Search

The Tarim basin not only is one of the main targets for hydrocarbon exploration in China, but also hosts the Early Permian LIP, thereby providing an ideal laboratory to investigate how the LIP eruptions interact with the petroleum system in the volcanic-affected basins. Six major second-order domes were identified in the first-order dome that involves the entire Tarim LIP, based on seismic probing and lithofacies and stratigraphic observations in boreholes and the stratigraphic sections. These second-order domes are characterized by abundant Permian basaltic dykes and volcanic craters, indicative of the origin from the LIP eruption. They also are the sites of the almost all Paleozoic oil and gas reservoirs in the Tarim basin. Dating on authigenic illites collected from 20 Silurian bituminous and oil-saturated sandstone samples in the Tarim basin, along with literature data, indicates that hydrocarbon charge and emplacement in the Paleozoic reservoirs prevalently occurred during 300–255 Ma, approximately concurrent with the eruption of the Tarim LIP lavas (300–262 Ma). Therefore, we propose that the LIP eruption not only created the second-order domes that provided space for the oil and gas charge but also triggered the rapid release of hydrocarbon through the volcanic vents, thereby controlling the formation of Paleozoic oil and gas fields in the Tarim basin.

Three upcoming Martian missions will deploy a ground-penetrating radar (GPR) to reveal the fine-resolution subsurface structure and dielectric properties of materials beneath the surface. Numerical forward simulations of radar echo using a model of the near-surface structure at the landing site can provide a valuable reference for processing and interpretation of future radar data collected on Mars. In this study, based on the geological information of the Jezero crater, a detailed stratigraphic model of the near-surface structure is derived, which includes several key features, for example, the randomness of the medium, terrain, and cracks. To identify correctly the reflections of subsurface interfaces and fractures from the radar image, a v(z) f-k migration is carried out, the performance of which is evaluated using the GPR data obtained near Antarctic Zhongshan Station since the electrical properties of Antarctic glaciers and Martian materials are to some extent comparable. The results in this work show that compared with common migration algorithm, the v(z) f-k method not only improves the clarity of radar image but also provides the permittivity profiles to infer the composition of the substrate, leading to a better understanding of Martian near-surface geology.

This study assesses the contribution of Landsat 7 ETM + and Landsat 8 OLI images to observe existing fractures and faults of at least 12 km in length around the lakes Nyos, Monoun and Oku whose are three major crater lakes in the Cameroon Volcanic Line (CVL) environment. The results obtained using principal component analysis, directional filters and linear densities show many similarities and some differences. In fact, Landsat 7 ETM+ and Landsat 8 OLI images present 427 lineaments in common, including all known geological linear structures, certain geophysical lineaments and some new fractures. This proves that the area is much more fractured than previously known and that only the environments of lakes Nyos and Monoun are crossed by faults and fractures. Apart from the similarities, the differences observed relate to the lineaments specific to each image, their main direction, their length and the values ​​of the fracturing densities. Also, the results show that the Landsat 7 ETM+ and Landsat 8 OLI images are suitable for the structural research in the CVL environment. But, the Landsat 8 OLI images are more efficient as they have made it possible to reconstitute almost all known geological structures and their lengths.

Gas-rich discharges of magma produced pyroclastic vents on the lunar surface. Calculations suggest those pyroclastic vents repeatedly generated 1012 to 1015 g of H2O and CO + CO2 for pyroclastic volumes of 10 to 500 km3 early in lunar history, particularly during the first billion years of lunar history. Some of those volatiles migrated to the lunar poles where they could be trapped in permanently shadowed regions (PSRs). The largest indigenous source of volatiles in the south polar region was volcanism that occurred on the floor of the Schrodinger impact basin. Here a large pyroclastic vent ceased erupting ∼ 3.70 +0.02-0.03 Ga, releasing H2O, CO-CO2, F, S, and Cl vapor species, including calculated values of 3.0 × 1013 to 1.6 × 1014 g H2O. A transport and depositional model suggests 1.1 × 1010 kg (12%) of that water may have been trapped in the south polar region.

The only martian rock samples on Earth are meteorites ejected from the surface of Mars by asteroid impacts. The locations and geological contexts of the launch sites are currently unknown. Determining the impact locations is essential to unravel the relations between the evolution of the martian interior and its surface. Here we adapt a Crater Detection Algorithm that compile a database of 90 million impact craters, allowing to determine the potential launch position of these meteorites through the observation of secondary crater fields. We show that Tooting and 09-000015 craters, both located in the Tharsis volcanic province, are the most likely source of the depleted shergottites ejected 1.1 million year ago. This implies that a major thermal anomaly deeply rooted in the mantle under Tharsis was active over most of the geological history of the planet, and has sampled a depleted mantle, that has retained until recently geochemical signatures of Mars’ early history., The ejection sites of the martian meteorites are still unknown. Here, the authors build a database of 90 million craters and show that Tharsis region is the most likely source of depleted shergottites ejected 1.1 Ma ago, thus confirming that some portions of the mantle were recently anomalously hot.

The area surrounding Jaboi volcano, Indonesia, has been planned for geothermal energy development with capacity of ~ 50 Mwe. Geophysical surveys can contribute to the understanding of the hydrogeology of the area because they can provide information without interferences, which could potentially react to the flow of hot water. In many cases, the occurrence of a hot spring is closely related to its local fault system, which permits the flow of thermal fluid to its surface. This research applied the very low-frequency electromagnetic (VLF–EM) method and then compared it with electrical resistivity data to map fractures, faults, and geological aspects in the Jaboi volcano manifestation area. In tropical areas such as Indonesia, the VLF–EM method has been applied widely in studying subsurface structures. However, it is rarely used in volcanic areas with high terrain conditions even though the mobility of VLF methods is simpler than the electrical resistivity method. At the west side of the volcano, the 2D models from both VLF–EM and electrical resistivity showed the conductive zone (log 0.5–1.5 Ωm) found as a response to the manifestation, which has a similar direction with a local fault known as the Ceuneuhot fault. At the east side, the 2D models from both methods showed a similar conductive zone at depths of 15–25 m, which is caused by the existence of bedrock (> log 2.5 Ωm). The bedrock at depths of 0–10 m inhibits the rise of fluid to the surface so that there is no geothermal manifestation in the other local fault known as the Leumomate fault. In addition, the 2D models from the two methods showed the contrast of some fracture zones as entry and exit points of fluid in the Jaboi volcano. In addition, analysis of Landsat 8 optical images also showed high-temperature values and low vegetation indices in several active craters as indicators of volcanic activity. Based on the processed data, it is concluded that VLF–EM can be used as a fast and accurate method to provide information about near-surface structures in a geothermal field, and it can be used safely to suggest a location for drilling programs or to give contributions to protect geothermal springs.

