CHAPTER 1
Marine Geology and Morphobathymetry in the Bay of Naples
(South-Eastern Tyrrhenian Sea, Italy)
G. Aiello, V. Budillon, G. Cristofalo, B. D' Argenio, G. de Alteriis, M. De Lauro, L Ferraro,
E. Marsella, N. Pelosi, M. Sacchi, and R. Tonielli
ABSTRACT
Recent multibeam bathymetry (Elac,Bottomchart MK2) and high resolution seismics (Subbottom
Chirp and 1-4 kJ Sparker source), acquired in the frame of an on-going programme of sea-floor
mapping of Naples and Salerno Bays (south-eastern Tyrrhenian margin, Italy) and financed by the
National Geological Survey of Italy, allows to put new insights into the recent evolution of the
bay. The morphology and stratigraphy of the continental shelf and slope appear strongly controlled by the interplay of volcanism and canyoning that acted along the Magnaghi and Dohrn
axes. Detailed bathymetry reveals the complexity of the drainage pattern which consists of a previously unknowntdense network of minor tributary channels. At places, the Dohrn and Magnaghi
canyon walls are intenSively affected by slope instability, as evidenced by numerous submarine
slides and scars involving large volumes of sediments. Previously unreported mound-shaped
morphological highs ("Bacarozzi" Facies), Holocene reworked sediments and sea-bottom creep
appear on acoustic Chirp profiles in the inner sectors of the bay and seem to be related to volcano-sedimentary processes. On the contrary, sedimentation over the shelf at the southern edge
of the bay (Sorrento-Capri) seems less influenced by volcanic activity and seabed features include
Late Pleistocene regressive sand bodies and Holocene patch reefs, coastal dunes and depositional terraces.
Introduction
An on-going programme of sea-floor mapping in
Naples and Salerno Bays (south-eastern
Tyrrhenian margin), is among the main research
projects of the Geomare Sud Institute, CNR
Naples, Italy. Financed by the National
Geological Survey of Italy (CARG project), this
research. aims at producing, during the years
1998-2000, geological maps of selected marine
coastal zones at the 1: 50.000 scale. Recent criteria for geological mapping of Italian marine
areas (joint CNR-SGN Committee, see Catalano
et al. 1996) have been followed.
For a review of recent geological and geophysical studies over the Naples offshore area, see
Latmiral et al. (1971), Finetti and Morelli (1974),
Pescatore et al. (1984), Fusi et al. (1991), Milia
(1996), Marsella et al. (1996), Aiello et al. (1997a,
b), Cinque et al. (1997), De Lauro et at. (1997).
Materials and Methods
Most of the data presented here have been
acquired in the frame of three oceanographic
cruises organised by the Geomare Sud and by
other institutions during the 1996-1998 time
span. The frrst cruise (RN Urania, GMS97-1;
October-November, 1996) was dedicated to the
acquisition of a high-resolution multibeam sur"veyofthe Bay of Naples (below the -50 m isobath)
and of a narrow belt south of the Sorrento
Peninsula (Figs. 1, 2). An ELAC Nautik
Bottomchart MK2 multibeam system was adopted with a bathymetric range of -50 I -3000 m. The
ELAC system is equipped with a transducer of
256 beams arranged to generate a 15 to 150 0 fan
width; the vertical accuracy is about 0.25% of
water depth whereas the spatial resolution (the
size of the «footprint") ranges from 1 to 5 m. The
maximum horizontal coverage is 7.5 times the
Istituto di Ricerca Geomare Sud, CNR, Via A. Vespucci 9,80142 Napoli, Italy
EM. Faranda, L. Guglielmo, G. Spezie (eds)
Mediterranean Ecosystems: Structures and Processes
@ Springer-Verlag ItaHa 2001
Marine Geology and Morphobathymetry in the Bay of Naples
(South-Eastern Tyrrhenian Sea, Italy)
G. Aiello, V. Budillon, G. Cristofalo, B. D' Argenio, G. de Alteriis, M. De Lauro, L Ferraro,
E. Marsella, N. Pelosi, M. Sacchi, and R. Tonielli
ABSTRACT
Recent multibeam bathymetry (Elac,Bottomchart MK2) and high resolution seismics (Subbottom
Chirp and 1-4 kJ Sparker source), acquired in the frame of an on-going programme of sea-floor
mapping of Naples and Salerno Bays (south-eastern Tyrrhenian margin, Italy) and financed by the
National Geological Survey of Italy, allows to put new insights into the recent evolution of the
bay. The morphology and stratigraphy of the continental shelf and slope appear strongly controlled by the interplay of volcanism and canyoning that acted along the Magnaghi and Dohrn
axes. Detailed bathymetry reveals the complexity of the drainage pattern which consists of a previously unknowntdense network of minor tributary channels. At places, the Dohrn and Magnaghi
canyon walls are intenSively affected by slope instability, as evidenced by numerous submarine
slides and scars involving large volumes of sediments. Previously unreported mound-shaped
morphological highs ("Bacarozzi" Facies), Holocene reworked sediments and sea-bottom creep
appear on acoustic Chirp profiles in the inner sectors of the bay and seem to be related to volcano-sedimentary processes. On the contrary, sedimentation over the shelf at the southern edge
of the bay (Sorrento-Capri) seems less influenced by volcanic activity and seabed features include
Late Pleistocene regressive sand bodies and Holocene patch reefs, coastal dunes and depositional terraces.
Introduction
An on-going programme of sea-floor mapping in
Naples and Salerno Bays (south-eastern
Tyrrhenian margin), is among the main research
projects of the Geomare Sud Institute, CNR
Naples, Italy. Financed by the National
Geological Survey of Italy (CARG project), this
research. aims at producing, during the years
1998-2000, geological maps of selected marine
coastal zones at the 1: 50.000 scale. Recent criteria for geological mapping of Italian marine
areas (joint CNR-SGN Committee, see Catalano
et al. 1996) have been followed.
For a review of recent geological and geophysical studies over the Naples offshore area, see
Latmiral et al. (1971), Finetti and Morelli (1974),
Pescatore et al. (1984), Fusi et al. (1991), Milia
(1996), Marsella et al. (1996), Aiello et al. (1997a,
b), Cinque et al. (1997), De Lauro et at. (1997).
Materials and Methods
Most of the data presented here have been
acquired in the frame of three oceanographic
cruises organised by the Geomare Sud and by
other institutions during the 1996-1998 time
span. The frrst cruise (RN Urania, GMS97-1;
October-November, 1996) was dedicated to the
acquisition of a high-resolution multibeam sur"veyofthe Bay of Naples (below the -50 m isobath)
and of a narrow belt south of the Sorrento
Peninsula (Figs. 1, 2). An ELAC Nautik
Bottomchart MK2 multibeam system was adopted with a bathymetric range of -50 I -3000 m. The
ELAC system is equipped with a transducer of
256 beams arranged to generate a 15 to 150 0 fan
width; the vertical accuracy is about 0.25% of
water depth whereas the spatial resolution (the
size of the «footprint") ranges from 1 to 5 m. The
maximum horizontal coverage is 7.5 times the
Istituto di Ricerca Geomare Sud, CNR, Via A. Vespucci 9,80142 Napoli, Italy
EM. Faranda, L. Guglielmo, G. Spezie (eds)
Mediterranean Ecosystems: Structures and Processes
@ Springer-Verlag ItaHa 2001