SSP1.7 | Reconstructing paleogeography and evolution of the Western Mediterranean area from Variscan to Present
EDI
Reconstructing paleogeography and evolution of the Western Mediterranean area from Variscan to Present
Co-organized by TS6
Convener: Rosanna Maniscalco | Co-conveners: Gaia Siravo, Riccardo Asti, Sabatino Ciarcia, Nicolas Saspiturry, Roberta Somma, Sebastiano Ettore Spoto
Orals
| Wed, 26 Apr, 08:30–10:15 (CEST)
 
Room -2.21
Posters on site
| Attendance Tue, 25 Apr, 16:15–18:00 (CEST)
 
Hall X3
Posters virtual
| Attendance Tue, 25 Apr, 16:15–18:00 (CEST)
 
vHall SSP/GM
Orals |
Wed, 08:30
Posters on site |
Tue, 16:15
Posters virtual
Tue, 16:15
In the last decades, the paleogeography, tectonic and kinematic evolution of Western Mediterranean region have been largely debated. One of the main difficulties in proposing consensual reconstructions is the complex patchwork of polysized blocks involved in the Variscan orogeny. The main blocks that experienced differential evolution during the Alpine cycle are Iberia, Adria and the Corsica-Sardinia/AlKaPeCa domains. The Cenozoic geodynamics of the Western Mediterranean and the diffuse Eurasia-Africa boundary hamper easy reconstructions. Evidence of the complex evolution, related to two superposed orogeneses, is recorded by several basins distributed along the Mediterranean area. The Variscan tectono-metamorphic phenomena are recorded in the Paleozoic successions exposed in the Betic-Rifian Arc, Algeria, Calabria-Peloritani Arc, Apennines, Corsica-Sardinia block, and the Alps. The Alpine tectono-metamorphic evolution, superposed on part of these ancient basements, is widespread in the Mesozoic to Cenozoic stratigraphic record preserved in the Mediterranean Alpine Chain with spectacular syn- to late-orogenic compressional and extensional deformation.
Several Permian to Mesozoic rift systems, conditioned by crustal-scale shear zones, developed in late/post-Variscan times. The polyphase evolution of these basins is related to the early breakup of Pangea and the opening of both the southern North Atlantic and the Bay of Biscay. These basins were subsequently inverted or involved in the Alpine orogens to accommodate the Africa-Eurasia convergence during Late Cretaceous to Tertiary times. The interplay between tectonics and sedimentation ruled the synorogenic sedimentation in the Foreland Basin System. Sedimentary facies analysis and paleoenvironment evolution of depositional systems, together with sediment provenance and paleogeographic/paleoecologic/paleoclimatic reconstructions, provide further constraints to trace the evolution of sedimentary basins. We welcome contributions dealing with prominent geological structures, mountain belts, and sedimentary basins which recorded the past configuration of the Iberia-Eurasia-Adria-Africa plate boundary(s). We encourage submission of studies presenting new insights including geology (tectonics, paleontology, stratigraphy, sedimentology, petrology, geochronology, thermochronology, and geochemistry), geophysics (paleomagnetism, seismicity, seismic imaging/anisotropy, gravity), modelling (numerical and analogue).

Orals: Wed, 26 Apr | Room -2.21

Chairpersons: Rosanna Maniscalco, Gaia Siravo, Riccardo Asti
08:30–08:35
5-minute convener introduction
08:35–08:45
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EGU23-2019
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ECS
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Virtual presentation
Cenozoic synsedimentary tectonics in the External Rif Zone (Maghrebian Chain, Northern Morocco) 
Soufian Maate, Rachid Hlila, Ali Maate, Manuel Martin Martin, Francesco Guerrera, Francisco Serrano, and mario tramontana

The Cenozoic tectono-sedimentary evolution of the External Rif Zone (ERZ) has been studied based on an integrated analysis of twenty-two representative stratigraphic successions grouped in seven sectors from N to S: Tangier, Asilah, Chaouen, Zoumi, Ouezzane, Ourtzarh and the Prerifian Ridges. The ERZ is divided classically, from N to S, into Intrarif, Mesorif and Prerif sub-domains. Each sub-domain is subdivided further in to internal and external. The Cenozoic stratigraphic record of the ERZ can be roughly separated into five main stratigraphic intervals bounded by five main unconformities corresponding to the Cretaceous-Paleogene, Eocene-Oligocene, Oligocene-Miocene, Burdigalian-Langhian and middle-late Mioceneboundaries. Each unconformity can be related to a local or regional tectonic events: (1) the Cretaceous-Paleogene boundary unconformity to the tectonic inversion (from extension to compression) occurring in the alpine Tethys domain in the upper Cretaceous ; (2) the Eocene-Oligocene boundary to a flexure phase in the Atlas front; (3) the unconformity that marks the Oligocene-Miocene boundary can result from the starting of the nappes stacking phase in the Internal Zone; (4) the Burdigalian-Langhian boundary unconformity to the end of structuring of the Internal Zone; and (5) the middle-late Miocene boundary unconformity to the nappes stacking phase in the ERZ. The Paleogene evolution can mainly be correlated with the so-called Eo-alpine orogenic phase, while the Miocene one is related to the Mio-Alpine, both recognized in the western Mediterranean area. As a fundamental part of this research, the analysis of synsedimentary tectonics have been performed, considering tectofacies, unconformity implications and subsidence analysis. Tectofacies (such as, turbidites, slumps, mass flow deposits, synsedimentary folds and faults) are checked from the upper Ypresian succession onward, but more frequently during the Oligocene and Miocene, which point out an upward increase in the tectonic activity. Considering the ERZ as a foreland basin, the Eocene foredeep area would correspond to the Internal Mesorif and Internal Prerif sub-domains. This foredeep was represented by a complex of two “sub-geosynclines” separated by a relative bulge located in the External Mesorif. In this way, the Intrarif could represent the relative orogenic front (advanging on the Internal Rif Zone). The Eocene forebulge was located in the External Prerif, while the Gharb Basin was the backbulge of the system. During the Oligocene the depocentral area migrated southward favoring a homogenization of subsidence in the whole ERZ. In this new configuration, the foredeep would be located in the External Mesorif (formerly a relative bulge) while the External Prerif and the Gharb Basin continued to act as the forebulge and the backbulge of the system, respectively. During the early Miocene a new diversification of depocenter took place with the main foredeep in the Internal Mesorif and secondary foredeeps areas in the externalmost and internalmost Intrarif. In this period, the forebulge should be located in the middle Intrarif. Finally, during middle Miocene foredeep were located in the externalmost Intrarif and Internal Prerif while in the late Miocene depocenter migrates southward to the Extenal Prerif-Gharb areas (formerly forebulge and backbulge areas).

