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Summary ¶The Campanian continental margin is characterised by asymmetric half grabens and large-volume volcanic deposits. Vesuvius and Campi Flegrei are active volcanoes located along the coast of Naples Bay along one of these half grabens. The interpretation of an extensive set of seismic reflection data allowed to reconstruct the stratigraphy and structural pattern in Naples Bay and their relationships with volcanism. The stratigraphic succession is characterised by a complex architecture due to the presence of 157Ka old submarine and subaerial vents, pyroclastic flow units associated to the Campanian Ignimbrite and the Neapolitan Yellow Tuff, and numerous tuff cones younger than 12Ka. These volcanic units occur within marine sediments deposited during the late Quaternary sea level oscillations. The structural pattern is characterised by late Quaternary NE- trending normal faults, NW-trending transtensional faults, E–W trending left-lateral faults and WNW-ESE directed folds. The overall fault kinematics and the evaluated very high displacement rates are consistent with an E-trending left-lateral transtensional shear zone located between 41° and 40°N latitude. The relationship between volcanism and tectonics in the Bay of Naples is explained with block rotation associated with this shear zone. Finally, tectonic and stratigraphic data argue against the occurrence of a caldera in the Bay of Naples.Received June 24, 2002; accepted November 8, 2002 相似文献
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Summary ¶The crustal structure of the Campania continental margin is synthesized from outcrop, seismic reflection and gravimetric data. Outcrop and subsurface geological data reveal the presence of NE–SW faults, E–W faults and NW–SE faults. An older extensional event occurred along NW–SE faults and was followed by the main extensional event linked to the activity of NE–SW normal faults. The latter were active between 700 and 400ka producing half-grabens filled by more than 5km of Quaternary deposits. The stratigraphic signature of these tectonic events corresponds to a Lower Pleistocene marine unconformity-bounded unit overlain by Middle Pleistocene rocks belonging to a transgressive-regressive cycle. A crustal section of the Campania margin displays an asymmetric linked fault system characterized by a 10–12km-deep main detachment level, listric normal faults and rollover anticlines. Structural and stratigraphic data document that the inception of volcanic activity at Vesuvius occurred at 400ka, just after the main extensional event, and the volcano is located at the margin of a rollover anticline.Received June 26, 2002; revised version accepted November 9, 2002 相似文献
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The Dohrn canyon: a response to the eustatic fall and tectonic uplift of the outer shelf along the eastern Tyrrhenian Sea margin, Italy 总被引：1，自引：0，他引：1
A. Milia 《Geo-Marine Letters》2000,20(2):101-108
Most of the recent models which aim at explaining the origins of canyons call on mechanisms of retrogressive failure. The
interpretation of high-resolution seismic reflection profiles permitted the recognition of the shelf and slope evolution of
Naples Bay (eastern Tyrrhenian Sea margin) during the formation of the Dohrn canyon. Stratigraphic and structural data collected
from this area suggest that the factor which triggered off the formation of the canyon was the tectonic uplift of both the
outer shelf and fluvial valley mouth which took place during the eustatic fall of sea level.
Received: 12 May 1999 / Revision accepted: 19 May 2000 相似文献
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A. Milia 《Geo-Marine Letters》1999,19(4):237-244
High-resolution seismic reflection data are used in the identification of the stratigraphic succession filling Naples Bay,
a tectonically active half-graben located in the extensional margin of the eastern Tyrrhenian Sea. The architecture of the
basin infill is characterized by fourth-order depositional sequences correlated to Quaternary eustatic oscillations. These
depositional sequences form aggrading and prograding stacking patterns bounded by tectonically enhanced unconformities. The
changes that the stacking patterns undergo record variations in accommodation space rates. These variations are a result of
the tectonic subsidence produced during the evolution of the half-graben.
