia Region, where it crops out extensively from north of the city of Lecce to Lèuca. A biostratigraphical (planktonic foraminifera and calcareous nannofossils) and chronostratigraphical study of the Pietra Leccese formation in the Lecce type area is reported. The work is based on 186 samples collected from 19 sections and 5 boreholes. As elsewhere in the Salento area, the sedimentation of the Pietra Leccese spans about 11 Ma, from the late Burdigalian (Globigerinoides trilobus Zone of the planktonic foraminifera, Helicosphaera ampliaperta Zone of the calcareous nannofossils) to the early Messinian (Globorotalia miotumida Zone and Amaurolithus delicatus-A. amplificus Zone of the two groups of organisms respectively). The deposition was interrupted by the repeated action of marine currents, which inhibited the accommodation of the sediments and/or eroded those previously formed, resulting in hiatuses (generally testified to by the occurrence of glauconite mineralization) of different durations even in successions that are located very close each other. The Lecce area was studied by considering four geographical sectors (north-western, north-eastern, south-western, and south-eastern) and three hiatuses were recognized, which in stratigraphical order are: - first hiatus, between the typical Pietra Leccese and the overlying weakly glauconitic Pietra Leccese. This hiatus separates the upper Burdigalian sediments of the G. trilobus Zone and H. ampliaperta Zone (Sphenolithus heteromorphus-Helicosphaera ampliaperta Subzone) from the Langhian ones of the Orbulina suturalis-Globorotalia peripheroronda Zone (O. suturalis Subzone) and S. heteromorphus Zone (S. heteromorphus-Helicosphaera waltrans Subzone). The gap is shorter in the succession of the Seminario Borehole (south-eastern sector). In fact, the first sediments above the hiatus pertain to the upper part of the Praeorbulina glomerosa s.l. Zone (Paragloborotalia ...
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