Green Tuff Research Articles

Rockfall source identification and trajectory analysis from UAV-based data in volcano-tectonic areas: a case study from Ischia Island, Southern Italy

Ischia (Southern Italy) is a volcanic island of the Phlegrean Volcanic District that was historically affected by multiple geological hazards, including floodings, landslides, rockfalls, and earthquakes. In this study, rockfall stability is analysed with an integrated approach aimed at investigating the rockfall source, the propagation, and the deposition areas. The case study is represented by two outcrops over a 400-m-wide cliff made of Green Tuff and located on the western area of Mt. Epomeo. They are respectively located at 280 and 420 m a.s.l., just uphill the village of Frassitelli, Forio d’Ischia, which is an area of high residential, tourist, and agricultural importance. We analysed the fracture systems of the tuff cliff to compute the kinematic analysis of the potential failure mechanisms and to perform numerical simulations of rockfall scenarios. Successively, numerical simulations of rockfall scenarios were computed based on the acquired structural information. This allowed us to identify the most hazardous scenarios based on the rock trajectories and the percentage of rock blocks affecting the urban area. The influence of the rock shape and volume on the rockfall trajectories was analysed. In the most likely scenarios, we observed that 15–25% of the rock blocks bypass the geomorphological barriers and reach the urban area, with kinetic energy values spanning between 102 and 104 kJ. Such detailed rockfall hazard analysis allowed the definition of the mitigation interventions necessary for the protection of the nearby residential area.

Green tuff supplementation improves plant growth and microbial interactions of soil aggregates and rhizosphere in cherry tomato (Solanum lycopersicum L. var. cerasiforme) cultivation

Soil and rhizosphere microorganisms play essential roles in nutrient cycling and plant growth promotion in agricultural systems. Natural mineral materials, such as zeolite, are widely used as soil amendment materials to create “healthy” conditions for microorganisms related to plant cultivation. However, the effects of these minerals on microbial community structures in the soil with different aggregate scales and rhizosphere are largely unknown. In this study, we used cherry tomato (Solanum lycopersicum L. var. cerasiforme) cultivation experiment fed with 80 kg/1000 m2 green tuff (GT) as a natural soil amendment material and without GT (control blank as conventional farming; CK). The total yield and average root weight in GT were 1.2-fold and 1.6-fold higher than those in CK, respectively. The 16S rRNA gene amplicon sequence analysis in size-fractionated soil samples showed that the genus Bacillus, known as plant growth-promoting bacteria (PGPB), was significantly increased in bulk soil (nonfractionated soil), large macroaggregates (LMA, 5.6 mm–1 mm diameter), and small macroaggregates (SMA, 1 mm–250 μm diameter) in GT, and the genus Nocardioides, known as PGPB, was significantly increased in the rhizosphere of GT compared with CK (p < 0.05). These microorganisms had significant positive correlations with several PGPB, such as Bacillus, Nocardioidaceae, and Mesorhizobium. These results suggest that green tuff supplementation improves the microbial interactions in the soils, yields and root weight of cherry tomato.

Lower Cambrian volcanism in the Hawker Group and the Billy Creek Formation, Arrowie Basin, Flinders Ranges, South Australia

Widespread tuffs are known from the lower Cambrian succession of the Arrowie Basin, Flinders Ranges, mainly from the lower parts of both the Mernmerna Formation and the Billy Creek Formation. Up to 2.5 m of potassium-rich (K2O 6.32–9.60 wt%) rhyolite tuffs are known from the Mernmerna Formation, with the ‘Big Green Tuff’ from Bunyeroo Gorge yielding a TIMS age of 515.4 ± 0.2 Ma (i.e. unnamed Cambrian stage 3). The petrography of the Big Green Tuff, with numerous glass shards, suggests an explosive subaqueous pyroclastic deposit or ash-flow tuff. The presence of several layers of identical green tuff indicates that these were produced by a multi-phase volcanic event. There are up to thirty tuff horizons (5–50 cm thick) within the Warragee Member of the Billy Creek Formation. The tuffs within the Billy Creek Formation occur over a wide area, with an east–west extent of 250 km and a north–south extent of up to 80 km. It is suggested that they are in part ash-flow tuffs. A previous TIMS age for the Billy Creek Formation was 511.87 ± 0.14 Ma (i.e. unnamed Cambrian stage 4). The source of the tuffs, both from the Mernmerna Formation and the Billy Creek Formation is unknown. Detailed study of the whole-rock and trace-element geochemistry is required to fully document them.

