Hypogene speleogenesis in carbonates by cooling, confined hydrothermal flow: The case of Mt. Berenike caves, Israel

The Berenike hypogenic cave system near Lake Kinneret, Israel, provides a valuable case study for investigating the recently proposed Confined-Cooling-Flow (CCF) speleogenesis model. Field and speleological surveys, along with existing research, are used to provide a thorough analysis. The CCF model relies on a simple thermo-hydro-chemical scenario, involving the rise of CO₂-rich hydrothermal fluids discharging into a confined layer. The cooling of these CO₂-rich fluids turns them into aggressive solutions due to the inverse relation between temperature and solubility of carbonates (retrograde solubility). Previous geochemical and numerical analyses of the CCF model predict localized and persistent dissolution and speleogenesis on short geologic timescales and reproduce common characteristics of hypogene cave morphology. The present study examines speleogenesis in Berenike by correlating it spatially and temporally with the geologic history and hydrogeology of the region and refers to the cave location and appearance in the rock section. The relatively clear and preserved morphologic features at various scales allow for further insights. Particularly, the CCF model can explain enigmatic field observations, such as the location of the largest passages at some distance away from the feeder. It also accounts for the formation of intricate maze-like networks in soluble rock successions and confined conditions, not explained by other models. Finally, this study suggests that the CCF model has broader applicability in understanding the formation of numerous large hypogenic karst and maze cave systems that are globally widespread.