How to cite: Maate, S., Hlila, R., Maate, A., Martin Martin, M., Guerrera, F., Serrano, F., and tramontana, M.: Cenozoic synsedimentary tectonics in the External Rif Zone (Maghrebian Chain, Northern Morocco), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2019, https://doi.org/10.5194/egusphere-egu23-2019, 2023.

08:45–08:55
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EGU23-707
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ECS
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On-site presentation
Polyphased contractions inside the Sicily Channel Rifting Zone: new evidence from seismic reflection profiles analysis and geodynamic implications 
Mariagiada Maiorana, Andrea Artoni, Nicolò Chizzini, Eline Le Breton, Attilio Sulli, and Luigi Torelli

The Sicily Channel, located in the foreland area of the African plate, is a very interesting geological area in the Western-Central Mediterranean, as it has undergone different tectonic processes because of its proximity to the convergence zone with the European plate. Extension and opening of a rift zone (Sicily Channel Rift Zone, including the Pantelleria, Malta, and Linosa grabens) occurred in the lower plate of the subduction zone marked by the Gela Thrust System and the Calabrian Accretionary Wedge, respectively located south and south-east of Sicily, and the Maghrebian chain to the west. We analyzed geological and geophysical data, such as variable penetration seismic reflection profiles integrated with borehole data; these allowed us to investigate subsurface structures down to the crust-mantle boundary. The crustal profile shows a Moho deepening down to 11.8 s/(TWT) under the Gela Thrust System and going up to 8 s/(TWT) under the Linosa Graben. Moreover, the presence of several hyperbolae zones and signal anomalies have been linked to a rise of deep fluids associated with mantle uplift and, upward, to magmatic intrusions. The sub-surface also shows evidence of a N-S oriented zone, from the Gela Thrust System to the Malta and Linosa grabens, which has undergone contractional tectonic events superimposed on previous extensional structures. Throughout this area, from the Early-Middle Miocene to the Early Pliocene, an extensional event occurred in association with the slab roll-back of the African Plate. In this phase, several volcanic intrusions concentrated near the grabens’ rims suggest a relation between the extension, the Moho rising, and the magmatic manifestations.  Afterward, a compressional event in the Madrepore and Malta Grabens was registered. This event has been correlated to the advance of the Gela Thrust Front, which, according to literature bio-chronostratigraphic analysis, had three stages of advancement in Zanclean, Piacenzian and Chibanian. Furthermore, a recent contractional event caused the folding of the seafloor in the central part of the Malta Graben. This latter phase has been related to a potential change in the subduction polarity. These results provide new insights into the regional kinematic setting of the Sicily Channel, suggesting that strain located within the African Plate can be explained through the overlapping of both intra-plate (localized asthenospheric rise) and inter-plate (compression transmitted from surrounding mountain belts) processes ongoing between Europa and Africa. Indeed, the Sicily Channel structural setting resulted from the interplay of the rollback of the African slab, the consequent changes in the asthenospheric flow that caused extension and local magmatic intrusions, and the active subduction front and its potential polarity reversal that caused local and polyphased compressional pulses.

How to cite: Maiorana, M., Artoni, A., Chizzini, N., Le Breton, E., Sulli, A., and Torelli, L.: Polyphased contractions inside the Sicily Channel Rifting Zone: new evidence from seismic reflection profiles analysis and geodynamic implications, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-707, https://doi.org/10.5194/egusphere-egu23-707, 2023.

08:55–09:05
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EGU23-9158
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Highlight
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On-site presentation
The Lost World of Cessaniti: palaeogeographic relevance of a Late Miocene mammal assemblage from the  Central Mediterranean area. 
Antonella Cinzia Marra

Data from the late Miocene site of Cessaniti (Vibo Valentia, Calabria, southern Italy) suggest the existence of a land connected to Africa in the central Mediterranean.

Although the site has been known since the XIX century for the abundant and well-preserved fossil echinoids of Clypeaster, in the last 20 years, Cessaniti released not only abundant remains of the Sirenian Metaxytherium serresii and rare Cetaceans (Odontocetes: Physiteroidea indet.; Mysticetes: Heterocetus cf. guiscardii) but also a consistent record of terrestrial mammals (Stegotetrabelodon syrticus, Bohlinia attica, Samotherium boissier, Tragoportax cf. rugosifrons,  ‘Ceratotherium’ advenientis, an undetermined Anthracotherid).

The stratigraphic succession outcropping at Cessaniti – “Gentile” Quarry, overlying in unconformity the Paleozoic crystalline basement, is made up of four informal units indicating a transgression from lagoonal to deep-sea environments, dated between 8.1  Ma (Chron C4n) and 7.2 Ma (nannoplankton zone CNM17). The main part of terrestrial mammals comes from the upper part of the shallow sea deposits, locally named “Clypeaster sandstones”, where almost two temporary falls in sea level, probably controlled by tectonics, are testified by the occurrence of soils and fluvial deposits. Only Stegotetrabelodon is also recorded in the underlying lagoonal deposits. The main part of the fossils was collected during quarry works by amateur palaeontologists who summarily recorded their findings. However, they notated the provenance from the upper part of the “Clypeaster sandstones” and noticed the presence of poorly preserved, oxidated echinoids. These letters are typical of the intercalated soils and fluviatile deposits, so the presence of bone beds in fluviatile deposits may be supposed.

The terrestrial mammal association has no insular adaptations nor relationships with the islands of central Italy (Tusco-Sardinian and Apulo-Abruzzi bioprovinces).  The occurrence of Stegotetrabeolodon syrticus represents the only “out of Africa and Arabia” record for the species and has plesiomorphic characters, coherent with an early arrival at Cessaniti. Giraffids suggest a westward expansion of the Pikermian biome from the Greco-Iranian  bioprovince through North Africa (where scanty remains are recorded) and then to Cessaniti. Tragoportax was widely spread in Eurasia and Africa. The new species‘Ceratotherium’ adenitis can be related to African Rhinocerontidae. The palaeoecology of the mammal association indicates a mosaic environment with open spaces, probably similar to the modern savannah but less arid, similar to that suggested for the Pikermian biome.

The stratigraphic and taphonomic data, the abundant record of the terrestrial mammals, and their palaeoecology and taxonomy support the hypothesis of a land in terrestrial continuity with North Africa. Therefore, the accumulation of floating carcasses coming from north Africa can be excluded.

How to cite: Marra, A. C.: The Lost World of Cessaniti: palaeogeographic relevance of a Late Miocene mammal assemblage from the  Central Mediterranean area., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9158, https://doi.org/10.5194/egusphere-egu23-9158, 2023.