Design and Experimental Study of Core Bit for Hard Rock Drilling in Deep-Sea

The hard rock stratum will seriously affect the efficiency of deep-sea drilling and greatly increase the cost of drilling operations due to its complexity. In ocean drilling operations, the design of the bit is critical. Therefore, the core bit should be able to drill in a variety of formations, especially in hard rock stratum, with the function of reducing the need to change the bit due to formation changes and improving the drilling efficiency. In this paper, three different core bits were designed according to the hard rock stratum of the seabed: the roller bit, diamond bit and bionic bit. According to the test results, it was observed that: (1) It is fully proven that the roller core bit has the characteristics of stable drilling in hard strata, small torque and high drilling efficiency. The same method can realize the core in shallow soft strata through the setting of drilling parameters. (2) For the diamond bit, the field test data show that the new formula diamond bit has a good adaptability to the changing hard rock strata in this area, with an average rate of penetration (ROP) of 4.4 m/h and a bit life of 137.75 m. (3) For the bionic bit, field experiment data showed that drilling in the formation lithology was gray green tuff, which had a core recovery up to 100%. The average ROP was 1.35 m/h, and the highest ROP was 1.88 m/h. The design and experiment of three kinds of drill bits have effectively solved the technical problem of efficient drilling in deep-sea hard-rock stratum.

Contrasting Styles of Inter-Caldera Volcanism in a Peralkaline System: Case Studies from Pantelleria (Sicily Channel, Italy)

The recent (&lt;190 ka) volcanic history of Pantelleria is characterized by the eruption of nine peralkaline ignimbrites, ranging in composition from comenditic trachyte to comendite to pantellerite. The ~46 ka Green Tuff (GT) was the last of these ignimbrites, which was followed by many effusive and explosive low-volume eruptions of pantellerite from vents within the caldera moat and along the caldera rim. Although recent studies have shed additional light on the age, petrochemistry, and volcanology of the older ignimbrites, there is very little knowledge of magmatism that occurred between these older ignimbrites, primarily due to the very scarce exposures. In this paper, we present new field descriptions and geochemical data for three local peralkaline centers never studied before, two pre-GT and one post-GT, which share a similar setting with respect to the caldera scarps but differ in terms of their age, composition, and eruptive style. These centers include: (i) the older (~125 ka) Giache center (comenditic trachyte), (ii) the ~67 ka Attalora center (comendite, pantellerite), and (iii) the younger (~14 ka) Patite center (pantellerite).

Trends of Geosciences after the Pacific War in Japan, 1945 to 1965 Part 7

Developments in geology, historical geology, sedimentology, and paleontology in Japan after the Second World War, from 1945 to 1965 are described. The Geological Society of Japan was reconstructed soon after the war and established the foundations for geological studies. The Tokyo Geographical Society compiled documents on geological research in East Asia before and during the war. The Coal Exploration Advisory Committee (CEAC) and the Petroleum Exploration Advancement Committee (PEAC) made progress on research related to oil and coal. New geological maps were compiled; the nomenclature of strata was formulated; and, regional geologies were summarized. Studies of Precambrian and Paleozoic strata continued to advance, while investigations on the geology of the Mesozoic challenged to establish theories posited before the war. Areas of studies such as “Green tuff,” radiocarbon measurement, tephrochronology, and neotectonics in the Cenozoic strata were opened up. Around 1950, sedimentological themes emerged; the Sedimentology Institute was founded at the University of Tokyo in 1951; and a sedimentology research group was formed in 1957. Research, for example, on recent sediments in Tokyo Bay were started. Soon after the war, the Palaeontological Society of Japan collated data on type species and their descriptions collected since 1868 for the development of palaeontological studies in Japan. Studies on Desmostylus, Naumann elephant, and Metasequoia fossils were launched. Micropaleontology including foraminifera studies made remarkable contributions.

