First Folia Occurrence From Greece
Publication Date: 2026/09/01
Publication Volume: Journal of Cave and Karst Studies 88 #3
DOI Link: https://dx.doi.org/10.4311/2025ES0118
ABSTRACT:
Folia are among the rarest speleothems, known from 28 caves worldwide, and their origin is still a matter of ongoing scientific discussion and investigation. This study presents the first documented occurrence of folia in a Greek cave (Stafni Cave, Northern Greece), thus expanding the known geographical distribution and morphogenetic spectrum of these formations. The cave exhibits a morphologically complex setting with clear markers of water table oscillations, such as notches and cupolas, and unique depositional sequences that include folia, cave rafts, and associated pool infills. Notably, the folia occur stratigraphically beneath the rafts, suggesting progressive lowering of the water table. The folia deposit display classical “leaf-like” laminae. The preservation of these deposits below a thick layer of cave rafts that form a pseudo-floor suggests that their apparent rarity may reflect limited accessibility rather than true scarcity. Morphological features of the cave are consistent with speleogenetic models involving sulfuric acid speleogenesis (SAS), including sulfate mineral occurrences and proximity to active hydrogen sulfide-rich Na–Cl thermal springs. Folia morphology and formation are discussed. This study provides 3D documentation of a folia sample and lays the groundwork for future mineralogical and geochemical analyses aimed at testing these formation models. The findings contribute to ongoing debates on folia genesis and highlight the role of hypogene processes in cave evolution.
SIMPLE LANGUAGE SUMMARY:
Folia are a very rare kind of cave formation. They look like stacked, overlapping leaves or small shelves of mineral on cave walls, and they are known from only 28 caves in the whole world. Scientists still disagree about exactly how they form. This study reports the first folia ever found in Greece, in Stafni Cave in northern Greece. The cave shows clear signs that the water level inside it once rose and fell, such as notches cut into the walls and dome-shaped hollows in the ceiling. The folia lie underneath a thick layer of “cave rafts,” thin mineral sheets that form on the surface of still water and then sink. This order suggests that the water level in the cave slowly dropped over time. Because the folia were hidden under this layer, they may be more common than people think, just hard to reach and see. The cave seems to have been carved by acid that formed from hydrogen sulfide gas linked to nearby hot springs, rather than by ordinary rainwater. The authors also made a 3D model of a folia sample to help future studies of how folia form.
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