Recent Volcanism Research Articles

The selective geography of volcanism in oral traditions

Abstract Oral traditions describing details of ancient volcanic eruptions and their effects survive throughout the inhabited world. Many such eruptions, especially those having catastrophic environmental and societal consequences, proved sufficiently memorable to form the basis of enduring oral traditions. Using global databases, we identified 2306 such eruptions from 477 inhabited locations that occurred before the start of the Common Era (CE) and are therefore likely to have been the subject of oral traditions. Of these, we selected 20 events (‘remembered’ Holocene eruptions) for which there are extant oral (-derived) traditions that demonstrate how such traditions can reveal details of past volcanism that often are undetectable by retrodictive geoscientific enquiry. We also selected 20 events (‘forgotten’ Holocene eruptions) about which no oral traditions are known and discuss the possible reasons for this. Such oral traditions, while often challenging for conventionally trained geoscientists to interpret, are valuable yet largely overlooked sources of information about the nature and effects of Holocene volcanism that can usefully complement geoscientific enquiry. In particular, we identified locations where memories of such volcanism appear ‘forgotten’ in the hope that scientists might focus their attention on revealing, identifying, and analyzing local traditions.

A state‐of‐the‐art review on geothermal energy exploration in Morocco: Current status and prospects

AbstractIn the last few decades, addressing the global challenge of implementation of strategies for renewable energy and energy efficiency has become crucial. Morocco, since 2009, has made a steadfast commitment to sustainability, with a particular focus on advancing the development of renewable energy resources. A comprehensive strategy has been formulated, centering on utilizing the country's energy potential to drive progress in this vital sector. Morocco is considered a country with abundant thermal water, indicating deep reservoirs with significant hydrothermal potential. Geothermal zones were selected based on the abundance of hot springs where water temperatures were high and geothermal gradients were significant. The abundance and importance of hot springs, combined with recent volcanism and ongoing non‐tectonic activity linked to alpine orogeny, strongly suggest that these regions are promising reservoirs for geothermal energy. This great potential also extends to neighboring countries. In northeast and south Morocco, the temperature of thermal water ranges from 26 to 54°C. This study serves as an inclusive review of the geothermal potentialities in Morocco.

Submarine volcanism in the Sicilian Channel revisited

The origin and role of volcanism in continental rifts remains poorly understood in comparison to other volcano-tectonic settings. The Sicilian Channel (central Mediterranean Sea) is largely floored by continental crust and represents an area affected by pronounced crustal extension and strike-slip tectonism. It hosts a variety of volcanic landforms closely associated with faults, which can be used to better understand the nature and distribution of rift-related volcanism. A paucity of appropriate seafloor data in the Sicilian Channel has led to uncertainties regarding the location, volume, sources and timing of submarine volcanism. To improve on this situation, we use newly acquired geophysical data (multibeam echosounder and magnetic data, sub-bottom profiles) and dredged seafloor samples to: (i) re-assess the evidence for submarine volcanism in the Sicilian Channel and define its spatial pattern, (ii) infer the relative age and style of magmatism, and (iii) relate this to the dominant tectonic structures in the region. Quaternary rift-related volcanism has been focused at Pantelleria and Linosa, at the northwest boundaries of their respective NW-SE trending grabens. Subsidiary and older volcanic sites potentially occur at the Linosa III and Pantelleria SE seamounts, collectively representing the only sites of recent volcanism that can be directly related to the main rift process. These long-lived polygenetic volcanic landforms have been shaped by magmatism that is directly correlated with extensional faulting and buried igneous bodies. Older volcanic landforms, sharing a similar scale and alignment, occur to the north at Nameless Bank and Adventure Bank. These deeply eroded volcanoes have likely been inactive since the Pliocene and are probably related to earlier stages of crustal thinning and underlying feeder structures in the northern region of the Sicilian Channel. Along a similar alignment, Pinne Bank, SE Pinne Bank and Cimotoe in the northern Sicilian Channel lack a surface volcanic signature but are associated with intrusive bodies or deeply buried volcanic rock masses. Terrible Bank, in the same region, also shows evidence of ancient, polygenetic magmatism, but was subject to significant erosion and lacks a prominent alignment. The much younger volcanism at Graham Volcanic Field and along the northern Capo-Granitola-Sciacca Fault Zone differs markedly from that observed in the other study areas. Here, the low-volume and scattered volcanic activity is driven by shallow-water mafic magma eruptions, which gave rise to small individual cones. These sites are associated with large fault structures away from the main rift axis and may have a distinct magmatic origin. Dispersed active fluid venting occurs across both ancient and young volcanic sites in the region and is directly associated with shallow magmatic bodies within tectonically-controlled basins. Our study provides the foundation for an updated tectonic and magmatic framework for the Sicilian Channel, and for future detailed chronological and geochemical assessment of the sources and evolution of magmatic processes in the region.