ВРЕМЕННЫЕ ИМПУЛЬСЫ КАЙНОЗОЙСКОГО ЭКСПЛОЗИВНО-ФРЕАТИЧЕСКОГО ВУЛКАНИЗМА В ЮГО-ЗАПАДНОМ ПРИМОРЬЕ. КОРРЕЛЯЦИЯ ИЗОТОПНЫХ И ФИТОСТРАТИГРАФИЧЕСКИХ ДАТИРОВОК

The Cenozoic tephra deposits - products of explosive phreatic eruptions of maar volcanoes in the southwest of Primorye are studied. The deposits represent rhyolitic ash and pumice pyroclastic beds with a high terrigenous component, including tephroid pseudo-conglomerates. Isotopic dating of tephra beds established two time pulses of explosive volcanism: 30–34 Mya and 23–24 Mya. The first time pulse coincided with the beginning of the formation of marginal seas and continental coal basins. It corresponds to the most productive stage of coal accumulation, the burial of wood wastes and their coalification at a faster rate, and the development of a high-temperature geothermal field and can be compared with the well-known catastrophic eruption of Mount St. Helens in the U.S.A. The second time pulse of explosive volcanism had a regional character of manifestation. It is characterized by the formation of green tuff complexes on submarine elevations of the Sea of Japan as well as along the western and eastern coasts of Japan. Synchronously with the volcanic activity started the acceleration of the sinking rate of the Sea of Japan bottom in response to the active rising of asthenospheric diapirs. The established isotopic ages do not conform to the ages determined for fossil leaves and pollen from the deposits, which may reflect the climate-forming type of such an explosive process.

Accelerating anaerobic propionate degradation and studying microbial community using modified polyvinyl alcohol beads during anaerobic digestion

Modified polyvinyl alcohol beads (PVA) are synthesized by adding conductive materials such as activated carbon (AC), magnetite particles (MT), and green tuff (GT) for serving as potential advantages carriers on anaerobic digestion (AD). This study aimed to study the effect of modified PVA beads on AD performance and investigate the probability of DIET occurrence on syntrophic propionate degradation, including microbial syntrophy of syntrophic partners and methanogens. Under anaerobic sequencing batch reactor (ASBR) operation, chemical oxygen demand (COD) degradation was 1.3-fold higher, and propionate degradation increased 1.7-fold more than sludge. Another on the continuous stirred-tank reactor (CSTR), the COD degradation reached a maximum rate of over 80%, and propionate was completely degraded. Moreover, modified PVA beads were significantly promoted by methane production, methane conversion rate, and methane yield. The microbial syntrophy of “Candidatus Methanofastidiosum” and Syntophobacter co-occurred in modified PVA beads, illustrating the potential of syntrophic partner for propionate degradation.

Assessing the effect of green tuff as a novel natural inorganic carrier on methane-producing activity of an anaerobic sludge microbiome