09:05–09:15
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EGU23-6232
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ECS
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On-site presentation
Evidence of tectonic inversion in the Northern Apennines Hinterland basins, the example of the Valdera-Volterra basin (Central Tuscany) 
Giovanni Poneti, Nicola Scarselli, Marco Benvenuti, and Jonathan Craig

Hinterland basins are low-lying and often heavily populated areas at the back of orogenic belts which have significant economic and infrastructural importance. The tectonic-stratigraphic and regional characterisation of hinterland basins is fundamental for evaluating their subsurface utilisation and potential geohazards.

This study focuses on the origin and development of the Tuscan hinterland basins of the Northern Apennines. These basins have been associated with a compressional regime lasting until the Late Pliocene-Pleistocene during which out-of-sequence thrusts and back-thrusts in the inner portion of the chain accommodated the compressive stress accumulated in the frontal zones. An alternative interpretation considers the evolution of these basins in an extensional regime as an effect of large-scale back-arc processes or gravitational collapse of thickened crust following the Apennine orogeny since the Early Miocene. In this tectonic regime, the basins have been interpreted as graben, half-graben or bowl-shaped basins evolving into graben.

Our work aims to determine the tectonic-sedimentary evolution of the Valdera-Volterra Basin through the analysis of  ~271.8 km of 2D seismic reflection profiles and wireline logs from two exploration wells. The Valdera-Volterra Basin basin is an NW–SE oriented depocenter ~60 km long ~30 km wide filled with a clastic succession of Miocene-Pleistocene fluvial-lacustrine to marine deposits up to ~2 km thick.

The analysis has revealed a polyphased tectonic history of the basin with a Messinian-Zanclean compressional phase deforming the basin-infill as indicated by seismic imaging of synformal geometries and strongly tilted unconformities. Such deformation is tentatively associated with E/NE vergent blind thrusts and SW vergent blind back-thrusts. During the Piacenzian, the activity of normal border faults and the presence in their hanging wall of associated sedimentary wedges thickening towards NE suggest an extensional phase following the earlier Messinian-Zanclean compression. Broad folding of the shallow Piacenzian units in the hangingwall of the normal faults suggests the occurrence of mild positive inversion at the end of the Piacenzian/Lowermost Pleistocene?.

This tectonic history has been associated with crustal shortening in the Northern Apennines hinterland, accommodated by thrusting, that occurred discontinuously until the end of the Pliocene/Lowermost Pleistocene?. The formation of the border faults during the Piacenzian has been related to a prolongated phase of tectonic quiescence that led to the collapse of the sedimentary pile and the Pre-Neogene substrate. In this setting, the positive inversion occurred at the end of the Piacenzian/Lowermost Pleistocene? represents the last compressive event related to crustal shortening.

How to cite: Poneti, G., Scarselli, N., Benvenuti, M., and Craig, J.: Evidence of tectonic inversion in the Northern Apennines Hinterland basins, the example of the Valdera-Volterra basin (Central Tuscany), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6232, https://doi.org/10.5194/egusphere-egu23-6232, 2023.

09:15–09:25
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EGU23-16943
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solicited
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Highlight
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On-site presentation
Deciphering the Cenozoic evolution of circum-Mediterranean fold-and-thrust belts through the integration of structural and thermal maturity studies of sedimentary basins 
Sveva Corrado

In recent decades, reconstructing the geometric and kinematic evolution of fold-and-thrust belts around the Mediterranean region has been one of the priority goals of the scientific community, also with the aim of energy resource retrieval. However, the frequent poor quality of subsurface constraints has sometimes led to the production of even very different geometric-kinematic evolutionary models, characterized by different amounts of shortening and deformation timing, with important implications on the kinematic reconstructions of the Africa-Europe convergence process. In this talk, I intend to propose a journey through a series of fold-and thrust belts around this region, that in recent years have been studied by the team of the Academic Lab of Basin Analysis or Roma Tre, in collaboration with many colleagues around the Mediterranean, through the integration of classical stratigraphic and structural data with the reconstruction of the paleo-thermal evolution of these structures. Particular attention will be paid to thermal modeling, constrained through different parameters of thermal and thermo-chronological evolution of both pre-orogenic and syn-orogenic sedimentary successions.

How to cite: Corrado, S.: Deciphering the Cenozoic evolution of circum-Mediterranean fold-and-thrust belts through the integration of structural and thermal maturity studies of sedimentary basins, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16943, https://doi.org/10.5194/egusphere-egu23-16943, 2023.

09:25–09:35
Discussion
09:35–09:45
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EGU23-14651
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ECS
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On-site presentation
Lithosphere-asthenosphere structure and impact on serpentinization processes and topography across the plate boundary between Iberia and Europe 
sepideh pajang, Frederic Mouthereau, Alexandra Robert, and Jean-Paul Callot

The tectonic evolution of the plate boundary between Iberia and Europe since the Variscan and more clearly since the Mesozoic rifting is at the origin of heterogeneities of densities and structure, in the crust and the mantle, which have an impact on the distribution of the current stresses and post-orogenic uplift in the Pyrenees. Here, we investigate the lithosphere structure across the Pyrenees and Western Europe using LitMod2D that integrates geophysical and petrological data sets to produce the thermal, density, and seismic velocity structure of the lithosphere and upper mantle. Of particular interest is the chemical composition of the mantle, including the degree of serpentinization near the North Pyrenean Fault (>10 km), and the shape of the lithosphere-asthenosphere boundary at a larger scale (>100 km). The topography and geophysical constraints, including LAB geometry, Vs, Vp data are well reproduced for a weak fertile Phanerozoic lithosphere. Our results suggest that accounting for serpentinization allows fitting second-order gravity and seismological features in the lithosphere, but not topography which is controlled to first-order by high lateral variability in crustal thickness and lithosphere strength.

How to cite: pajang, S., Mouthereau, F., Robert, A., and Callot, J.-P.: Lithosphere-asthenosphere structure and impact on serpentinization processes and topography across the plate boundary between Iberia and Europe, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14651, https://doi.org/10.5194/egusphere-egu23-14651, 2023.

09:45–09:55
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EGU23-7288
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Highlight
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On-site presentation
Mesozoic evolution of the Atlantic-Tethys junction: a kinematic description 
Gianluca Frasca and Gianreto Manatschal

Diverging plates are reconstructed through well-defined time-steps and direction of motion thanks to oceanic magnetic anomalies and fracture zones. None of these two oceanic features can nevertheless be used if the divergent boundaries are reactivated in orogenic belts. Convergence erases indeed the dense oceanic material and the related kinematic markers and leave as main witnesses suture zones and associated remnants of the former continental margins. The pre-orogenic plate template of the Alps remains debated for this reason, leading to debate on the size of subducted oceanic domains, and on the complex paleogeography at the Tethys-Atlantic junction. Unravelling size and fate of the pre-orogenic domain remains difficult and asks for a new, holistic restoration approach. Here we use a rift domain approach that enables us to quantify width and formation ages of margins of the Iberia-Eurasia-Adria-Africa plate boundaries. We jointly use a global kinematic restoration software (Gplates) and new rift concepts that allow us to propose a tight fit restoration and evolution of the Atlantic Tethys junction during the Mesozoic. Kinematic restorations of the Mesozoic evolution of what is now the Western Mediterranean must build on independent approaches. A first approach is the correct restoration of the major surrounding plates. A second approach is the restoration of the intra-continental extension accommodated in reactivated rifted margins that can be in the order of several hundreds of kilometers. Remnants of the former margins allow to define so-called building blocks and appear as a good base for restoration where vestiges of a standard oceanic crust are missing.

