Anomalous drip in the Punkva caves (Moravian Karst): relevant implications for paleoclimatic proxies

Abstract

Abstract:The anomalous drip in the Punkva caves (Moravian Karst) shows specific hydrogeochemical properties such as low SI calcite~0 .14 ± 0.11 (standard deviation), low mineralization (4.53 ± 0.42) × 10 À3 mol l À1, and enhanced values of δ 13 C (À7.85 to À8.35‰ VPDB), Mg/Ca × 1000 ratio (45.7 ± 3.3), and Sr/Ca × 1000 ratio (0.65 ± 0.06). By these properties, the anomalous drip significantly differs from other regular drips in the same cave and other caves in the region. The study suggests that the anomalous drip properties are a consequence of prior calcite precipitation or/and water mixing along the water flow path. As the former processes are spatially controlled, the knowledge of dripwater flow path seems to be necessary for correct paleoclimatic/paleoenvironmental reconstructions.

Low-Calcium Cave Dripwaters in a High CO2 Environment: Formation and Development of Corrosion Cups in Postojna Cave, Slovenia

“…From a visual inspection of the ceiling, we concluded that precipitation does not readily occur at the ceiling. However, PCP could be important, as many of the geochemical parameters resulting from this process were found in our data (low SEC, low SI cc and low mineralisation [27,57]). However, to diagnose PCP, at least the ratios of the trace elements (e.g., Mg/Ca and Sr/Ca) and the δ 13 C signature would need to be determined, with higher values being a key signal for this process.…”

“…However, to diagnose PCP, at least the ratios of the trace elements (e.g., Mg/Ca and Sr/Ca) and the δ 13 C signature would need to be determined, with higher values being a key signal for this process. Alternatively, mixing corrosion could provide a source of potential dissolution in the Red Hall [57]. However, both mixing corrosion and PCP in the vadose zone are highly unlikely to control the geochemistry in our case, as there is simply an abundance of corrosion features over a wide area fed by several hundred different drips.…”

Low Calcium Cave Dripwaters in a High CO₂ Environment: Formation and Development of Corrosion Cups in Postojna Cave, Slovenia

“…From visual inspection of the ceiling, we concluded that precipitation does not readily occur at the ceiling. However, PCP could be important as many of the geochemical parameters resulting from this process are found in our data (low SEC, low SIcc and low mineralisation; [58]). However, to diagnose PCP, at least the ratios of trace elements (e.g.…”

“…Mg/Ca and Sr/Ca) and the δ 13 C signature would need to be determined, with higher values being a key signal for this process. Mixing corrosion as a source of potential dissolution in the Red Hall might also play a role [58], but this scenario, as well as PCP that would have to take place in the vadose zone, are highly unlikely to control the geochemistry in our case, as there is simply an abundance of corrosion features over a wider area fed by several hundred different drips.…”