Abstract The present study starts from an exigency to uniformate all geological and geomorphological knowledges and the new data on continental Campi Flegrei marine deposits. That is because they are the better indicators of the very articulated geomorphological evolution experienced by this volcanic sector during the Holocene. The oldest of them are "La Starza" terraced deposits (11.000-5.000 years b. p.) consisting of alternance of marine and subaereal sediments. They are organized in four cycles reflecting evidently the volcanic and volcano-tectonic vicissitudes of that area. Post-roman and medieval marine deposits, marine erosional tracks and other archaeological evidences of coastal submergence are present on the Phlegrean coastal sector, testifying its complex geomorphological evolution in the last 2000 years b.p. about. This coastal sector, in fact, has experienced episode of submergences more than once answering to vertical ground movements caused by volcanic activity (bradiseismic movements). The subaereal deposits interbedded with marine ones clearly indicate both moment of pauses, more or less prolonged, during the general lowering motus and/or uplift of Phlegrean ground connect to approaching of volcanic paroxysm. The analysis of geological, geomorphological and geo-archaeological data evidence that the Phlegrean coastal sector with its bradiseismic lowering has been submerged three times during post-roman age: between IV-V sec., between VII-VIII sec. and between XIV-XV sec. The maximum rate of submergence of Puteolan ground has been 17 m at least, only a little part (6-7 m) of which is came back to subaereal environment with the subsequent bradiseismic uplift movements. Regarding these values we may explain also, in part at least, the genesis of some marine intervals of "La Starza" terraced sequence. In fact, "La Starza" sequence may be the result of both volcano-tectonic, responsible of the birth and extinction of the sedimentary basin, and bradiseismic (really volcanic) vertical movements, responsible of sedimentary control and of the basin morphology variations. There are also evidences that the last one type of movement may be interagent with glaceo-eustatic rising of sea-level during the lower Holocene.
Riassunto Questo studio nasce dall'esigenza generale di "fare il punto" della situazione dei depositi marini olocenici presenti nell'area dei Campi Flegrei. Questo perché: l) le informazioni finora note su questi depositi e le forme associate sono alquanto incomplete, frammentarie e troppo localizzate; 2) non esiste ancora un quadro sufficientemente completo dell'entità, tipo e distribuzione di questi depositi; 3) la loro successione stratigrafica non è ancora nota con certezza e tanto meno le loro relazioni con i fenomeni bradisismici, vulcanici e vulcano-tettonici tipici dell'area flegrea. Con questa nota, quindi, si intende uniformare tutte le conoscenze, edite e inedite, su questi depositi per evidenziarne il giusto ruolo da essi giocato nell'ambito dell'evoluzione geomorfologica di quest'area vulcanica e per fornire utili spunti di discussione e di ricerca finalizzati a definire, con maggiore dettaglio, la storia geomorfologica recente dei Campi Flegrei ed i movimenti relativi del suolo. La notevole mole di bibliografia esaminata e riferita a questo argomento, nonché i dati e le osservazioni originali riportati nel presente studio, sono per gran parte il frutto di ricerche condotte dallo scrivente durante il periodo 1985-1988, con la supervisione del Prof. L. Brancaccio e in stretta collaborazione col Prof. A. Cinque nell'ambito della Convenzione di ricerca «Bradisismo e fenomeni connessi» stipulata tra l'Università di Napoli e la Regione Campania. È stato, questo, un importante momento di rinnovato interesse scientifico pluridisciplinare per lo studio dell'area flegrea che seguiva di poco la grande "crisi" bradisismica del 1982-1984. I dati geo-archeologici, inoltre, sono il risultato parziale di ricerche ancora in corso.
I depositi marini olocenici nei Campi Flegrei: testimonianze di una evoluzione geomorfologica complessa
RUSSO F
2003-01-01
Abstract
Abstract The present study starts from an exigency to uniformate all geological and geomorphological knowledges and the new data on continental Campi Flegrei marine deposits. That is because they are the better indicators of the very articulated geomorphological evolution experienced by this volcanic sector during the Holocene. The oldest of them are "La Starza" terraced deposits (11.000-5.000 years b. p.) consisting of alternance of marine and subaereal sediments. They are organized in four cycles reflecting evidently the volcanic and volcano-tectonic vicissitudes of that area. Post-roman and medieval marine deposits, marine erosional tracks and other archaeological evidences of coastal submergence are present on the Phlegrean coastal sector, testifying its complex geomorphological evolution in the last 2000 years b.p. about. This coastal sector, in fact, has experienced episode of submergences more than once answering to vertical ground movements caused by volcanic activity (bradiseismic movements). The subaereal deposits interbedded with marine ones clearly indicate both moment of pauses, more or less prolonged, during the general lowering motus and/or uplift of Phlegrean ground connect to approaching of volcanic paroxysm. The analysis of geological, geomorphological and geo-archaeological data evidence that the Phlegrean coastal sector with its bradiseismic lowering has been submerged three times during post-roman age: between IV-V sec., between VII-VIII sec. and between XIV-XV sec. The maximum rate of submergence of Puteolan ground has been 17 m at least, only a little part (6-7 m) of which is came back to subaereal environment with the subsequent bradiseismic uplift movements. Regarding these values we may explain also, in part at least, the genesis of some marine intervals of "La Starza" terraced sequence. In fact, "La Starza" sequence may be the result of both volcano-tectonic, responsible of the birth and extinction of the sedimentary basin, and bradiseismic (really volcanic) vertical movements, responsible of sedimentary control and of the basin morphology variations. There are also evidences that the last one type of movement may be interagent with glaceo-eustatic rising of sea-level during the lower Holocene.| File | Dimensione | Formato | |
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