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Boris
Behncke (2000)
Palaeocoastlines captured in volcanic facies:
An approach to dating of
karst phenomena of the Hyblean Plateau, SE Sicily
Speleologia Iblea, volume 8, pages 37-42
(Atti del I Seminario di Studi sul Carsismo negli Iblei e nell'Area
sud Mediterranea,
Eremo della Giubiliana, Ragusa 9-11 April 1999)
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Facies changes in
volcanic deposits, especially when recording transitions from submarine
to subaerial deposition and vice versa, are among the best indicators
of palaeocoastlines and palaeoenvironmental changes, and thus may yield
crucial information about palaeoaquifers leading to kars formation.
Multiple eruptive events occurred on the Hyblean Plateau in SE Sicily
during the late Pliocene and early Pleistocene in a shallow marine to
subaerial environment, before the area became submerged and was covered
by a thick sequence of marine carbonate sediments. At least two volcanic
events are known during which deposition was at least partially subaerial,
one in the late Pliocene and the other in the early Pleistocene. Subaerial
deposition may have occurred thanks to three distinct processes: (1)
growth of volcanic edifices above the sea level, (2) isostatic regional
uplift, and (3) eustatic lowering of the sea level. While the first
of these processes is not relevant for the study of karst phenomena,
the other two processes point to conditions during the periods of emergence
which may have allowed karst erosion. Tracing the palaeoclastlines in
the volcanics of those periods, it is possible to outline the areas
which were possibly the sites of karstic processes.
Keywords: Volcanism - Hyblean Plateau - Karst
phenomena - Volcanic facies - Emergence - Isostasy/Eustacy
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