Groundwater recharge sources and mechanisms in the Ethiopian central Afar rift: Insights from isotopic and hydrogeochemical tracers.

Groundwater flow and recharge mechanisms in the central Afar rift and the associated western marginal grabens and Northwestern Plateau (NWP) are poorly understood because of the complex geology and spatial heterogeneity in the aquifer systems. The major aquifers in the region include the Oligocene and Pliocene to recent volcanics and recent alluvio-lacustrine sediments. We employed hydrogeochemical, stable isotopes of water (18O and 2H), and geological structures insights to identify groundwater recharge sources and mechanisms, aiming to develop a representative conceptual groundwater flow model. Water samples from groundwater and surface water were collected based on lithological/aquifer variation and geomorphological setup for isotope and hydrochemical analysis. Findings reveal distinct isotopic differences between the deep (>350 m) and shallow groundwater systems of the Afar rift, with deep systems showing relative isotopic depletion, indicating varying recharge sources. The deep groundwater exhibited a similar isotopic signature to that of the marginal grabens and NWP. The distribution of major ion chemistry and electric conductivity (EC) of groundwaters from the western plateau to the Afar rift show significant spatial variability. However, in some corridors of western parts of the rift, there is a clear geochemical evolution along the flow paths inferring groundwater flow continuity between aquifers. The results revealed the existence of preferential deep groundwater recharge from the NWP through the highly fractured linking zones, interacting fault zones in between the marginal grabens, to the deeper volcanic aquifers of the central Afar rift. The proposed groundwater flow model of this study illustrates the deep groundwater flow from the NWP to the Afar rift is primarily directed by the orientations of the faulted marginal grabens and the highly fractured interacting zones. This model is pivotal for understanding groundwater dynamics in similar continental rift environments, offering insights for effective groundwater management.

Reconciling Mars InSight Results, Geoid, and Melt Evolution With 3D Spherical Models of Convection

AbstractWe investigate the geodynamic and melting history of Mars using 3D spherical shell models of mantle convection, constrained by the recent InSight mission results. The Martian mantle must have produced sufficient melt to emplace the Tharsis rise by the end of the Noachian–requiring on the order of 1–3 × 109 km3 of melt after accounting for limited (∼10%) melt extraction. Thereafter, melting declined; however, abundant evidence for limited geologically recent volcanism necessitates some present‐day melt even in the cool mantle inferred from InSight data. We test models with two mantle activation energies and a range of crustal Heat Producing Element (HPE) enrichment factors and initial core‐mantle boundary temperatures. We also test the effect of including a hemispheric (spherical harmonic degree‐1) step in lithospheric thickness to model the Martian dichotomy. We find that a higher activation energy (350 kJ mol−1) rheology produces present‐day geotherms consistent with InSight results, and crustal HPE enrichment factors of 5–10‐times produce localized melting near or up to present‐day. The 10‐times crustal HPE enrichment is consistent with both InSight and geochemical results and also produces present‐day geoid power spectra consistent with Mars. However, calculations that match the present‐day geoid power spectra require more than 60% melt extraction to produce the Tharsis swell. The addition of a degree‐1 hemispheric dichotomy, as an equatorial step in lithospheric thickness, does not significantly improve upon melt production or the geoid.