How to cite: Frasca, G. and Manatschal, G.: Mesozoic evolution of the Atlantic-Tethys junction: a kinematic description, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7288, https://doi.org/10.5194/egusphere-egu23-7288, 2023.

09:55–10:15
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EGU23-17274
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solicited
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Highlight
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On-site presentation
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Tectono-magmatic and kinematic evolution of the Africa-Europe plate boundary: from Cadomian subduction to Western Mediterranean tectonics 
Frédéric Mouthereau and Paul Angrand

Processes driving orogenic styles and long-term isostatic versus dynamic support of the topography have been largely debated in domains of plate convergence. The tectonic evolution of orogens reflect the interactions between mantle flow driving plates and the inherited rheology and composition of moving plates. Here we show that the tectono-magmatic evolution of the European lithospheric mantle and structure, which inherits past subduction/collision (e.g. Cadomian, Variscan) and rifting events (Tethys/Atlantic), control first-order crust-mantle coupling, plate-mantle coupling, defining Alpine-type orogens. The lack of thermal relaxation needed to maintain rheological contrasts over several hundreds of millions of years requires high mantle heat flux below Central Europe since at least the Permian. A combination of edge-driven convection on craton margins and asthenospheric flow triggered by rift propagation during the Atlantic and Tethys rifting is suggested to be the main source of heat. Timing and rates of exhumation recorded across Western Europe during the Cenozoic convergence reveal an additional control by the architecture of Mesozoic rifted margins that defined a complex array of small continental blocks with European affinity (e.g. S-Iberia, Ebro/Sardinia-Corsica) caught between the East European and West African cratons, and Adria. By 50 Ma the acceleration of orogenic exhumation, from the High Atlas to the Pyrenees, occurred synchronously with the onset of extension and magmatism in the West European Rift. Extension marks the onset of distinct orogenic evolution between Western Europe (Iberia) and the Alps (Adria) in the east, heralding the opening of the Western Mediterranean. While the details of the Cenozoic topographic history of peri-Mediterranean orogens are understood to be controlled by the rheology and architecture of rifted margins combined with changing large-scale kinematic boundary conditions (e.g. Atlas, Betics, Pyrenees, Alps), their post-10 Ma, quaternary to current surface and tectonic evolution appears to illustrate increasing control by magmatism and flow at the asthenosphere-lithosphere boundary.

How to cite: Mouthereau, F. and Angrand, P.: Tectono-magmatic and kinematic evolution of the Africa-Europe plate boundary: from Cadomian subduction to Western Mediterranean tectonics, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17274, https://doi.org/10.5194/egusphere-egu23-17274, 2023.

Posters on site: Tue, 25 Apr, 16:15–18:00 | Hall X3

Chairpersons: Rosanna Maniscalco, Gaia Siravo, Riccardo Asti
X3.51
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EGU23-13922
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ECS
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Highlight
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Coastal carbonate systems: evolving paleoclimatic and paleoenvironmental proxies to relative sea-level change 
Martina Forzese, Rosanna Maniscalco, Ádám Nádudvari, Dirk Nürnberg, Fabio Speranza, Alessandro Todrani, Udo Zimmermann, and Robert WH Butler

Ancient coastal carbonate depositional systems provide exceptional records of past changes in relative sea level– globally and locally (tectonics) – and of paleoenvironmental variations. Here we present new work on carbonate outcrops within the UNESCO Rocca di Cerere Geopark in central Sicily (Caltanissetta and Enna districts). They show superb sub-vertical cliffs made of Pleistocene packstones with clinoforms which provide a high-resolution record of relative sea-level changes that correlate with precession cycles. Regionally these successions deposited during Plio-Quaternary forced regression caused by late-orogenic uplift. However, their deposition within local thrust top basins was modulated by local uplift and tectonic tilting. Collectively these global, regional, and local processes are recorded by offlapping of successive depositional cycles. Moreover, the high-resolution photogrammetric surveys we developed, revealed that the underlying anticlines tilted the original beds of almost 20°. The packstones are derived from fauna: micro-habitat variations have been here traced by changes in sediment provenance, fossil assemblages, and preservation. The resultant stratal architectures reflect the interplay between the efficiency of this carbonate factory, the environmental conditions, the minute siliciclastic input, and the evolution of accommodation space. Bio- and magneto-stratigraphy were fundamental to date, the parasequences, while organic and inorganic chemistry, benthic foraminifera assemblages, as well as stable isotopes analyses (δ18O and δ13C) are used as environmental and climatic proxies (where possible) to reconstruct coastal dynamics (physical and biological), in relation to the tectonic history and sea-level change.
These outcrops provide analogues to interpret stratal patterns in subsurface examples where these types of strata form important aquifers – and shallow gas reservoirs.

How to cite: Forzese, M., Maniscalco, R., Nádudvari, Á., Nürnberg, D., Speranza, F., Todrani, A., Zimmermann, U., and Butler, R. W.: Coastal carbonate systems: evolving paleoclimatic and paleoenvironmental proxies to relative sea-level change, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13922, https://doi.org/10.5194/egusphere-egu23-13922, 2023.

Vimeo: EGU23-13922-material-r0
X3.52
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EGU23-1624
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ECS
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Pre-Miocene Paleomagnetic Data from the Calabrian Block Document a 160° Post-Late Jurassic CCW Rotation 
Gaia Siravo, Fabio Speranza, and Patrizia Macrì

The Calabrian block, along with Alboran, Kabylies and Peloritani, form isolated and enigmatic igneous/metamorphic terranes (AlKaPeCa) stacked over the Meso-Cenozoic sedimentary successions of the Apennines and Maghrebides. The long-lasting debate on the origin and evolution of such crustal terranes include different paleogeographic interpretations. Some authors considered them as: i) remnants of a micro-continent lying between Eurasia and Africa; ii) fragments of the Hercynian margin of Europe separated from Africa during Early Jurassic Alpine Tethys spreading, later detached from Corsica-Sardinia and/or Catalan-Provençal margin, and then stacked over Apennine-Maghrebian sediments during Neogene roll-back episodes; iii) portion of the Africa-Adria paleomargin deformed and involved into the orogenic pile.

