New sedimentological and coastal and marine geological data on the Quaternary marine deposits of the Ischia Island (Gulf
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ORIGINAL
New sedimentological and coastal and marine geological data on the Quaternary marine deposits of the Ischia Island (Gulf of Naples, Southern Tyrrhenian Sea, Italy) Gemma Aiello 1 Received: 12 September 2019 / Accepted: 31 March 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Quaternary marine deposits of the Ischia Island have been analyzed based on marine geological survey and sedimentological data. The Ischia Island represents the emerged part of a large volcanic field, extending from the Procida island to the submerged volcanoes of the western Ischia offshore. The volcanic field develops over an area of about 42 km2, E-W trending, composed of calderas, such as the Ischia caldera, linked to the great explosive eruptions, plinian and ignimbritic (“Sintema del Rifugio di S. Nicola”). The grain-size analyses of sea bottom samples have shown that gravelly sands, sands, silty sands, muddy sands, sandy silts, and silts all occur. The comparison of the obtained results with previous sedimentological data collected in the Ischia offshore, coupled with the construction of marine geological maps at the 1:10,000 scale, has shown that sands seem to prevail in the eastern Ischia offshore, while gravelly sands, mainly bioclastic, are located at the top of relict volcanic edifices, such as the Forio Bank (western Ischia offshore) and the Ischia Bank (south-eastern Ischia offshore). Moreover, the obtained data show that rhodolith beds occur on the relict volcanic edifice of the Ischia Bank, on the related parasitic vent, and in the Ischia Channel, a morphological saddle located between the Ischia and Procida islands.
Introduction The main goals of this paper include the sedimentological study of sea bottom samples and the presentation of new coastal and marine geological data on the Quaternary marine deposits of the Ischia Island. These data have been collected in the frame of the realization of the geological map n. 464 “Isola d’Ischia” (Ischia Island) at the 1:10,000 scale (Aiello et al. 2009a; Sbrana et al. 2011). Detailed geologic maps, showing the distribution of sediments cropping out at the sea bottom, have been constructed based on a previous geological survey at the 1:10,000 scale. Moreover, the sedimentological analyses of marine sea bottom samples collected during oceanographic cruises carried out onboard of the R/V Urania and Thetis (National Research Council of Italy) in 2002 and 2003 are herein shown, with the aim of constraining the distribution of the facies cropping out at the sea bottom and to * Gemma Aiello [email protected]; [email protected] 1
Consiglio Nazionale delle Ricerche (CNR), Sezione Secondaria di Napoli, Istituto di Scienze Marine (ISMAR), Calata Porta di Massa, Porto di Napoli, 80133 Naples, Italy
compare these sedimentological and geological results with previous results obtained in the same areas (Ferraro and Molisso 2003; Toscano et al. 2006). Another goal of this paper is to improve the knowledge of the bioclastic deposits occurring in
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