Central Mediterranean tephrochronology for the time interval 250-315 ka derived from the Fucino sediment succession

In the lacustrine succession F4-F5 of the Fucino Basin, central Italy, 20 visible tephra layers were identified in the time interval 250-315 ka (Marine Isotope Stages 8-9). Fifteen of them contained suitable material to explore their volcanic sources. Among these tephra some well-known eruptions and eruptive sequences of the Roman and Roccamonfina volcanoes were identified, such as the Tufo Giallo di Sacrofano and the Lower White Trachytic Tuff, respectively. Furthermore, the sediment succession documents a more complex eruptive history of the Sabatini, Vulsini, Colli Albani and Roccamonfina volcanic complexes during the investigated period, as inferred from previously undescribed tephra deposits. Single-crystal-fusion 40Ar/39Ar dating of two of the inspected tephra layers combined with two already published tephra ages provided the basis for a Bayesian age-depth model. The modelled tephra ages allow chronological constraining of so-far undefined eruptions of the Sabatini (272.5 +/- 4.7, 281.8 +/- 4.7, 308.5 +/- 2.8, 312.8 +/- 2.1 ka), the Vulsini (311.7 +/- 2.3, 311.9 +/- 2.3 ka) and the Colli Albani (301.0 +/- 3.6 ka) volcanic districts. Two tephra layers of an undefined volcanic source from the Roman volcanoes have modelled ages of 309.5 +/- 2.7 and 310.5 +/- 2.6 ka. The new 40Ar/39Ar and modelled ages were further used for a reassessment of the timing of already known and dated eruptive units, such as the Tufo Giallo di Sacrofano (40Ar/39Ar: 289.3 +/- 4.8 ka). Tephra tentatively correlated with the Valle Santa Maria, Case Pisello and the White Trachytic Tuff Unit E3 or Unit F offer modelled ages for these eruptions of 296.6 +/- 3.9, 301.8 +/- 3.5 and 303.6 +/- 3.4 ka, respectively. The results complete the tephrostratigraphical investigations of the c. 425 ka old F4-F5 record, extend the Mediterranean tephrostratigraphical framework and provide a significant contribution for improving knowledge on Italian volcanic explosive activity. The sediment succession of the Fucino Basin hosts a unique palaeoclimate archive with a vast number of tephra layers. Here tephra layers of the time interval 250-315 ka are explored for their volcanic sources and potential equivalents to study the past peri-Tyrrhenian explosive volcanic activity and to extend the Central Mediterranean tephrostratigaphical framework. The resulting tephrochronological reference section provides new insights for the application of tephra based dating and synchronizing of sedimentary archives.image

Automated summary

In the lacustrine succession of the Fucino Basin in central Italy, visible tephra layers were identified and analyzed to understand the volcanic sources and age of eruptions. By dating these tephra layers, the study contributes to the knowledge of Italian volcanic explosive activity and expands the understanding of the Central Mediterranean tephrostratigraphical framework.