Paleomagnetic data are crucial to properly reconstruct the drift of the AlKaPeCa blocks and their lasting geological history, however no paleomagnetic data could be obviously obtained from the Hercynian crystalline rocks of the AlKaPeCa. Besides the well-defined ∼20° clockwise (CW) rotation, constrained between 1 and 2 Ma and related to changes occurring in the roll-back system and spreading episodes in the Tyrrhenian Sea, the tectonic behavior of the Calabrian block during the Early Jurassic rifting episodes, the Early-mid Cretaceous transcurrent tectonics, the Late Cretaceous-early Cenozoic Africa-Europe collision, and Eocene-Miocene counterclockwise (CCW) 90° rotation of the Corsica -Sardinia block, to which Calabria was likely solidly attached, remains completely speculative.

We report on the paleomagnetism of upper Triassic-lower Miocene sedimentary rocks from the Longobucco succession that is transgressive over the crystalline Sila Massif (NE Calabria). Well-defined remanent magnetization directions carried by hematite were isolated in 10 sites (122 samples) in Jurassic rocks. Nine Toarcian and one Tithonian Ammonitico Rosso sites yielded a dual polarity “A” magnetization component whit a direction over 40° from the geocentric axial dipole (GAD) field direction, that supports a positive fold test. Five sites yielded a “B” normal polarity component NE (<40°) of the GAD direction characterized by a negative fold test. We interpret the B component as a Miocene magnetic overprint later clockwise rotated by ∼20° during the Pleistocene (1–2 Ma) rotation of Calabria. When corrected for such rotation, the A component defines a ∼160° CCW rotation of the Calabrian block with respect to Europe. Of these, ∼90° likely occurred along with Corsica-Sardinia block during its Eocene-Miocene rotation from the Provençal margin. Thus, the Calabrian block underwent an additional Cretaceous-Eocene 70° CCW rotation that we relate to Early-mid Cretaceous >500 km left-lateral transcurrent motion between Africa and Europe.

How to cite: Siravo, G., Speranza, F., and Macrì, P.: Pre-Miocene Paleomagnetic Data from the Calabrian Block Document a 160° Post-Late Jurassic CCW Rotation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1624, https://doi.org/10.5194/egusphere-egu23-1624, 2023.

X3.53
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EGU23-2691
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ECS
Progressive localization of a diffuse transtensional plate boundary: the example of the Iberia-Eurasia plate boundary during the opening of the Bay of Biscay (Late Jurassic-Early Cretaceous) 
Riccardo Asti, Nicolas Saspiturry, and Paul Angrand

Most plate kinematic reconstructions concerning the Iberian plate imply a major (>400 km) left-lateral displacement between Iberia and Eurasia during the opening of the Bay of Biscay (Late Jurassic-Early Cretaceous). In the past, authors identified the North Pyrenean Zone (NPZ) as the domain accommodating this lateral displacement, while more recent works tend to distribute the deformation in two or three transtensional corridors located in the NPZ and in the Iberian Chain basins. Nevertheless, field evidence contrasts with such models, since no structure seems to have accommodated such huge amount of displacement. Moreover, debate exists concerning the timing of the left-lateral displacement between Iberia and Eurasia (Late Jurassic vs Early Cretaceous).

We present a review of the tectono-sedimentary and kinematic evolution of rift basins distributed across the wide Iberia-Eurasia plate boundary that recorded the Late Jurassic-Early Cretaceous rifting phase, from the Iberian Chain basins (in the southwest) to the northern part of the Aquitaine domain aligned with the Armorican Margin (to the northeast). To the first order, these basins experienced the same tectonic evolution, with an initial Permian-Triassic rifting phase related to the breakup of Pangea, and a subsequent Late Jurassic-Early Cretaceous rifting phase related to the opening of the Bay of Biscay. For this latter phase, authors have proposed contrasting kinematic models, with opening mechanisms varying between orthogonal rifting and transtensional/pull-apart tectonics. Our review allows to propose a reappraisal of the kinematic evolution of the Iberia-Eurasia diffuse plate boundary during the Late Jurassic-Early Cretaceous rifting, which consists in four phases: (i) a Late Jurassic phase of transtensional deformation localized at the borders of the system (Asturian Basin/Southwesternmost Iberian Chain basins and Armorican Margin), while the rest of the basins underwent orthogonal rifting, contemporaneous with rifting in the Bay of Biscay margins; (ii) a Neocomian phase of generalized marine regression; (iii) a Barremian-Early Albian phase of distributed left-lateral transtension, contemporaneous with crustal breakup in the Bay of Biscay; (iv) an Albian-Cenomanian phase of left-lateral transtension localized in the Basque-Cantabrian/North Pyrenean corridor, contemporaneous with ocean spreading in the Bay of Biscay, while the rest of the rift basins within the plate boundary became tectonically inactive. This evolution highlights a trend of progressive localization of the plate boundary from the Late Jurassic to the Early Cretaceous in response to the different tectonic phases of the Bay of Biscay margins. This work also allows to highlight the role of some rift basins in accommodating part of the deformation between Iberia and Eurasia which have been often disregarded, due to their position below the Cenozoic cover of the Pyrenean foreland basins, such as the Ebro and Aquitaine domains.

How to cite: Asti, R., Saspiturry, N., and Angrand, P.: Progressive localization of a diffuse transtensional plate boundary: the example of the Iberia-Eurasia plate boundary during the opening of the Bay of Biscay (Late Jurassic-Early Cretaceous), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2691, https://doi.org/10.5194/egusphere-egu23-2691, 2023.

X3.54
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EGU23-9397
Broken pebbles and cobbles from the middle-upper Miocene siliciclastic deposits of the Peloritani Mountains (Sicily, Italy): evidence of extensional paleotectonics? 
Rosanna Maniscalco, Roberta Somma, and Sebastiano Ettore Spoto

In the Peloritani Mountains (North-Eastern Sicily, Italy), evidence of several fractured pebbles and cobbles was found in the coarse-grained siliciclastic deposits of the middle-upper Miocene San Pier Niceto Formation. The pattern of this pebble/cobble fracturing is analogous in type and orientation. These broken pebbles and cobbles appear fractured and affected by normal subparallel faults in a single clastic element, with mm- to cm offset. Such peculiar structures have been commonly associated with active tectonics in recent deposits. 
The present research is therefore devoted to the study of the middle-upper Miocene San Pier Niceto Fm. in Peloritani Mountains for i) characterizing the morphologic properties and orientation of clasts, ii) defining the spatial orientation of faults and principal stresses, iii) understanding their tectono-sedimentary genesis. The goal is to ascertain that broken clasts may or may not represent paleoseismic evidence and coseismic deformation during the initial stages of the extensional tectonics in the still active area of the Calabrian Arc.

