Neogene to Quaternary evolution of the Calabrian Subduction System, (Central Mediterranean)

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Abstract

We construct an ESE striking to WNW geological cross-section across the Calabrian Subduction System (CentralMediterranean) using seismic near vertical profiles and field data. The interpreted profiles were time-to-depthconverted, merged and translated in a geological section stretching from the Marsili Oceanic Basin (SouthernTyrrhenian Sea) to the Ionian accretionary complex . Moving toward the east, the resulting section through thePaola, Amantea, and Crati basins, the Coastal Chain and Sila Massif and Crotone basin. The maximum elongationof these basins change progressively moving toward the east: from NNW in the Paola to NS in the Crati to the NNEin the Crotone basins. Data we present suggest that: Across the Calabria Tyrrhenian Continental Margin (CTCM),top of Kabilian-Calabrian Unit (KCU) is laterally variable in depth forming basins, which are separated by majorstructures with contractional or transcurrent kinematics, filled by Oligo-Miocene clastic to evaporitic deposits up to1500m thick. Plio-Quaternary deposits display a remarkable variation in thickness from 4.5 km in the Paola Basinto less than 400m in the central sector of the margin. Plio-Quaternary sediments are internally sub-divisible intofour sub-units (namely D1-D4) separated by tectonics enhanced angular unconformities. W-ward vergent reversefaults with limited vertical displacement offset the top of KCU as well as the Oligo-Miocene sedimentary and evaporiticunits in the eastern side of the Paola basin. On land (Amantea – Crati) and farther to the east (Crotone basin)below a Messinian-Pleistocene deposits the top of KCU is variable structured and covered by a Oligo-Mioceneclastic deposits with different thickness. The Plio-Quaternary deposits, unconformably overlay the Messinian andolder deposits, show the maximum thickness in the Crotone basin. Two main tectonic unconformities within thePlio-Quaternary deposits have been recognised allowing the separation of this unit into three sub-units. In theoffshore portion of the Crotone basin, SE-ward reverse faults dissect the KCU and the Oligo-Miocene up to theMessinian deposits. While the pre-Messinian tectonic history across the Calabrian Subduction System seems tobe quite similar, a main reorganization of the system occurring during the (?) early and (?) middle-Pliocene. Geometricaland stratigraphic relationship show that several W-ward and E-ward vergent reverse faults in the Paolaand Crotone basins, respectively, cut and offset Messinian evaporites and older sedimentary units, controlling thegeometry of the basins. In the Paola Basin the amount of subsidence gradually increase during deposition of subunitsD2 and D3, which are probably Pliocene in age. On land, the evidence of the unconformities in the Crotonebasin indicate that Pliocene deposition occurring during the uplift of the Sila Massif. Therefore uplift of the Silarange occurred during the strong subsidence of the Paola and Crotone basins.The evolution of the overall structure can be then divided in two different steps: 1)the onset of subsidence startedin the Late Miocene and covered a large areas presently occupied by the Paola and Crotone basins. This basin, wasprobably already separated into sub-basins but evolved in a slowly subsiding and poorly deformed area locatedbetween the active accretionary prism and the volcanic arc. Therefore in the Middle-Upper Miocene this basincould be defined as forearc basin. 2)In the Pliocene the structure of this large basin was fragmented due to the upliftof a central range (Sila Massif) with an overall pop-up like structu
Lingua originaleEnglish
Pagine1-1
Numero di pagine1
Stato di pubblicazionePublished - 2009

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