This report gives a brief description of field work on the Kuril Islands in summer 2021 carried out by staff of the Institute of Volcanology and Seismology of FEB RAS within the framework of the Institute research theme and projects of the Russian Science Foundation (RSF) and Russian Fund for Basic Research (RFBR). To study chemical erosion of volcanic islands and to estimate hydrothermal export of magmatic volatiles, hydrological and hydrochemical works were carried out on the rivers draining the slopes and thermal fields of the Baransky volcano and the Bogdan Khmelnitsky volcanic massif (Iturup Island). Detailed hydrochemical studies with water sampling at different depths and a bathymetric survey of Lake Kipyashchey located in the caldera of Golovnin volcano (Kunashir Island) were performed. We also proceeded with studying the CO2 diffusion flux through thermal fields and volcanic lakes. In the course of ongoing regime observations on Ebeko volcano (Paramushir Island), aerial and infrared imaging of its near-crater part was carried out. For the first time since the eruption began in 2016, a quadcopter survey of the lake located in the Srednii (middle) crater of the volcano was conducted. For further analytical studies a large number of water and gas samples were taken, and the collection of sediments was replenished.

About 14.5 months after the 2018 eruption and summit collapse of Kīlauea Volcano, Hawai'i, liquid water started accumulating in the deepened summit crater, forming a lake that attained 51 m depth before rapidly boiling off on December 20, 2020, when an eruption from the crater wall poured lava into the lake. Modeling the growth of the crater lake at Kīlauea summit is important for assessing the potential for explosive volcanism. Our current understanding of the past 2500 years of eruptive activity at Kīlauea suggests a slight dominance of explosive behavior over effusive. The deepened summit crater and presence of the crater lake in 2019 raised renewed concerns about explosive activity. Groundwater models using hydraulic-property data from a nearby drillhole successfully forecast the timing and rate of lake filling. Here we compare the groundwater-model predictions with observational data through the demise of the crater lake, examine the implications for local water-table configuration, consider the potential role of evaporation and recharge (neglected in previous models), and briefly discuss the energetics of the rapid boil-off. This post audit of groundwater-flow models of Kīlauea summit shows that simple models can sometimes be used effectively to simulate complex settings such as volcanoes.

—Modeling the relative motion of large crustal blocks vitally depends on an adequate description of the forces acting between the blocks. To describe motion at high strain rates, it proved necessary to assume a dry friction to depend on the shear strain rate and, in some cases, on the amplitude of fault side displacement. The best known examples of large-scale motions with dynamically decreasing friction are long-runout rock avalanches and gravity-driven collapsing of the transitional cavities of large impact craters. In this work, the experience is discussed of using the model of acoustic fluidization as a factor of a temporary decrease in friction to quantitatively simulate impact crater shape on the Earth and other planetary bodies. Immediate promising ways to find more adequate models are outlined.

The Salpeterkop volcano forms part of what has been referred to as the Upper Cretaceous Sutherland Suite of alkaline rocks, an igneous province composed of olivine melilitites, carbonatites, trachytes and ultramafic lamprophyres. Salpeterkop is a remnant of the summit tuff ring structure that surrounds a crater which is almost 1 km in diameter and is filled with epiclastic strata.Five pieces of silicified wood were collected from the crater filled sediments, sectioned and identified as a new species of Cupressinoxylon, C. widdringtonioides. This is the first example of the fossil genus in South Africa. Only one member of the Cupressaceae s.l. occurs in southern Africa today. From the wide and indistinct growth rings in the fossil wood it can be deduced that the local climate was warm and humid with little or no seasonality, in support of global records of a warm Late Cretaceous. The preservation of the crater further signifies the low level of erosion the region has experienced since its emplacement.

This study is concerned with the Raikoke volcanic massif, part land, part undersea, situated in the northern Central Kuriles. It consists of Raikoke volcano-island and the Quaternary undersea volcano 3.18. The eruption of June 2019 did considerable damage to the fauna and flora of Raikoke Island, changing its aspect one more time. A lake appeared in its crater. Raikoke volcano-island is composed of moderate potassium rocks of medium alkalinity belonging to the tholeiitic series from basalts to andesites, which are typical arc lavas. This occasion is the first to publish the compositions of six samples taken on the island. The undersea volcano 3.18 at a depth of ~800 m has its base coalescing with Raikoke volcano-island. The near-summit part at depths of 260–230 m has several peaks, while extrusions have been identified in the northeastern and southeastern parts of the base. Volcano 3.18 is composed of andesites and basaltic andesites. The basaltic andesites belong to lavas of the moderately potassium suite in the normal-alkaline series. Our surveys suggest that undersea volcano 3.18 was formed during a geomagnetic reversal. Its edifice was found to contain feeding conduits and peripheral magma chambers.

The major earthquakes often trigger unrest of surrounding volcanic magma chambers. In recent years, three major earthquakes occurred around the Changbaishan volcano, but it was unclear whether these earthquakes triggered the unrest of the magma chamber. Based on geodetic data, we analyzed the volcanic activity according to the Global Position System (GPS) and leveling sites time-series and re-estimated the location and volume change of magma chamber from 2002 to 2005. Meanwhile, we calculated the dilatational strain variations of the deep magma chamber resulting from coseismic deformations caused by the 1999 Mw7.0 and 2002 Mw7.3 Wangqing deep earthquakes and the 2011 Mw 9.0 Tohoku-oki earthquake. Our results show: (1) Changbaishan has experienced four stages of unrest since 1999, and the biggest unrest of the shallow magma chamber occurred from 2002 to 2005; (2) the parameters of the shallow magma chamber simulated by the Mogi and Point Compound Dislocation Model (pDCM) show that the magma chamber is located in the northern part of the crater, with a depth of approximately 7 km. The volume of the magma chamber increased by 25–28 × 106 m from 2002 to 2005; (3) the strain variation beneath the Changbaishan volcano corresponding to the 1999 Wangqing earthquake was small. The 2002 Wangqing earthquake produced an expansion strain of about 4.4 nano-strain on the magma chamber at a depth of 550 km, and probably promoted the unrest of the Changbaishan volcano. The 2011 Tohoku earthquake induced the expansion of the shallow magma chamber and compression of the deep magma chamber. Although this event promoted shallow magma unrest, it inhibited deep magma unrest. This may explain why the Changbaishan did not show obvious unrest after the 2011 Tohoku earthquake. Therefore, more attention should be paid to earthquakes that can promote deep magma unrest in the Changbaishan volcano.

