Mineral deposits in the Cupp‐Coutunn/Promeszutochnaya cave system (Turkmenia, central Asia) record a phase of hydrothermal activity within a pre‐existing karstic groundwater conduit system. Hydrothermal fluids entered the caves through fault zones and deposited sulphate, sulphide and carbonate minerals under phreatic conditions. Locally, intense alteration of limestone wall rocks also occurred at this stage. Elsewhere in the region, similar faults contain economic quantities of galena and elemental sulphur mineralization. Comparisons between the Pb and S isotope compositions of minerals found in cave and ore deposits confirm the link between economic mineralization and hydrothermal activity at Cupp‐Coutunn. The predominance of sulphate mineralization in Cupp‐Coutunn implies that the fluids were more oxidized in the higher permeability zone associated with the karst aquifer. A slight increase in the δ34S of sulphate minerals and a corresponding δ34S decrease in sulphides suggest that partial isotopic equilibration occurred during oxidation. Carbonate minerals indicate that the hydrothermal fluid was enriched in 18O (δ18OSMOW ∼ + 10‰) relative to meteoric groundwater and seawater. Estimated values for δ13CDIC (δ13CPDB ∼ − 13‰) are consistent with compositions expected for dissolved inorganic carbon (DIC) derived from the products of thermal decomposition of organic matter and dissolution of marine carbonate. Values derived for δ13CDIC and δ18Owater indicate that the hydrothermal fluid was of basinal brine origin, generated by extensive water–rock interaction. Following the hydrothermal phase, speleothemic minerals were precipitated under vadose conditions. Speleothemic sulphates show a bimodal sulphur isotope distribution. One group has compositions similar to the hydrothermal sulphates, whilst the second group is characterized by higher δ34S values. This latter group may either record the effects of microbial sulphate reduction, or reflect the introduction of sulphate‐rich groundwater generated by the dissolution of overlying evaporites. Oxygen isotope compositions show that calcite speleothems were precipitated from nonthermal groundwater of meteoric origin. Carbonate speleothems are relatively enriched in 13C compared to most cave deposits, but can be explained by normal speleothem‐forming processes under thin, arid‐zone soils dominated by C4 vegetation. However, the presence of sulphate speleothems, with isotopic compositions indicative of the oxidation of hydrothermal sulphide, implies that CO2 derived by reaction of limestone with sulphuric acid (‘condensation corrosion’) contributed to the formation of 13C‐enriched speleothem deposits.

Abstract:Modeling landscape evolution requires quantitative estimates of erosional processes. Dating 12 erosional landscape features such as escarpments is usually difficult because of the lack of datable deposits. 13Some escarpments and valley margins are associated with the formation of mass-movement caves, sometimes 14 known as 'gull' or 'crevice' caves, which are typically restricted to within 0.5 km of the valley margin or scarp 24Quantifying rates of landscape processes is an essential requirement for constructing, validating and 25 constraining increasingly sophisticated landscape evolution models (Pazzaglia, 2003; Tucker and 26 Hancock, 2010). With quantitative data, rates of landform development can be evaluated, enabling 27 the relative importance of geomorphological processes to be established and facilitating the 28 development of more realistic landscape evolution models. Moreover, quantification is extremely 29 important in predictive work, as it is required for estimating the impact of future global climate 30 change. Whilst some geomorphological processes can be easily quantified, such as the rate of valley 31 incision by dating river terrace sequences (Maddy, 1997; Maddy et al., 32 2000;Maddy et al., 2001), dating cave levels in carbonate terrains (Farrant et al., 1995; Palmer, 33 2007), or by dating other alluvial materials such as tufa (Banks et al., 2012), deducing the timing and 34 rates of other processes such as valley widening and escarpment ( or 'scarp') retreat is harder to 35 determine. However, both rates of valley incision and scarp retreat are required to understand how 36 valleys evolve. Do they develop by progressive incision and valley widening through fluvial channel 37 migration and concurrent hill slope retreat or is the gross relief generated 'in-situ' by the progressive 38 removal of the more erodible lithologies over multiple glacial-interglacial cycles? In the latter 39 scenario, valley width is influenced more by lithological heterogeneity and variable susceptibility to 40 periglacial weathering (Murton and Belshaw, 2011) fissures may contain speleothem deposits which can be precisely dated using uranium series 53 methods (Lenart and Pánek, 2013). As the gull-caves can only develop after a scarp has formed, the 54 basal age of the oldest speleothems within them provide a minimum age for cave inception and 55 hence scarp formation. Moreover, as the gull-caves only form close to the scarp edge, they can be 56 used to determine a chronology of scarp retreat. Taken together with rates of valley incision 57 determined from fluvial terraces, the spatial and temporal pattern of valley development and scarp 58 formation can be resolved and models of regional landscape evolution erected. 59The study area 60In this paper, we use the lower Severn valley and the Cotswold Hills in southern England (Figure 1) Triassic and Lower Jurassic (Lias Group) mudstones ( Figure 1) that occupy the core of this basin. The 77 eastern side is marked by the prominent escarpment of the Cotswol...

UDC: 551.435.8(410.1)"627" Charles A. Self & Graham J. Mullan: Rapid Karst development in an English Quartzitic SandstoneMany karst features, including caves, have been found in the outcrop of the Fell Sandstone in Northumberland, England. These features are Holocene in age, since the area was glaciated during the Devensian cold stage. It is suggested that tectonic inception and selective arenisation of rock faces that remain damp are responsible for these karst features. The limitations of textbook definitions of the term karst are discussed.

Siga se izloča kot sekudarni jamski mineral, njeno notranjo zgradbo lahko preučujemo z mineraloškimi metodami. Ontogenija mineralov je metoda, razvita v Rusiji, pri kateri so posamezni kristali in njihovi agregati preučevani kot fi zična telesa in ne kot mineralna vrsta. Članek podaja kratek vodnik po terminologiji ontogenije s poudarkom na jamskih mineralih.Speleothems are secondary cave mineral deposits whose internal organization can be studied by mineralogical techniques. The ontogeny of minerals is a technique developed in Russia whereby individual crystals and their aggregates are studied as physical bodies rather than as mineral species. This paper gives a concise guide to the terminology of ontogeny, as applied to cave mineral deposits.