Hypogenic speleogenesis, late stage epigenic overprinting and condensation-corrosion in a complex cave system in relation to landscape evolution (Toirano, Liguria, Italy)

Stalagmite-Inferred Climate in the Western Mediterranean during the Roman Warm Period

“…Considering the reported calcite-aragonite offsets of 1.1-2.3‰ [38], the values of aragonitic BA14-1 δ 13 C ranging from −6 to −11‰, are equivalent to calcitic carbon isotopic compositions of ~−7 to −13‰, well within the predicted C3-type carbon δ 13 C range (−6 to −14‰). This result agrees with previous studies, which suggest that C3-type plants dominate the vegetation surrounding Bàsura cave in modern times [42]. However, vegetation changes are not likely to control BA14-1 δ 13 C variations during the late Holocene since this region has been persistently dominated by C3-type plants, even in glacial times [21,43,44].…”

“…Under warm or humid conditions, dense vegetation coverage atop the cave and enhanced soil biological activity could lead to negative values in soil δ 13 C [45]. Meanwhile, increased precipitation could enhance the drip water and infiltration rates, with a reduction in drip water CO 2 degassing and more negative speleothem δ 13 C values [37,39,42], and vice versa. Prior carbonate precipitation (PCP) [46,47] is an additional factor affecting stalagmite δ 13 C values.…”

“…Hence, a negative δ 18 O shift reflects strong precipitation or dominant Atlantic-sourced moisture carried by the westerly winds. In the Mediterranean region, the control of δ 13 C and δ 18 O covariation has been suggested to be mainly hydroclimatic, e.g., [42,44,48] since high precipitation can decrease δ 13 C by promoting soil activity and vegetation respiration, and δ 18 O by the amount effect. A degree of similarity (r = 0.53, n = 286, p < 0.05) between BA14-1 δ 13 C and δ 18 O data supports that stalagmite δ 13 C variations document precipitation changes, with high (low) precipitation corresponding to low (high) δ 13 C values.…”

Hints on the Late Miocene Evolution of the Tonale-Adamello-Brenta Region (Alps, Italy) Based on Allochtonous Sediments From Raponzolo Cave

“…In this case, burial time corresponds to the approximate age of the phreatic karst network at specific water table levels (Granger et al, 2001;Häuselmann and Granger, 2005). Accordingly, cosmogenic dating on cave sediments has been successfully applied in the North-Western calcareous Alps (Häuselmann and Granger, 2005), in the Eastern Austrian Alps (Häuselmann et al, 2020), in the Southern calcareous Alps of Slovenia (Häuselmann et al, 2015) and in other karst areas of the World (Anthony and Granger, 2007;De Waele et al, 2012;Calvet et al, 2015;Granger et al, 2015;Columbu et al, 2021). Nonetheless, a set of conditions has to be satisfied to consider a cave as a potential site for sediment burial studies and to meaningfully link cave development to tectonic evolution: 1) The presence of quartz-rich terrains in the vicinity of the karst system, procuring the sediment source; 2) geological and environmental conditions able to transport these allogenic sediments from the source area to the karstified units; 3) the injection of the sediment into the phreatic or epiphreatic conduits, often developed close to the local water table.…”