Mars's Crustal and Volcanic Structure Explained by Southern Giant Impact and Resulting Mantle Depletion

AbstractMars features a crustal dichotomy, with its southern hemisphere covered by a thicker basaltic crust than its northern hemisphere. Additionally, the planet displays geologically recent volcanism only in its low latitude regions. Previous giant impact models coupled with simulations of mantle convection have shown that the crustal dichotomy can be explained by post‐impact melt crystallization that emplaced a thick crust in the southern hemisphere. In this study, we show that the depleted residue left behind by the original post‐impact crustal formation can spread laterally, potentially persisting beneath the northern hemisphere to the present‐day. Such a large‐scale mantle province would concurrently explain both the prevalence of long‐term magmatism on Mars and its strong preference for localized equatorial regions.

Detecting surface change on Venus from Magellan and VERITAS radar images

Detection of surface changes due to recent volcanism on Venus is a major focus of upcoming orbiting radar missions like VERITAS (Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy). The longest time baseline is to the Magellan mission, but these images will differ in wavelength (3.8 cm for VERITAS and 12.6 cm for Magellan), and often in incidence angle coverage. We explore the range of backscatter differences due to self-affine scaling properties of surface topography, using a model derived from terrestrial measurements. For moderately rough surfaces at least a 3-dB difference in backscatter coefficient above (rougher new flows) or below (smoother new flows) a model-scaled Magellan echo is required for confident change detection given uncertainty in the Hurst exponent of the topography. As roughness increases, echo saturation occurs due to diffuse scattering, and detectable change is due only to smoothing of the surface between the two missions. Quasi-specular echoes make change detection more challenging when the Magellan incidence angle is <30o (corresponding to latitudes below 35oS or above 55oN). At higher latitude, stronger correlative evidence from geologic context and more attention to local slope is required to infer surface change. There will be significant differences in the extent of mapped surficial mantling units between the two wavelengths. Further radar image data linked with terrestrial field measurements at the few-cm scale can validate the empirical model that relates surface roughness to wavelength dependence in radar scattering.

Pliocene-to-Holocene volcano-tectonic activity on Mohéli Island (Comoros archipelago) constrained by new K[sbnd]Ar ages

The volcanism of the Comoros archipelago (from west to east: Grande Comore, Mohéli, Anjouan, and Mayotte islands) has been under renewed scientific scrutiny since the eruption of a new submarine volcanic edifice (Fani Maoré) which begun in May 2018 east of Mayotte. West of Mayotte, Mohéli island has received little attention from the geoscience community, despite its largely uneroded volcanic landscapes suggesting a recent activity that has not been dated. Here we address this gap in knowledge by applying KAr geochronology on groundmass and major-trace element analyses to subaerial and submarine rocks, in an attempt to reconstruct the volcano-tectonic and geochemical evolution of Mohéli. Our results show that Mohéli's volcano-tectonic evolution proceeded in two constructional stages, including a primary edification along a N070°E axis from before ca. 3.8 Ma to ca. 3 Ma (Stage 1), and a second construction along a N110°E ridge shaping the present-day island since ca. 2 Ma (Stage 2). The two stages were separated by an increased subsidence (≥0.2 mm/yr) that drowned a large part of the N070°E primary edifice. The two identified volcano-tectonic stages are reflected also in the geochemical evolution of emitted magmas, which were moderately silica-undersaturated in Stage 1 and moderately to highly silica-undersaturated in Stage 2. Silica undersaturation increases with time up to the olivine melilitite field, together with enrichments in Ca, P, and incompatible trace elements, suggesting the increasing contribution of a metasomatized mantle in melts. The coeval changes of construction orientations and magmas compositions of Mohéli suggest a modification in the tectonics of the Comoros related to magmatism at about 2 Ma. The most recent volcanic morphology investigated is an olivine nephelinite lava flow on the north coast of the island dated at 8 ± 2 ka. This finding of Holocene volcanism on Mohéli implies that the entire Comoros archipelago should be considered as an active zone in any volcanic hazard assessment. The melilite-bearing rocks of Mohéli share geochemical similarities with those of Mayotte and of the Cenozoic volcanic provinces of Madagascar, further pointing to similar melting sources and magmatic processes over the Mozambique channel.

