The MIS 5 marine terraces on the Tyrrhenian Sea coast of central Italy between Civitavecchia and the Fiora River
Journal
CATENA
ISSN
0341-8162
Date Issued
2025-04
Author(s)
Komen, R
Seijmonsbergen, A C
DOI
10.1016/j.catena.2025.108817
Abstract
We reconstruct the marine terraces of the Marine Isotope Stage (MIS) 5 and the landscape evolution of the
Tyrrhenian Sea coastal area between the Fiora River and Civitavecchia (central Italy), based on extensive
fieldwork, biostratigraphical, palaeoecological, and geomorphological analyses, and 40Ar/39Ar dating. Our
geomorphological mapping approach uses object-based image analysis, guided by field observations, to identify
and map marine terraces using metrics calculated from a LiDAR-based digital terrain model. A suite of three
marine terraces at elevations around 40 m, 20 m, and 6 m a.s.l. is recognized through this combined approach in
the southwestern sector of the investigated area between Civitavecchia and Marina Velca. Geochronologic
constraints based on 40Ar/39Ar dating of detrital sanidine extracted from the sedimentary deposits set a terminus
post quem for the marine terraces, suggesting their correlation with MIS 5e, MIS 5c, and MIS 5a. We have
reconstructed an extensive paleosurface in this portion of the coastal area, marked by a CaCO3-rich, cemented,
Thetystrombus latus-bearing biodetrital conglomerate that gently dips seaward from ca. 20 m to the present sea
level and represents a range of environments from coastal to shelf. Despite the occurrence of the mollusc species
considered distinctive for the MIS 5e highstand, combined geochronologic constraints and paleoecological reconstructions
support its attribution to MIS 5c. The lowest terrace forms a narrow strip along the coastline and
comprises near shore deposits, including a second, distinct biodetrital platform, at 2–3 m a.s.l. which, assuming a
staircase geometry for the suite of terraces, is correlated with MIS 5a. Such geomorphological setting coincides
with that reconstructed in the adjacent coastal sector between Civitavecchia and the Tiber delta, pointing at a
significant late Quaternary regional uplift.
Tyrrhenian Sea coastal area between the Fiora River and Civitavecchia (central Italy), based on extensive
fieldwork, biostratigraphical, palaeoecological, and geomorphological analyses, and 40Ar/39Ar dating. Our
geomorphological mapping approach uses object-based image analysis, guided by field observations, to identify
and map marine terraces using metrics calculated from a LiDAR-based digital terrain model. A suite of three
marine terraces at elevations around 40 m, 20 m, and 6 m a.s.l. is recognized through this combined approach in
the southwestern sector of the investigated area between Civitavecchia and Marina Velca. Geochronologic
constraints based on 40Ar/39Ar dating of detrital sanidine extracted from the sedimentary deposits set a terminus
post quem for the marine terraces, suggesting their correlation with MIS 5e, MIS 5c, and MIS 5a. We have
reconstructed an extensive paleosurface in this portion of the coastal area, marked by a CaCO3-rich, cemented,
Thetystrombus latus-bearing biodetrital conglomerate that gently dips seaward from ca. 20 m to the present sea
level and represents a range of environments from coastal to shelf. Despite the occurrence of the mollusc species
considered distinctive for the MIS 5e highstand, combined geochronologic constraints and paleoecological reconstructions
support its attribution to MIS 5c. The lowest terrace forms a narrow strip along the coastline and
comprises near shore deposits, including a second, distinct biodetrital platform, at 2–3 m a.s.l. which, assuming a
staircase geometry for the suite of terraces, is correlated with MIS 5a. Such geomorphological setting coincides
with that reconstructed in the adjacent coastal sector between Civitavecchia and the Tiber delta, pointing at a
significant late Quaternary regional uplift.