Travertine Research Articles

Various morphological types of thermogenic travertines in Northern Euboea and Eastern Central Greece

In the northern part of Euboea Island and the neighbouring part of the mainland in eastern central Greece, many hot springs exist and some of them create travertine deposits. The objectives of the study were to identify and describe the various morphological types of the thermogenic travertine deposits. The samples were studied at the lab with optical microscopy, X-Ray Diffraction, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), in order to verify their main mineralogical composition and their mineral chemistry. The studied travertine deposits consist mainly of aragonite and calcite, but in some cases, as main mineral phase, an amorphous hydrous ferric oxyhydroxide (ferrihydrite), was also identified. The morphological types that were identified were of great variety (mounds, travertine caves etc) and some of them were quite rare (cascades, remora etc). Morphological data and field observations suggest possible inorganic and organic controls on carbonate precipitation. Similar morphological types have been recorded at large travertine systems like Mammoth hot springs, Yellowstone National Park in USA and at Rapolano Terme, Italy.

Effect of different drying methods on the mechanical behavior and the microstructure of an Algerian compacted limestone crust

This experimental work aims to better understand the hardening process of limestone tuff after compaction when water content varies. Indeed, the pavements built with wet calcareous crust or tuff are hardened by the effect of compaction followed by water evaporation but this cohesion after compaction disappears completely by total saturation. In order to classify the materials according to geotechnical specifications related to limestone crusts, tuff from Faidh el Botma area was studied by following the change of compressive strength measured on specimens prepared at different water contents and stored for several days either under air (for fast drying) or in non-hermetic bags (for slow drying). The first series of specimens appeared more resistant than the second one. As explanation of the hardening, the possible precipitation of new phases such as carbonate during the fast drying is discussed based on chemical and microstructural observations as well as the effect of suction than could change the microstructural arrangement of tuff particles when the moisture content varies.

Controls on the stable isotope compositions of travertine from hyperalkaline springs in Oman: Insights from clumped isotope measurements

Carbonate formation at hyperalkaline springs is typical of serpentinization in peridotite massifs worldwide. These travertines have long been known to exhibit large variations in their carbon and oxygen isotope compositions, extending from apparent equilibrium values to highly depleted values. However, the exact causes of these variations are not well constrained. We analyzed a suite of well-characterized fresh carbonate precipitates and travertines associated with hyperalkaline springs in the peridotite section of the Samail ophiolite, Sultanate of Oman, and found their clumped isotope compositions vary systematically with formation environments. Based on these findings, we identified four main processes controlling the stable isotope compositions of these carbonates. These include hydroxylation of CO2, partial isotope equilibration of dissolved inorganic carbon, mixing between isotopically distinct carbonate end-members, and post-depositional recrystallization. Most notably, in fresh crystalline films on the surface of hyperalkaline springs and in some fresh carbonate precipitates from the bottom of hyperalkaline pools, we observed large enrichments in Δ47 (up to ∼0.2‰ above expected equilibrium values) which accompany depletions in δ18O and δ13C, yielding about 0.01‰ increase in Δ47 and 1.1‰ decrease in δ13C for every 1‰ decrease in δ18O, relative to expected equilibrium values. This disequilibrium trend, also reflected in preserved travertines ranging in age from modern to ∼40,000years old, is interpreted to arise mainly from the isotope effects associated with the hydroxylation of CO2 in high-pH fluids and agrees with our first-order theoretical estimation. In addition, in some fresh carbonate precipitates from the bottom of hyperalkaline pools and in subsamples of one preserved travertine terrace, we observed additional enrichments in Δ47 at intermediate δ13C and δ18O, consistent with mixing between isotopically distinct carbonate end-members. Our results suggest that carbonate clumped isotope analysis can be a valuable tool for identifying and distinguishing processes not readily apparent from the carbonate bulk stable isotope compositions alone, e.g., kinetic effects or mixing of different carbonate end-members, which can significantly alter both the apparent formation temperatures and apparent radiocarbon ages. The isotope trends observed in these travertine samples could be applied more broadly to identify extinct hyperalkaline springs in terrestrial and extraterrestrial environments, to better constrain the formation conditions and post-depositional alteration of hyperalkaline spring carbonates, and to extract potential paleoclimate information.