Silicic frothy xenoliths (xeno-pumice) in recent volcanics from Gran Canaria, Canary Islands

The Quaternary small-volume alkaline magmatic episode on Gran Canaria erupted dominantly basanite and nephelinite lavas and scoria deposits that contain a range of mantle and crustal xenoliths. These xenoliths comprise peridotite nodules, partially melted plutonic and volcanic rock fragments, and a group of light colored, felsic, and commonly frothy quartz-bearing rock fragments (xeno-pumice) that show evidence for intense interaction with their host magmas. Here we study a selection of these felsic and, in part, glassy and vesicular xenoliths from North and North-East Gran Canaria, with the aim to unravel their ultimate origin and learn more about magma storage and ascent within and below the island. Inspection of textures, mineral assemblages and glass compositions reveal one group of felsic xenoliths with fresh to partly altered igneous phenocryst assemblages and relict magmatic textures in addition to δ18O values of 3.6 to 6.6‰. This group is interpreted to be of igneous origin. A second group of frothy felsic xenoliths displays mineralogy and textural characteristics more similar to sedimentary rocks with frequent occurrence of quartz, a mineral usually not present as phenocrysts in magmatic rocks from the Canary Islands. This second group displays relatively high δ18O values (8.1 to 16.8‰), more typical for sedimentary lithologies, and is thus interpreted to represent material derived from the extensive pre-island sedimentary part of the ocean crust. The investigated xenoliths from North Gran Canaria thus provide a snapshot of pre-island sedimentary geology as well as the island's “magmatic” interior. These new data help constrain the available subsurface compositional variations within and below the Canary Islands and will hence be useful in interpreting magma evolution trends and magma storage levels.

The spatial and volcanic evolution of Ayelu, Abida and Yangudi volcanoes in the Northern Main Ethiopian Rift – Southern Afar, Ethiopia

The region between the Northern Main Ethiopian Rift and Southern Afar is a key link between two important sectors of the East African Rift System. Recent volcanism in this area occurs as a chain of NNE-SSW trending axial Quaternary volcanoes and volcanic fields, segmented and offset laterally by WNW-ESE trending right-steps. Here, we present the first whole-rock major element geochemical dataset from volcanoes in one such volcanic segment, the Adda'do Magmatic Segment (AMS). We combine these geochemical data with detailed remote sensing mapping of the region, to produce a relative chronology of the volcanic units. We investigate the volcanic evolution and composition of these volcanoes and find that all three volcanoes in the AMS exhibit similar evolutionary patterns, beginning with a base of older (presumed Plio-Pleistocene age) lavas, followed by a period of large-volume evolved magmatism, and recent basaltic-intermediate eruptions. Our results show evidence for at least three cycles of mafic-to-felsic evolution in the southern AMS, in agreement with earlier studies, indicating that the AMS has long been a site of volcanic activity.

