Surface Geomorphology Research Articles

Cenozoic Reactivation of the Penacova-Régua-Verin and Manteigas-Vilariça-Bragança Fault Systems (Iberian Peninsula): Implication in Their Seismogenic Potential

The Penacova-Régua-Verin (PRV) and the Manteigas-Vilariça-Bragança (MVB) are two of the longest faults of the Iberian Peninsula. These faults striking NNE–SSW, over lengths of >200 km, were developed during late-Variscan Orogeny and reactivated in response to the Alpine Cycle tectonics. Their tectonic evolution during Alpine compression (Cenozoic) and their implication in the active tectonic activity of Iberia are under discussion. Their recent tectonic activity is recorded in the vertical offset of geomorphological surfaces, in the associated pull-apart basins, and in M > 7 paleoseismic events. Based on the vertical surface offset of Pliocene surfaces (140–300 m for the MVB fault and 150–200 m for the PRV), together with the horizontal offset (1300–1600 m for MVBF fault and 600–1400 m for PRVF), we can conclude that they were reactivated as left-lateral strike-slip faults with a reverse component during the Pliocene (3.6 Ma)–present. These results indicate that these faults are not related to the strain transmission during the collision with Eurasia (Eocene–Oligocene). However, they are related to the intraplate strain of the southern collision with the African plate during the Upper Neogene. The estimated slip-rate is 0.2–0.5 mm/a for both faults. These slip-rates evidence important implications for the seismic hazard of this intraplate region.

3D Map Application on Cave Geosites in Relationship of Cave Morphometry and Surface Geomorphology in Karst Areas at Ngalau Basurek Cave, Silokek Geopark

On 2 January 2018, the local government proposed Silokek, a region in the Sijunjung Regency, West Sumatra Province, Indonesia, as a geopark, based on district rule number 188.45/3/KPTS-BPT-2018. This arrangement was based on the idea that a geopark would provide tourist destinations with natural tourism and archaeological, environmental, historical, educational, and cultural components in addition to geology, making this place an indirect example of a complex tourist destination. The Ngalau Basurek Cave is a geosite in this area that is a well-liked tourist destination, although it does not yet have a useful and instructive cave morphometry map. Producing cave morphometric data using the compass and step mapping method and geomorphological analyses of Landsat 8 image data is suggested to identify patterns of relationships with surface karst morphological features. A northeast dip angle trend was visible in the fresh limestone of the Kuantan Formation, which formed cave features as a result of dissolution. The dolinas, uvalas, and cone–kart features, which are represented on topographic maps (DEM-SRTM), demonstrate comparable trends. Dip-angle and strike-line trends were used to obtain a complete relationship between cave morphometry and surface geomorphology in Silokek Geopark.

Land use and land cover patterns as a reflection of subsurface architecture groundwater quality in a large urban center (Varanasi) in the Ganges river basin, India

Varanasi is an exponentially developing city in the Himalayan-sourced Ganges river basin. To understand the sustainable groundwater-sourced drinking water in Varanasi, it is essential to study the land use-land cover that reflects the surface geomorphology vis-a-vis sub-surface geology, and influence groundwater conditions. We incorporate lithological and groundwater data obtained from an extensive network of boreholes in and around the city at 110 sites, reaching a maximum depth of 100 m below ground level (bgl). The unconsolidated subsurface are primarily composed of sand, silt, clay, and gravel where, silty clay layer. Groundwater quality and stresses were determined through multi-dimensional hydrogeological approaches. The data were analyzed through multivariate statistics (Principal Component Analyses to identify the governing factor influencing the broad hydrogeochemistry. PC1 for urban areas has higher loading values for Fe, Cl− compared to Semi-urban areas highlighting contamination by municipal wastewater. PC2 for urban areas shows higher loading values for Mg2+ and HCO3− compared to semi-urban areas. Due to heavy urbanization in Varanasi, the aquifer suffers substantial groundwater abstraction during particular times of the day compared to the agricultural lands. An increase of about 9% in built-up areas within a span of 10 years (2012–2022) poses a threat to the aquifer system of our study area, jeopardizing access to sustainable drinking water. With the expansion of urbanization and unregulated groundwater extraction, the vulnerability of the aquifer system will probably increase in the foreseeable future. Implementation of sustainable water management policies, engaging all economic sectors of the population in Varanasi, can expedite the process and safeguard the aquifer from attaining its emerging vulnerability. Thus, comprehending evolving groundwater risks through non-invasive methods like that discussed in the present study, holds significant promise for effectively targeting safe groundwater availability in future.

Use of unmanned aerial vehicle (UAV) in the analysis of natural risks: Landslides in the Ancoa Reservoir Sector, Linares Province, Maule Region.

On July 20, 2022 at 9:00 p.m., a landslide-type mass removal was recorded on route L-39, specifically at km 30.7 of the area of the first viewpoint of the Ancoa Reservoir, which is frequented by residents and visitors who come to this tourist sector. The landslide generated a road cut of 200 m, with the affected area of the hillside approximately 5,251 m2. UAV (Unmanned Aerial Vehicle) flight was carried out in the study area, to obtain geographic information, data collection and geomorphological surface processes of the landslide, based on orthophoto measurements and generation of surface elevation models (DSM). The results show that photogrammetry from UAVs provides flexible and effective tools to evaluate and analyze geomorphological characteristics, in addition to mapping and monitoring this type of mass removal, being the basis for generating multitemporal studies.

