Mantle Deposits Research Articles

Ice Content of Mantling Materials in Deuteronilus Mensae, Mars

AbstractLayers of ice and dust (i.e., “mantle”) are found throughout the mid‐latitudes of Mars, where they drape and mute topography and record the recent climate history. Many of the youngest Late Amazonian “latitude‐dependent mantles” have been characterized, but the full range of mantle characteristics, including variations in ice content and age, has not been well documented. To advance our understanding of these ice‐dust units, we use SHAllow RADar (SHARAD) radar sounding data to constrain the subsurface physical properties of a widespread Middle Amazonian mantle unit within Deuteronilus Mensae. This region hosts a high density of glacial landforms, which allows assessment of the stratigraphic relationship between mantle deposits and glacial ice. SHARAD reflectors at the base of the mantle units are used to determine moderate dielectric constants (∼5.75) and high loss tangents (∼0.038). These radar properties imply relatively limited ice content and high‐loss mantling materials with possible enhanced roughness or subsurface scattering. Further, we interpret deeper reflectors that are continuous with glacier basal reflectors and that suggest materials with lower dielectric constants (∼3.2–4.5) and loss tangents (0.0071–0.0120) to be due to extensions of stagnant, possibly lithic‐rich, glacier ice that are buried by a mantle layer. This study demonstrates the high variability in the origins and evolution of mid‐latitude mantling units on Mars. While the most recent latitude‐dependent mantling deposits may still be ice‐rich, older deposits, such as those preserved in Deuteronilus Mensae and elsewhere in the mid‐latitudes of Mars, may be largely desiccated or contain a more heterogeneous and limited distribution of ice.

Friction Experiments on Lunar Analog Gouges and Implications for the Mechanism of the Apollo 17 Long Runout Landslide

AbstractThe Light Mantle landslide is a hypermobile landslide on the Moon. Apollo 17 astronauts collected a core sample of the top 60 cm of the Light Mantle deposit, which is currently being analyzed as part of the NASA's Apollo Next Generation Sample Analysis program. The origin of its hypermobility remains undetermined, as the proposed mechanisms are difficult to prove because of the lack of theoretical and experimental support and the scarcity of field data related to the internal structures of its deposit. Regardless of the emplacement mechanisms, it has been proposed that localized dynamic frictional weakening is responsible for the early stage instability that leads to catastrophic failure. Here, we conduct friction experiments under vacuum to investigate the viability of dynamic friction weakening in lunar analog anorthosite‐bearing gouges (i.e., rock powders). Our results show that localized dynamic friction weakening does not occur in these gouges at loading conditions where, instead, weakening is observed in other materials on Earth. Therefore, possibly other fluidization‐related mechanisms contributed to the initiation of the hypermobile Light Mantle landslide. Finally, we describe the microstructures formed in the experiments, including the presence of clast cortex aggregates. Preliminary investigation of the Light Mantle core samples (73001/73002) shows the presence of similar microstructures. Therefore, our microstructural observations will help the analysis and interpretation of the Apollo 17 core samples, as keys to insights about internal processes occurring during the emplacement of the landslide.

The upper-mantle density variation beneath the South Atlantic Ocean and its implications for hotspots and large igneous provinces

The South Mid-Atlantic Ridge (SMAR), the most typical slow-spreading ridge on the earth, is a significant area to study the oceanic crust-mantle evolution. We used gravity data and the S-wave velocity model to derive a 3D density model of the upper-mantle beneath the South Atlantic Ocean to better understand the relationship between ridges, hotspots, and large igneous provinces. The density variations in the upper-mantle are related to thermal and compositional changes. The segment near the Agulhas-Falkland Fracture Zone (AFFZ) is characterized by low-density but inconspicuous low-velocity anomalies reflecting the depleted composition. Its composition is different from the northern part of the SMAR. A low-density layer at 100 km that extends 200 km from the ridge to the Discovery hotspot and that disappears near the AFFZ, is also present. The higher degree of mantle melting beneath the segment near the AFFZ is most probably influenced by the residual plume materials from the Discovery hotspot. Deep low densities beneath the Rio Grande Rise (RGR) and the Walvis Ridge (WR) indicate a higher degree of melting and their formation is probably influenced by the Tristan da Cunha plume. When the RGR is driven away from the plume, its original hot materials cool down and present as cold and dense uppermost mantle deposits. As the plume is located in the African plate, the WR was continuously formed as a seamount chain by intraplate volcanism of mantle plume.