Geothermal flow in Northern Morocco: A machine learning approach

To model the geothermal flow in northern Morocco, we apply a machine learning (ML) approach by analyzing the geological and geophysical data at boreholes, where direct heat flow data is available. The data includes geothermal flow, geothermal gradient, Bouguer gravity, aero-magnetic field, tectonic fracture density and the proximity level to the major faults, thermal spring data (location, temperature, density), geochronological age of formations, Earthquake data (density, magnitude, location), and the proximity level to the recent volcanism in Morocco. These data represent factors that generally control the spatial variation of geothermal flow. For this purpose, we used four ML techniques: Multi-Layer Perceptron, Support Vector Regression, K-Nearest Neighbors, and Decision trees, and examined the impact of parameter settings for each ML technique on the performance results. In specifically, we examine two parameter tuning methods: Grid Search (GS) and the Python Tool's default parameters. To determine the significance of the performance differences and rank ML techniques according to their performances, the Skott-Knott test, and the Borda Count voting system were investigated. We identified the optimized MLP by means of GS as the best ML technique. The cartographic representation of predicted geothermal flow values, by the optimized MLP (GS + MLP) model over the northern Morocco, shows areas of high geothermal flow values. These areas often correspond to magmatic intrusions at depth connected to the regional geodynamic context. The lowest values of geothermal flow are less than 40 mW m−2 and are mainly predicted in the Anti-Atlas chain of Precambrian age and in which is part of the West African Craton. This method is a new approach that may help to identify areas with high geothermal potential based on geological and geophysical data.

The recent volcanism of Flores Island (Azores), Part II: Stratigraphy and eruptive history of the Comprida Volcanic System

The stratigraphy and eruptive history of a volcanic system are key to forecast the timing and style of future eruptions. Flores is a small volcanic island in the Azores Archipelago with no record of eruptions since its settlement in the 15th century, although at least six eruptions are known to have occurred during the Holocene. Thus, Flores must be considered potentially active, and its volcanic hazard should not be disregarded. The most recent eruptions clustered at two centres of activity: the Funda Volcanic System (FVS) and the Comprida Volcanic System (CVS). Here, we reconstruct for the first time the eruptive history of CVS, the youngest volcanic system of Flores. Based on detailed tephrostratigraphic and geomorphological work, combined with radiocarbon dating and glass shard geochemistry, we show that – despite featuring five (maybe six) phreatomagmatic craters – CVS was formed in a single volcanic eruption at ∼3180 cal yr BP. This eruption started with Hawaiian-style lava fountaining followed by Strombolian activity, dispersing tephra fallout across the central part of the island. Lava flows were also emitted during the initial phase, which drained to the west and cascaded over the older deposits of the massive slump of Fajãzinha–Fajã Grande, and possibly reached the coastline to form the Fajã Grande lava delta. The initial magmatic phase was followed by phreatomagmatic explosions that formed several maars and tuff rings. Hence, groundwater played an important role in the eruption by transforming a mild Hawaiian-Strombolian eruption into a highly explosive phreatomagmatic event, possibly due to oscillations in the eruption rate. The occurrence of a large landslide contemporary to the eruption, raises the possibility of a combined threat. A new and more robust volcanic hazard assessment for the island involving scientists and civil protection authorities is desirable.

Compositional Evolution of Polygenetic Fissure Volcanic Systems: Insights From the Latest Eruptions at Craters of the Moon Volcanic Field

AbstractThe Craters of the Moon (COM) Volcanic Field in Idaho is the largest mostly Holocene lava field in the conterminous U.S. and the site of the most recent volcanism in the Yellowstone‐Snake River Plain province. This prominent example of a polygenetic fissure field has produced over 60 eruptions over the past 15,000 years from the Great Rift fissure system. The eight most recent lava flows, known as Period A, were erupted between about 2,500 and 2,000 years ago. In this study, major and trace element and Pb‐Sr‐Nd isotope data were obtained, with several samples collected from each flow from widely spaced locations to evaluate heterogeneity in their source magmas. The results reveal three previously unrecognized compositional groups that may represent separate magma batches, and that assimilation and fractional crystallization (AFC) controlled the evolution of the entire Period A suite. The three oldest flows were periodic withdrawals from a body of highly evolved and poorly homogenized magma, and four later flows represent successive samplings from a stratified body of more primitive magma. These two flow groups are related via variable AFC modeled with Magma Chamber Simulator software, with Neogene rhyolite as a plausible crustal assimilant. A third compositional type that requires a different parent magma and AFC history is represented by a single flow erupted from vents a few km away from the others. The compositional evolution and variability observed in this sequence of flows provide new insights into how magmas are generated, modified, and delivered in such polygenetic fissure systems.