A field study of thermal and hygric inertia and its effects on indoor thermal comfort: Characterization of travertine stone envelope

Energy consumption in Algerian residential buildings is very high, especially during the summer season. The thermal inertia of the building envelope may contribute to improving the thermal comfort and even lead to replacing air conditioning systems. This passive process is typically associated with an external wall made of heavy construction counteracting the strong changes in temperature. In reality, other parameters are acting to influence this property. The present paper describes a three-year field case study devoted to monitoring an inhabited stone house, dating from the colonial era in the town of Guelma (Algeria), exposed to a hot and sub-humid climate. Results from the monitoring program indicate that the passive process called “hygric inertia”, in association with the “thermal inertia” of porous and hygroscopic local materials adapted to the regional climate, has led to improving thermal comfort and humidity regulation: a drop of more than 14.5 K was recorded. Permeable coverings may have exerted an impact on indoor hygrothermal conditions, in generating a temperature drop of 1.5 K, which corresponds to a 31.5% energy savings rate. Other parameters, including the construction system, are also involved in stabilizing the indoor temperature and moisture. The results of a modeling run using the TRNSYS software showed good agreement between simulated and measured air temperature readings, which validates the effect of thermal inertia. The two humidity models implemented in this software do not take moisture transfers in the wall into account. The low spreads in relative humidity measurements however have confirmed that the effect of hygric inertia on ambient temperature inside this house is not as significant as that of thermal inertia. It can be concluded that a 100% hygroscopic house does not actually exist.

Tectonics, hydrothermalism, and paleoclimate recorded by Quaternary travertines and their spatio-temporal distribution in the Albegna basin, central Italy: Insights on Tyrrhenian margin neotectonics

The Neogene–Quaternary Albegna basin (southern Tuscany, central Italy), located to the south of the active geothermal field of Monte Amiata, hosts fossil and active thermogene travertine deposits, which are used in this study to reconstruct the spatio-temporal evolution of the feeding hydrothermal system. Travertine deposition is controlled by regional tectonics that operated through distributed N-S– and approximately E-W–striking transtensional fault arrays. The geochronological data set ( 230 Th/ 234 U, uranium-series disequilibrium) indicates a general rejuvenation (from >350 to 13 C and positive δ 18 O trends with younger deposition ages and lower depositional elevations provide evidence for a change in space and time of the hydrothermal fluid supply, suggesting a progressive dilution of the endogenic fluid sources by increasing meteoric water inputs. Comparison with paleoclimate records suggests increased travertine deposition during humid interglacial periods characterized by highstands of the water table. Travertine deposits of the Albegna basin record the interactions and feedbacks among tectonics, hydrothermalism, and paleoclimate within a region of positive geothermal anomaly during the Quaternary. Our study also sheds light on the neotectonic evolution of the Tyrrhenian margin of central Italy, where hydrothermalism has been distributed along margin-transverse structures during the Pleistocene and Holocene. It is hypothesized that originally upper-crustal, margin-transverse faults have evolved to through-going crustal features during the Quaternary, providing structurally controlled pathways for hydrothermal fluids. We suggest that this was the consequence of a change in the relative magnitude of the principal stress vectors along the Tyrrhenian margin that occurred under a regional stress field dominated by a continuous extensional regime.

Growth of a Pleistocene giant carbonate vein and nearby thermogene travertine deposits at Semproniano, southern Tuscany, Italy: Estimate of CO2 leakage

A giant carbonate vein (≥50m thick; fissure ridge travertines) and nearby travertine plateaus in the Semproniano area (Mt. Amiata geothermal field, southern Tuscany, Italy) are investigated through a multidisciplinary approach, including field and laboratory geochemical analyses (U/Th geochronology, C, Nd, O and Sr isotope systematics, REE abundances, and fluid inclusion microthermometry). The main aim of this work is to understand: (1) modes and rates for the growth of the giant vein and nearby travertine deposits within a Quaternary volcano-tectonic domain; (2) implications in terms of the CO2 leakage; and (3) possible relationships with Quaternary paleoclimate and hydrological oscillations. Results show that the giant vein was the inner portion of a large fissure ridge travertine and grew asymmetrically and ataxially through repeated shallow fluid injections between >650 and 85ka, with growth rates in the 10−2–10−3mm/a order. The giant vein developed mainly during warm humid (interglacial) periods, partially overlapping with the growth of nearby travertine plateaus. Estimated values of CO2 leakage connected with the vein precipitation are between about 5×106 and 3×107mola−1km−2, approximately representing one millionth of the present global CO2 leakage from volcanic areas. Temperature estimates obtained from O-isotopes and fluid inclusion microthermometry indicate epithermal conditions (90–50°C) for the circulating fluid during the giant vein growth, with only slight evidence of cooling with time. Geochemical and isotope data document that the travertine deposits formed mainly during Pleistocene warm humid periods, within a tectonically-controlled convective fluid circuit fed by meteoric infiltration and maintained by the regional geothermal anomaly hosted by the carbonate reservoir of the Mt. Amiata field.