The upflow anaerobic sludge blanket (UASB) process is an anaerobic biological system that is widely used for the treatment of a variety of wastewater owing to its benefits such as low energy requirements and energy recovery as methane gas; however, unstable reactor performance is often observed. To solve this problem, several inert inorganic carriers and polymer materials have been studied for stabilization of the sludge microbial community and promotion of methane production. In this study, we demonstrate the effects of green tuff (GT) as a novel natural inorganic carrier on methane-producing activity (MPA) in combination with syntroph/methanogen-utilizable substrates and on the microbial community assembly of methanogenic batch cultures fed with granular sludge collected from UASB reactors treating milk- (MMW) or soy sauce- (SSW) manufacturing wastewater. The MPAs of MMW cultures with GT were 4.56- (propionate), 2.01- (n-butyrate), 1.37- (n-valerate), and 1.22- (benzoate) fold higher than those without GT. Likewise, SSW cultures with GT showed 1.34- (acetate) and 1.42- (propionate) fold higher MPA than those without GT. These results indicate that GT has potential to enhance MPAs during methanogenic degradation of these substrates. According to 16S rRNA transcripts-based community profiling, populations of syntrophic bacteria (Syntrophobacter and Smithella) and hydrogenotrophic methanogens (Methanobacterium and Methanolinea) in the cultures with GT were higher than in those without GT. Therefore, GT can be a potential solution for the activation of syntrophic partnerships and improvement/stabilization of reactor performance.

Extremely high-grade, lava-like rhyolitic ignimbrites at Osham Hill, Saurashtra, northwestern Deccan Traps: Stratigraphy, structures, textures, and physical volcanology

In many continental flood basalt (CFB) provinces of the world, widespread silicic lavas and ignimbrites overlie the mafic lavas. Our knowledge of this post-flood basalt silicic volcanism in the Deccan Traps CFB province of India remains limited. Here we describe the stratigraphy, structures, and textures of the rhyolites of Osham Hill in Saurashtra, in the northwestern Deccan Traps. Basaltic lavas forming the lower parts of the hill are overlain by the “Lower Rhyolite” (LR), which is tens of meters thick and shows intense rheomorphic deformation (flow banding and folding) at microscopic, outcrop, and tens of meters scales. The LR is overlain by a “Green Tuff and Pitchstone” (GTP) band 20–40 m thick, containing massive green tuff to strongly rheomorphic, commonly spherulitic pitchstone, both types showing sharp but irregular contacts. The GTP is overlain by the “Upper Rhyolite” (UR), with an ~100 m preserved thickness. This resembles the LR in many structural features, and also contains a thin (~1 m), laterally discontinuous basal layer of unbedded, nonwelded lapilli tuff. The LR and UR locally contain basal autobreccias which are unlike crumble breccias of rhyolitic lava flows. In thin section the LR and UR are microcrystalline and lava-like, though they contain many relict vitroclasts (glass shards and pumice fragments). The LR also shows rare millimeter-size basaltic lithic clasts. The GTP contains abundant vitroclasts. We interpret the LR and UR as extremely high-grade, intensely welded, lava-like ignimbrites, and the GTP as a low-grade ignimbrite with varying degrees of welding and rheomorphic deformation. The absence of sedimentary interbeds and soil horizons suggests that the whole Osham ignimbrite sequence was deposited subaerially and rapidly. The eruptive vent locations are unknown. However, a rhyolite dyke intruding basalts at the southeastern end of Osham Hill is pyroclastic, showing a eutaxitic to microcrystalline interior and margins of welded and rheomorphic tuff-pitchstone. Basaltic lithic fragments found in the dyke margins suggest that it may be the feeder of the LR. The LR and UR show many close similarities to “Snake River-type” ignimbrites (large-volume, metaluminous, high-temperature, lithic- and crystal-poor, intensely welded, rheomorphic and lava-like ignimbrites). These render Osham Hill a newly recognised and important locality of such ignimbrites.

Green Tuff: Gamma Index in a Typical Building Material of Ciglio Area (Ischia Island)

Radiological characterization of tuff of Ciglio area in Ischia Island was performed to assess the potential radiological hazard associated with its use. For this purpose, high resolution gamma-ray spectroscopy was used. In five green tuff samples was measured the activity concentration of natural gamma-ray emitting radionuclides 226Ra, 232Th and 40K so, the mean gamma index was calculated. The mean value of the gamma index resulted lower than the reference level and it meets the dose criterion for the safety use of green tuff as building material.