Gas Emissions and Subsurface Architecture of Fault‐Controlled Geothermal Systems: A Case Study of the North Abaya Geothermal Area

AbstractEast Africa hosts significant reserves of untapped geothermal energy. Exploration has focused on geologically young (&lt;1 Ma) silicic calderas, yet there are many sites of geothermal potential where there is no clear link to an active volcano. The origin and architecture of these systems are poorly understood. Here, we combine remote sensing and field observations to investigate a fault‐controlled geothermal play located north of Lake Abaya in the Main Ethiopian Rift. Soil gas CO2 and temperature surveys were used to examine permeable pathways and showed elevated values along a ∼110 m high fault, which marks the western edge of the Abaya graben. Ground temperatures are particularly elevated where multiple intersecting faults form a wedged horst structure. This illustrates that both deep penetrating graben bounding faults and near‐surface fault intersections control the ascent of hydrothermal fluids and gases. Total CO2 emissions along the graben fault are ∼300 t d−1; a value comparable to the total CO2 emission from silicic caldera volcanoes. Fumarole gases show δ13C of −6.4‰ to −3.8‰ and air‐corrected 3He/4He values of 3.84–4.11 RA, indicating a magmatic source originating from an admixture of upper mantle and crustal helium. Although our model of the North Abaya geothermal system requires a deep intrusive heat source, we find no ground deformation evidence for volcanic unrest or recent volcanism along the graben fault. This represents a key advantage over the active silicic calderas that typically host these resources and suggests that fault‐controlled geothermal systems offer viable prospects for geothermal exploration.

Paleomagnetism, rock magnetism and age determination of effusive and explosive Holocene volcanism in the Momotombo-Managua-Masaya region, Nicaragua

The Central America Volcanic Arc shows an intense and continuous volcanic activity spanning the last 10 ky because of the subduction processes parallel to the Middle America Trench. Several volcanic events have occurred during the Plio-Holocene, along the coastal Nicaraguan region, characterized either by explosive or effusive activity. Volcanic deposits were emplaced at high temperatures and have similar basaltic-andesitic composition suggesting a long-lived magma chamber but emplaced and cooled by different mechanisms. We present paleodirectional and paleointensity results of four lava flows, and the paleointensity recorded on different pyroclastic deposits in the Managua-Masaya region, western Nicaragua. For each, we characterize the rock magnetic properties as a function of temperature and magnetic field. Absolute paleointensity experiments estimated a mean range from 38.6 to 52.9 μT; and a mean virtual axial dipole moment from 9.4 × 1022 Am2 to 12.8 × 1022 Am2. Two paleomagnetic ages were determined for two cooling units: (1) the Masaya Caldera Walls with an age range of 8580–8535 BP, and (2) a dating for a lava flow from Momotombo Volcanic Complex estimated of 1500–1600 CE. These results are consistent with the expected values according to the actual paleosecular variation global models, and with the regional stratigraphy and historical ages. The high reliability of paleointensity determination from these pyroclastic deposits and lava flows suggest that both are suitable for paleomagnetic dating. Finally, an accurate chronology of the volcanic events, will improve the understanding of the evolution of the volcanism and their implications for volcanic risk on the region. This knowledge will help to decrease the considerable hazard for the population on the surrounding areas.