The effects of freeze–thaw (F–T) cycles on the Gödene travertine used in historical structures in Konya (Turkey)

Travertine, a building material used around the globe for its decorative and easy-to-be-worked features from past to present, is naturally exposed to the freeze–thaw (F–T) process in cold regions in winters. As a result of this process, building stones deteriorate partially or completely. The greatest factor during the F–T process is the existence of water. The water contained in the body (in discontinuities and pores) of a building stone freezes along with the fall of temperature below 0°C. Following freezing, the volume of water contained in discontinuities and pores increases. New fractures develop on the surfaces of pores as a result of outward pressure due to this increase in volume. As the temperature drops below 0°C, the volume of water increases again, due to freezing. This process repeats itself with the decrease and increase in temperature and causes undesired deteriorations in the bodies of stones.This issue is quite important from the point of view of preservation and restoration of historical buildings, and foreseeing the effects of the F–T process on new buildings to be designed.In this study, the effects of the F–T process on Gödene travertine were investigated. Gödene travertine is a stone that has been widely used in historical buildings in Konya, a city that also covers Çatal Höyük, which is known as one of the oldest human settlements in Anatolia. The stone is still being used in buildings constructed in the region. Fresh travertine stones obtained from the quarry were exposed to freeze and thaw cycles in different numbers. Values of porosity (n), uniaxial compressive strength (σu), point load strength (Is(50)), Brazilian tensile strength (σt), Böhme abrasion loss (BA) and P wave velocity (Vp) were statistically evaluated and thus, the effects of the number of cycles on basic physical and mechanical characteristics of the Gödene stone were investigated. Furthermore, deteriorations that took place in historical structures in the region were case-studied.

Comparison of Artificial Stone Made from Sludge Stone with Travertine Stone Waste of Stone Cutting Factory

Using from Stone factory waste was obtained a high-quality artificial stone. The basis of these stones is factory waste; i. Sludge stone cutting factory (SSCF) and ii. The pure waste of travertine stone (WTS).Basic formulation of artificial stone is SSCF or WTS, 50 wt.% of sludge stone is cement, 12 wt.% of cement is unsaturated polyester resin (UPR), 25 wt.% is water, 7 wt.% is the filler consists of micro-silica and different amounts of TiO2-NP. Artificial stones production with this method than to natural stone are pressure-resistant, highly flexible, resistant to freezing and scrapes, lightweight, ability to cut and form the low thickness and is self-cleaning.Artificial stones made of SSCF in all mechanical properties are better than WTS, because the density of the SSCF is much greater than the powder prepared from WST and SSCF is all wastewater leaving the factory after cutting various types of decorative stones. As well as for preparation of artificial stone from WTS should be done once milled and powdered waste, this step increases the cost of them.Keywords: Artificial stone; Sludge stone cutting factory (SSCF); Waste of travertine stone (WTS); Nanoparticles of TiO2; Cement.

Hidden sinkholes and karst cavities in the travertine plateau of a highly-populated geothermal seismic territory (Tivoli, central Italy)

