The sea bottoms of the continental shelf of the Naples Bay (southern Italy): inferences of volcanic and sedimentary processes on the stratigraphic architecture

Aiello, Gemma and Marsella, Ennio (2013) The sea bottoms of the continental shelf of the Naples Bay (southern Italy): inferences of volcanic and sedimentary processes on the stratigraphic architecture. In: Continental Shelf Geographical Distribution, Biota and Ecologic Significance. Nova Science Publishers, New York, pp. 1-122. ISBN 978-1-62948-331-3

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Abstract

The continental shelf of the Naples Bay has been intensively studied and analyzed through high resolution seismic reflection profiles coupled to morpho-bathymetric data, including Multibeam bathymetry and Side Scan Sonar imagery and sea bottom samples. Marine geological maps of the Naples Bay have been constructed by using an experimental approach to the geological maps, according to guidelines to Italian Marine Cartography suggested by the ISPRA, formerly the Italian Geological Survey. Some criteria and examples of marine geological mapping relative to the geological map n. 465 “Procida” (Naples Bay) both at the scales 1:10.000 and 1:25.000 are here presented. The cartographic approach is based on the recognition of laterally coeval depositional systems, representing portions of system tracts of the Late Quaternary depositional sequence. The integrated geological interpretation of seismic, bathymetric and Sidescan Sonar data have been tied by sea bottom samples and piston cores. The geological structures and the seismic sequences, both volcanic and sedimentary, have been studied with detail through multichannel and single-channel seismic profiles of different resolution and penetration, often integrated with marine magnetics. Seismic interpretation allowed for the reconstruction of stratigraphic and structural setting of shelf-slope successions, separated by tectonic and eustatic regional unconformities. In the Naples Bay the Dohrn and Magnaghi canyons, eroding the slope up to – 1000 m of water depth, represent main morpho-structural lineaments at the boundary between the sedimentary units of the eastern shelf and the volcanic units of the western shelf, in correspondence to the Phlegrean Fields, Ischia and Procida volcanic complexes. The marine geological maps, so realized, show the distribution of several lithostratigraphic units cropping out at the sea bottom and of the main morphological lineaments. The stratigraphic units belong to the Late Quaternary Depositional Sequence, showing the spatial and temporal geological evolution and the lateral and vertical migration of marine coastal, continental shelf and slope depositional environments during the Late Pleistocene-Holocene glacio-eustatic cycle. The stratigraphic succession studied through the geological survey has recorded the variations of the accommodation space of the Late Quaternary deposits during the last 4th order glacio-eustatic cycle, ranging between 128 ky B.P. (Tyrrhenian stage) and the present (isotopic stage 5e). The geomorphology and seismic stratigraphy of the continental shelf and slope appear strongly controlled by the interplay of volcanism and canyon formation acting in correspondence to the Magnaghi and Dohrn axes. Mound-shaped morphological highs genetically related to the emplacement of the Neapolitan Yellow Tuff volcanic unit (13 ky B.P.), widely cropping out onshore, Holocene reworked sediments and sea-bottom creep appear on acoustic Chirp profiles in the inner sectors of the bay. These features appear to be related to the interaction among volcanic, tectonic and sedimentary processes conditioning the geological evolution of the Naples Bay during the Late Quaternary. On the contrary, the sedimentation over the shelf at the southern edge of the bay (Sorrento Peninsula-Capri island) seems less influenced by volcanic activity and seabed features include Late Pleistocene regressive sand bodies and Holocene patch reefs, coastal dunes and depositional terraces.

Item Type:	Book Section
Subjects:	500 Scienze naturali e Matematica > 550 Scienze della Terra > 551 Geologia, Idrologia, Meteorologia > 551.4 Geomorfologia e idrosfera
Depositing User:	Dr Gemma Aiello
Date Deposited:	19 Dec 2013 08:48
Last Modified:	19 Dec 2013 08:48
URI:	http://eprints.bice.rm.cnr.it/id/eprint/8047

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