A 3D shear wave velocity model of the subsurface of Popocatepetl volcano was obtained using ambient noise tomography, employing the principal cross-terms of the empirical Green’s function. Daily cross-correlation waveforms were computed from the data recorded by four seismic broadband stations in 2012. Dispersion curves were estimated from the stack of anti-causal and causal parts for the three ground motion components. In the period ranging between 0.5 and 7 s, the radial component provided the most well-defined group velocity dispersion curves for Rayleigh waves. Dispersion curves for long paths (> 9.5 km) suggested the presence of a layered structure with group velocity values ranging from 0.5 to 3.0 km/s. Dispersion curves for short paths (< 7 km) and close to the volcano showed values similar to those for long paths but with a velocity inversion occurring between 3- and 5-s periods. Despite the scarce ray-path coverage, a tomography inversion provided the means to image an S-wave velocity anomaly (2.5–3.0 km/s) in the northern part of the crater at depths not larger than 6 km. The volcano-tectonic seismicity during 2012–2013 was found to be concentrated in the southern segment of this anomaly, which seems to mark a boundary between a solidified body (possibly a product of ancient volcanic craters) and the softer material.

PurposeAleppo city in Syria has witnessed severe bombardment since the 2011 war affecting its landscape heritage, causing explicit geomorphological changes with anthropogenic qualities. The research aims to log observations on the patterns of bombardment craters. It investigates their key role in guiding post-war recovery plans. Currently, the interpretation of war scars is not considered in the reconstruction plans proposed by local administrations and here lies the importance of the research.Design/methodology/approachThe study investigates the geomorphological transformations along the southern citadel perimeter in old Aleppo. Currently, digital tools facilitated data prediction in conflict areas. The research employs an empirical method for inhabiting war craters based on both qualitative and quantitative approaches. The former utilizes satellite images to define the geographical changes of landscape heritage. The latter applies geostatistical data analysis, validation, interpolation and simulation for multi-temporal Google Earth maps. The study exploits Surfer 13 software to localize and measure the preserved craters.FindingsThe research employs the generated models in a landscape design proposal examining the method's applicability. Finally, it offers a methodological toolkit guiding post-war landscape recovery toward the interpretation of conflict geography.Practical implicationsThe paper enables a practical understanding of the contemporaneity of landscape heritage recovery as an action between sustainable development and conservation.Social implicationsThe paper integrates the conflict geographies to the people's commemoration of places and events.Originality/valueThe article offers an insight into the rehabilitation of war landscapes focusing on land craters, exploiting geostatistical data prediction methods.

The Bosumtwi impact crater in Ashanti, Ghana is one of the most thoroughly investigated impact structures in Africa. Nevertheless, by the evaluations of Sentinel 1 and 2, and Landsat data as well as by ALOS PALSAR, ASTER and SRTM digital elevation model (DEM) data further geomorphological and structural knowledge can be derived. Morphometric maps were used to visualize the concentric and radial drainage and valley pattern surrounding the impact crater. The larger valleys are arranged in a nearly concentric and radial pattern like the river Pra and its tributaries, the Ofin, Anum and Brim river, tracing the outer, southern border of the impact affected area. From the ASTER and SRTM DEM data the morphological drainage basin was calculated. The drainage basin-outline is nearly circular, discharging into the Pra river in the southern part. Structural evaluations of satellite radar and optical data reveal that linear and circum-linear features can be detected more than 80 km around the Bosumtwi impact crater. Small-scale/artisanal mining activities in this area are visible on satellite images and, thus, indirectly tracing ore deposits. As detailed mineral maps are not publicly available, the position and distributions of mining areas was used as indicator for the occurrence of mineral deposits, especially placer deposits. Their occurrence and the distribution of the mining areas follows the larger rivers. Weathering processes along the deformation pattern and erosion and sedimentation probably had an influence on placer deposit development.

The waveforms and spectral content of the earthquakes that were recorded during the period of higher activity on Avachinsky Volcano in 2019 were studied to identify three commonly accepted types of volcanic earthquake (VE), viz., volcano-tectonic, hybrid, and long-period events, as well as a fourth type, a “special” VE type having certain special features in its waveforms. We have identified 15 plane-oriented clusters and determined characteristics of the seismogenic planes. An analysis of the seismic events that were recorded in the fall of 2019 on the Molodoi Konus of Avachinsky Volcano suggests that the resumption of activity was related to the magma bodies due to the 1991 eruption which exist in the cone body and to their interaction with atmospheric precipitation. The most likely cause of light flashes above the crater observed on December 8 seems to have been interaction between hydrogen-charged volcanic gas and air oxygen.

Tourism activities can never be separated from requires good policy and planning. As the development of TWA Ijen Crater in the CA area of Ijen Merapi Crater Ungup - Ungup, the location of which is a conservation area makes TWA Ijen Crater vulnerable to changes in terms of both the physical and social environment of the community. The importance of this analysis is to minimize the negative impacts so that the development of TWA Crater Ijen tourism will be sustainable, the research method used is descriptive qualitative with methods of collecting observation data, in-depth interviews, FGD quantitative supporting data in the form of questionnaires. The concept of analysis is the impact of tourism development on the physical and social environment, public perceptions and theories about Butler's tourism area life cycle. The development of TWA Ijen Crater which tends to lead to mass tourism activities has an impact on the carrying capacity of the environment both physically and socially, tourist activities offered by blue fire and spot sunrise tend to lead to limited and protected areas of use. Tourism is considered as an activity that will improve the welfare of the community so that an increase in the number of tourist arrivals will affect the people's income through tourist service businesses used by tourists.

The Chicxulub science museum is special, in that it is built around an event in geological time representing a turning point in the planet's history and which brings together the Earth system components. Studies on the Chicxulub impact, mass extinction and Cretaceous–Paleogene boundary provide an engaging context for effective geoscience communication, outreach and education. The museum is part of a research complex in Yucatán Science and Technology Park in Mexico. Natural history museums with research components allow for the integration of up-to-date advances, expanding their usefulness and capabilities. The impact ranks among the major single events shaping Earth's history, triggering global climatic change and wiping out ∼76 % of species. The ∼200 km Chicxulub crater is the best preserved of three large terrestrial multi-ring impact structures, being a natural laboratory for investigating impact dynamics, crater formation and planetary evolution. The initiative builds on the interest that this geological site has for visitors, scholars and students by developing wide-reaching projects, a collaboration network and academic activities. The Chicxulub complex serves as a hub for multi- and interdisciplinary projects on the Earth and planetary sciences, climate change and life evolution, fulfilling a recognized task for communication of geosciences. After decades of studies, the Chicxulub impact remains under intense scrutiny, and this programme with the core facilities built inside the crater will be a major player.