Sinkholes and other karst structures in settled carbonate lands can be a significant source of hazard for humans and human works. Acque Albule, the study area of this work, is a Plio-Pleistocene basin near Rome, central Italy, superficially filled by a large and thick deposit of late Pleistocene thermogene travertine. Human activities blanket large portions of the flat territory covering most evidence from geological surface processes and potentially inducing scientists and public officials to underestimate some natural hazards including those connected with sinkholes. To contribute to the proper assessment of these hazards, a geomorphologic study of the basin was performed using digital elevation models (DEMs), recent aerial photographs, and field surveys. Historical material such as old aerial photographs and past geomorphologic studies both pre-dating the most part of quarrying and village building was also used together with memories of the elderly population. This preliminary study pointed out the presence of numerous potentially active sinkholes that are at present largely masked by either quarrying or overbuilding. Where this first study pointed out the apparent absence of sinkholes in areas characterized by high density of buildings, a detailed subsurface study was performed using properly-calibrated electrical resistivity tomography (ERT) and dynamic penetration measurements (DPSH), together with some borehole logs made available from the local municipality. This second study highlighted the presence of sinkholes and caves that are, this time, substantially hidden to the resolution of standard methods and materials such as aerial photographs, DEMs, and field surveys. Active sinkhole subsidence in the Acque Albule Basin may explain, at least in part, the frequent damages that affect numerous buildings in the area. The main conclusion from this study is that the mitigation of sinkhole hazard in highly populated areas has to pass through a thorough search of (hidden) sinkholes that can be masked by the Anthropocenic molding and blanketing of the territory. For these purposes, data from historical (pre-Anthropocene) documents as well as, where possible, subsurface investigations are fundamental.

Depositional architecture of a mixed travertine-terrigenous system in a fault-controlled continental extensional basin (Messinian, Southern Tuscany, Central Italy)

The extensional Neogene Albegna Basin (Southern Tuscany, Italy) includes several thermogene travertine units dating from the Miocene to Holocene time. During the late Miocene (Messinian), a continental fault-controlled basin (of nearly 500-km2 width) was filled by precipitated travertine and detrital terrigenous strata, characterized by a wedge-shaped geometry that thinned northward, with a maximum thickness of nearly 70m. This mixed travertine–terrigenous succession was investigated in terms of lithofacies types, depositional environment and architecture and the variety of precipitated travertine fabrics.Deposited as beds with thickness ranging from centimetres to a few decimetres, carbonates include nine travertine facies types: F1) clotted peloidal micrite and microsparite boundstone, F2) raft rudstone/floatstone, F3) sub-rounded radial coated grain grainstone, F4) coated gas bubble boundstone, F5) crystalline dendrite cementstone, F6) laminated boundstone, F7) coated reed boundstone and rudstone, F8) peloidal skeletal grainstone and F9) calci-mudstone and microsparstone. Beds of terrigenous deposits with thickness varying from a decimetre to >10m include five lithofacies: F10) breccia, F11) conglomerate, F12) massive sandstone, F13) laminated sandstone and F14) claystone.The succession recorded the following three phases of evolution of the depositional setting: 1) At the base, a northward-thinning thermogene travertine terraced slope (Phase I, travertine slope lithofacies association, F1–F6) developed close to the extensional fault system, placed southward with respect to the travertine deposition. 2) In Phase II, the accumulation of travertines was interrupted by the deposition of colluvial fan deposits with a thickness of several metres (colluvial fan lithofacies association, F10 and F12), which consisted of massive breccias, adjacent to the alluvial plain lithofacies association (F11–F14) including massive claystone and sandstone and channelized conglomerates. Travertine lenses, of 2–3-m thickness, appeared intermittently alternating with the colluvial fan breccias. 3) In the third phase, the filled fault-controlled basin evolved into an alluvial plain with ponds rich in coated reed travertines, which record the influence of freshwater (travertine flat lithofacies association, F7–F9).This study shows the stratigraphic architecture and sedimentary evolution of a continental succession, wherein the hydrothermal activity and consequent travertine precipitation were driven by the extensional tectonic regime, with faults acting as fluid paths for the thermal water. Fault activity created the accommodation space for travertine and colluvial fan accumulation. Erosion of the uplifted footwall blocks provided the source of sediments for the colluvial fan breccias, which alternated with the thermogene travertine precipitation. Climatic oscillations might have led to the recharge of the aquifer that fed the hydrothermal vents.The studied continental succession in an extensional basin provides valuable information about the interplay between thermogene travertine and alluvial/colluvial deposition, which in turn might improve the understanding of similar fault-controlled continental depositional systems in outcrops and the subsurface.

