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| Titel |
Age and speleogenesis of epigenic gypsum caves in the northern Apennines (Italy) |
| VerfasserIn |
Andrea Columbu, Veronica Chiarini, Jo De Waele, Russell Drysdale, Paolo Forti, John Hellstrom, Jon Woodhead |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121486
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| Publikation (Nr.) |
 EGU/EGU2016-237.pdf |
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| Zusammenfassung |
| Triassic and Messinian gypsum beds host the majority of the caves in the eastern flank of the northern Apennines. To date, more than six hundreds voids have been mapped, including the longest known epigenic gypsum cave system in the world (Spipola-Acquafredda, ~11 km of tunnels) (De Waele et al., 2013). Superimposed caves are typically sub-horizontal (Klimchouk, 2000) and connected through vertical shafts, reflecting the palaeo base-level variations. When preserved, river terraces at the surface lie at the same palaeo altitude of the base level and horizontal cave passages.
Notwithstanding the well-known geology of the area known (Vai and Martini, 2001), the age of these caves has been greatly underestimated in the past. Considering the rapid dissolution of the gypsum and uplifting of the area, the start of speleogenesis activity was considered to have occurred during the last glacial age.
The age of karst voids can be only indirectly estimated by the dating of the infilling sediments. U-Th dating on carbonate speleothems provides high-precision and accurate ages (Hellstrom, 2003; Scholz and Hoffmann, 2008). We thus applied this methodology to 20 speleothems coming from 14 different caves belonging to the Monte Tondo, Spipola Acquafredda, Castelnuovo, Stella-Rio Basino and Brisighella systems. The results show that: i) caves were forming since at least ~300 ka; ii) the peak of speleogenesis was reached during relatively cold climate stages, when rivers formed terraces at the surface and aggradation caused paragenesis in the stable cave levels (Columbu et al., 2015).
Besides the significant contribution to the understanding of the Apennines evaporite karst evolution, this study (and its further advancement) may also refine knowledge of the local vs regional uplifting rates and base-level variations since the late Pleistocene (Wegmann and Pazzaglia, 2009).
References
Columbu, A., De Waele, J., Forti, P., Montagna, P., Picotti, V., Pons-Branchu, E., Hellstrom, J., Bajo, P., and Drysdale, R., 2015, Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region: Geology.
De Waele, J., Fabbri, F., Forti, P., Lucci, P., and Marabini, S., 2013, Evoluzione speleogenetica del sistema carsico del re Tiberio (Vena del gesso Romagnola): I gessi e la cava di Monte Tondo. Memorie dell'istituto Italiano di speleologia.
Hellstrom, J., 2003, Rapid and accurate U/Th dating using parallel ion-counting multi-collector ICP-MS.: Journal of Analytical Atomic Spectrometry, v. 18.
Klimchouk, A. B., 2000, Speleogenesis in noncarbonate lithologies: In: Klimchouk, A.B., Ford, D.C., Palmer, A.N., Dreybrodt, W. (Eds.) Speleogenesis, evolution of karst aquifers, p. 430-442.
Scholz, D., and Hoffmann, D., 2008, 230Th/U-dating of fossil corals and speleothems: Quat. Sci. J, v. 57, p. 52.
Vai, G. B., and Martini, I. P., 2001, Anatomy of an orogen: The Apennines and adjacent Mediterranean:: Dordrecht, Netherlands, Kluwer Academic Publishers,, p. 631.
Wegmann, K. W., and Pazzaglia, F. J., 2009, Late Quaternary fluvial terraces of the Romagna and Marche Apennines, Italy: climatic, lithologic, and tectonic controls on terrace genesis in an active orogen: Quaternary Science Reviews, v. 28, no. 1, p. 137-165. |
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