Flank margin caves owe their formation to fresh and marine water mixing, inducing corrosion processes (Mylroie and Carew, 1990). They are very abundant on tropical islands characterized by eogenetic carbonates such as the Bahamas, Bermuda, Guam, and Cuba. Recently several flank margin cave systems have been documented in telogenetic carbonates of the Italian peninsula (Arriolabengoa et al., 2017). Generally, these caves present typical geomorphological features such as galleries with rounded cross-sections, swiss-cheese or spongework patterns, abrupt dead-endings moving away from the coastline, and horizontal notches. They lack alluvial sediments, but their entrances are often infilled with marine deposits. This work describes three flank margin caves found in Apulia and Sicily: Sant’Angelo (Ostuni, Apulia), Pellegrino (Siracusa, Sicily) and Carburangeli caves (Palermo, Sicily). All these caves are now in vadose conditions opening along paleo-cliffs at altitudes varying from ~ 25 to 150 m asl and were carved along prominent fractures (secondary porosity). They are characterized by several sub-horizontal arrangements and show evident notches with flat roofs and spongework patterns. We found Lithophaga litophaga boreholes inside Carburangeli Cave, and marine deposits in the entrance of Pellegrino Cave, demonstrating important marine influences, whereas speleothems due to the seepage of meteoric waters through the host-rock occurred during subsequent stages partially covering typical flank margin cave features. Being formed by salt-fresh water mixing, they are valuable indicators of past eustatic sea levels, and if dated can allow to estimate coastal uplift rates.
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|Titolo:||Flank margin caves as signatures for past sea level fluctuations in Apulia and Sicily (southern Italy)|
|Data di pubblicazione:||2018|
|Appare nelle tipologie:||4.2 Abstract in Atti di convegno|