Effect of inorganic compound on artificial stones’ properties

Many natural mines of decorative stones have been seen in the mountainous areas of the province Lorestan (Iran). Due to the traditional harvesting methods, these processes cause irreparable environmental damages. The formulation of decorative stone consists of travertine stone (TS) and marmarit stone (MS) with stone seeds 8–200 and 10–200. Cement, water, unsaturated polyester resin and fillers are used in the production of artificial stone composites from lesions of stone factory. The mechanical properties of TS with grain of size 10–200 are better than other grains and stones. The compressive strength of the samples was increased by reducing water content to 25 % and increase of unsaturated polyester resin percentage to 12 %. To improve the properties of the samples and minimization of their pores, we used fillers such as calcium carbonate, silica, silane, titanium dioxide and zinc oxide. Calcium carbonate causes softening and loss of the composite samples. The results showed that use of the fillers including micro-silica, silane and titanium dioxide increases mechanical properties and eliminated close to all pores significantly. Unlike the concrete, artificial stone composite obtained in the absence of water pool showed better properties that increase with time.

Thermogenic travertine deposits in Thermopylae hot springs (Greece) in association with cyanobacterial microflora

The present paper deals with the investigation of abiotic and biotic influence on thermogenic travertine formation in Thermopylae hot springs, one of the largest active thermogenic travertine systems in Greece. Geological, mineralogical and microbiological data from three different types of travertines (cascades, terraces and fluvial crusts) revealed different cyanobacterial communities. Microscopic analysis of fresh and cultured material has shown that epilithic and endolithic cyanobacteria are almost the exclusive components of travertines’ photosynthetic microflora. Thirty-one (31) taxa of cyanobacteria are presented here, among them the frequently found, in such environments, Phormidium incrustatum and Aphanocapsa thermalis, as well as the taxonomically interesting diazotrophic morphotype identified as Chlorogloeopsis sp. Sampling sites I and II have similar formation conditions characterized by laminated travertines with low porosity and shrub lithotypes, with the cyanobacterium Leptolyngbya ercegovicii occupying an endolithic zone, while the upper part is occupied by colonial chroococcalean species. On the contrary, sampling site III is characterized by laminated travertine with fenestrial type porosity and absence of shrub lithotypes resulting in a completely different community of cyanobacteria.

Distribution and Controls on Silver Mineralization in the Hackett River Main Zone, Nunavut, Canada: An Ag- and Pb-enriched Archean Volcanogenic Massive Sulfide Deposit

Research Article| June 01, 2015 Distribution and Controls on Silver Mineralization in the Hackett River Main Zone, Nunavut, Canada: An Ag- and Pb-enriched Archean Volcanogenic Massive Sulfide Deposit Hannah L.J. Grant; Hannah L.J. Grant † 1Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada †Corresponding author: e-mail, hgrant@geomar.de Search for other works by this author on: GSW Google Scholar Daniel Layton-Matthews; Daniel Layton-Matthews 1Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada Search for other works by this author on: GSW Google Scholar Jan M. Peter Jan M. Peter 2Central Canada Division, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Hannah L.J. Grant † 1Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada Daniel Layton-Matthews 1Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada Jan M. Peter 2Central Canada Division, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada †Corresponding author: e-mail, hgrant@geomar.de Publisher: Society of Economic Geologists Received: 14 Apr 2014 Accepted: 24 Sep 2014 First Online: 09 Mar 2017 Online ISSN: 1554-0774 Print ISSN: 0361-0128 © 2015 Society of Economic Geologists. Economic Geology (2015) 110 (4): 943–982. https://doi.org/10.2113/econgeo.110.4.943 Article history Received: 14 Apr 2014 Accepted: 24 Sep 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Hannah L.J. Grant, Daniel Layton-Matthews, Jan M. Peter; Distribution and Controls on Silver Mineralization in the Hackett River Main Zone, Nunavut, Canada: An Ag- and Pb-enriched Archean Volcanogenic Massive Sulfide Deposit. Economic Geology 2015;; 110 (4): 943–982. doi: https://doi.org/10.2113/econgeo.110.4.943 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEconomic Geology Search Advanced Search Abstract The 2.67 Ga Hackett River volcanogenic massive sulfide (VMS) deposits located in the northeastern Slave province, Nunavut, Canada, are among the largest undeveloped massive sulfide resources in Canada and are silver rich compared to other such deposits of similar age, with Ag grades up to 3,000 g/t.The deposits are hosted by the Ignerit Formation of the felsic to intermediate calc-alkaline Hackett River Group metavolcanic rocks that are part of the province-wide supracrustal Yellowknife Supergroup. One of the most economically significant of the Hackett River deposits is the Hackett River Main zone (Main zone), which consists of two parts: a stratigraphically lower chalcopyrite-rich stringer zone and an upper massive to semimassive polymetallic sulfide lens. The mineralization is subdivided into five types based on mineralogy, textures, and approximate stratigraphic position: (1) disseminated footwall sulfides, (2) copper-rich stringer sulfides, (3) pyrite-poor sphalerite-pyrrhotite-chalcopyrite mineralization at the top of the stringer zone, (4) mineralization in calc-silicate–altered calcareous tuff units, and (5) sphalerite-pyrite massive sulfide. In type 1 mineralization, disseminated pyrite, pyrrhotite, and sphalerite contain negligible Ag and in type 2, Bi-Ag-(Pb) sulfides, Ag-Bi-Se–enriched galena and chalcopyrite are the dominant Ag hosts. Within type 3, Ag-rich tetrahedrite (freibergite) and galena are the main Ag hosts. In type 4, Ag is hosted in disseminated electrum and freibergite, and within type 5 mineralization, freibergite hosts 99% of the Ag. Overall within the Main zone, Ag-rich freibergite contains 79.4% of the Ag, whereas chalcopyrite hosts 6.3% and galena contains 1.8%. Trace minerals such as electrum host the remainder of the Ag, and these have a limited spatial distribution.Zone refining is the most important control on the distribution of Ag within the Main zone and the principal controls on Ag residence are mineralizing fluid temperature, deposit-scale relative redox conditions, sulfidation state, location of the mineralization relative to the hydrothermal conduit, and the ratio of Bi to Sb in the mineralizing fluid available for coupled substitution. Within the freibergite and chalcopyrite, Ag directly substitutes for Cu and replaces Pb in galena by coupled substitution with Bi and, to a lesser extent, Sb. Lower temperatures <ca. 250°C and more oxidizing conditions favored partitioning of Ag into freibergite and less oxidizing conditions favored galena as a host. At higher temperatures, >ca. 250°C, the most reducing conditions favored incorporation in Ag-Bi-rich galena (plus Se) and Bi-bearing sulfides or Ag-rich chalcopyrite under lesser reducing conditions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The role of the petrophysical characteristics on the durability and conservation of some porous calcarenites from Southern Italy