Enhancing anaerobic syntrophic propionate degradation using modified polyvinyl alcohol gel beads

Modified polyvinyl alcohol (PVA) beads serve as effective anaerobic microbe immobilization carriers. PVA beads were mixed with different conductive materials, activated carbon, magnetite, and green tuff stone powder. In this study, modified PVA beads were used to investigate the effect of using, promote methane production, and enhance direct interspecies electron transfer (DIET) on the anaerobic syntrophic degradation of propionate, which is an essential intermediate process for generating methane in anaerobic digesters. The batch experiment showed that PVA mixed with activated carbon had the highest methane conversion rate of 72%, whereas the rates for control (sludge) was 61%. Moreover, the lag time during the second and third feedings was shorter by 5-fold than for the first feeding when modified PVA beads were added. The syntrophic propionate degrading microorganisms in the modified PVA beads was Syntrophobacter and Methanobacterium, either Methanoculleus or Methanosaeta. The modified PVA beads hold at least 10 times larger syntrophs than normal PVA. Therefore, composite PVA with conductive materials can promote methane production, accelerate propionate consumption, and enhance electron transfer in related microbial species.

Radiation Protection Legislation and Sustainable Development of a Rural Green Tuff Village of Ischia Island

Radiological risk affects the quality of the environment in buildings since population and workers can be potentially exposed to high levels of radiation. Radon gas emanating from both subsoil and building materials represents the most important source of radiation exposure for people. This study investigates the sustainability concept of a small rural village of Ischia Island, named Ciglio, in relation to radiation protection legislation concerning the radiological risk for workers. Radon activity concentration was measured in typical green-tuff dwellings and in water samples collected from a local waterfall E-Perm devices. Moreover, for green tuff as building material, the radon emanation coefficient was calculated by gamma spectroscopy. The results highlight the importance of performing environmental radon monitoring and investigating the radon content of building materials, especially in geographical areas characterized by traditional use of typical stones for constructions. In conclusion, the sustainable development of rural buildings is possible if the radiological risk for inhabitants and workers is assessed in line with the national radiation protection legislation.

Influence of Green Tuff Fertilizer Application on Soil Microorganisms, Plant Growth, and Soil Chemical Parameters in Green Onion (Allium fistulosum L.) Cultivation

Organic farming (OF) has been increasing in popularity over recent years, but unfortunately tends to have lower yield, due to lower nutrient availability and pest problems. To better understand how OF influences plant growth, we must elucidate the impact of such practices on the microbial community, an important factor in soil management. In this study, we examined the relationship between farming practice, changes in plant growth, and soil microbial community for green onion (Allium fistulosum L.) cultivated over 313 days in green houses with OF using composts with natural green tuff as soil conditioner (EF1) or inorganic fertilizer (EF2). Average yields of EF1 were generally higher than EF2, reaching up to 12% higher (p &lt; 0.05; day 131). The observed soil microorganism phylotypes and phylogenetic diversity (Faith’s phylogenetic diversity (PD)) were both significantly higher (p &lt; 0.05) in EF1 than EF2 on days 93, 191 (only for PD), and 261, based on microbial richness indices. Several phylotypes belonging to the Bacillus-related microbial order Bacillales were found at higher abundances in EF1 soils, positively correlated with specific soil properties (i.e., humus, ammonium, and pH), and may associate with plant growth promotion and/or fungal toxin degradation. These results point towards novel positive effects of OF and provide insights into the management of soil microorganisms using organic fertilizers.