The possibility of a "death from above" cause for biotic crises and extinction events is intriguing, to say the least, but such claims must be supported by reliable and reproducible data, not only impact diagnostic criteria, but also accurate and precise radioisotopic ages of the impact structures/events. To date, only one example of such an impact-related global extinction event is confirmed, at the end of the Cretaceous period. Here we present and discuss results of newly obtained Ar-40/Ar-39 data from step heating analysis of impact melt rock samples from the 40 km-in-diameter Puchezh-Katunki impact structure, Russia, which allow us to precisely and accurately date its formation at 195.9 +/- 1.0 Ma (2 sigma; P = 0.10). Based on these new data, we challenge the proposed temporal correlation with as many as five different extinction events (including the end-Triassic mass extinction) that were based on previous age estimations ranging from similar to 164 to 203 Ma. Our new age for the formation of the Puchezh-Katunki impact structure allows us to exclude a relationship between this impact event and a known extinction event. We also show that careful sample preparation and methodology can overcome problems with inherited and trapped Ar-40, issues that are common when dating impact melt rocks. This is supported by Ar-40* diffusion and mixing numerical models showing that the most prominent negative effects in the case of the Puchezh-Katunki impact melt rock samples are caused by hydrothermal alteration and undegassed melt rock domains present in an otherwise homogenized melt rock. Numerical modeling also shows that the Ar-40* from high-Ca inherited crystals or clasts is decoupled from the melt rock during step heating experiments allowing to safely recover a plateau age. Finally, our results highlight the importance of improving the database of ages of impact structures and show that caution should be practiced when suggesting connections between specific impact events and extinction events, especially in the case of poorly dated impact structures. (C) 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

This study aims to gain a better understanding of the factors leading to the expressed shape of individual maars in volcanic fields. Maars are volcanic features produced by phreatomagmatic eruptions which excavate a crater beneath the pre eruptive surface through the explosive interaction of magma and water. Maar craters take on a wide range of shapes including, circular, elliptical, and polylobate. Across all maar fields, the existence of one or more axis of elongation is commonplace. Identification of the factors which lead to, and control, elongation in individual maars will help improve the accuracy of current hazard mapping and safety protocols. In order to determine whether the orientations of elongation are controlled by existing structures and regional stress, the primary and secondary directions of elongation of maar craters from a range of tectonic settings were measured. Maars were found to exhibit similar primary elongation orientations within each field. Influence of regional stress was identified in the geographic placement of maars along lineaments in most fields. Although many maars were found in lineaments identified through nearest neighbor analyses, they rarely share primary elongation orientations with the lineaments they compose. Furthermore, maars which shared similar primary elongation orientations with one another were not found to be grouped close together geographically. Overall, the number of maars in each field which share primary elongation orientations with existing structures (faults) and nearest neighbor lineaments does not suggest regional structural control over primary elongation orientation in any field. The tendency of maars to exhibit similar primary elongation orientations within a field, coupled with the lack of correlation with structural controls shows that the elongation orientations of maars are likely governed by more local controls related to host rock material, explosion induced changes to the stress regime, or hydrology.

On El Hierro (Canary Islands, Spain), the company Gorona del Viento El Hierro S.A. carried out the construction of a Wind‐Pumped Hydro Power Station in order to achieve the energy autonomy on the island through 100% renewable energy. The station consists of two man‐made water reservoirs, whose design was adapted to the island topography and emplaced in a valley and an inactive crater. In order to study the subsurface of both reservoirs, the characteristic heterogeneity of volcanic materials was taken into account. Therefore, a research campaign combining different methods was proposed; mechanical investigations traditionally applied in engineering (rotary boreholes, dynamic probing super heavy tests and pits) and geophysical methods (seismic refraction tomography and electrical resistivity tomography) were both utilized. The aims were to determine the geological structure of each site, detect possible anomalies or structures (i.e., faults, volcanic cavities, etc.), identify the different lithologies, determine the soil thickness and depth to bedrock, predict the excavatability of the materials, and obtain data about the physical properties and mechanical behaviour of the ground in an effort to carry out a geotechnical site characterization of both sites. At the site of the upper reservoir, electrical resistivity tomography recorded a high thickness of low resistivity soils, which were subsequently investigated by deep boreholes in order to sample and test them properly, since they could generate high settlements during the construction of the reservoir. At the site of the lower reservoir, the existing palaeorelief in the basaltic bedrock was detected by seismic refraction tomography, which allowed for the selection of the appropriate excavation machinery for the planned earthworks. The geological interpretation of the P‐wave velocity models and electrical resistivity models are shown in this paper, as well as a correlation between geotechnical parameters and geophysical properties of volcanic materials and recent deposits, which will be useful for other civil projects which may be carried out in the future at sites with similar geological conditions.

The Koźle Basin in Poland was radically transformed by aerial bombardment during the Second World War. Today, the region has approximately 6000 well-preserved bomb craters with diameters ranging from 5–15m and depths often exceeding 2m. Combining remote-sensing data and fieldwork with historical accounts, this article analyses these craters, demonstrating that their varied morphologies derive from the weight of the bombs that created them, and on the type and moisture content of the soil on which the bombs fell. Based on their results, the authors issue a call for the official protection of the Koźle landscape, which has particular historical, educational and ecological value.

The earth crust is made up of variety of minerals. These minerals are having very significant applications in our day today life. The various studies, characterizing physical, chemical, electrical, structural properties, have been carried out on the Lonar crater for studying mineralogy, surface morphology and geology but has not been done by remote sensing technology. So, the proposed work focused on exploring the mineralogy at the Lonar crater by using high resolution hyperspectral imageries. The spectral reflectance of minerals was characterized by using FieldSpec4 spectroradiometer. The minerals at Lonar crater were explored by performing preprocessing and spectral analysis. The techniques used in the work are Spectral Angle Mapper and Spectral Feature Fitting. The results of the work marked the presence of pigeonite and augite at Lonar crater which indicates that this crater is the result of extrusive volcanic activity. Also, the presence of augite underneath basaltic igneous rocks as the rock type of Lonar crater. The salinity of the Lonar lake is proved by the presence of mirabilite and salt. Thus, the important results of this work are presence of minerals quartz, actinol, jarosite, pigeonite, augite, albite, mirabilite and scolecite. The significance of these minerals related to the crater is discussed here. It also validated the existence of these minerals which were identified through the previous geological, chemical, physical, electrical and magnetic studies and the minerals pyrite, chlorite, richter, illite, limonite, allanite, amphibolite and margarite were also identified.