Identification of Volcanic Geothermal Systems Based on Integrated Study of Volcanostratigraphy, Structural Geology, and Fluid Geochemistry in Southern Ngada Field, Indonesia

Southern Ngada is one of the areas that shows occurrence of volcanic geothermal potential in East Nusa Tenggara. The spreading volcanoes in the study area raised a hypothesis that the Southern Ngada Geothermal Field consists of several geothermal systems. The spreading volcanoes showed the presence of at least three volcanoes and manifestation clusters, which are Nage, Keli-Bena, and Wolo Puti Clusters. This research aimed to identify the number, type, and characteristics of geothermal systems in Southern Ngada Geothermal Field. The identification is conducted through the integration of geomorphology, volcanostratigraphy, structural geology, and geochemistry of fluid manifestation. The determination of geothermal system in Southern Ngada Geothermal Field is important to identify the field characteristics and reduce exploration risks. The Southern Ngada Field constitutes of the pre-caldera, post-caldera, and recent volcanism products. The study area is intensively deformed through strike slip faults and resembled Riedel Shear patterns. Fluid manifestation geochemistry in the study area showed various type of waters, which consists of Cl-SO4, SO4, and SO4-HCO3 waters with meteoric water mixing. The solfatara is associated with active magmatic gases due to boiling of reservoir beneath cinder cones. The fluid mixing processes are explained furthermore in Schoeller diagram plot. The integration of analyses showed the presence of Nage, Keli-Bena, and Wolo Puti Geothermal Systems with each different volcanostratigraphy, structural setting, and fluid mixing processes. The Nage System is associated with inferred heat source beneath the Nage Caldera and eastern part master and antithetic fault. The Keli-Bena System is associated with inferred heat source beneath Bena Crater and western antithetic fault. The Wolo Puti System is associated with inferred heat source beneath cinder cone volcanoes and northern extensional structures.

Ostracod and Foraminifer Responses to Late Pleistocene–Holocene Volcanic Activity in Northern Victoria Land as Recorded in Ross Sea (Antarctica) Marine Sediments

The impacts on ostracods and foraminifers caused by three Late Quaternary ashfalls of different intensities and recovered in the ANTA02-NW2 core sediments (Drygalski Basin, western Ross Sea) were analysed for the first time. Albeit with different timing, both associations demonstrated similar response patterns associated with the deposition of material from volcanic eruptions. In particular, based on the palaeontological evidence, it was possible to divide the cores into four intervals/phases recording the evolution of the ecosystem before and after the deposition events: (1) Pre-extinction phase (high abundance and high diversity values). (2) Extinction phase, characterised by the complete disappearance of ostracod fauna; the foraminiferal assemblage, although not entirely absent, records extremely low values of abundance and diversity (survivor assemblage). (3) Recovery phase (increasing abundance and diversity values), characterised by the recolonisation of some opportunistic taxa; species such as Australicythere devexa and Australicythere polylyca dominate the ostracod assemblage. (4) Post-extinction phase (high abundance and high diversity values), with the return to an environmental equilibrium characterised by the colonisation of specialised taxa such as Argilloecia sp., Cytheropteron sp., Echinocythereis sp., and Hemicytherura spp. Our results may aid in the understanding of how communities (i.e., ostracods and foraminifers) recovered after the impact of direct deposits of volcanic ash into ocean waters. The mechanisms by which disappearance and/or mortality was induced are still not clear. The release of toxic metals during the reaction of the volcanic ash with seawater, the resulting chemical alteration in the seawater, and the change in pH, together with the possible suppression of planktonic organisms, may have caused the two main extinction phases recorded by the ANTA02-NW2 core sediments.

An overview of the design and development of lunar rover (Chandrayaan-2) for space applications