Abstract Highly porous and soft calcarenites, often called ‘calcareous tuffs’, are commonly found throughout Southern Italy and are traditionally used as building materials. The petrophysical features of some of them were determined, focusing on the microstructure (fabric and porosimetric characteristics) and on the properties related to water absorption, drying and water vapour permeability; the compressive strength was also measured. The mineralogical composition was analysed and a variable presence of clay minerals was found for the different varieties. Diverse levels of damage under a salt crystallization test were related to the mineralogical, petrographic and porosimetric features, the latter being a source of the heterogeneity of the investigated stones. Results of laboratory tests and observations of decay in the field suggest protection against water penetration as the primary requirement for slowing down the decay of such highly porous and soft stones. Some water-repellent products were tested for effectiveness in reducing water absorption and for compatibility with the original stones’ properties. Their use in the presence of salts was taken into account, including the performances of the treated stones under the salt crystallization test. Treatment issues were found to be strongly influenced by the porosimetric characteristics of the studied materials.

Out of the dark: transitional subsurface-to-surface microbial diversity in a terrestrial serpentinizing seep (Manleluag, Pangasinan, the Philippines).

In the Zambales ophiolite range, terrestrial serpentinizing fluid seeps host diverse microbial assemblages. The fluids fall within the profile of Ca2+-OH−-type waters, indicative of active serpentinization, and are low in dissolved inorganic carbon (DIC) (<0.5 ppm). Influx of atmospheric carbon dioxide (CO2) affects the solubility of calcium carbonate as distance from the source increases, triggering the formation of meter-scale travertine terraces. Samples were collected at the source and along the outflow channel to determine subsurface microbial community response to surface exposure. DNA was extracted and submitted for high-throughput 16S rRNA gene sequencing on the Illumina MiSeq platform. Taxonomic assignment of the sequence data indicates that 8.1% of the total sequence reads at the source of the seep affiliate with the genus Methanobacterium. Other major classes detected at the source include anaerobic taxa such as Bacteroidetes (40.7% of total sequence reads) and Firmicutes (19.1% of total reads). Hydrogenophaga spp. increase in relative abundance as redox potential increases. At the carbonate terrace, 45% of sequence reads affiliate with Meiothermus spp. Taxonomic observations and geochemical data suggest that several putative metabolisms may be favorable, including hydrogen oxidation, H2-associated sulfur cycling, methanogenesis, methanotrophy, nitrogen fixation, ammonia oxidation, denitrification, nitrate respiration, methylotrophy, carbon monoxide respiration, and ferrous iron oxidation, based on capabilities of nearest known neighbors. Scanning electron microscopy and energy dispersive X-ray spectroscopy suggest that microbial activity produces chemical and physical traces in the precipitated carbonates forming downstream of the seep's source. These data provide context for future serpentinizing seep ecosystem studies, particularly with regards to tropical biomes.