Changing modes and rates of mafic magma supply at Pantelleria (Sicily Channel, Southern Italy): new perspectives on the volcano factory drawn upon olivine records

AbstractThe island of Pantelleria, located in the Sicily Channel Rift Zone (Italy), has been the site of violent peralkaline silicic magmatism alternating with minor effusive to low-intensity Strombolian eruptions of basaltic composition. The basaltic rock suites exposed on the island were sampled to investigate the plumbing system dynamics through the study of chemical stratigraphy and temporal records of olivine crystals. Our petrographic and geochemical observations, together with the compositional variability of olivine, suggest different evolutionary histories for basaltic magmas erupted over two major periods divided by the ∼45 ka Green Tuff (GT) eruption. Core-to-rim compositional traverses across olivine crystals document different types of zoning. We recognized olivine zones affected by Fo oscillations at very fine scales in the inner cores, rims and/or in intermediate portions of crystals and used them to reconstruct the residence and passage of crystals through different magmatic environments, with P–T–ƒO2 and compositional characteristics constrained by thermodynamic modeling. The sequence of magmatic environments evidenced by olivine zoning indicate that the pre-GT volcanic period was dominated by injection at shallow crustal levels (∼300–200 MPa) of primitive melts, initially moving from a deep storage zone at the crust-mantle boundary. Supply of this magma significantly decreased after the GT eruption, while the dynamics of magma transfer within the upper portion of the plumbing system were greatly enhanced. The diffusive relaxation of olivine zoning provided the timing of storage and migration of a crystal through different environments. For magmas feeding the ancient (&amp;gt;45 ka) basaltic activity we retrieved transfer histories that are much longer (up to ∼3 years) if compared with those calculated for the post-GT basalts (1–9 months). The compositional and temporal dataset presented in this study supports the idea that the GT eruption and the subsequent collapse of the volcanic edifice could have caused major changes to the internal structural setting of Pantelleria, creating more favorable conditions for the migration of magmas in the upper portions of the plumbing system.

Removal of Banana Tree Fungi Using Green Tuff Rock Powder Waste Containing Zeolite

Hinai green tuff, which is found in Akita Prefecture, Japan, is used for the production of building materials, etc. About 60% of all stone is emitted as waste powder and therefore it is important to find ways for recycling it. In this work, the characteristics of green tuff powder have been investigated. The results of scanning electron microscope (SEM) and elemental map observations indicate that the green tuff contains TiO2 on zeolite. The green tuff can therefore be used as a natural catalyst for producing hydrogen peroxide with moisture and oxygen with light. The optimum calcined temperature of the green tuff powder is about 800 °C, producing the hydroxyl radical from hydrogen peroxide decomposition without ultraviolet light (UV) and decomposition of the superoxide anion. As the application of green tuff powder, Cavendish banana trees found in the Philippines infected by a new Panama disease were treated with powder suspension in order to remove the fungus (a type of Fusarium wilt) due to the photocatalyst characteristics of powder. The suspension, prepared by using the powder was sprayed on the infected banana trees for about one month. Photograph observation indicated that the so-called 800 °C suspension spray was more effective in growing the infected banana trees.

About metallogeny of the pacific volcanic belts

The article discusses the actual aspects of the metallogeny of the Pacific volcanic belts (PVB), which are a complexes of volcanogenic-plutogenic formations associated with the development of the marginal lithosphere and has an expressive specificity of ore formation. It is shown that over time the notions of metallogenic homogeneity of PVB have received a new justification from the position of global plate tectonics. Metallogenic significance of Ag/Au relationships in ore deposits of the PVB is shown. The correlation between porphyry-epithermal and the VMS ore-forming systems, regenerated and rejuvenated epithermal deposits is discussed. Global metallogenic homogeneity of the Pacific ore belt suggests a wide development of analogues of American volcanogenic deposits in its Asian half, including in the North-East of Russia. The main part of the internal zone of the Okhotsko-Chukchi marginal volcanic belt the Udo-Murgal island-arc belt, as well as the Uyandino-Yasachensky and Oloysky volcanic belts, are similar in geological structure not only to the Japanese green tuffs province, but also to other Pacific volcanic zones of the island-arc type and, therefore, within their limits, there is a high probability of revealing the entire variety of deposits of the VMS ore-formation series.