The paper gives an brief overview of the design and development of lunar rover (Chandrayaan-2) for space applications. The Moon has always been the center of attention for mankind, more than any other heavenly body in More than any other heavenly body in the night sky, the Moon has long been the focus of human interest. The Moon has always presented mankind with a challenge to learn more about it and to marvel at its wonders because it bears the early history of the solar system. We can uncover the early evolution of the solar system and that of planet Earth by having a better understanding of the Moon. With the 2008 launch of the Chandrayaan-1 orbiter mission to the Moon, India's planetary exploration program was launched by the Indian Space Research Organization (ISRO). India launched Chandrayaan-2, its second lunar exploration mission, nearly twelve years after its first lunar exploration mission. Chandrayaan-2, India's most technologically advanced aircraft, is on an unprecedented mission. The South Polar Region of the Moon will be studied by India's second lunar trip, which will draw on nearly ten years of scientific and Engineering advancement. A major accomplishment for both India and humanity, Chandrayaan-2 was the first mission ever to be sent to the southern pole of the moon. Both the high cold and constant darkness in this area make it extremely unsafe and have a bad impact on missions. India faced a tremendously difficult assignment as a result, and the entire world was interested in its outcome. Chandrayaan-1's eleven remote-sensing scientific instruments from ISRO, NASA, and ESA have made important discoveries, such as the identification of a water signature, the discovery of spinel minerals, lunar lava tubes, signs of recent volcanism, impact-triggered boulder movements, and the detection of sputtered atomic oxygen and backscattered helium on the lunar surface. Three components made up Chadrayaan-2: an orbiter, a lander, and a rover. 2019 saw the launch of this mission. During this mission, the Orbiter was successful in reaching the moon's orbit, but communication with the Lander was lost, which caused Lander to perform poorly and crash with the Pragyan rover and other scientific equipment. The work given here is a mini-project that is taken up as a part of the curriculum completed by electronics and communication engineering students in the second year of the electronics &amp; communication engineering department at Dayananda Sagar College of Engineering in Bangalore.

Mantellic degassing of helium in an extensional active tectonic setting at the front of a magmatic arc (central Mexico)

Abstract The physicochemical and isotopic characteristics of groundwater and dissolved gas of central Mexico provide valuable information about the geologic and tectonic context of the area. Low–high-enthalpy manifestations (up to 98 °C in springs and more than 100 °C in geothermal wells) are distributed within the San Juan del Río, Querétaro, and Celaya hydrologic basins, located at the boundary between the current Mexican magmatic arc and an extensional continental area with intraplate volcanism called Mesa Central Province. Groundwaters in the study area represent a mixture between the cold water end-member with a Ca2+-Mg2+-HCO3-composition and a hydrothermal end-member enriched in Na+, K+, SO42−, and Cl-. Cold and hot groundwaters δ2H and δ18O plot along the same evaporation lines and do not exhibit a magmatic input. Dissolved and free gas do not show a typical volcanic composition signature. He and Ne isotope composition provide evidence of an important contribution of non-atmospheric noble gases. Although helium composition mainly has a crustal origin (21–83%), the mantellic contribution (1–39%) is higher than expected for an area lacking recent volcanism. A volatilerich magma aging at depth was discarded as the source of this mantellic helium signature but points out a recent mantellic contribution. Thus, we propose that mantellic helium comes from the sublithospheric mantle into the shallow crust through the highly permeable tectonic boundaries between the geologic provinces, namely the N−S Taxco−San Miguel de Allende and Chapala-Tula fault systems. Mantellic helium flow rates through these fault systems were estimated to have values ranging from 0.1 m/yr to 2.9 m/yr. This He flux range implies that aside from subduction, mantle volatile degassing enhanced by crustal fault systems is the main degassing process in the region studied.

Geologically Recent Areas as One Key Target for Identifying Active Volcanism on Venus

AbstractThe recently selected NASA VERITAS and DAVINCI missions, the ESA EnVision, the Roscosmos Venera‐D will open a new era in the exploration of Venus. One of the key targets of the future orbiting and in situ investigations of Venus is the identification of volcanically active areas on the planet. The study of the areas characterized by recent or ongoing volcano‐tectonic activity can inform us on how volcanism and tectonism are currently evolving on Venus. Following this key target, Brossier et al. (2022, https://doi.org/10.1029/2022GL099765) extend the successful approach and methodology used by previous works to Ganis Chasma in Atla Regio. Here we comment on the main results published in Brossier et al. (2022, https://doi.org/10.1029/2022GL099765) and discuss the important implications of their work for the future orbiting and in situ investigation of Venus. Their results add further lines of evidence indicating possibly recent volcanism on Venus.