Study of the Buried Basin C-H, Based on the Multi-Source Remote Sensing Data

We use multi-source remote sensing data to identify the details of a mascon south-east of the lunar Copernicus crater. Studies of the topography, gravity, geochronology and mineral are combined to prove that the mascon is a buried peak-ring basin with diameters of about 130 km and 260 km. The underground structure is covered by 890 m thick mare basalts, as determined by analyzing the spectral features of the impact crater, Copernicus H. The determination of the crater size–frequency distribution (CSFD) suggests that the impact that created the C-H basin occurred earlier than 3.9 Ga. Then, a Hawaiian-style eruption in the late Imbrian period formed the Sinus Aestuum-I dark mantling deposit (DMD). Soon, mare basalts covered the basin several times from 3.8 Ga. Finally, the ejecta from the Copernicus impact event at about 800 Ma, and the weathering processes caused the disappearance of the C-H basin rim from the lunar surface.

Petrological and Mineralogical Characteristics of Exposed Materials on the Floors of the Lavoisier and Surrounding Craters

Five floor-fractured craters (FFCs), Lavoisier crater and four craters surrounding it (Lavoisier C, Lavoisier E, Lavoisier F, and Lavoisier H), are distributed along the boundary between the northwestern part of the Oceanus Procellarum and the highlands. This study examines the uplifted or exposed materials on the fractured floors of these five impact craters using petrological, mineralogical, and morphological analyses. We inferred the processes that uplifted or exposed the materials from the subsurface to the crater floor using the Chandrayaan-1 Moon Mineralogy Mapper (M3) level 1b (thermally and topographically corrected spectral radiance) data and level 2 (spectral reflectance) data. The elemental abundances, petrological, and mineralogical characteristics of the study regions were mapped. We confirm that mare basalts and dark mantle deposits exist on the floors of these five craters. These two materials (mare basalts and dark mantle deposits) were used to identify minerals exposed on the floor surface of craters using spectral reflectance spectra. Two mineral groups were identified: pigeonite (or orthopyroxene in norite (low-Ca pyroxene) occurred in the craters Lavoisier, Lavoisier F, and Lavoisier H, and subcalcic augite (high-Ca pyroxene) occurs in the craters Lavoisier C and E. Our approach demonstrates that the characterization of uplifted or exposed surface minerals using elemental maps, spectral parameter composite maps, and reflectance spectra can provide information critical for prospective studies involving lunar geology and in situ resource utilization.

The Identification and Analysis of Gas-Related Volcanic Features within Chang’e-5 Landing Region

Chang’e-5 (CE-5) successfully landed on the young basalts area in the northeastern Oceanus Procellarum on 1 December 2020. Recent studies on the CE-5 landing area have shown that the lack of gas-related volcanic morphology indicates that the volatile elements captured in the interior of the Moon within late-stage magma is relatively low. Typical lunar gas-related volcanic features include dark mantle deposits, volcanic pits, irregular mare patches and so on. Based on orbital images, topography, and spectral data obtained from multiple missions restricted by the morphologic and compositional characteristics of typical volcanic explosive features, this study investigated the morphological characteristics of the volcanic features in detail and found that there are three dark mantle deposits (DMDs) near the source area of Rima Mairan that have unusually low albedo and abnormally high titanium and iron content than those of the surrounding material. Combined with M3 spectral analysis, it is shown that DMDs contain some volcanic glass components, which indicates a gas-rich explosive eruption process. In addition to DMDs, irregular mare patches (IMPs) and a volcanic depression/pit have been recognized in this area, both of which indicate a history of gas-related volcanic eruptions. Based on this study and combined with past studies, we determined the volcanic history in the source area of Rima Mairan, including both effusive and explosive volcanic activities.

