The framework of this thesis investigated the effect of the Messinian Salinity Crisis (MSC; 5.97-5.33 Ma) in the Adriatic Sea, one of the most controversial geological events that occurred in the Mediterranean Basin. The main objectives included the analysis of surfaces and units of the MSC to evaluate the thickness of the MSC deposits and their relationships with the effect of different phenomena such as erosion, non-deposition, and Plio-Quaternary deformation, all related to the geological evolution of the Adria plate and its role as Apennine foreland. Moreover, the Adriatic Sea represents a not fully understood problem in the framework of the MSC and its connection with the other Mediterranean basins. The Adriatic Sea is one of several restricted basins located in the Mediterranean Basin. It represents the foreland of three orogenic belts: the Southern Alps to the North, active since the Cretaceous time; the Dinarides to the East, active during the Eocene; and the Apennines to the West, active since the Paleogene. For the aim of this thesis, more than 10000 km long 2D multichannel seismic profiles were analyzed, calibrated by 218 boreholes, covering almost the whole Adriatic Sea in the Italian and partially Croatian offshore. The interpretation of the seismic lines in the Adriatic Sea has been carried out thanks to the IHS Kingdom Suite software. A precise and careful seismo-stratigraphy analysis was performed to recognize the different facies of the sedimentary sequence, focusing on the MSC expression. Analysis of the MSC surfaces and unit allowed to produce of the map of the base of the Plio-Quaternary sequence and the thickness of the evaporites. In particular, the Adriatic Sea was divided into three main geographical areas based on the occurrence of the MSC. Our results showed that the Northern Adriatic Sea during the MSC experienced subaerial exposure in front of the Trieste and Venice Gulfs. At the same time, evaporite deposition occurred in the modern Rimini foredeep. The Central Adriatic Sea shows the combined effect of deposition and erosion, with several channel incisions in this area, are related to paleo-drainage systems. The Southern Adriatic Sea shows an intense erosion on the carbonate platform, while MSC evaporites are present and eroded along the margins of the South Adriatic Basin. Following the MSC, the east migration of the Apennine Chain was covered with the external thrust and obliterated part of the MSC. From the Late Pliocene, the Adriatic Sea underwent different evolutionary steps. Boreholes calibration highlight the presence of locally very thin Pliocene succession in the entire Adriatic Sea. The main effect of the Apennines' eastward migration occurred during the Lower Pliocene, as testified by the regional tilting of the MSC reflectors, onlapped by Plio-Quaternary (PQ) parallel reflectors. The Southern Adriatic Sea was affected, starting from the Pliocene, by the Albanides orogenesis, as testified by the eastward foreland tilting, where PQ sediments onlap the MSC unconformity.

The Messinian Salinity Crisis in the Adriatic Sea

LANZONI, ALESSANDRA
2022

Abstract

The framework of this thesis investigated the effect of the Messinian Salinity Crisis (MSC; 5.97-5.33 Ma) in the Adriatic Sea, one of the most controversial geological events that occurred in the Mediterranean Basin. The main objectives included the analysis of surfaces and units of the MSC to evaluate the thickness of the MSC deposits and their relationships with the effect of different phenomena such as erosion, non-deposition, and Plio-Quaternary deformation, all related to the geological evolution of the Adria plate and its role as Apennine foreland. Moreover, the Adriatic Sea represents a not fully understood problem in the framework of the MSC and its connection with the other Mediterranean basins. The Adriatic Sea is one of several restricted basins located in the Mediterranean Basin. It represents the foreland of three orogenic belts: the Southern Alps to the North, active since the Cretaceous time; the Dinarides to the East, active during the Eocene; and the Apennines to the West, active since the Paleogene. For the aim of this thesis, more than 10000 km long 2D multichannel seismic profiles were analyzed, calibrated by 218 boreholes, covering almost the whole Adriatic Sea in the Italian and partially Croatian offshore. The interpretation of the seismic lines in the Adriatic Sea has been carried out thanks to the IHS Kingdom Suite software. A precise and careful seismo-stratigraphy analysis was performed to recognize the different facies of the sedimentary sequence, focusing on the MSC expression. Analysis of the MSC surfaces and unit allowed to produce of the map of the base of the Plio-Quaternary sequence and the thickness of the evaporites. In particular, the Adriatic Sea was divided into three main geographical areas based on the occurrence of the MSC. Our results showed that the Northern Adriatic Sea during the MSC experienced subaerial exposure in front of the Trieste and Venice Gulfs. At the same time, evaporite deposition occurred in the modern Rimini foredeep. The Central Adriatic Sea shows the combined effect of deposition and erosion, with several channel incisions in this area, are related to paleo-drainage systems. The Southern Adriatic Sea shows an intense erosion on the carbonate platform, while MSC evaporites are present and eroded along the margins of the South Adriatic Basin. Following the MSC, the east migration of the Apennine Chain was covered with the external thrust and obliterated part of the MSC. From the Late Pliocene, the Adriatic Sea underwent different evolutionary steps. Boreholes calibration highlight the presence of locally very thin Pliocene succession in the entire Adriatic Sea. The main effect of the Apennines' eastward migration occurred during the Lower Pliocene, as testified by the regional tilting of the MSC reflectors, onlapped by Plio-Quaternary (PQ) parallel reflectors. The Southern Adriatic Sea was affected, starting from the Pliocene, by the Albanides orogenesis, as testified by the eastward foreland tilting, where PQ sediments onlap the MSC unconformity.
PIPAN, MICHELE
DEL BEN, Anna
34
2020/2021
Settore GEO/11 - Geofisica Applicata
Università degli Studi di Trieste
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3030771
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