Marino, Camilla (2021) Holocene vertical deformation in the offshore sector of the Campi Flegrei caldera based on seismo-stratigraphic and archaeological sea-level markers. [Tesi di dottorato]
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| Item Type: | Tesi di dottorato | ||||||
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| Resource language: | English | ||||||
| Title: | Holocene vertical deformation in the offshore sector of the Campi Flegrei caldera based on seismo-stratigraphic and archaeological sea-level markers | ||||||
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| Date: | 9 December 2021 | ||||||
| Number of Pages: | 98 | ||||||
| Institution: | Università degli Studi di Napoli Federico II | ||||||
| Department: | Scienze della Terra, dell'Ambiente e delle Risorse | ||||||
| Dottorato: | Scienze della Terra, dell'ambiente e delle risorse | ||||||
| Ciclo di dottorato: | 34 | ||||||
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| Date: | 9 December 2021 | ||||||
| Number of Pages: | 98 | ||||||
| Keywords: | Offshore seismo-stratigraphy; Prograding wedges; Archaeological sea-level indicators; Ground displacements; Volcano-tectonics; Campi Flegrei caldera. | ||||||
| Settori scientifico-disciplinari del MIUR: | Area 04 - Scienze della terra > GEO/02 - Geologia stratigrafica e sedimentologica Area 04 - Scienze della terra > GEO/03 - Geologia strutturale Area 04 - Scienze della terra > GEO/11 - Geofisica applicata |
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| Date Deposited: | 11 Jan 2022 11:35 | ||||||
| Last Modified: | 28 Feb 2024 11:36 | ||||||
| URI: | http://www.fedoa.unina.it/id/eprint/14323 |
Collection description
Rapid, positive and negative ground movements have been observed since historical time and are documented in the geological record in the coastal part of the Campi Flegrei caldera (Campanian region, Southern Italy), which formed as a consequence of the 15 ka Neapolitan Yellow Tuff (NYT) eruption. Several reconstructions of ground movements associated with ground uplift and subsidence were proposed based on volcanological and geo-archaeological observations onshore; however, the offshore deformation pattern remains poorly constrained. The southern sector of the caldera, which represents over one-third of its area, is submerged beneath the Pozzuoli Bay and includes part of the resurgent dome developed inside the caldera. Due to its history of large-scale explosive eruptions, ongoing episodes of unrest, and high population density living in the close vicinity, the Campi Flegrei caldera represents one of the world’s maximum volcanic risk areas. The current thesis is based on high-resolution multichannel seismic reflection data acquired in the offshore sector of the Campi Flegrei caldera and nearby the Gulf of Naples. Analysis of high-resolution seismic profiles integrated with coastal archaeological data has allowed the first quantitative reconstruction of long-term (~18 ka) ground deformation in the offshore part of the Campi Flegrei resurgent caldera and its peripheral areas. The submerged caldera infill preserves the seismic record to decipher the volcano-tectonic evolution, outlining the interplay with sea level variations. The present study uses the alternation of Prograding Wedges (PWs) and Aggrading Fills (AF) to provide seismo-stratigraphic evidence of relative sea-level changes and estimate the amount of vertical deformation in the Pozzuoli Bay. Five generations of PWs have been documented as associated with distinct periods of relative ground stability separating cyclic alternations of uplift and subsidence. In the external part NYT caldera, between Miseno and Posillipo offshore, growth of four PWs have been detected since the LGM (Last Glacial Maximum). A first wedge, PW-X1, is observed south of Penta Palummo and Miseno Banks and is related to the LGM lowstand at ~18-18.5 ka. The wedge PW-X2 is observed in the same areas of PW-X1 but in a shallower position and is dated between ∼14.9-14.3 ka. A slightly younger wedge, PW-X3 (∼12.3-11.9 ka), is well distributed around the main volcanic banks and external continental shelf. Finally, the shallowest wedge recognized in this sector is PW-X4 (∼11.2-10.6 ka). This wedge is observed in the offshore sector between Posillipo and Nisida Island, in the northern and north-eastern flank of Penta Palummo and Miseno Banks. The PWs also record a long-term subsidence trend with a rate of 2 mm/a in the external part of the caldera. Inside the NYT caldera, in the western sector of the Pozzuoli Bay, growth of PW1 (∼9.6–9.1 ka) suggests the existence of a previous uplift that affected the peripheral caldera areas in the early stages of the post-collapse activity. Following the stability documented by PW1, the development of AF1 above PW1 underpins subsidence at ∼9.1-5.9 ka. After 5.9 ka, a rapid growth of the resurgent dome in the central part of the caldera occurred, and starting at ∼5.2 ka, led to the formation of PW2a. PW2a growth was interrupted at ∼4.4 ka by an abrupt uplift episode responsible for the partial erosion of the wedge on the shelf overlying the resurgent dome. A new wedge, PW2b, grew down-stepping below the older wedge until ∼3.7 ka. After ∼3.7 ka, subsidence caused deposition of AF2 above the wedge, but since ~2.1 ka, it was interrupted by short-term uplift episodes that led to the growth of PW3 (∼2.1-1.9 ka), PW4 (∼1.4-1.2 ka), and PW5 (∼0.6-0.5 ka). Displacement of coastal infrastructures belonging to the Roman age (∼2 ka BP) suggests a short-wavelength vertical deformation signal confined to the Pozzuoli Bay, which reflects the contribution of intra-caldera sources. This local signal is superposed to a long-wavelength regional subsidence increasing between Naples and Procida Island from 1.5 to 2 mm/a, respectively. The east-to-west increasing subsidence reflects the transition between the uplifting Apennines and the Tyrrhenian back-arc basin. Findings from the current thesis represent a significant advancement towards understanding the evolution of the Campi Flegrei caldera as well as the regional tectonic assessment of this sector of the Campanian Plain. The suitability of high-resolution seismic reflection data to investigate partly submerged collapse calderas may also apply to other partly or totally submerged calderas.
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