Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst
The evolution of alluvial megafans has mainly been investigated in unconfined settings; however, at the boundary of these large depositional systems, the development of fluvial channels can be affected by structural constraints with regional extent. Here we present the study of the eastern sector of...
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MDPI AG
2023-05-01
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| Online Access: | https://www.mdpi.com/2076-3263/13/5/135 |
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| author | Livio Ronchi Alessandro Fontana Ana Novak Annamaria Correggiari Sašo Poglajen |
| author_facet | Livio Ronchi Alessandro Fontana Ana Novak Annamaria Correggiari Sašo Poglajen |
| author_sort | Livio Ronchi |
| collection | DOAJ |
| description | The evolution of alluvial megafans has mainly been investigated in unconfined settings; however, at the boundary of these large depositional systems, the development of fluvial channels can be affected by structural constraints with regional extent. Here we present the study of the eastern sector of the megafan of Isonzo River, in the Gulf of Trieste, where this system fed through the southern Alps is constrained by the Karst and Istria cliffs. Although this area is now submerged under the northern Adriatic Sea, stratigraphy from seismo-acoustic profiles, drill cores and multi-beam bathymetry allows us to reconstruct the paleochannel system of the Isonzo River in detail, which was likely active within the period of 21–17.5 ka cal BP, at the end of LGM. This was reconstructed for over 50 km and currently represents the longest abandoned fluvial channel in the Mediterranean seabed. The occurrence of the mountain fringe and competition with nearby alluvial systems forced the paleochannel to follow the present coastline and conditioned the slope of its thalweg to decrease almost to null, resulting the transformation from the megafan to the undifferentiated alluvial plain. |
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| issn | 2076-3263 |
| language | English |
| last_indexed | 2024-03-11T03:42:03Z |
| publishDate | 2023-05-01 |
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| spelling | doaj.art-ec356318c71c44f99fd81384b21240392023-11-18T01:30:55ZengMDPI AGGeosciences2076-32632023-05-0113513510.3390/geosciences13050135Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the KarstLivio Ronchi0Alessandro Fontana1Ana Novak2Annamaria Correggiari3Sašo Poglajen4Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131 Padova, ItalyDepartment of Geosciences, University of Padova, Via G. Gradenigo 6, 35131 Padova, ItalyGeological Survey of Slovenia, 1000 Ljubljana, SloveniaIstituto di Scienze Marine (ISMAR CNR), 40129 Bologna, ItalySirio d.o.o., 6000 Koper, SloveniaThe evolution of alluvial megafans has mainly been investigated in unconfined settings; however, at the boundary of these large depositional systems, the development of fluvial channels can be affected by structural constraints with regional extent. Here we present the study of the eastern sector of the megafan of Isonzo River, in the Gulf of Trieste, where this system fed through the southern Alps is constrained by the Karst and Istria cliffs. Although this area is now submerged under the northern Adriatic Sea, stratigraphy from seismo-acoustic profiles, drill cores and multi-beam bathymetry allows us to reconstruct the paleochannel system of the Isonzo River in detail, which was likely active within the period of 21–17.5 ka cal BP, at the end of LGM. This was reconstructed for over 50 km and currently represents the longest abandoned fluvial channel in the Mediterranean seabed. The occurrence of the mountain fringe and competition with nearby alluvial systems forced the paleochannel to follow the present coastline and conditioned the slope of its thalweg to decrease almost to null, resulting the transformation from the megafan to the undifferentiated alluvial plain.https://www.mdpi.com/2076-3263/13/5/135marine geologyCHIRPstratigraphybathymetrylast glacial maximumadriatic sea |
| spellingShingle | Livio Ronchi Alessandro Fontana Ana Novak Annamaria Correggiari Sašo Poglajen Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst Geosciences marine geology CHIRP stratigraphy bathymetry last glacial maximum adriatic sea |
| title | Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst |
| title_full | Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst |
| title_fullStr | Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst |
| title_full_unstemmed | Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst |
| title_short | Late-Quaternary Evolution of the Semi-Confined Alluvial Megafan of Isonzo River (Northern Adriatic): Where the Fluvial System of the Southern Alps Meets the Karst |
| title_sort | late quaternary evolution of the semi confined alluvial megafan of isonzo river northern adriatic where the fluvial system of the southern alps meets the karst |
| topic | marine geology CHIRP stratigraphy bathymetry last glacial maximum adriatic sea |
| url | https://www.mdpi.com/2076-3263/13/5/135 |
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