STRATIGRAFIA E CARATTERISTICHE FISICHE DEI DEPOSITI OLOCENICI DEL PORTO DI MISENO, GOLFO DI POZZUOLI (TIRRENO CENTRO-ORIENTALE)

Abstract

The stratigraphic study of five deep cores (30-40 m) drilled in the harbor of Miseno (western Flegrean Fields), along with radiometric
age dating (14C AMS) of two peat layers and a number of geotechnical tests, allowed for the reconstruction of the stratigraphic framework and the determination of physical and mechanical properties of the Holocene succession beneath the sea floor. Based on
these data we outline the evolution of the study area during the last 10.000 years.
The Holocene succession of Porto Miseno is characterized by transgressive volcanic sandy deposits which include a 1÷5 m thick pyroclastic unit (Unit C). Two resting phases, which closes regressive episods, are testified by two peat layers which have been cored within unit B (layer t1) and at the transition between units D and E (layer t2). Samples collected from the peat layers yielded radiometric ages of 3560±40 years B.P. and 7815±55 years B.P., respectively. This suggests a correlation between the cored peat layers and two paleosols documented on land that are associated with resting periods during the volcanic activity of Flegrean Fields. Chronostratigraphic constraints, based on these radiocarbon age determinations, allowed for the evaluation of sedimentation rates during Late Holocene, which are in the order of 3.5 m/ka for the lower units (E-D) and 2.2 m /ka for the upper part of the section (units B-A).
The Holocene deposits of Porto Miseno can be correlated with distinct seismic-stratigraphic units identified in the subsurface of the
southern and central sectors of Pozzuoli Bay. They can be also correlated with the section cropping out onshore, along the erosional
slope of “La Starza” terrace, where the marine Holocene sequence has been uplifted about 40 m above the sea level in the last few
thousand years.