How to cite: Maniscalco, R., Somma, R., and Spoto, S. E.: Broken pebbles and cobbles from the middle-upper Miocene siliciclastic deposits of the Peloritani Mountains (Sicily, Italy): evidence of extensional paleotectonics?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9397, https://doi.org/10.5194/egusphere-egu23-9397, 2023.

X3.55
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EGU23-7642
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ECS
The transition from convergence to extension in the NW Mediterranean: insights from the thermochronologic and tectono-sedimentary record in the Eastern Pyrenees and Empordà basin (NE Spain) 
Sabí Peris, Albert Griera, David Gómez-Gras, and Antonio Teixell

The Empordà basin is located in NE Catalonia (Spain), overprinting the Eastern Pyrenees where this mountain belt reaches the Mediterranean Sea. The area offers an opportunity to study cycles of orogenic evolution, from mountain building to destruction, although with some peculiar features. Following Pyrenean contractional structures that ceased in the Oligocene, earlier than in the Central and Western Pyrenees finished during the lower Miocene, the extension that depressed the Empordà basin seems to be a younger event (late Miocene-Pliocene) than the opening of the Western Mediterranean (Gulf of Lyon and Valencia trough; late Oligocene-Miocene). The regional NE-SW extensional fault systems that dominate from the Gulf of Lion to the Catalan Coastal Ranges and Valencia grabens contrast with the NW-SE normal faults in the Empordà basin, which are also associated with alkali volcanism during the Neogene. This feature is still poorly understood, together with the absence of crustal root in the adjacent relict relief of the Pyrenees despite the relatively high elevation.

To gain insights into these questions and into the detailed geochronology and mechanisms of the transition from convergence to extension, we have revisited the tectono-sedimentary record of the South-Pyrenean and Empordà basins. First, the provenance of the clastic deposits from the Paleogene to the Neogene gives information about the evolution of the sedimentary systems, as well as the tectonic changes in the source regions. This data combined with low-temperature thermochronology of source reliefs and basin sedimentary units allows characterizing part of the geodynamic evolution from the NW Mediterranean realm. Complementary, new structural data from field observations and seismic profile interpretation provide us with inferences on a new structural model of the region.

How to cite: Peris, S., Griera, A., Gómez-Gras, D., and Teixell, A.: The transition from convergence to extension in the NW Mediterranean: insights from the thermochronologic and tectono-sedimentary record in the Eastern Pyrenees and Empordà basin (NE Spain), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7642, https://doi.org/10.5194/egusphere-egu23-7642, 2023.

X3.56
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EGU23-8123
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ECS
From shoreface to riverbed – Facies evolution in Burdigalian deposits of the North Alpine Foreland Basin 
Tim Drießle and Felix Hofmayer

During the Burdigalian the North Alpine Foreland Basin, as part of the central and western Paratethys, underwent various paleogeographic and paleoenvironmental changes which led to the deposition of different sedimentary facies. For instance, the Ottnangian regional stratigraphic stage (18.2 – 17.3 Ma) was characterized by a major transgression in the beginning, with the deposition of several littoral facies along the northern coastline of the North Alpine Foreland Basin. Successively, the late Ottnangian documents the final retreat of the Paratethys Sea from the North Alpine Foreland Basin and the deposition of widely distributed fluviatile units. The outcrop Neustift in southeast Germany bears many different siliciclastic facies and shows the transition of the Ottnangian marine realm towards a riverine-deltaic environment. Despite the exceptional size and complexity of the succession, this outcrop is only poorly studied. Anyhow, this section gives unique potential for the understanding of the facies evolution during the terminal Ottnangian. In total a 70 m long and 15 m high sedimentary log was recorded together with several micropaleontological samples (1 kg each) for the reconstruction of the depositional environment and stratigraphic positioning. The micropaleontological samples yielded 164 genera of benthic foraminifera and 144 species of ostracods. Moreover, these deposits are extremely rich in macrofossils (elasmobranchia, mollusca, brachiopoda, echinoidea) which are also poorly studied. We found out, that the lowermost segment of the section belongs to the marine “Littoral Facies of Holzbach-Höch”, which deposited directly on top of a transgressive layer on the crystalline basement. Several of the observed ostracod species are new to these deposits. Large-scale cross-bedding structures show that this shallow marine environment was affected by strong tidal currents along the rocky shoreline. The fine-grained sediments with wavy and lenticular bedding on top of the littoral deposits show an ongoing transgression, with neritic foraminiferal assemblages and bioturbation. They were assigned by biostratigraphy to the uppermost Neuhofen Formation. Finally, the marine deposition is replaced by a large-scale deltaic system, resulting into the deposition of the fluviatile Ortenburg gravel. This preliminary study should draw some more attention to this unique outcrop in the North Alpine Foreland Basin and the potential for further studies in the realm of sedimentology and paleontology. 

How to cite: Drießle, T. and Hofmayer, F.: From shoreface to riverbed – Facies evolution in Burdigalian deposits of the North Alpine Foreland Basin, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8123, https://doi.org/10.5194/egusphere-egu23-8123, 2023.

X3.57
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EGU23-11990
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ECS
Plate interface frozen at the very end of continental subduction 
Kevin Mendes, Philippe Agard, Alexis Plunder, and Clement Herviou

Continental subduction and collision are not merely follow-ups of oceanic subduction but mark the transition from lithospheric-scale deformation localized along the subduction interface to crustal-scale deformation distributed across the orogen. In order to unravel the processes typifying the dynamic changes from oceanic subduction to collision, we have characterized pressure-temperature (P-T) and spatio-temporal evolution of rocks on either side of the tectonic contact (Briançonnais/Liguro-Piemont contact – Br/LP contact) separating the subducted oceanic remnants from the subducted continental fragments along the length of the Western Alps. West of the contact, the Briançonnais zone is considered as a micro-continent composed of pre-Alpine basement and Paleozoic to Meso-Cenozoic cover units. East of the contact, the Liguro-Piemont zone corresponds to a nappe-stack, with three groups of oceanic (upper, middle and lower) units. The Piemont zone is pinched in between the two in the southern part of the Western Alps and correspond to the distal part of the Briançonnais continental margin.