The geochemistry of volcanic gases has been fruitfully applied to identify important changes in the volcanic activity. This study reviews the dataset of the volcanic gas survey performed during 2009 and 2010 at Stromboli (Aeolian Islands - Italy). Dry gas collection occurred discontinuously at the crater fumaroles for subsequent chemical and isotopic (δ13C-CO2) analyses in the laboratory.A tailor-made device enabled continuous survey of H2 molar fraction and CO2 flux on the same site. Evaluation of the raw data was performed in accordance with air temperature, atmospheric pressure, wind speed and wind direction dataset. Both MLR (Multiple Linear Regression) and FFT (Fast Fourier Transform) analyses allowed filtering the dataset from the environmental effects. The MLR analysis indicated that wind speed and air temperature affected the CO2 flux. Changes in the atmospheric pressure promoted pumping effect of the fumarole gas and caused changes in the H2 molar fraction. The power spectral analysis revealed daily cycles in both gases. A digital signal filtering procedure enabled minimizing the environmental effects.This study confirmed that gas emissions from the crater fumaroles have both chemical ad isotopic composition similar to the magmatic gas phase. The results of the continuous survey showed that changes of both H2 and CO2 correlated with changes of the volcanic activity. Therefore, H2 and CO2 resulted effective tracers of the dynamics involving the plumbing system of Stromboli. Identification of changes in the gas emissions at open conduit volcanoes offers a great advance over the ground gas survey. The results of the continuous survey at Stromboli showed that H2 could apply as an auxiliary parameter of the CO2 flux in the surveillance programs of active volcanoes.

The aim of this research is to analyze economic, social, and environmental impacts of International Tour de Banyuwangi Ijen (ITdBI) to local community development in Ijen Crater – tourist destinati...

Sulphur miners in Ijen crater, Banyuwangi, Indonesia has been undergoing life changing experience for many years. It happened due to the natural phenomena of the area. Mount Ijen has a potential natural tourism that might attract domestic and international tourists. In addition, the area has high sulphur contents. The management of sulphur is fully authorized by CN Company. The traditional miners deposit the mining results to the company. Working in sulphur mining is very risky, especially for the carriers who are paid based on the quantity of sulphur they bring up from the crater. This study explores in deep the profile of the traditional sulphur miners in Ijen crater, Banyuwangi. It employs a qualitative approach to obtain the real image of their profile. The research results are (1) three types of traditional sulphur miners in Ijen crater are found. Two of them are permanent employees of the company while the remaining type of the miners is independent worker, whose activities are searching and carrying the sulphur. The Ijen crater miners had an uncertain income, depending on the amount of sulphur successfully transported. (2) The minimum income of the traditional miners leads them to transform the job into businesses. (3) The transformation lets them contribute more to their family life.

This study investigates anti-Chinese violence in the American West—focusing primarily on events in the Arizona Territory between 1880 and 1912—and the role of diplomatic relations between the United States and China in tempering the worst excesses of that violence. Recent scholarship asserts that the Chinese rarely suffered lynching and were commonly targeted for other types of violence, including coercion, harassment, and intimidation. Building on that work, this study advances a definition of racist violence that includes a broad spectrum of attacks, including the threat of violence. While affirming that such “subtler” violence achieved many of the same objectives as the “harsher” violence, it seeks to explain why whites used such radically different and less openly violent methods against this minority and explains why this difference mattered. Using these insights to interrogate the complex relationship between the United States and China, this essay shows that Chinese diplomatic influence stifled anti-Chinese mob violence by white Americans. It argues that this relationship denied white racists the same agency against the Chinese immigrants as they possessed against other racial and national minorities and thus forced them to “choose” the “subtler” acts of violence against this group rather than those usually employed against these others.

The Simlipal complex in eastern India is an elliptical structure with diameter of ca. 50 km coinciding with an elliptical region of high gravity. It overlies the Archaean basement of the Singhbhum craton and has a ring structure characterized by complex series of concentric ridges with inward dipping slopes. Quartz clasts in melt-breccias from the complex display diagnostic shock metamorphic features such as two to three sets of decorated and annealed planar deformation features (PDFs), spall and concussion micro-fractures, and the presence of coesite. They also preserve microstructures suggestive of crystallographically-controlled melting/amorphization along two or three planar directions, and within concussion micro-fractures. The inferred shock pressures in excess of 40–60 GPa are possible only during bolide impact. The Simlipal structure is possibly the remnant of a large complex impact crater having an original diameter of at least 50 km. Although zircons from an impact melt rock furnish a concordia age of 3107±14 Ma, in the absence of any unambiguous shock metamorphic effects in them, it is difficult to assign the age to the impact event. Therefore, the age of the impact is currently unconstrained.

We present the results of geological and morphological analysis of LROC NAC images of a small volcanic crater Ina, D-shaped in plan view (2.9 × 1.9 km), and its immediate surroundings. This crater is located at the top of a very gently sloping shield volcano, the slopes of which, judging by the density of superimposed small craters, were formed ~3.5 Ga ago. Inside the crater there is a region with uneven relief and low hills, the density of small craters on which corresponds to an age of

This article assesses how the ground-penetrating radar RIMFAX will image the crater floor at the Mars 2020 landing site, where lithological compositions and stratigraphic relationships are under discussion prior to mission operation. A putative mafic unit (lava flow, volcanic ash, or volcaniclastic deposit) on the crater floor will be crucial in piecing together the chronology of deposition and for understanding the volcanic history in the region. In order to see how lithological properties and subsurface geometries affect radar sounding, a synthetic radargram is generated through forward modeling with a finite-difference time-domain method. The acquisition is simulated across the mafic unit as a succession of lava flows, exploring detection of internal structures and contacts to adjacent lithologies. To compare modeling results with the alternative formation scenarios, a discussion about sounding over a tephra or volcaniclastic material is presented. Similarities and differences between Martian and terrestrial lithologies can be related to electromagnetic properties relevant for radar sounding. This article, therefore, evaluates potential scientific insights gained from acquisition across the disputed mafic unit, in light of proposed hypotheses of lithological generation.

As the second common type of volcanic vent on Earth, maar-diatreme volcanoes and their post-eruptive lacustrine sediments are a main focus of volcanology, palaeolimnology, palaeoclimatology and palaeontology. A number of maar-type volcanoes have been found in Leizhou Peninsula, South China, but little is known about their eruption processes and detailed stratigraphy of the post-eruptive sediments. We present a combined geophysical and geological analysis to study the eruptive history and post-eruptive sediment stratigraphy of a large maar, the elliptical (1.8 × 3.0 km2) Jiudouyang (JDY) maar. The lacustrine stratigraphy revealed by drilling cores shows that the JDY maar lake has three major stages of evolution: (i) deep-lake sedimentary environment characterized by high autochthonous diatom productivity; (ii) shallow lake to swamp with very low water levels, characterized by a high total organic carbon (TOC) and abundant wood fragments; and, (iii) intermittent shallow lake and alluvial deposits composed of clay minerals and sand. The electrical resistivity tomography (ERT) values and lithological features are highly consistent, which clearly reveal the presence of ca. 50 m thick lacustrine sediments, directly underlain by a ca. 70 m thick basaltic lava rather than diatreme breccia in the crater. This infill sequence implies an alternation of eruption style from phreatomagmatic to Strombolian and/or lava flow, due to high magma flux and ascent rate of the Hainan Plume during the middle Pleistocene. The ERT data also reveal the initial phreatomagmatic crater floor at ca. 120 m depth. The initial crater had a large diameter/depth ratio (ca. 17), with an elongated shape (major axis to minor axis = 0.6), implying possible lateral vent migration during the eruption. A significant erosion under tropical weathering condition during the last few hundred thousand years, accounted for the large size of the maar crater. The study provides insights into the eruptive history and post-eruptive evolution of a large maar, as well as the spatial distribution of the lacustrine sediments.

