Le variazioni geomorfologiche indotte dalla tettonica recente in Appennino meridionale

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Collocazione:
Il Quaternario Italian Journal of Quaternary Sciences, 16(1), 2003, 133-140
Autore/i:
Alessandra ASCIONE & Aldo CINQUE
Abstract:

Accanto agli effetti derivanti dallo scuotimento sismico, le deformazioni tettoniche generano nel paesaggio modificazioni i cui tipi edentità sono funzione dal rapporto tra i tassi delle deformazioni ed i ritmi dei processi eroso/deposizionali con i quali esse interagiscono.In questo lavoro vengono esaminati i principali tipi di variazioni ambientali causati dalle deformazioni tettoniche tardo-quaternarie in Appennino meridionale, una regione nella quale i lineamenti tettonici ad attività recente sono caratterizzati da una debole espressione morfologica. Ciò appare rappresentare la risposta ad una tettonica che si manifesta con fagliazioni distribuite su numerosi lineamenti,ciascuno dei quali registra bassi tassi deformativi, cui si oppone una dinamica esogena che, grazie al clima, al giovane rilievo ed all’elevata erodibilità dei terreni occupanti vaste aree, risulta particolarmente vivace.

Besides the effects resulting from the seismic shaking (landslides, sinking, etc.), active tectonics may affect the environment, on a longertime scale, through changes whose types and magnitudes depend on the relationships between the rates of deformation and the rates of geomorphic processes. Type and magnitude of changes will thus vary according to the geomorphic scenario in which deformation stake place.In this paper is presented an overview on the changes triggered by recent deformations (e.g. to tectonics active since the lateQuaternary) in environments characterised by different rates of the erosional/depositional processes. The scenarios examined are river valleys, intramontane basins, coastal plains and slope areas. In the region, the observed environmental changes appear on the whole quite subdued: this is due to the interplay between the low slip rates (on the order of few tenths of mm/yr) of the numerous and widely distributed normal faults active within the present extensional regime, and the high rates of the exogenous processes. The latter are controlled by the aggressive Mediterranean climate, by the high relief of the young chain (that formed starting from the Miocene) and by the widespread occurrence of highly erodible rocks. In contrast, in the volcanic district of the Campania region (which comprises the Phlegrean Fields, the Somma-Vesuvius and the neapolitan islands), high rate volcano-tectonic vertical movements triggered strong and rapid environmental changes in the Holocene; in the coastal Campana Plain, these vertical movements were roughly counter balanced by high rates pyroclastic deposition.

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