Results indicate that the maximum temperature and pressure difference on each side of the contact is generally < 30°C and < 0.3 GPa, evidencing that (i) no significant metamorphic gap exists between both sides and that (ii) offscraping of the continental fragments occurred at the same depth as the oceanic ones. The dataset also shows a northward increase of peak P-T conditions from ~300°C-1.2 GPa to ~500°C-2.0 GPa. The preservation of similar P-T conditions on both sides of the Br/LP contact can tentatively be assigned to either (1) offscraping of the Liguro-Piemont and later of the Briançonnais at similar depths or (2) entrainment and joint burial of the Liguro-Piemont (previously accreted or subducted) fragments together with the Briançonnais margin. The latter hypothesis, however, is not supported by the ~10 My gap between the peak burial of the Briançonnais and Liguro-Piemont zones. The recurrent depth range of the various units, which reflects systematic variations of slicing and mechanical coupling along the plate interface (Herviou et al., 2022), suggests that (1) similar slicing mechanisms and strain localization prevailed during both oceanic and continental subduction and (2) shows that the Br/LP contact represents a frozen-in subduction interface. The end of high-pressure and low-temperature metamorphism and continental subduction at ~33 Ma would thus mark the stalling of subduction interface dynamics and the onset of strain distribution across the plate interface and into the lower plate.

 

  • Herviou, C., Agard, P., Plunder, A., Mendes, K., Verlaguet, A., Deldicque, D., Cubas, N., 2022. Subducted fragments of the Liguro-Piemont ocean, Western Alps: Spatial correlations and offscraping mechanisms during subduction. Tectonophysics 827, 229267. https://doi.org/10.1016/j.tecto.2022.229267

How to cite: Mendes, K., Agard, P., Plunder, A., and Herviou, C.: Plate interface frozen at the very end of continental subduction, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11990, https://doi.org/10.5194/egusphere-egu23-11990, 2023.

X3.58
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EGU23-13909
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ECS
The Messinian Erosion Surface along the Eastern Sardinian Margin, Western Tyrrhenian: New Insights from Very High-Resolution Seismic Data (METYSS 4) 
Romain Sylvain, Virginie Gaullier, Louise Watremez, Frank Chanier, Fabien Caroir, Fabien Graveleau, Johanna Lofi, Agnès Maillard, Françoise Sage, Isabelle Thinon, and Gaia Travan

The Eastern Sardinian margin consists in a hyper-extended rifted margin, located in the western Tyrrhenian Sea, a recent back-arc basin (late Neogene). This area was affected by strong aerial erosion during the Messinian Salinity Crisis (MSC, 5.96 – 5.33 My) associated with the drop of sea level (> 1500 m) which occurred throughout the whole Mediterranean. The Gulf of Orosei and surrounding offshore areas are characterized by small and diffuse drainage systems input, where the Messinian Erosion Surface (MES) has rarely been studied while it has been in large fluvial systems (Rhone, Ebro). The MES was already found in the Cendrino valley (which flows in the Gulf) and in the East-Sardinia Basin but the link between onshore and offshore was never been studied in the area. The “METYSS 4” cruise (June 2019, R/V “Téthys II”) allowed acquiring more than 2000 km of very high-resolution (VHR) seismic data (Sparker), following a dense grid (1.5 km average profile spacing), on the Eastern Sardinian continental shelf, and especially in the Orosei Gulf area, that has been little explored until now. While the main limitation on seismic data (air-gun) interpretation is often due to the occurrence of sea bottom multiple, the limitation for Sparker data may also be due to very short shot intervals at greater water depth. The seismic trace ends where there still is signal of interest. Thus, we applied a simple method to increase investigation depth for short shot intervals (0.333 - 0.533 ms), which allowed interpretation on the continental slope. This approach consists in copying the raw data and concatenating the copied data under the raw data with a shift of 1 shot point. To constrain the MES depth on the continental slope and shelf we compared air-gun seismic data from previous METYSS surveys, where the MES has already been interpreted by a strong erosional discordance between Plio-Quaternary deposits and pre-MSC units, with the new VHR data. The restoration of the morphological features of the Orosei canyon at Messinian times shows that the former Messinian canyon network is very similar to the present-day one. The present-day canyon and its tributaries show sub-marine erosion in the talwegs. The heads of the canyons present gravitational features, highlighted by chaotic deposits near the talweg of the canyon or in-between the Plio-Quaternary strata. Offshore Arbatax, south Orosei, the seismic profiles show no significant Plio-Quaternary deposits (thickness < 0.1 sTWT), which allows polygenic pre-MSC units to occur at the seafloor. In the Gulf, we observe thick deposits (0.4 - 0.5 sTWT) on the right bank of Orosei Canyon, making it more complicated to image the MES in this area. The sedimentation rate on this margin is very low (c.a. 9 cm/ka in the Gulf of Orosei), which is consistent with previous studies on the East-Sardinian basin (3-20 cm/ka). These preliminary results will allow correlating for the first time the MES distribution from the onshore to the offshore continental slope of the Eastern Sardinian Margin in order to improve the MSC understanding in this key area.

How to cite: Sylvain, R., Gaullier, V., Watremez, L., Chanier, F., Caroir, F., Graveleau, F., Lofi, J., Maillard, A., Sage, F., Thinon, I., and Travan, G.: The Messinian Erosion Surface along the Eastern Sardinian Margin, Western Tyrrhenian: New Insights from Very High-Resolution Seismic Data (METYSS 4), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-13909, https://doi.org/10.5194/egusphere-egu23-13909, 2023.

X3.59
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EGU23-12441
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ECS
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Extension of a lower plate passive margin coeval with subduction of the adjacent slab: The Western Alps and Maghrebides cases 
Aboubaker Farah, Omar Saddiqi, Moulley Charaf Chabou, and André Michard

The Piemonte-Ligurian-Maghrebian Tethys or “Alpine Tethys” developed at the western tip of the Tethys Ocean between Eurasia and Gondwana. The evolution of the Alpine Tethys during the post-Pangea rifting and oceanic expansion from the Early Jurassic to the Early Cretaceous has been well documented compared to its evolution from the onset of the African-Eurasian convergence during the Late Cretaceous upward. In this contribution, based on our studies and the literature, we try to decipher the evolution of this ocean through the study of its inverted margins during Late Cretaceous-Paleocene times. In the Western Alps, the Briançonnais domain, which constituted the distal European magma-poor passive margin of the Alpine Tethys, was affected by a systemic extension in the Late Cretaceous-Paleocene. This late extension, poorly described so far, operated only a few million years before the Briançonnais encroached the SE-dipping subduction zone under the Adria microplate. In the Maghrebides transects from the Rif belt (Northern Morocco) to the Peloritani Mountains of Sicily (e.g., Bouillin, 1986; Bouillin et al., 1986) the Alkapeca (Alboran-Kabylias-Peloritan-Calabre) terranes were part of south-eastern Iberia until the Early Jurassic opening of the narrow Betic Ocean (Puga et al., 2011) or OCT domain (Jabaloy Sánchez et al., 2019). The Alkapeca blocks preserve in their “Dorsale calcaire” units remnants of the northern margin of the Alpine Tethys and then are southwestern equivalents of the Briançonnais domain, except they were fragmented and carried onto the African and south-eastern Iberia margins during the Tertiary opening of the back-arc Mediterranean basins. We observe that the Dorsale calcaire units testify to extensional deformation like the Briançonnais during the Late Cretaceous-Paleocene, i.e., when Africa-Eurasia-Iberia convergence was active and then subduction of the intervening Tethyan slab must have occurred somewhere. We propose here for the first time that the Late Cretaceous-Paleocene subduction of the Ligurian-Maghrebian slab occurred under the North African margin in the southward continuation of the Alpine subduction. Contrary to some early claims, the North African margin did not experience significant compression during the Late Cretaceous-Paleocene, which compares with the Adria margin case during the same period. During the Eocene, a Subduction Polarity Reversal occurred, which was associated with the relocation of the subduction zone along the Alkapeca blocks. This was the beginning of the Apenninic subduction, which triggered the back-arc opening of the Mediterranean basins and corresponds to the back-thrusting tectonic phase in the Western Alps.