During the field campaign in August 18–30, 2020 the meteorological regime and heat balance of the glacier surface were investigated in the crater of Mt Elbrus Eastern Summit (5600 m a.s.l.) together with the GPR measurements of the ice thickness and seasonal snow cover. Preliminary data analysis allowed the following features: the predominance of synoptic fluctuations over the diurnal ones; the high values of average and maximum wind speed associated with the impact of jet streams and with influence of leeward storms; extremely high temporal variability of relative humidity and its very high deficit in cloudless conditions conducive to intensive evaporation and sublimation from the snow surface. The maximum thickness of ice in the crater reaches 100 m, and the average is 34 m. A new ice core with a length of 96.01 m from the glacier surface to its bed had been obtained. The drilling speed varied from 11 to 1 m/h, decreasing with depth from 4.5 to 4.0 m/h on average. The thickness of the snow-firn mass is about 20 m, which is three times less than on the Western Plateau of Mt Elbrus. According to measurements in the borehole, temperature at the glacier bed is −0.6 °C. The calculated heat flux is 0.39 W/m2. Air sampling was carried out in the crater of the Eastern Summit of Elbrus and on the Garabashi glacier. Repeated measurements of the soil temperature in the fumarole field on the outer edge of the crater of the Elbrus Eastern Summit allow the conclusion that the temperature regime is stable.

This work analysis an 81 km long 1.85 km wide fluvial valley on Mars (at 2°55’ South and 111°53’ East) for the first time, located near to the so-called Palos carter and Tinto Vallis, called Tinto-B hereafter. The length of the valley is approximately 81 km, and the average width is ~1.85 km, depth ~250 m. The hypsometric curves were created in 5 different buffer sizes on the main valley and the biggest tributary valley. The tributary valley shows a youth stage in the geomorphological evolution opposite to the main valley, which shows a mature stage. The crater statistical analysis based age of the main valley (2.9 Ga) poorly correlates with the early wet period of the red planet, thus, formed somehow later than most Martian valleys. Using the model SIMWE (SIMulated Water Erosion), for the to identify the small-scaled tributary valley systems and the small-scaled erosional landforms showed area elevated drainage density. The highest density of the tributary sections is 29.02 km/km2 , and the average is 3.09 km/km2. Considering only the main valley 0.017 km/km2 would have been measured, suggesting dozen(s) early tributaries were heavily eroded.

The 1.85 Ga Sudbury impact structure is considered a remnant of a peak-ring or multi-ring basin with an estimated original diameter of 150 to 200 km. The Offset Dikes are radial and concentric dikes around the Sudbury Igneous Complex (SIC) and are composed of the so-called inclusion-rich Quartz Diorite (IQD) and inclusion-poor Quartz Diorite (QD), and in some Offset Dikes, Metabreccia (MTBX). We carried out a detailed field and analytical investigation of MTBX from the Parkin Offset Dike in the North Range of the Sudbury structure. Our observations suggest that MTBX represents impact breccia that originally formed underneath the Main Mass of the SIC and that was subsequently contact-metamorphosed and entrained during the emplacement of the Parkin Offset Dike. The MTBX bears no resemblance to the QD and IQD in which it is hosted, but it does share many similarities with Footwall Breccia (FWBX), suggesting that the two shared a similar initial origin. A genetic relationship between MTBX and FWBX is also supported by whole rock geochemical analyses.

According to data of dendrochronological investigations of larch trees that had grown on the Patom crater (Irkutsk oblast, Bodaibinskii district) and near its base, the initial period of the formation of the crater can be dated back to the late 15th‒early 16th centuries. In 1841‒1842, the trees under investigation recorded in annual rings a catastrophic event which caused a disturbance to their root systems, damage to tree stems, and the formation of compression wood. It is obvious that the event is associated with the time of formation of the late stage ring swell on which sparse larch trees are 93‒101 years of age, and on the central mound emerging upon completion of the formation of the Patom crater the age of the oldest tree is 7 years. Thus dendrochronological investigations confirm a long-lasting and multievent formation of the Patoma crater. In some periods, the deposition cone was evolving with a different intensity, sometime showing an explosive character. X-ray fluorescent analysis revealed a double Sr enrichment of larch wood at the time of significant activity of crater formation (1852‒1859) when plutonic fluids from the igneous source were able to enter the upper horizons of the Earth’s crust at the time of magma intrusion into water-containing rocks. The fluids were enriched with CO2 and transported significant amounts of Sr, as a result of which the 87Sr/86Sr ratios in carbonate and terrigenous rocks assumed higher values in sandstone and schists on the early stage ring swell of the Patoma crater. The findings, coupled with geological data, suggest that the Patom crater emerged as a result of a phreatic explosion that occurred either at the time of magma intrusion into water-containing rocks or as a consequence of the fault and decompression of heated water-containing rocks.

We studied the distribution and abundance of African elephants in Ngorongoro Crater (NC), northern Tanzania to test whether male and female elephants select different habitats and to assess whether...

The Pico do Fogo volcano, in the Cape Verde Archipelago off the western coasts of Africa, has been the most active volcano in the Macaronesia region in the Central Atlantic, with at least 27 eruptions during the last 500 years. Between eruptions fumarolic activity has been persisting in its summit crater, but limited information exists for the chemistry and output of these gas emissions. Here, we use the results acquired during a field survey in February 2019 to quantify the quiescent summit fumaroles' volatile output for the first time. By combining measurements of the fumarole compositions (using both a portable Multi-GAS and direct sampling of the hottest fumarole) and of the SO2 flux (using near-vent UV Camera recording), we quantify a daily output of 1060±340 tons CO2, 780±320 tons H2O, 6.2±2.4 tons H2S, 1.4±0.4 tons SO2 and 0.05±0.022 tons H2. We show that the fumarolic CO2 output from Pico do Fogo exceeds (i) the time-averaged CO2 release during 2015-type recurrent eruptions and (ii) is larger than current diffuse soil degassing of CO2 on Fogo Island. When compared to worldwide volcanoes in quiescent hydrothermal-stage, Pico do Fogo is found to rank among the strongest CO2 emitters. Its substantial CO2 discharge implies a continuous deep supply of magmatic gas from the volcano’s plumbing system (verified by the low but measurable SO2 flux), that becomes partially affected by water condensation and sulphur scrubbing in fumarolic conduits prior to gas exit. Variable removal of magmatic H2O and S accounts for both spatial chemical heterogeneities in the fumarolic field and its CO2- enriched mean composition, that we infer at 64.1±9.2 mol. % H2O, 35.6±9.1 mol. % CO 0.26±0.14 mol. % total Sulfur (S ), and 0.04±0.02 mol. % H2.