A New Density Model of Quartz Solubility in H2O-CO2-NaCl Ternary Systems up to High Temperatures and High Pressures

A novel density model for computing quartz solubility in H2O-CO2-NaCl hydrothermal fluids applicable to wide ranges of temperature and pressure is proposed. Based on the models of Akinfiev and Diamond (2009) and Wei et al. (2012), the effective partial molar volume of water (VH2O∗) is replaced by the partial molar volume of water (V¯H2O) by implementing an empirical correction, and water molar fraction (xH2O) is modified with water activity (aH2O), in addition to a series of changes to the model coefficient forms. The absolute values of averaged relative deviation of this model compared to the experimental data sets in pure water, H2O-CO2, and H2O-NaCl solutions are 5.74%, 6.69%, and 7.09%, respectively, which are better than existing models in the literature. The model can be reliably used for computing quartz solubilities in pure water from 0°C to 1000°C, from 0 bar to 20,000 bar, and in CO2- and/or NaCl-bearing solutions from 0°C to 1000°C, from 0 bar to 10,000 bar (with slightly lower accuracy at 5000-10,000 bar in H2O-NaCl systems) in the single liquid region. Moreover, the trends and overall ranges of this model may probably be more accurate in the H2O-CO2-NaCl fluid mixtures compared to the limited experimental data. In addition, a bisection algorithm for deriving the isopleths of quartz solubilities based on this new model is first proposed, and application perspectives are discussed for various geologic settings including subduction zone, lower crust-upper mantle, migmatite, pegmatite, porphyry, and orogenic deposits.

Characterization of D‐Type Spectra Based on Hyperspectral Remote Sensing of the Lunar Surface

AbstractWe surveyed dark, red‐sloped, and featureless visible and near‐infrared spectra on the lunar surface, similar to those of D‐type asteroids. Using the hyperspectral data obtained by Spectral Profiler onboard SELENE, we examined the distribution of sites showing low albedo and high spectral redness, irrespective of absorption features. We found that regions around several dark mantle deposits, such as Sinus Aestuum, Rimae Bode, Vaporum, Sulpicius Gallus, Oppenheimer, and Taurus Littrow, are the darkest, reddest sites on the lunar surface. In addition, dark mare regions (albedo < 4%) are shown to be high in TiO2 abundance, while red mare regions (spectral redness > 2.3) are low in TiO2 abundance. Interestingly, according to the criterion of asteroidal taxonomic classification used in previous studies, most of these geological features are classified as D‐type, which are characterized by featureless spectra, although they show absorption bands at visible, 1 μm, and/or 2 μm regions. This is because the asteroidal taxonomic classification relies on a small number of spectral bands of scaled reflectances, while the presence of absorption bands should be identified based on the continuum‐removed reflectance of the hyperspectral data. Thus, our results suggest that the D‐type group classified in previous studies consists not only of primitive objects of carbonaceous chondritic materials but also differentiated objects composed of rocky materials that may be found on the Moon. To provide better constraints for D‐type bodies regarding their composition from remote‐sensing data, a quantitative assessment based on an analysis of the continuum‐removed reflectance of hyperspectral data may be required.

Ice-rich landforms of the southern mid-latitudes of Mars: A case study in Nereidum Montes

Mapping of Viscous Flow Features (VFFs), a general grouping of ice-rich flow features that includes Lobate Debris Aprons (LDA), Concentric Crater Fill (CCF), Lineated Valley Flow (LVF), small lobate flows (i.e., glacier-like flows, or GLFs), and arcuate ridges, in the southern hemisphere of Mars shows a dense concentration in Nereidum Montes, along the northern rim of Argyre basin. Further mapping within a subregion in northwest Nereidum Montes (45.3°–48.5° S, 307°–312° E) shows a large number of well-preserved VFFs and ice-rich mantling deposits. Processed SHARAD data across a VFF within the region indicates that it is composed of nearly pure water ice.Model ages obtained from crater counts and their associated size-frequency distributions (SFDs) on both ice-rich mantling deposits and small lobate VFFs suggest that the deposits stabilized several to tens of Ma ago in the Late Amazonian Epoch, and that small lobate VFFs likely formed due to the mobilization of mantling deposits. SFD for a larger VFF shows a model age of 100 s of Ma, consistent with ages for LDAs in eastern Hellas. Deposition of ice in Nereidum Montes that led to the formation of VFFs likely occurred during periods of high obliquity in the Late Amazonian.Our results show that VFFs have more complete and diverse preservation states in Nereidum Montes than similar features in other regions on Mars. This region contains uniquely well-preserved mantling deposits above arcuate ridges and beyond the margins of lobate VFFs and gully aprons. This key observation ties arcuate ridges to the flow of mantling deposits, part of a continuum model for mid-latitude ice-rich landforms.