References  

Bouillin J-P, 1986. Le « bassin maghrébin » : une ancienne limite entre l’Europe et l’Afrique à l’ouest des Alpes. Bull. Soc. Géol. Fr. (8) 2 :547-558.

Bouillin JP, et al., 1986. Betic-Rifian and Tyrrhenian Arcs : Distinctive Features, Genesis and Development Stages. Developments Geotect. 21:281-304.

Puga E, et al., 2011. Petrology, geochemistry and U-Pb geochronology of the Betic Ophiolites: Inferences for Pangaea break-up and birth of the Westernmost Tethys Ocean. Lithos 124:265-272.

Jabaloy Sánchez A, et al., 2019. Lithological successions of the Internal Zones and Flysch Trough Units of the Betic Chain. In : Quesada C and Oliveira JT (eds.), The Geology of Iberia: A Geodynamic Approach. Region. Geol. Rev. (Springer Nature Publ.)

How to cite: Farah, A., Saddiqi, O., Chabou, M. C., and Michard, A.: Extension of a lower plate passive margin coeval with subduction of the adjacent slab: The Western Alps and Maghrebides cases, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12441, https://doi.org/10.5194/egusphere-egu23-12441, 2023.

Posters virtual: Tue, 25 Apr, 16:15–18:00 | vHall SSP/GM

Chairpersons: Roberta Somma, Sabatino Ciarcia
vSG.6
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EGU23-4235
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ECS
Palaeoenvironmental reconstruction of the Mio-Pliocene succession of the Miscano River: insights on sedimentation after the Messinian salinity crisis in the southern Apennines 
Andrea Infante, Giuseppe Aiello, Diana Barra, Sabatino Ciarcia, Valentino Di Donato, Simona Morabito, Ernesto Paolo Prinzi, and Stefano Vitale

We present a study of a Mio-Pliocene marine to a continental clastic sedimentary succession of the southern Apennines Foreland Basin System well exposed in the Miscano River in the Irpinia sector of the chain. These well-bedded wedge-top basin deposits host a significant angular unconformity between a post-evaporitic succession (uppermost Messinian-lowermost Pliocene), developed on top of the evaporite deposits related to the Messinian Salinity Crisis, and an overlying upper part of the Zanclean sediments. The unconformity witnesses a major tectonic shortening stage of the southern Apennines characterized by out-of-sequence thrusting that involved the Mio-Pliocene wedge-top basin deposits. Meio-microfaunal and nannofloral fossil assemblages were analyzed to define the depositional environments and biostratigraphy of the two successions. In addition, benthic foraminiferal and ostracod assemblages were studied in detail, and their autochthonous/allochthonous provenience was discussed from a paleoecological point of view. The relative response of these assemblages to environmental parameters, such as salinity, oxygenation, paleobathymetry and climatic changes, allowed us to reconstruct the paleoenvironmental evolution of these wedge-top basin deposits.

How to cite: Infante, A., Aiello, G., Barra, D., Ciarcia, S., Di Donato, V., Morabito, S., Prinzi, E. P., and Vitale, S.: Palaeoenvironmental reconstruction of the Mio-Pliocene succession of the Miscano River: insights on sedimentation after the Messinian salinity crisis in the southern Apennines, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4235, https://doi.org/10.5194/egusphere-egu23-4235, 2023.

vSG.7
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EGU23-2648
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ECS
A multidisciplinary study of the “Bolle della Malvizza” mud volcanoes (southern Italy) 
Carmela Fabozzi, Stefano Albanese, Maurizio Ambrosino, Sabatino Ciarcia, Domenico Cicchella, Jacopo Natale, Ernesto Paolo Prinzi, Francesco Verrilli, and Stefano Vitale

We present a study on the mud volcanoes of Bolle della Malvizza located in the Irpinia sector of the southern Apennines (southern Italy). These structures are hosted in the Upper Cretaceous-Upper Miocene Fortore succession (Lagonegro-Molise Basin) and emit mud and bubbles of methane and CO2. Mud volcanoes are focused in a narrow area of ca. 5000 m2, consisting of eight main emission centres and several minor craters. We approached this research with a multidisciplinary study, including stratigraphic and structural surveys, geophysical and geochemical investigations and morphometric analyses. This study aims to investigate the origin of fluid migration and shed light on the pathways mainly controlled by faults.

How to cite: Fabozzi, C., Albanese, S., Ambrosino, M., Ciarcia, S., Cicchella, D., Natale, J., Prinzi, E. P., Verrilli, F., and Vitale, S.: A multidisciplinary study of the “Bolle della Malvizza” mud volcanoes (southern Italy), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2648, https://doi.org/10.5194/egusphere-egu23-2648, 2023.

vSG.8
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EGU23-1865
Neogene synorogenic stratigraphic evolution of southern Apennines 
Sabatino Ciarcia and Stefano Vitale

We present a study of the synorogenic deposits associated with the orogenic construction of the southern Apennines. This orogen is a segment of the Alpine chain system bounding the central-western Mediterranean Sea. Southern Apennines form an orogenic belt consisting of the superposition of some successions of the downgoing Adria plate, made of shallow-water to pelagic sedimentary successions. The synorogenic sedimentation was ruled by the migration of the forebulge-foreland basin system, with the flexure of the continental part of the Adria plate since the Oligocene (forebulge stage), mainly due to the slab retreat process. The thrust front-foredeep-forebulge system migrated toward E/NE until the middle Pleistocene. We focussed our attention on the Foreland Basin System synorogenic deposits mainly consist of back-bulge, foredeep, and wedge-top basin sediments.

How to cite: Ciarcia, S. and Vitale, S.: Neogene synorogenic stratigraphic evolution of southern Apennines, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1865, https://doi.org/10.5194/egusphere-egu23-1865, 2023.