Lower Cretaceous volcanic rocks that contain major natural fractures are the main natural gas reservoirs in the deep Xujiaweizi depression of the northern Songliao Basin in China. Natural fractures are mainly tectonic fractures, in addition to some shrinkage, dissolution, and cryptoexplosive fractures. Analyzing various sources of data revealed that fractures are generally better developed in the rhyolites and trachytes of the crater and near-crater group. Also, tectonic fractures are developed to a higher degree in the hanging wall of faults, with the degree of development decreasing with increasing distance from the fault planes. More than 85% of these fractures are found to be unfilled and, when connected by pores, provide the main effective storage volume for these volcanic reservoirs (up to ∼75%). Natural gas production is closely related to the linear density (P10) of unfilled tectonic fractures and the angle between the orientation of unfilled tectonic fracture and the corresponding direction of the maximum horizontal stress component. The results show that natural gas production is elevated when the average P10 exceeds 2 m−1, and the average included angle is less than 30°. Finally, it was concluded that within the study area, unfilled tectonic fractures of near east-west strikes, which have smaller included angles (

The deeply eroded Acraman structure in the Mesoproterozoic Gawler Range Volcanics, Gawler Craton, South Australia, ranks among the world’s largest known impact structures, with a transient crater ∼...

This study was performed to identify and interpret airborne geophysical responses and landform features of the Cabeça de Sapo Structure (CSS), a 6 km-diameter circular structure located in northeastern Brazil, SW of the Maranhão State, suspected of having been formed by the impact of a solid body. The application of processing techniques addressed to enhance the images from the remotely sensed data (gamma-ray spectrometry, magnetic, Sentinel 2B and ALOS PALSAR) enabled the identification of two airborne geophysical responses (ring-shaped magnetic anomaly and radiometric patterns) and five landform features ("A", "B", "C","D" and "E"). The ring-shaped magnetic anomaly is related to a 5.4 km-diameter well-defined circular structure and the depth of its magnetic sources is estimated in 300 m. Those sources are unknown, but they probably occur due to layers of dolerite sills. The radiometric patterns identified seem to be related to the "A" and "D" landform features. Feature "A" is an elevated area at the center of CSS. The radiometric response (high eTh, eU, and low K) at the top of this area possibly reflects the weathering effect, while the radiometric response (high K and low eTh, eU) at the hillside is possibly from the lithotypes that have supported this elevation. Feature “D” is a 6 km – diameter circular elevated area that corresponds to the outer boundary of CSS. This boundary is characterized by increased eU counts, which may happen due to weathering-resistant mineral content (e.g. zircon) present in eolian sandstones. Features “C” and “E” are outside of CSS. The first is interpreted as plateau-shaped residual relief formed by differential erosion of basaltic rocks and sandstones and the second is interpreted as a flat-relief dominated by eolian sandstones. This flat-relief may represent the landscape that has not been affected by the formation process of CSS, while the affected internal region may be represented by feature “B”. The interpretations also have revealed that CSS shows some similarities with typical features of impact structures, namely: disruption of the magnetic field by a ring-shaped magnetic anomaly; central elevation surrounded by a raised outer rim; local control of drainage and; differences in the relief pattern of internal and external parts of the structure. Those similarities reinforce the possibility of an exogenous origin of CSS, but new studies are required to confirm or refuse such possibility.

Multidisciplinary petrologic, mineralogical, and geochemical studies have been carried out for the first time concerning near-crater tephra from the world-largest intraplate stratovolcano (Erebus). The volcano is characterized by a unique basanite–phonolite effusive lineage. We studied the grain-size and chemical compositions of the tephra and the concentration of trace elements in it, the mineral phase composition, lithogenic gases encapsulated in the tephra, an atomically dispersed carbonaceous substance, and the isotope composition of carbon in it. We came to the conclusion that the tephra studied here can be treated as an explosive analogue of anorthoclase lava phonolites that terminate the continuous series of magmatic differentiates known as the Erebus lineage.

The phreatomagmatic eruption at Aso volcano on October 8, 2016, released PDC and fallout up to 320 km from the vent, providing an opportunity to study the dispersal and sedimentation of tephra bearing wet and dry aggregates. We investigated fresh air-fall tephra and conducted both dry- and wet-sieving to assess the size distribution of both aggregate-bearing deposits on the ground and particles in the plume prior to aggregation. The tephra was asymmetrically distributed in the ENE direction, with a relatively wide distribution and small maximum grain sizes north of the depositional axis, reflecting different wind directions at each altitude. The secondary accumulation maxima at 4–8 km NE from the vent was characterized by the segregation of lapilli followed by accretionary pellets that were rapidly created by aggregation in the wet plume, thereby enhancing the removal of airborne ash. Coalesced aggregates possibly arose from salt precipitation processes. For dry aggregates fallen in medial-to-distal regions, observed deposition duration and fall velocity calculations concluded that fine ash was deposited not as individual particles but as aggregates. Most grain-size distributions along the dispersal axis based on the two sieving methods used were multimodal, with the coarser mode fining according to distance from the vent and the finer mode stabilizing at around 4ϕ; this is interpreted as resulting from the mixture of grain-size distributions with different origins, i.e., the normal settling of individual clasts and particle aggregation. The wet-sieved total grain-size distribution included 20.4 wt% fine ash compared with only 2.4 wt% fine ash in the dry-sieved distribution, suggesting that aggregated particles accounted for 18 wt% of the deposit. Total grain-size distributions based on wet-sieving showed extremely poor sorting that could be explained by the following causes: the release of coarse-grained ejecta originating from the host rock of the crater, fine particles due to fragmentation from a phreatomagmatic eruption, the supply of water and salt from the crater to the plume, and aggregation enhancement of the fine ash on the ground, reflecting the effect of the crater lake as external water source.