Received: 7 July 1998 / Revision received: 29 March 1999 相似文献
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A sedimentary sequence overlying a granite pluton near Ishkarwaz (upper Yarkhun valley, Chitral, Pakistan; Karakorum Microplate) contains abundant, but poorly preserved, acritarchs probably referable to the late early Arenig-early late Arenig interval. The palynological assemblages of Karakorum show a marked similarity to the cold water Peri-Gondwana assemblages; i.e. to those of Li Jun's Arbusculidium-Coryphidium-Striatotheca 'Mediterranean' Bioprovince. Biogeographical and geological comparisons suggest that, before the accretion of Cimmerian microplates to the Eurasian continent, the Karakorum Microplate was located along the northern margin of Gondwana in a latitude intermediate between the Mediterranean region and South China (Yangtze Platform). 相似文献
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P. Petrosino I. Arienzo F. C. Mazzeo J. Natale M. Petrelli A. Milia D. Perugini M. D&#x;Antonio 《第四纪科学杂志》2019,34(6):393-404
Central–southern Italy is one of the most suitable areas in the world for tephrostratigraphic studies, owing to the numerous volcanic sources with explosive activity during the Pleistocene. This work presents a systematic investigation of the chemical (trace elements) and isotopic (Sr and Nd) compositions of the main tephra markers within lacustrine sediments of the San Gregorio Magno Basin (Campania, southern Italy). This study: (i) provides full geochemical (trace elements and isotopes) characterization of eight significant Upper Pleistocene marker layers (X‐6, X‐5, C‐22, MEGT/Y‐7, CI/Y‐5, C‐10, Y‐3, NYT/C2) widely dispersed over the Mediterranean area; (ii) proposes a new tephra marker for Marine Isotope Stage 7, dated to 240 ka; and (iii) refines the correlations of tephra levels belonging to the investigated sequence. This study highlights that in most cases the Nd isotope composition of the glass and Sr isotope composition of the coexisting minerals are more reliable than 87Sr/86Sr of the glass, and hence is more helpful as a further tool for tephrostratigraphic correlations, as recently proposed in the literature. Moreover, this study is a first step towards the construction of a complete geochemical database for future tephra investigations in the Mediterranean area. Copyright © 2019 John Wiley & Sons, Ltd. 相似文献
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Pozzuoli Bay is located in the eastern Tyrrhenian Sea and is an area characterized by active tectonics and volcanism. On the basis of high-resolution seismic reflection profiles, it was possible to reconstruct the stratigraphy and three-dimensional stratal architecture of the Holocene succession. Two volcanic units and three sedimentary ones were recognized. The basal unit NC consists of volcanic deposits and dates at 10.0-8.0 ka B.P. It is followed by unit D, deposited between 8.0 and 5.5 ka B.P., which displays a backstepping configuration in the central area and a forestepping configuration in the northern area. Unit D is covered by the progradational unit B which is elongated in a SE-NW direction. Unit C is interbedded between unit B and is interpreted as the volcanic products of the Agnano-Monte Spina eruption which occurred 4.4 B.P. Unit A, the youngest unit, shows a progradational configuration and is elongated in a E-W direction. The sedimentary units record the transgressive and highstand of the eustatic sea level. They show vertical and lateral variations in the depositional architecture. Changes in the stacking pattern record variations in tectonic subsidence and hydrodynamic regimes. 相似文献
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High-resolution seismic reflection data are used to identify structural features in Naples Bay near Vesuvius Volcano. Several
buried seismic units with reflection-free interiors are probably volcanic deposits erupted during and since the formation
of the breached crater of Monte Somma Volcano, which preceded the growth of Vesuvius. The presumed undersea volcanic deposits
are limited in extent; thus, stratigraphic relationships cannot be established among them. Other features revealed by our
data include (a) the warping of lowstand marine deposits by undersea cryptodomes located approximately 10 km from the summit
of Vesuvius, (b) a succession of normal step faults that record seaward collapse of the volcano, and (c) a small undersea
slump in the uppermost marine deposits of Naples Bay, which may be the result of nueé ardentes that entered the sea during
a major eruption of Vesuvius in 1631. Detection of these undersea features illustrates some capabilities of making detailed
seismic reflection profiles across undersea volcanoes.
Received: 16 September 1997 / Accepted: 23 November 1997 相似文献
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