Potential Use of Waste Marble Powder as an Adhesive Filler in the Manufacture of Laminated Veneer Lumber

The waste powder occurring during the manufacture of marble, which is preferred a lot in the construction sector, has been the cause of environmental pollution to a significant extent in recent years. The reutilization of marble waste powder would provide a contribution to the protection of nature. The potential usability of waste marble powders as an additive substance in the manufacture of wood-based panels was investigated in this study. With this objective, laminated veneer lumber (LVL) panels were manufactured by adding marble factory waste powders in different ratios to polyvinyl acetate (PVAc) and urea-formaldehyde (UF) adhesives. The waste powders of beige marbles and travertine marbles were mixed by weight with adhesives in the ratios of 0%, 10%, 20%, 30%, 40% and 50% (by weight). Physical and mechanical tests were performed on the specimens obtained from the LVL panels. According to the results obtained from the present study, while a very high resistance was obtained with the waste beige marble powder at high ratios of mixture and with the waste travertine marble powder at low ratios of mixture with the PVA adhesive, a poor performance was displayed for the travertine powder with the UF adhesive.

Geo-mythology and Its Influences on Tourist Attraction (Case Study: Geological Phenomenon and Geo Morphology of Baba Gorgor Village, Kurdistan

Abstract. Given the importance of agriculture in the economy and the increasing role of potato and onion in the diet, this paper predicts the consumption of these products using a statistical model. Therefore, based on single and multi-variable models, data from 1970-2013 was applied to predict potato consumption using double exponential adjustment model and ARIMA (2, 1, 3) model was applied to predict onion consumption in 2015-2018. The results not only show a suitable prediction based on error criteria for the above mentioned models, but also reveals the fact that the application of an annual series using appropriate and valid models can provide acceptable results. The comparison of these Predictions with actual values is a sign for the high prediction power of these models and confirm this claim. According to our study, it is anticipated that per capita consumption of potato and onion will reach to 31.4 and 18.9 kg at the end of the year 2018. Geological phenomena and morphological forms sometimes appear in special and unique shapes. In the past and even now in some cultures and subcultures, because there was no response and rational justification for their formation and to satisfy their curiosity, people resort to (draw on) some legends and superstitions in order to explain their formation.Considering this issue, Baba Gogor village in Ghorveh, Kurdistan, has been investigated in a new category called geo mythology due to the myths and beliefs, due to the activity of several springs which were very active in the past and now show limited activity, various unique travertine and tofu forms have been formed near the springs. Due to the diverse and unique activities of the springs, different beliefs and superstitions have spread amongst the inhabitants of the neighboring villages and even more distant regions. Each year, thousands of tourists from all over Kurdistan and even the neighboring provinces are attracted in the region. The present study aims to investigate geo mythology in the world in general and in Ghorveh specifically and continues to investigate the relationship between geo-mythology and tourist attraction. To this end, different field methods such as interview and questionnaire have been used. At first, using open-ended interview and questionnaire, superstitions and beliefs regarding to different geological forms and phenomena and the available geology of the region (Baba Gorgor Village) have been gathered and in the next step the researcher designed a combined questionnaire (open-ended and closed) and 50 participants (the tourists in Baba Gorgor Village) completed it. The data were analyzed using SPSS Software and in other word the role of mythology in attracting tourists was investigated. The results show that among the available forms and phenomena, the hill known as the Dragon has the largest role in attracting people. Also, if we explain for the tourists in a simple way (language) how the forms and springs operate, the tourists suspicions can be removed to some extent.

