Bacterial influence on speleothem oxygen isotope composition : an example based on cave pisoids from Perlová Cave (Slovakia)

The origin of recently growing irregular cave pisoids in Perlova Cave (Velká Fatra Mts, Slovakia) seems to be due to the activity of hydrogen-oxidizing bacteria. Several samples of water and freshly deposited calcite from cave pisoids were analysed for stable oxygen isotope ratios. The obtained values were checked using the O’Neil equation. Almost all the calcite samples display values more positive than their calculated counterparts. This phenomenon is ascribed to a fractionation process mediated by bacteria. The light isotope of oxygen is preferentially taken up by the hydrogen-oxidizing bacteria. It causes the relative enrichment in the heavy isotope in the bacterias’ surroundings, which is recorded in the calcite precipitated around the bacterial cells

Needle-fibre calcite and nanofibres as components of holocene fissure-filling carbonates in southern Poland

The article deals with the carbonates, filling fissures in limestone bedrock and presently exposed in a south-facing rock wall of Kramnica hill (Pieniny Klippen Belt, southern Poland). The carbonates are composed of (i) needle-fibre calcite crystals, (ii) carbonate nanofibres, (iii) carbonate nanoparticles, and (iv) micrite and sparite calcite crystals. Detrital grains from the carbonate bedrock occur subordinately. The spatial relationships of the components give documentation that the nanofibres were formed simultaneously with or slightly later than the needle-fibre calcite crystals. There exists a continuous chain of forms from nanoparticles to elongated nanofibres. This, in turn, indicates that all the above morphological forms are related genetically. In relatively wide fissures, the carbonates studied formed stepped microterracettes, similar to those of speleothems, mainly of moonmilk type. Conversely, narrow fissures are completely filled with carbonates, which display parallel lamination. The carbonates were formed in the late Holocene. However, "dead carbon effect" precludes the possibility of any precise dating of them. Their \sigma13C and \sigma18O values are in ranges from -5.1‰ to -3.8‰ and from -6‰ to -4.7‰, respectively. The carbonates studied bear a strong resemblance to soil and spelean, moonmilk-type carbonates. This indicates that continuity exists between the depositional environments of soil and spelean carbonate

Morphotype variation of orthophragminids as a palaeoecological indicator : a case study of Bartonian limestones, Pod Capkami Quarry, Tatra Mts, Poland

Nummulites-Discocyclina bioclastic packstone and Discocyclina rudstone occur in the transgressive sequence of the Middle–Upper Eocene deposits in the Tatra Mts. The succession of the studied facies is a direct response to a rapid environmental change, related to progressive deepening. Facies transition from Nummulites- Discocyclina bioclastic packstone of proximal mid-ramp to Discocylina rudstone of distal mid- and outer-ramp is an exemplary record of a deposition during deepening conditions. Increasing of diversity of the genus Discocyclina, decreasing of diversity of other foraminifera up the section and vertical variation of orthophragminid mor- photypes from the ovate- through saddle- to the disc-shaped tests are related to deepening and shadowing of the depositional environment

Origin of calcite-cemented Holocene slope breccias from the Długa Valley (the Western Tatra Mountains)

New locality of slope breccias was found in the Western Tatra Mts. It occures in the Długa Valley on a steep slope of ravine beneath the belt of Jurassic radiolarite cliffs. The brecccia consists of angular clasts of radiolarite bound with calcite cements. Void spaces between the clasts contain shells of Holocene snails. The cements are built of columnar crystals composed of acicular subcrystals and of skeletal crystals. The crystals grew rapidly from supersaturated solution due to CO2 degassing. Cementation occurred in vadose conditions in the Atlantcic Phase soon after the scree formation

Artesian origin of a cave developed in an isolated horst : a case of Smocza Jama (Kraków Upland, Poland)

The cave of Smocza Jama located in the centre of Kraków is developed in the Wawel Horst built of Upper Jurassic limestone and surrounded by grabens with Miocene clays. The cave is composed of two series: the old one has been known for ages and the new one was discovered when an artificial shaft was mined in 1974. The new series comprises small chambers separated by intervening thin walls while the old series consists of three connected together spatial chambers. The cave abounds in extensively developed solution cavities – cupolas and ceiling pockets. The internal fine-grained deposits, predominantly representing clay fraction are built of illite, mixed layer illite-smectite, kaolinite and iron oxides. They are probably the residuum after dissolution of Jurassic limestone. The cave originated in phreatic condition due to water input from below. The new series represents juvenile stage of cave evolution. The water rose through fissure-rifts located in chamber bottoms, circulated convectionally within particular chambers, finally led to bleaching of intervening walls, and hence to connection of the neighbouring chambers. The evolution of the old series is far more advanced. The rounded solution cavities imply that the cave was formed by water of elevated temperature. The lack of coarse-grained fluvial deposits, Pleistocene mammal remains and Palaeolithic artefacts prove that the cave was isolated since its inception till Holocene time. The cave originated due to artesian circulation, when the Wawel Horst was covered by imper- meable Miocene clays. A foreland basin with carbonate basement, filled with fine-grained molasse-type deposits seems to be particularly favourable for the development of artesian caves

New data on pre-Eocene karst in the Tatra Mountains, Central Carpathians, Poland

Sparry limestone, ferruginous muddy limestone and limestone breccia have been found in the Western Tatra Mts. They occur within Jurassic rocks of the Choč Nappe just below red conglomerates of probable Eocene age. The deposits found bear strong resemblance to the infill of subterranean karst forms. They differ significantly from Quaternary karst deposits of the Tatra Mts. The δ18O values of spelean carbonates suggest crystallisation at relatively high temperatures (over 20°C) whereas their relatively negative δ13C values imply the presence of soil-derived CO_2 linked with vegetation dominated by C3 pathway plants. The karst forms and their infill were formed before the Eocene transgression, which shows unequivocally that the Tatra Mts. were subjected to karstification at that time