• 标题：Age attribution to a karst system using river long profile analysis (Hyblean Plateau, Sicily, Italy).
• 关键词：Cassibile River;Hyblean Plateau;Karst caves;Long profile
• 作者：Pavano;Tortorici;Romagnoli;Catalano

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In steady-state tectonic-climate systems, the fluvio-karst processes attain a stable base level, whether it be local or global. In contrast, in an uplifting region, relative base-level changes force river incision processes and a concurrent lowering of the karst water-table. Even at local scales (e.g., single fault-controlled valley), combined tectonically- and climatically-driven base-level drops induce geomorphic and hydrogeological disequilibrium. Thus, the karst system develops vertically and the water-table lowers trying to attain the new local base level. Conversely, the paleo-karst network dries, and becomes abandoned as a hanging relic with aligned karst morphologies. They are exhumed by the entrenchment of the fluvial network, as base-level fall related knickpoints migrate upstream. We propose a geomorphic approach to build fluvio-karst age models, based upon the analysis of river long-profiles. This approach is complementary to altimetric correlation between karst horizons and coastal paleo-sea level markers. Our approach is useful for an inland study area that is far from the marine terraced coast or where active faulting cuts off the coastal area from the inland landscape. We tested the approach in the eastern sector of the Hyblean Plateau (Sicily, Italy), where a carbonate sequence experienced Middle-Late Pleistocene tectonic uplift combined with active faulting. Specifically, we investigated the Cassibile River basin, at the footwall of the active Cassibile-Noto Fault. By reconstructing river paleo-long profiles we fixed time-space reference lines, connecting the abandoned and hanging fluvio-karst levels to the correlative marine strandlines carved along the fault-controlled coastal landscape. • Proposal of a new karst system dating method for the Hyblean Plateau (Sicily) • Uses paleo-river profiles and marine strandlines as space-time reference lines • Correlates level of abandoned karst caves along the Cassibile R. valley to OIS 7 • Karst features related to a paleo-water-table, exhumed by knickpoint migration • Transfer of marine terrace age model to fluvial-karst level in fault-deformed area