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Thermal Spring Cones of the Tihany Peninsula
Abstract
Tihany is a spectacular volcanic peninsula of Lake Balaton, where more than a hundred cones deposited by thermal waters rise. The calcareous and siliceous building materials overlie basaltic tuff layers of maar-type volcanism. Their formation is related to the existence of an underlying magma chamber, which heated up the surrounding karst water. Hot karst waters spouted to the surface, where the dissolved silica and carbonates precipitated and deposited. During the stage of mofetta development hot spring water accumulated in ponds where organic limestone deposited. The further heating of karst water modified the composition of spring water and, in parallel, the composition of the cones. The mofetta stage was succeeded by the fumarola stage, when siliceous minerals precipitated from spring water and added further substances to the spring cone edifices. These minerals supplanted the calcites and filled cavities and cracks.
... There was mining activity on the sandstone fields of the Kál Basin. The Pannonian sand became cemented with the amorphous silica that had precipitated from the hot water of post-volcanic activity [22] on which a rich karren landscape developed [23]. In the area of the Szentbékálla block field, the material of blocks was partly exploited (during this, several karren features may have been destroyed) for millstone, while that of Kővágóőrs block field was used to build houses. ...
... Their number exceeds 100, and they are developing at present too. They are areic, aligned in rows, elongated, and grike-like, but there are also features with circular ground plans [23] (Figure 9). Where cover is present, they are inherited onto the cover, and they resemble subsidence dolines (pseudokarstic subsidence doline) in this case. ...
... Mining 2022, 2, FOR PEER REVIEW 10 Figure 8. Map of bed IV of Á rmin mine [28] Their development can be explained by the material equilibrium resulting from the mining of coal beds situated below each other. During this, the covering Eocene limestone warped, tension stress developed at the margin of the warping, which resulted in the development of tension grikes in the rock, then the cover collapsed into some grikes [23] ( Figure 10). Their development can be explained by the material equilibrium resulting from the mining of coal beds situated below each other. ...
This study describes the direct and indirect effects of mining on the karst of the Bakony Region. For this, the results of geological and mining research of the last century, the results of hydro-logical research of fifty years, as well as the investigations of several decades on the karst of the mountain region are used. Direct effects include the exploitation of filling materials (limonite, kaolinite, manganese ore, and bauxite) from paleokarst features, dolomite rubble, activities ex-ploring or destroying cavities, and the pollution of cavity systems with mining waste (dirt). An indirect effect is karst water extraction. Mining activities (coal and quarrying) resulting in the development of pseudokarstic features are also mentioned here. It can be stated that the effects on the karst and karst features may be permanent and even renewing, but the original state may also have returned or can be expected in the near future. Damages may be local or regional. A regional effect is the decrease in karst water level, which has the most significant effect on the environment, but it has already reached its original state by now.
... Among them are the landmarks of the region: Badacsony, Szent György-hegy and the former basalt quarry of Hegyestű, developed as an open-air geological museum [33]. The Tihany peninsula hosts other volcanism-related landforms such as old geyser cones and maars [34]. Other geomorphological phenomena include karst (with a few caves accessible to the public) and picturesque sandstone crags. ...
Geoparks are territorial organizations, whose primary aim is to foster sustainable local development through the promotion of geoheritage, geotourism and geoeducation. Sites of significant interest from the perspective of geosciences (geosites), as well as the overall geodiversity of the territory, are the fundamental resources for geopark activities. The distribution of these resources in the geographical space of geoparks may, however, be uneven. We first review four cases of UNESCO Global Geoparks from different European countries (Czechia, Germany, Hungary, Portugal) where such a situation occurs, with consequences on tourism development. Then, we place particular focus on an aspiring geopark of the Land of Extinct Volcanoes in SW Poland, providing evidence of its geoheritage and geodiversity values. The aspiring geopark integrates a mountainous–upland terrain and a lowland part, the latter with much fewer sites of interest and, apparently, fewer opportunities to successfully develop geotourism. Recognizing the challenges emerging from the non-uniform distribution of resources and learning from established geoparks, we highlight various opportunities to encourage (geo)tourism in the less diverse sections of the geoparks. Implementation of the ABC (abiotic–biotic–cultural) concept could be particularly helpful, as could be various events organized in these areas.
In this chapter, we describe the caves of the southwestern part of the Transdanubian Mountains, the Bakony Region and the Vértes Mountains, which we consider the most significant. We present the general genetic grouping of the caves and then characterize the major caves of the two mountains according to a system of criteria. Such as their geographical location, their host rock, the genetics and the speleothem of the caves.KeywordsBakony regionVértes mountainsKarstic cavePseudokarstic caveCave geneticsCave morphology
Two UNESCO Global Geoparks were established in Hungary. This paper presents the Bakony - Balaton Geopark, located in the western part of the country, predominantly within the Transdanubian Range. It includes uplands and low-elevation mountains of North Bakony, South Bakony, Balaton Uplands and Keszthely Mountains, with basins situated in between, as well as Lake Balaton itself. Geologically, the dominant part of the territory is underlain by Mesozoic sedimentary rocks, mainly limestones and dolomites. Other significant rock formations are Eocene limestones, Mio-Pliocene sediments of the Pannonian Sea and end-Neogene basalts. Karst phenomena, residual volcanic hills, fossil sinter cones and river gorges are the most characteristic geomorphologicalfeatures of the Geopark. Forty-five geosi- Tes have been recognized in the Geopark, although access facilities and interpretative content vary from site to site. The territory of the Geopark is also rich in cultural heritage and its southern part counts as the major tourist region of Hungary.