The effects of bedding directions on abrasion resistance in travertine rocks

Travertine rocks are currently used in various architectural applications, cut perpendicular or parallel to bedding planes. Travertine stones used without enough attention paid to the cutting directions easily wear off in locations where pedestrian traffic is heavy and can cause some unexpected complications in practice. This study was conducted to elucidate the effects of cutting directions on the abrasion resistance of travertine stones. Travertine blocks were cut perpendicular and parallel to bedding planes, and their abrasion resistances were determined by means of the Bohme abrasion loss test. Travertine blocks were chosen from 6 different quarries whose products are currently in commercial use in Turkey and abroad. The rocks used in this study were macroscopically and microscopically described in terms of sizes, distribution patterns, and area ratios of pores, which were calculated using image analysis technique; the effects of these features on the abrasion resistances of the samples were expressed numerically. The relationships between pore area ratios and the Bohme abrasion loss values, in relation to the bedding directions, were also studied. The issues of cutting travertine rocks perpendicular or parallel to their bedding planes and how to extend the lifespan are also discussed. According to the findings, surface abrasion losses in all travertine samples cut perpendicular to their bedding plates were found to have been less than those of the samples cut parallel. Moreover, sizes and distribution patterns of the pores were found to be effective on the abrasion resistance; the pores on the surfaces cut perpendicular were smaller in size, flatter, and discontinuous, while the pores on the surfaces cut parallel were relatively greater in size, connected to each other, and with larger surface areas.

Hydrochemical evolution and reaction simulation of travertine deposition of the Lianchangping hot springs in Yunnan, China

Located in western Yunnan of China, the Lianchangping hot springs are of SO4·HCO3–Ca·Na type with total dissolved solids (TDS) ranging from 3560 to 4240 mg/L. Large amounts of travertine are deposited near the hot springs with a variety of travertine morphology, including travertine terrace, slope and ridge. Travertine is precipitating along the slope near one of the spring's thresholds. Chemical compositions of the hot water samples collected along travertine slope show that PCO2, TDS and contents of HCO3 and Ca decrease downstream along the travertine slope due to travertine deposition. The initial milliequivalent ratio of γCa2+/γHCO3− is greater than 1.5 before travertine precipitation and there is an increasing trend in the ratio downstream along the travertine slope. High levels of sulphate are probably the result of gypsum dissolution in the sediments widespread in the Lianchangping area. The spring waters issuing from the land surface are slightly supersaturated with respect to calcite, dolomite, fluorite, kaolinite, halite, plagioclase, and carbon dioxide. Hydrochemical evolution of the Lianchangping spring water along the slope is calculated with the Phreeqc Interactive 2.12.5. Sets of minerals and gases reacted in appropriate amounts are recognized through reaction simulation, quantitatively accounting for the variations in chemical compositions, especially depositing minerals along the flow path on the travertine slope.

Origin and palaeo-environmental significance of the Berrazales carbonate spring deposit, North of Gran Canaria Island, Spain

The Berrazales carbonate spring deposit is a small outcrop constituted mainly by cascade-like geometries. Four main facies have been identified: fibrous dense macrocrystalline formed by rapid degassing under high-flow conditions; framestones of coated plant moulds formed in moderate energy flow favoured by the presence of biogenic support; micrite/microsparite are primary precipitates in which crystalline aggregates nucleated on organic filaments and/or EPS; banded micrite-coarse crystalline were the result of alternating physically, chemically and biologically induced precipitation in areas of varying flow-velocities. Most facies underwent different degrees of micritization processes. Micrite is distributed as thin lines penetrating the crystals, as irregular patches or as micrite layers. In the first case organic filaments penetrate crystals, suggesting that micritization is mainly biogenically driven. In the latter cases micritization is caused mostly by partial dissolution. Microbe participation in micrite formation increased micrite MgCO3 content in comparison with coarse crystalline facies.Isotopic analyses show positive δ13C values (+2.63 and +4.29‰ VPDB) and negative δ18O (−5.65 and −4.48‰ VPDB) values. Positive δ13C values clearly indicate “deep-sourced” fluids.The Berrazales spring deposit studied here very probably is a small part of a larger carbonate building that was largely eroded by fluvial incision. Calculations of spring water temperature give a range from 20°C to 35°C, characteristic of a cold to warm spring favouring precipitation of calcite and important biogenic activity (framestones). Although the study deposit has textural characteristics of tufas, proving that the CO2 sourced from deep fluids, it should be considered as thermogene travertine, being one more example of the difficulty of using those terms for ancient sedimentary deposits. Carbonate spring deposits, very rare in the Canary Islands, are good archives of recent volcanic activity, fluvial processes and vegetation regimes prevailing in the islands in recent times.