An investigation of potential pyroclastic deposits on the southeast limb of the Moon

We investigated the physical and spectral properties of potential dark mantling deposits (PDMDs) previously and newly identified on the SE limb of the Moon, near the craters Humboldt and Petavius. The goals of this investigation were to constrain the composition and mode of emplacement of these poorly studied deposits, to identify interdeposit variations, and to use these results to draw conclusions about regional and subsurface geologic processes. Our investigation involved an assessment of both the physical properties (size, texture, morphology) and spectral properties (albedo, absorption bands, color ratios) utilizing remote sensing data from multiple lunar orbital missions. We found that many of the SE Limb deposits previously identified as possibly pyroclastic in origin were likely effusively emplaced. However, we also identified several likely pyroclastic deposits, including three not previously mapped. We found that the volcanic deposits across the study area comprise three major spectral groups: one similar to Mare Fecunditatis, one similar to Mare Australe, and one similar to known glassy pyroclastic deposits elsewhere on the Moon. We conclude that volcanism across the SE limb was likely fed from at least two distinct magma source regions, and that the type and extent of surface expression of this volcanic activity was possibly influenced by regional variations in crustal thickness. Our documentation and analysis of the complex volcanic history in this region of the Moon supports ongoing efforts to develop increasingly detailed interpretations of the volcanic history of the entire Moon.

Geological conditions of suffosion processes development and their acitivity at Sal-Don neotectonic upland (Rostov NPP area)

Suffusion processes and their influence on the stability of the Rostov NPP site are investigated. Geological, tectonic, geomorphological, hydrogeological conditions, as well as anthropogenic factors affect the development and intensification of suffusion. These conditions and factors include the following: predominance of Pliocene and Quaternary sands in the geological cross-section; the presence of clay aquiclude underlying sandy deposits; natural seasonal and human-induced fluctuations of the water level in the Tsimlyansk reservoir; as well as pumping of groundwater. The buried relief in the shape of a slope dissected by erosional gullies are also of great importance. These erosional depressions are probably channels, along which sand is removed to the Tsimlyansk water reservoir. It is suffusion that may be the reason of surface subsidence that causes deformation of ground basements and inclinations of some engineering structures at NPP. Recent tectonic conditions control the formation of active zones and fracturing in the mantle deposits favoring percolation of surface water. Suffusion amplified by tectonic and technogenic factors results in the subsidence of soil basement in some places at the NPP site, displacement of reference marks, and inclination of engineering structures.

Geophysical model of the mantle ore-forming system

The paper deals with a generalized geophysical model of the mantle ore-forming system that covers three main parts: a) the area of origin of the ore substance; b) its transportation zone and c) the area of concentrated ore-formation ― a deposit. The essence of the model uses the modern achievements of metallogeny and deep geophysics on one hand, as well as original quantitative data on the structure of the astenosphere in the regions of large deposits of non-ferrous and metal ores deposits in Central Srednogorie and the Central Rhodopes on the other. As a result of geophysical studies longitudinal and transversal mantle faults have been tracked as well as the lifting of the heated roof of the asthenospheric layer. In addition quantitative data have been obtained on considerable vertical amplitudes of tectonic ruptures both on the Moho division of more than 7―14 km and on the upper boundary of asthenospheric layer where the amplitude is more than 60 km. The structure of endogenous ore-forming system described shows that two of its main parts, namely origination and localization of ore-bearing products are completely situated in asthenosphere and earth crust respectively. The third main part ― the transporting one occupies some restricted area of the upper mantle and the whole vertical size of the earth crust coincident with crust-mantle nods. The features of tectonosphere revealed within the limits of the mantle ore areas as well as specific geophysical character of asthenospheric layer certificate that within these areas favorable conditions were generated for emergence and functioning of convecting cells and ascending magmo-fluid flows. All the mentioned, stimulated origination of ore-bearing magma in asthenosphere layer and their movement to the surface, where in the Late Cretaceous (Srednogorie) and Paleogenic (Rhodopes) the mantle deposits were formed. The results of the studies conducted are the important step in clearing the problem of origination of the ore matter realized in asthenosphere.