On the Metallogeny at the Pacific Volcanic Belts

This paper discusses currently interesting aspects of metallogeny at the Pacific volcanic belts (PVBs); these consist of complex volcanogenic–plutonic features related to the evolution of the marginal-sea lithosphere, which exhibits a remarkable mineralization peculiarity. We show that as time has passed, the ideas of a metallogenetic homogeneity of the PVBs received a new substantiation from the standpoint of plate tectonics. We show the metallogenetic value of the Ag/Au ratio in ore deposits at the PVBs. We consider the relationships between porphyritic epithermal and pyritaceous complex mineralizing systems, as well as regenerated and rejuvenated epithermal deposits. The global metallogenetic homogeneity of the Pacific ore belt suggests a wide occurrence of analogues of the American volcanogenic deposits in its Asian half, including the Russian Northeast. The bulk of the Okhotsk–Chukchi Volcanic Belt (OChVB), namely, the Uda–Murgali island arc belt, equally as the Uyandina–Yasachnaya and Oloi belts, are similar in geological structure not only to the Japanese green tuff province, but also to the other Pacific volcanic belts of the island arc type; hence, they are very likely to contain the entire diversity of deposits that belong to the complex pyritaceous ore–formation type.

Production of the Hydroxyl Radical and Removal of Formaldehyde by Calcined Green Tuff Powder and Tile

Waste green tuff powder produced by cutting Towada stone has been utilized to eliminate formaldehyde related to greenhouse gases. The green tuff contains TiO2 on zeolite as observed by scanning electron microscope (SEM)t. The green tuff is a natural catalyst that can produce hydrogen peroxide with moisture and oxygen with light. The optimum temperature for calcination of the green tuff powder has been investigated in order to produce hydroxyl radicals from the decomposition of hydrogen peroxide using ultraviolet light (UV) and no light. The green tuff calcined at 800 °C showed a high decomposition rate of hydrogen peroxide with no UV light under high alkaline conditions when measured by using ESR. With UV light, the optimum temperature for calcination of green tuff powder in order to reduce the hydroxyl radical was also 800 °C. Next, the powder calcined at 800 °C was used to produce the tile by compression and heating, and then the formaldehyde adsorption rate was measured. The green tuff powder calcined at 800 °C showed a high adsorption rate, similar to that of the activated carbon. The tiles formed at 40 MPa and heated at 1100 °C were the strongest and also showed adsorption with respect to formaldehyde. The adsorbed formaldehyde on the green tuff tile and powder was possibility decomposed by the hydroxyl radical produced by photocatalysis.

Prospecting for Clinoptilolite-Type Zeolite in a Volcano-Sedimentary Terrain Using ASTER Data: A Case Study from Alborz Mountains, Northern Iran

Zeolites are hydrated alumino-silicates of alkali metals and alkaline earth cations which occur in sedimentary and volcano-sedimentary terrains. In this study, visible–near-infrared and shortwave infrared data of ASTER were evaluated in prospecting for zeolite in part of the green tuff belt of the Alborz Mountains, northern Iran. The study area is dominantly covered by sedimentary and volcano-sedimentary rocks, in which zeolite minerals occur only in the Late Eocene vitric tuff. Principal components (PC) analysis and spectral information divergence (SID) were used to discriminate and map the sedimentary and volcano-sedimentary units and the zeolite-rich areas, respectively. The X-ray diffraction and reflectance spectroscopy results indicated that clinoptilolite is the major type of zeolite mineral in this area. Comparing a color composite image, produced from PC images 1–3–5 as R–G–B, with the published geological map and the field investigations indicated that major sedimentary and volcano-sedimentary units as well as their alluvial deposits were discriminated efficiently. Results of the SID method, using an image-derived spectrum of clinoptilolite as a reference, showed good agreements with the field observations. The results of this study indicated that ASTER data are useful for discriminating various sedimentary and volcano-sedimentary units as well as clinoptilolite-type zeolite-rich areas in arid and semiarid terrains.