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Digital Elevation Model (DEM) showing the investigated area of the Tiber River Valley and the Tyrrhenian Sea coast.
Modified after TINITALY/01 square WA 6570, used with permission of the Istituto Nazionale di Geofisica e Vulcanologia, Rome.
A) Malagrotta section exposing the sedimentary deposit of the Valle Giulia Formation (MIS 13), erosionally above those of the older Ponte Galeria 2 Formation (MIS 17).
A massive, sand matrix supported gravel layer (a,c) is present at the base of the incision hosting the aggradational succession of the Valle Giulia Formation (MIS 13), which cut through the sand deposit of the Ponte Galeria 2 Formation (MIS 17).
The gravel is laterally in contact with both the primary deposit of the TGPP (d), as well as with abundant, sub-primary volcanic deposit (a,b), providing further evidence that the pyroclastic-flow deposit was emplaced during an erosive phase. The Tufo del Palatino (TP) pyroclastic-flow deposit outcrops at variable elevation throughout the area of Rome (Fig. It follows channels within the paleovalley of the Tiber River, where it occurs at lower elevation with respect to the plateau-like area in the vicinity of the city center (see also Supplementary Figure 2, reconstructing the base surface of TP).
These paleogeographic features suggest that the pyroclastic-flow deposit was emplaced during a marked erosional period, which caused the deep excavation of the river valleys.
1) is a natural laboratory for investigating the timing of the Pleistocene glacial terminations, thanks to the presence of two active volcanic districts, yielding continuous intercalation of tephra layers within the fluvial and coastal sediments.
C age constraints on the aggradational succession of the modern Tiber River, (refs 8 and 9) have shown that the accumulation of a several meters-thick basal gravel layer within the Tiber valley occurred since 15.1 ± 0.1 ka, and that the abrupt sedimentologic transition to a several tens of meters-thick sandy clay package of sediments occurred synchronously in a 30 km-long terminal tract of the river channel, between 13.6 ± 0.2 and 12.8 ± 0.1 ka.
Stratigraphic evidence at Viale Tiziano and at Capitoline Hill (Fig.To accomplish this, we employed a method relying on the ratio of immobile elements (i.e.Zr/Y vs Nb/Y)By using ages of four selected tephras interbedded within the aggradational succession, we provide independent time constraints with analytical uncertainties on the order of ±2 ka (2σ) on the associated sea-level fluctuations during MIS 13 and on glacial termination VI.Moreover, the ages obtained for this study give us the opportunity to compare the timing of the sea-level fluctuations inferred from the stratigraphic record and that provided by the astrochronologic calibration of the Oxygen isotopic curves, and to assess the calibrations of Assessing ages of sedimentary successions deposited in near-coastal environments in response to sea-level fluctuations is a straightforward mean to investigate the timing of glacio-eustatic cycles and provide insights on their forcing mechanisms.In this light, the coastal plain of the Tiber River near Rome (Fig.