Field Trip D (27 September 2018): characteristics and development of the Mesozoic–Tertiary weathering mantle and Pleistocene periglacial slope deposits in the Hintertaunus mountainous region

Abstract. The Devonian slates and sandstones of the Rhenish Massif were subject to deep and intensive weathering under (sub)tropical climate conditions during the Cretaceous, the Paleogene and the Neogene, which caused the development of a weathering mantle (regolith) >100 m thick, consisting of kaolinitic saprolite and paleosols as well as correlated sediments. Especially the tectonic uplift of the Rhenish Massif and climate change during the Neogene and the Pleistocene led to a vast denudation of the weathering mantle. Only in less uplifted areas of the mountainous region did thick remnants of saprolites remain, and they were covered by Neogene sediments as well as Quaternary periglacial slope deposits. As the kaolinitic weathering products serve as raw materials for the clay industry, unique exposures are available in the Hintertaunus which offer impressive insights into the landscape development of the past ∼80 million years: the excursion proceeds from Giessen to Limburg and further south and southwest to the eastern and western Hintertaunus area. At site 1 near the village of Langhecke, characteristics and properties of the fresh, unweathered slates will be demonstrated. Excursion sites 2 and 3 are situated near the village of Eisenbach. In two open-cast clay mines, both a terrestrial and a semi-terrestrial saprolite from silt slate, covered by periglacial layers, are exposed. Properties and genesis will be discussed on the basis of morphological characteristics and mineralogical and geochemical analyses, as well as isovolumetric elemental mass balances. At site 4 a former basalt quarry near the village of Biebrich exposes a Paleogene Plinthosol above saprolite. The autochthonous paleosol was preserved below Upper Oligocene basalt tuff and periglacial layers. Site 5 is situated within a huge pit for mining of Upper Oligocene to Miocene quartz gravel near the village of Wasenbach. A Miocene Plinthosol developed from alluvial sediments on top of the gravel beds and was covered by periglacial slope deposits. At nearly all sites the basal layers of the periglacial cover beds consist of kaolinitic paleosol/saprolite material, which has an important influence on the site properties of the Holocene soils.

Characterizing dark mantle deposits in the lunar crater Alphonsus

We analyze available remote-sensing data of the crater Alphonsus, focusing on the analysis of the crater's dark mantle deposits (DMDs), which includes images from NASA Clementine and Lunar Reconnaissance Orbiter (LRO), Japanese Selene (Kaguya), and Indian Chandrayaan-1 missions. The Alphonsus DMDs are gentle-sloped flat hills with typical heights of several meters, which are presented with pyroclastic materials. Our determination of the absolute ages of the Alphonsus DMDs by the technique of crater size-frequency distributions shows that they are ∼200–400 m.y. old. However, being geologically young, the Alphonsus DMDs are not seen in OMAT maps. The DMDs have noticeably lower content of TiO2 (2–3%) than the mare regions to the west (>4%). The assessment of total pyroxene shows it has a higher abundance in the DMDs, although LRO Diviner measurements of the Chirstiansen feature suggest, rather, a high abundance of olivine. The DMDs pyroclastic material has no signs of OH/H2O compounds. We may suggest that this characteristic of the DMDs either relates to their impact reworking and loss of the OH/H2O compounds or to the non-water volatiles as the driving agent of the pyroclastic activity. The compositional assessments of the DMDs may be flawed from contamination with the surrounding material due to horizontal and vertical transportation due to impacts. This effect probably can be observed in LROC NAC images of high resolution. A very dark material outcropping on the slopes of the vent depression is seen due to renovation of the regolith on the steep walls of the depression. Thus, at smaller phase angles, the pyroclastic material is dark and at larger phase angles it appears almost like the surrounding material. This means that the phase dependence of the outcropping dark material is shallow; i.e. the dark surface is smoother than its surroundings. This may suggest venting of gases resulting in fluidization of the granular pyroclastic material of the deposit.