Two UNESCO Global Geoparks were established in Hungary. This paper presents
the Bakony – Balaton Geopark, located in the western part of the country, predominantly
within the Transdanubian Range. It includes uplands and low-elevation mountains of North
Bakony, South Bakony, Balaton Uplands and Keszthely Mountains, with basins situated in
between, as well as Lake Balaton itself. Geologically, the dominant part of the territory is
underlain by Mesozoic sedimentary rocks, mainly limestones and dolomites. Other significant
rock formations are Eocene limestones, Mio-Pliocene sediments of the Pannonian Sea and
end-Neogene basalts. Karst phenomena, residual volcanic hills, fossil sinter cones and river
gorges are the most characteristic geomorphological features of the Geopark. Forty-five geosites
have been recognized in the Geopark, although access facilities and interpretative content
vary from site to site. The territory of the Geopark is also rich in cultural heritage and its southern part counts as the major tourist
region of Hungary.
Keywords: Geopark, geoheritage, geosites, karst, volcanism, Transdanubian Range
The structure and microbiology of active travertines is described from Canary and Minerva springs, with emphasis on ‘shrubs’ growing in terracette pools. These dendritic growths of aragonite consist of intricately branched sprays containing thousands of radiating needles. Shrub microstructure could be explained by the principle of ‘Keimauslese” and the preferential elongation of sharp protuberances in a rapidly depositing environment.
The shrubs, and other active travertines, contain unicellular and filamentous bacteria. Estimates of total bacteria numbers ranged from 0.6−1.7 × 10 ⁵ mm ⁻³ but biomass was low, and always less than 1% of the travertine by weight. No evidence was found to indicate that bacteria played a role in shrub growth or morphology, but crystal trapping on bacterial strings may influence travertine fabrics on cascades. The shrubs are considered to have developed by inorganic processes, in hot spring waters supersaturated with aragonite.
Dolomite, despite its thermodynamic stability and abundance in the ancient rock record, is rarely found forming in Holocene environments. This enigma is frequently called the Dolomite Problem. The recent discovery of modern dolomite formation in Lagoa Vermelha, a shallow-water isolated coastal lagoon east of Rio de Janeiro, Brazil, provides a new environment to investigate the factors promoting dolomite precipitation under earth surface conditions. Lagoa Vermelha serves as a natural laboratory in which the dolomite formation process was studied using an integrated hydrologic, geochemical, and sedimentological approach. The results of this study indicate that Ca-dolomite precipitation occurs under anoxic hypersaline conditions within a black sludge layer directly overlying the water/se iment interface. With deposition, the dolomite undergoes an "ageing" process, whereby increased ordering of the crystal structure occurs. Both the initial precipitation and subsequent early diagenesis are strongly mediated by microbial activity. In fact, using sulfate-reducing bacteria cultured from Lagoa Vermelha samples, a highly ordered dolomite has been produced in the laboratory at low temperatures. These experimental results combined with the study of the natural environment mandate that a microbial factor be added to the list of factors capable of causing dolomite precipitation. Considering the Lagoa Vermelha system, we propose a new actualistic model for dolomite formation, which we call the microbial dolomite model.
The solubility of quartz in water was investigated by three sets of experiments 1. (1) at 1000 atm P H 2 O and temperatures ranging from 45° to 300°C 2. (2) at water pressures appropriate for the coexistence of three phases, gaseous water, liquid, and quartz, at temperatures ranging from 69° to 240°C 3. (3) a long term study of the dissolution of quartz grains which were continuously tumbled in water at room temperature. Saturated silica solutions in equilibrium with quartz were obtained in a few days at temperatures above 100°C. Equilibrium is shown by reproducible results for runs of different durations and by the precipitation of quartz from initially supersaturated solutions. The differential heat of solution derived from the data obtained at 1000 atm pressure is 5.38 kcal/mole. At room temperature and pressure, highly supersaturated silica solutions were obtained by continuously rotating quartz grains and water in plastic bottles at 75 rev/min. In one run the amount of silica in solution increased to a maximum value of 395 p.p.m. after 370 days. Another run reached 80 p.p.m. silica after 386 days and then dropped to 6 p.p.m. silica. It is concluded that quartz was precipitated at room temperature from this supersaturated solution and that 6 p.p.m. is essentially the true solubility of quartz at 25°C. In contrast to the runs rotated at 75 rev/min, quartz grains, and also silica glass grains, continuously rotated in water at rev/min, each contributed less than 1 p.p.m. colorimetric silica into solution after 1 year. Thus, vigorous agitation of the liquid is necessary to remove dissolved silica from the vicinity of surfaces of both quartz and glass. Two significant factors that may have contributed to the formation of supersaturated silica solutions in the runs rotated at 75 rev/min at room temperature are 1. (1) stresses and structural irregularities at the surfaces of the crushed quartz grains, which contributed silica into solution more readily than well crystallized quartz 2. (2) the very slow rate at which dissolved silica polymerizes to species appropriate to act as nuclei for quartz growth. At the termination of the runs rotated at 75 rev/min, spikelike projections were present on many of the quartz grains. These are interpreted as indicating that abrasion was not the dominant cause for the great supersaturations which were obtained.