During the 2018 eruption of Kīlauea Volcano, Hawai'i, scientists relied heavily on a conceptual model of explosive eruptions triggered when lava-lake levels drop below the water table. Numerical modeling of multiphase groundwater flow and heat transport revealed that, contrary to expectations, liquid water inflow to the drained magma conduit would likely be delayed by months to years, owing to the inability of liquid water to transit a zone of very hot rock. The summit of Kīlauea subsequently experienced an ∼2-month period of consistent repeated collapses, and the crater now extends below the equilibrium position of the water table. Liquid water first emerged into the deepened crater in late July 2019. The timing of first appearance of liquid water (about 14 months postcollapse) and the rate of crater lake filling (currently ∼27 kg/s) were well-predicted by the numerical modeling done in late spring 2018, which forecast liquid inflow after 3 to 24 months at rates of 10 to 100 kg/s. A second-generation groundwater model, reflecting the current crater geometry, forecasts lake filling over the next several years. The successful 2018 to present forecasts with both models are based on unadjusted in situ permeability estimates (1 to 6 × 10-14 m2 ) and water-table elevations (600 to 800 m) from a nearby research drillhole and geophysical surveys. Important unknowns that affect the reliability of longer-term forecasts include the equilibrium water-table geometry, the rate of evaporation from the hot and growing crater lake (currently ∼29,000 m2 at 70-80 °C), and heterogenous permeability changes caused by the 2018 collapse.

Introduction: The results of a comprehensive study of the geological structure and material composition of the weathering crust of the kimberlites in north-east Angola are presented. An important applied problem is the assessment of the degree of enrichment of the weathering crust by deep minerals for forecasting and searching for new diamond deposits of both primary and placer types. Methodology: The Catoca kimberlite pipe, characterized not only by an insignificant erosional section and preservation of the crater structure, but also by a wide petrographic spectrum of rocks and their intense post-magmatic and hypergenic variation, was chosen as a reference object. The collection of ore samples and flow samples from the upper horizons of the Catoca pipe and a number of other bodies of this field, as well as rocks containing kimberlites, were collected for the study of the geological structure and material composition of weathering crusts of weakly eroded Angola kimberlite pipes. Results and discussion: Two genetic types of rocks were distinguished in the Catoca kimberlite pipe: kim- berlites with their derivatives and a complex of volcanic-sedimentary formations filling the upper parts of the crater of diatreme. In general, the profile of the weathering crust is divided into two parts: lower and upper. The lower part (disintegration zone) is represented by slightly altered autolithic kimberlite breccias, fractured and partially ocherized. The upper, the most hypergene-altered zone, in turn, is divided into carbonate and non-carbonate parts. Conclusions: Two processes of changes in the kimberlite rocks of the region were revealed. The first process is the phased conversion of olivine to high-temperature, then low-temperature serpentine. The second process is the degradation of serpentine with the simultaneous emergence of a series of swellable minerals, starting with saponite through a series of intermediate metastable mixed-layer formations, out of which the ordered variety of lyzardite-saponite, identified for the first time, was relatively more stable compared to other ordered mixed-layer phases of the trioctahedral type. This finding emphasizes the specific conditions of crust formation of the weathering kimberlites of the African region.

Pyroclastic deposits of the Holocene Igwisi Hills kimberlite volcanoes, Tanzania, preserve unequivocal evidence for rapid, syn-eruptive agglutination. The unusual pyroclasts are composed of ash-sized particles agglutinated to each other by thin necks. The textures suggest the magma was disrupted into droplets during ascent. Collisions between particles occurred within a volcanic plume and on deposition within the conduit to form a weakly agglutinated, porous pyroclastic deposit. Theoretical considerations indicate that agglutination occurred over short timescales. Agglutinated clasts were entrained into weak volcanic plumes and deposited around the craters. Our results support the notion that agglutination can occur during kimberlite eruptions, and that some coherent, dense rocks in ancient kimberlite pipes interpreted as intrusive rocks could instead represent agglutinated pyroclastic rocks. Differentiating between agglutinated pyroclastic rocks and effusive or intrusive rocks in kimberlite pipes is important because of the potential effects that pyroclastic processes might have on diamond concentrations in deposits.

Cenozoic basalt, which is widespread in Mongolia, has been attracting the attention of Central Asian researchers since the beginning of the last century. This study identified the geomorphological shape of the Khorgo volcano. The main purpose of the study is to determine the origin and morphological form of Khorgo volcano, a key representative of Cenozoic volcanism. In general, there are several types of morphological forms associated with lava overflow, and it is important to determine which types are the most common and also to establish a link between them. Geomorphological studies in this area have not been conducted in Mongolia. Spatial improvement and morphometric methods satellite imagery had identified Khorgo volcanic faults.Khangai magmatism had thinned its crust to 45 km during the Tariat-Chuluut volcanic activity. It can be concluded that this was due to the thinning of the continental crust in the Khangai Mountains because of mantle plume. During this time, tectonic faults formed were formed, which had broken through the earth's crust. Part of this fault was formed in the vicinity of Khorgo Mountain from northwest to southeast, and lava flowed with the basic composition, which led to the formation of the current morphological form of Khorgo volcano. The lava flow was less than 45% silica and potassium-dominated, which blocked the Suman River valley and formed the present-day Terkhiin Tsagaan Lake. The morphometric analysis compared the morphology of a typical volcano, which showed that the mouth of the crater of the Khorgo volcano has a slope slanting about 45 degrees, it is about 100 meters in depth, with a diameter of about 500 meters. By comparing the basalt composition of the Khorgo volcano and its morphometric characteristics with other standard volcanoes, it has been determined that it is in the form of a lava dome.

We investigated the magmatic–hydrothermal system of Aso Volcano, Japan, using broadband magnetotelluric (MT) data. To establish the nature of the shallow crust, a previous resistivity model based on data from 100 measurement sites in and around Aso volcano was revised using data from 9 additional sites near Naka-dake crater, which is located in the central part of the volcano. The components of MT impedance and the tipper vector were used to obtain the resistivity structure by three-dimensional inversion. The resistivity structure shows a subvertical low-resistivity (

The atmospheric pollution associated with the volcano Copahue activity was evaluated by analyzing the concentration of 33 elements including heavy metals in lichens. Fruticose thalli were collected between 7 and 18 km from the volcano crater, comprising a geothermal zone. Analytical data and geographic parameters were evaluated by Principal Component Analysis. Enrichment Factors was also calculated from elemental concentrations in the lichens. The Principal Components Analysis grouped the observations corresponding to the lichen samples in relation to the volcano crater distance, the thermal areas and the direction of the prevailing winds. The less impacted area by volcanic products presented a lower concentration of toxic elements (S and Hg) and a higher concentration of biological elements (Ca, K, Mg and Mn) than the other areas. All studied sites showed S and Se enrichments, even in the most distant areas from the volcano crater. The S concentrations in lichen recorded in areas of volcanic activity were higher for the volcanic complexes: Copahue-Caviahue and Puyehue-Cordon-Caulle (2800-12000 µg/g) than those reported for the rest of the world (600-2800 µg/g).