Investigation of Lunar Spinels at Sinus Aestuum

AbstractSinus Aestuum is the only known location on the Moon where orbital data have detected Fe‐and/or Cr‐spinel. We analyzed Moon Mineralogy Mapper (M3) visible to near‐infrared data of the largest and strongest spinel signatures and determined that these locations always correspond to impact craters. M3 spectra show that at least three types of spinels may be present, all of which exhibit a strong and broad absorption at ~2100 nm, and also one of the following: (1) a narrow 700–750 nm absorption, (2) a broad 600–900 nm absorption, or (3) both a weaker 700 nm and stronger 1000 nm absorption. All the spinel detections occur on either larger highland massifs that make up Sinus Aestuum east and west or smaller highland kīpukas and buried highlands within the mare. Almost all of the spinel signatures occur within the mapped pyroclastic dark mantle deposit (DMD). The strong correlation between spinel and DMD distribution on the highlands at Sinus Aestuum is best explained if the spinels were emplaced during the same explosive eruption(s) that deposited the pyroclastics in the Sinus Aestuum DMD. Our observations are most consistent with models of melt‐rock reactions in the anorthositic lunar crust that produce contaminated (high‐Al) regions within a volcanic dike or magmatic reservoir that was capable of erupting pyroclastic glass beads containing pleonaste spinel [Mg,Fe]Al2O4. Over billions of years, this surface layer of spinels and pyroclastics became heterogeneously mixed into and partially buried within the highland regolith where younger impact craters may sometimes expose it.

Reflectance spectroscopy of chromium-bearing spinel with application to recent orbital data from the Moon

Visible to near-infrared (V-NIR) remote sensing observations have identified spinel in various locations and lithologies on the Moon. Experimental studies have quantified the FeO content of these spinels (Jackson et al. 2014), however the chromite component is not well constrained. Here we present compositional and spectral analyses of spinel synthesized with varying chromium contents at lunar-like oxygen fugacity ( f O2). Reflectance spectra of the chromium-bearing synthetic spinels (Cr# 1–29) have a narrow (~130 nm wide) absorption feature centered at ~550 nm. The 550 nm feature, attributed to octahedral Cr3+, is present over a wide range in iron content (Fe# 8–30) and its strength positively correlates with spinel chromium content [ln(reflectancemin) = −0.0295 Cr# – 0.3708]. Our results provide laboratory characterization for the V-NIR and mid-infrared (mid-IR) spectral properties of spinel synthesized at lunar-like f O2. The experimentally determined calibration constrains the Cr# of spinels in the lunar pink spinel anorthosites to low values, potentially Cr# < 1. Furthermore, the results suggest the absence of a 550 nm feature in remote spectra of the Dark Mantle Deposits at Sinus Aestuum precludes the presence of a significant chromite component. Combined, the observation of low chromium spinels across the lunar surface argues for large contributions of anorthositic materials in both plutonic and volcanic rocks on the Moon.

Complex geomorphologic assemblage of terrains in association with the banded terrain in Hellas basin, Mars

Hellas basin acts as a major sink for the southern highlands of Mars and is likely to have recorded several episodes of sedimentation and erosion. The north-western part of the basin displays a potentially unique Amazonian landscape domain in the deepest part of Hellas, called “banded terrain”, which is a deposit characterized by an alternation of narrow band shapes and inter-bands displaying a sinuous and relatively smooth surface texture suggesting a viscous flow origin. Here we use high-resolution (HiRISE and CTX) images to assess the geomorphological interaction of the banded terrain with the surrounding geomorphologic domains in the NW interior of Hellas to gain a better understanding of the geological evolution of the region as a whole. Our analysis reveals that the banded terrain is associated with six geomorphologic domains: a central plateau named Alpheus Colles, plain deposits (P1 and P2), reticulate (RT1 and RT2) and honeycomb terrains. Based on the analysis of the geomorphology of these domains and their cross-cutting relationships, we show that no widespread deposition post-dates the formation of the banded terrain, which implies that this domain is the youngest and latest deposit of the interior of Hellas. Therefore, the level of geologic activity in the NW Hellas during the Amazonian appears to have been relatively low and restricted to modification of the landscape through mechanical weathering, aeolian and periglacial processes. Thermophysical data and cross-cutting relationships support hypotheses of modification of the honeycomb terrain via vertical rise of diapirs such as ice diapirism, and the formation of the plain deposits through deposition and remobilization of an ice-rich mantle deposit. Finally, the observed gradual transition between honeycomb and banded terrain suggests that the banded terrain may have covered a larger area of the NW interior of Hellas in the past than previously thought. This has implications on the understanding of the evolution of the deepest part of Hellas.