The Petrogenetic Classification of carbonate rocks is a complex but flexible nomenclatorial system developed in an effort to organize some of the descriptive properties of this extremely complicated group of rocks into a systematic and genetically significant relationship. The properties recognized in this classification are grouped under three headings: A) Compositional elements, B) Texture, and C) Chemical composition. Winnowing, and the roundness,sorting, and size of all constituents of the rock that have been physically transported in the solid state are measured and the overall maturity ascertained. Together these properties, briefly stated, make up the first element, texture, of a tripartite "Complete Carbonate Rock Name." The second term, Main Rock Name, is based on the relativ proportions of carbonate compositional elements present in the rock under consideration. Carbonate constituents recognized in this classification are located at the poles of a ternary diagram in the following manner. All microcrystalline and sedentary fossil constituents are counted under Pole I of the triangular diagram. Under Pole II are located all allochemical elements (pellets, oolites, intraclasts, and bioclasts), and under Pole III--all pore filling cement, recrystallized and replaced minerals. The third and last part of the Complete Carbonate Rock Name is the chemical composition, commonly expressed as a calcium-to-magnesium (or Mg/Ca) ratio. The chemical make-up may also be presented as percent oxides, or mineral percentages if normative calculations are preferred. Although this classification is basically petrographic and designed for laboratory utilization, emphasis on the textural term at the expense of less easily determined compositional elements can make it a useful field tool. Application of this system to problems requiring detailed consideration of variability, rather than to studies of a reconnaissance nature, will constitute the most efficient use of the classification. Carbonate rock terminology utilized in this paper is defined and discussed in some detail, and expansion for special-purpose use is explained. Inclusion of porosity data in the textural term, for example, and correlation of pore size distribution with petrographic type may aid in oil reservoir valuation and stimulation studies, as well as gas storage problems. Similarl , addition of a term based on chemical analysis data to the petrographic name may prove valuable in the exploitation of limestone as an economic mineral.
A late Miocene (7.56 Ma) maar volcanic complex (Tihany Maar Volcanic Complex Ð TMVC) is preserved in the Panno-nian Basin and is part of the Bakony±Balaton Highland Volcanic Field. Base surge and fallout deposits were formed around maars by phreatomagmatic explosions, caused by interactions between water-saturated sediments and alkali basalt magma carrying peridotite lherzolite xenoliths as well as pyroxene and olivine megacrysts. Subsequently, nested maars functioned as a sediment trap where deposition built up Gilbert-type delta sequences. At the onset of eruption, magma began to interact with a moderate amount of groundwater in the water-saturated sand. As eruption continued phreatomagmatic blasts excavated down-ward into limestones, providing access to abundant karst water and deeper to sandstones and schist both providing large amount of fracture-®lling water. At the surface, thiwet' eruption led to the emplacement of massive tuff breccias by fall, surge, mud¯ow and gravity ¯ow deposition. The nature of the TMVC maar eruptions and their deposits appears to depend on the hydrological condition of the karst and/or fracture-®lling aquifer, which varies seasonally with rainfall and spring runoff. The West and East Maar volcanoes of TMVC are interpreted to represent low water input from the karst and/or fracture-®lling aquifersummer vent'), whereas the East Maar is interpreted to have formed when abundant karst and/or fracture-®lling water was availablespring vent'). q 2001 Elsevier Science B.V. All rights reserved.
A general review of the nature and classification of tufas is presented and the available literature is summarised. An attempt is made to standardise the terminology currently in use and to distinguish clearly between ambient temperature deposits (tufas), thermal deposits (travertines) and speleothems. Consideration is also presented of the physico-chemical and biological processes, often acting together, which are responsible for the precipitation of freshwater calcium carbonate within tufa systems. These processes appear to be climatically controlled. Therefore, tufas may be of value in palaeo-environmental reconstruction, especially if intercalated with peaty material. While the majority of tufa deposits are of post-glacial age some of the most spectacular carbonate precipitates are thermal travertines.The second part of the paper deals with a world-wide survey of the principal deposits of tufa and travertine. Space prevents a fuller account of the European deposits and the reader is preferred to Pentecost (1995) for a wide range of specific examples from Europe and Asia Minor.
Published 3.6. Fisica del vulcanismo