Speleogenesis in a lens of metamorphosed limestone and ankerite: Ochtiná Aragonite Cave, Slovakia

Abstract

The Ochtiná Aragonite Cave (Western Carpathians) represents an unique natural phenomenon. It originated under particular lithological and hydrogeological conditions of the Ochtiná Karst in which several isolated lenses of Paleozoic crystalline limestone (marbles), partly metasomatically altered to ankerite, are enclosed by phyllites. Meteoric water seepage through non-carbonate rocks dissolved limestone and caused the oxidation of ankerite to Fe oxyhydroxides. Carbon dioxide produced during ankerite oxidation enhanced limestone dissolution. The maze cave consists of parallel fault-controlled linear passages and chambers interconnected by transverse horizontal passages. Phreatic and epiphreatic solution morphologies resulted from slowly moving or standing water. These include flat ceilings (Laugdecken), facets (planes of repose, Facetten), lateral notches, convection ceiling cupola-shaped depressions, and spongework-like hollows. Flat ceilings were developed in several altitude positions, each of them probably closely below the slightly oscillated water table. Primary phreatic cupola-shaped depressions, truncated by flat ceilings, represent relics of the oldest cavities (pre-Quaternary? to Early Pleistocene). Inward-sloping smooth facets were not developed only in passages with flat ceilings, but also in the passages and halls with a vaulted ceiling. The asymmetrical shape of cusped depressions above the facets were documented in detail by a high-resolution cave topography with terrestrial laser scanning and digital photogrammetry. Middle–Late Pleistocene accumulation phases, identified by magnetostratigraphy of cave sediments and U-series dating of speleothems, are associated with phreatic and later epiphreatic development. The deposition on the bottom bedrock began before 1.8 Ma. The Brunhes/Matuyama boundary (0.773 Ma) and Jaramillo magnetozone (0.990–1.071 Ma) were recorded in the profile in the Oválna chodba Passage. Slow depositional rate (~0.09 cm/kyr) calculated from magnetostratigraphy resulted from slow water movement in confined conditions in marbles completely enclosed by phyllites and no direct relation to the surface. Only occasionally turbid water was loaded in extremely fine-grained infiltration material and autochthonous Fe oxyhydroxides. The depositional rate in Mn-rich layer was much slower (~0.03 cm/kyr). Additional U-series dating confirmed that old aragonite generations (with ages about 500–450 ka and 143–121 ka) were partly corroded by repeated floods during Late Pleistocene humid episodes. Aragonite younger than 13.5 ka is not corroded.

Cross-Polarized SfM Photogrammetry for the Spatial Reconstruction of Challenging Surfaces, the Case Study of Dobšiná Ice Cave (Slovakia)

“…Traditional geodetic methods are nowadays well established and commonly used [39][40][41], but they do not always allow a sufficiently accurate capture of cave spaces or are time consuming. Therefore, in recent years, technologies such as TLS and digital photogrammetry have also come to the fore in the field of cave mapping, allowing the surveying of even larger cave systems with high detail and accuracy in a short time [22,23,25,58,59].…”

Reconstruction of ancient drainage in the contact karst of the Harmanecká dolina Valley, Western Carpathians, based on mineralogical data from the allochthonous sediments and isobase geomorphometry

“…Cave could have started to form already during the dissection of this older planation surface by primary shallow valleys and the subsequent lateral enlargement of their floors, before the main uplift of the surrouding area and cutting of the valleys. Several caves in the Western Carpathians, which are at approximately the same or similar relative elevation above the current valley floor, were formed before the Late Pliocene (Bella, 2022); the caves of Pliocene age occur at a lower relative elevation above the current valley floor (e.g., Bella et al, 2011Bella et al, , 2014. The different relative elevations may have been caused by different neotectonic uplift (Bezák et al, 2004;Maglay et al, 1999a), but this issue will probably not be resolved until dating the age of burial of the allochthonous cave sediments.…”

Review of Photogrammetric and Lidar Applications of UAV

“…The deployment of TLS and the SfM photogrammetric method has also been successful in the documentation of underground cave spaces [6,74,75] to create 3D models of them. The authors of [6] used the SfM photogrammetric method to take images with a Pentax K-5 DSLR digital camera with a Pentax SMC DA lens in Ochtiná Aragonite Cave, Slovakia.…”