Turbidite deposition from multiple sources; Quaternary Paola Basin (eastern Tyrrhenian Sea)

Abstract

ABSTRACT The western margin of the Calabrian Arc is underlain by a thick (as much as 5 km) post-Miocene sedimentary succession. The uppermost part of this margin sequence is referred to as the Paola Basin System (Quaternary in age) and partially fills a present-day physiographic slope basin. Seismic and high. resolution reflection profiles reveal that a prominent unconformity marks the base of the Paola Basin System (PBS). The unconformity connects upslope to an area of recurrent shelf. edge instability and is overlain by large mass-failure deposits over much of the basin area. Basin-wide sedimentary drape deposits form stratigraphic markers that subdivide the Paola Basin System into three stages, each with unique patterns of slope erosion, including mass wasting, and lower.slope to basin-floo turbidite deposition. Three major sediment pathways elongated perpendicular to the margin developed between the unconformity and the first basin-wide drape. Upsection, sediment input for turbidite sedimentation in Paola Basin has involved many, commonly ephemeral, point sources. Most of the turbidite deposits do not form complete submarine fan sequences but consist of only a few turbidite elements. Changes in the size and type of turbidite elements through time suggest a decrease in the size and/or duration of individual sediment sources in the latest Pleistocene. The Paola Basin System is an example of a complex fill of a tectonically controlled basin where the effects of cyclic eustatic changes in sea level modify the effects of longer-term changes in sedimentation driven by tectonic ctivity in the source region and structural deformation in the depositional area.