A multidisciplinary approach in sinkhole analysis: The Quinis village case study (NE-Italy)

During the last recent years, in Quinis, a small village sited in the Alta Val Tagliamento valley (Friuli Venezia Giulia Region, NE Italy), the inhabitants faced with instability phenomena related to the presence of soluble rocks in the subsurface. The evaporite bedrock is mainly mantled, in fact, by high thickness deposit. This paper explains the methodological approach that we used to identify the instabilities in a very complex geo-structural environment where the urbanization limits the applicability of several investigation techniques. Different methods were used to define the bedrock morphology, to characterize the mantling deposits and to identify the processes behind. What emerged from the study is a mandatory multidisciplinary approach to characterize the subsoil, because each technique is not able individually to take to a unique result. The data collected allowed to draft a geo–hydrogeological conceptual model of the Quinis village.The lessons learned, even if with some site-specific dependency, demonstrate the importance of broad-spectrum investigations, which are essential to understand the subsurface characteristics avoiding relevant socio-economic impact and supporting an adequate future territorial planning.

Extensive Middle Amazonian mantling of debris aprons and plains in Deuteronilus Mensae, Mars: Implications for the record of mid-latitude glaciation

The mid-latitudes of Mars are host to a record of recent episodes of accumulations of ice-rich materials. The record includes debris aprons, interpreted to be debris-covered glaciers, that may represent the preserved remnants of a much more extensive ice sheet. We assessed the possibility of former glacial extents by examining debris aprons and the surrounding plains in Deuteronilus Mensae. Geomorphic units and stratigraphic relationships were mapped and documented from Mars Reconnaissance Orbiter (MRO) Context (CTX) and High Resolution Imaging Science Experiment (HiRISE) camera images, and crater retention ages were estimated from crater size–frequency distributions. Three major units are observed within the study area: debris aprons, lower plains, and upper plains. Debris aprons exhibit characteristics typical for these features documented elsewhere and in previous studies, including integrated flow lineations and patterns, convex-upward profiles, and knobby and brain terrain surface textures. A lower bound on the age for debris aprons is estimated to be 0.9Ga. Debris aprons are superposed on a lower plains unit having a lower bound age of 3.3–3.5Ga. A 50–100m thick upper plains unit superposes both debris apron landforms and lower plains units and has a best-fit minimum age of 0.6Ga. The upper plains unit exhibits characteristics of atmospherically-emplaced mantle material, including fine-grained nature, sublimation textures, cyclic layering, draping character, and widespread spatial distribution. Fracturing and subsequent sublimation/erosion of upper plains on debris aprons has contributed to many of the surface textures on debris aprons. The upper plains unit has also been eroded from the lower plains and plateaus, evidenced by isolated blocks of upper plains in the interiors of craters and on the walls and tops of plateaus. While no conclusive evidence diagnostic of former cold-based ice sheets are observed in the plains within the study region, such landforms and units may have been poorly developed or absent, as is often the case on Earth, and would have been covered and reworked by later mantling episodes. These observations suggest that emplacement of thick ice-rich mantle deposits extended at least to near the Early/Middle Amazonian boundary and overlapped with the waning stages of glaciation in Deuteronilus Mensae.

Examining spectral variations in localized lunar dark mantle deposits

The localized lunar dark mantle deposits (DMDs) in Alphonsus, J. Herschel, and Oppenheimer craters were analyzed using visible-near-infrared spectroscopy data from the Moon Mineralogy Mapper. Spectra of these localized DMDs were analyzed for compositional and mineralogical variations within the deposits and were compared with nearby mare basalt units. Spectra of the three localized DMDs exhibited mafic absorption features indicating iron-rich compositions, although the DMDs were spectrally distinct from nearby mare basalts. All of the DMDs contained spectral signatures of glassy materials, suggesting the presence of volcanic glass in varying concentrations across the individual deposits. In addition, the albedo and spectral signatures were variable within the Alphonsus and Oppenheimer crater DMDs, suggesting variable deposit thickness and/or variations in the amount of mixing with the local substrate. Two previously unidentified localized DMDs were discovered to the northeast of Oppenheimer crater. The identification of high concentrations of volcanic glass in multiple localized DMDs in different locations suggests that the distribution of volcanic glass across the lunar surface is much more widespread than has been previously documented. The presence of volcanic glass implies an explosive, vulcanian eruption style for localized DMDs, as this allows volcanic glass to rapidly quench, inhibiting crystallization, compared to the larger hawaiian-style eruptions typical of regional DMD emplacement where black beads indicate a higher degree of crystallization. Improved understanding of the local and global distributions of volcanic glass in lunar DMDs will further constrain lunar degassing and compositional evolution throughout lunar volcanic history.