Pedological formations on old mountain geomorphological surfaces of central Spain

The chemo-morphological properties of soils on ancient landforms (quarzitic pliocene alluvial fans, pleistocene terraces), namely “rañizos”, on middle-high mountains (Eastern-Central System, Iberian Peninsula, Rio Negro, Cogolludo) were investigated. Several properties were analyzed by standard procedures. A detailed soil diagnostics and classification on “rañizos” were done, unlike those widely studied on “rañas” (similar landform), by identifying parallel pedogenetic processes in both formations. The genetic and geographic features of Alfisols, Ultisols and Inceptisols are closely related to the nature of their parent materials, based on quartzite and quartz conglomerates, sometimes with an arkosic matrix, red shale, polygenic gravels and pebbles. Soil features were determined by genuine soil-forming inherent lithological rock properties. Other driving factors were flat topography and enough soil formation time to allow intense pedogenesis. The main soil-forming processes were intense weathering, clay enrichment horizons with illuviation, red color caused by iron oxide dehydration and signs of pseudogleyzation processes. Such pedological formations can be considered endemisms; that is, “rare” soils and, up to a point, “relict”. The soil reaction is acid/slightly acid with low base saturation. Despite lying on mountains, soils are characterized by moderate-low organic matter content. Soil conditions and climate provide good vine production requirements despite acidity levels. A common feature of all Rio Negro soils is the presence of gravel (size up to 3–5 cm), which is evenly distributed on arable layers. The results can be used to assess vineyard soil use in a potential Pago (Protected Denomination of Origin) and to extend the database of vineyard soils from poorly studied Mediterranean continental mountain regions.

Reconstruction of fluvio‐lacustrine landscapes and settlement history in the Texcoco region, Mexico, using a modern geomorphic analog

AbstractLocated in the Basin of Mexico, the eastern shore of former Lake Texcoco sustained a variety of human occupations throughout the Holocene, including preceramic hunter‐gatherers, incipient agriculturalists, and a variety of settlements in the ceramic periods. Nonetheless, the environmental dynamics of occupations on the lakeshore have not been fully addressed. The Archaic preagricultural Texcoco Man site (>5000 B.C.E.) and the Late Formative TX‐LF‐14 site (c. 550‐200 B.C.E.), among others, occupy this fluvio‐lacustrine transitional environment. Few stratigraphic works in and around the sites have been performed. Consequently, it is difficult to understand the dynamics of the sedimentary system in space and time. This work highlights and describes the fluvio‐lacustrine sedimentary dynamics and the resulting landscape that past societies inhabited on the eastern shore of Texcoco Lake. Because the study area has been altered by historic and modern draining, our work employs Lake Santiaguillo and its main tributary, the Tejamen River in the Durango state, as a modern analog to study their sedimentary dynamics. The analyses of surface geomorphology in the Texcoco study area were employed to corroborate the modern analog interpretation. To achieve these goals, we conducted a GIS‐based morphometric analysis and LANDSAT‐8 imagery to study the variations in landforms through wet and dry events. The results indicate an increase in the lake volume, low bifurcation in the active fluvial channels, few inundated surfaces, and the presence of bird‐foot deltaic channels during high precipitation events. In contrast, low precipitation events are characterized by reduced lake volume, increased fluvial channel bifurcation, and expanded floodplains. This heterogeneous landscape thus provided a rich source of diverse natural resources of saline and freshwater aquatic habitats. Simultaneously, constant or recurring flooding events generated a challenging landscape for prehistoric settlers who implemented diverse technologies, such as the construction of tlateles, on the levees of deltaic channels to reduce the risk and impact of flooding events.

Selecting and refining suitable methods of developing digital elevation models to represent geomorphic features and characteristics of smaller wetlands in data-scarce environments

Land surface geomorphology plays an important role in water and sediment dispersal processes in wetlands. For wetland practitioners and researchers to engage with these processes in time and space, they require topographic data in order to derive wetland surface gradient, cross-sectional shape and area, surface and subsurface hydrological connectivity, and hydraulic characteristics. A range of data options, with varying spatial resolutions, are available, ranging from free national and global resources (e.g. contour data and global elevation models) to project-specific high-resolution surveys (e.g. Differential Global Positioning Systems (DGPS), Photogrammetry, Light Detection And Ranging (LiDAR)). Due to the scarcity of high-resolution and high-accuracy data, especially in developing countries, data gathering and processing costs can be significant. This paper presents a commentary on a range of topographic data and processing options for a relatively small (~ 40 ha) floodplain wetland in the Eastern Cape, South Africa. It critically reviews the usefulness and shortfalls of various wetland-related applications ranging from gradient calculations to more detailed hydraulic modelling, and the data resolution required for each application. Free, low-resolution, datasets have a limited representation of geomorphology at this scale due to the relatively low-resolution and large vertical error. Field-based surveys (using survey-grade equipment such as a DGPS) have the benefit of providing accurate terrain results in areas with dense vegetation and surface water, while photogrammetry and LiDAR data are useful to represent the higher resolution morphology across the wetland, despite shortcomings regarding the penetration of dense vegetation and surface water. However, combining DGPS data with LiDAR proves to yield the best model for detailed process modelling for wetlands at the local scale.

Improved Automatic Classification of Litho-Geomorphological Units by Using Raster Image Blending, Vipava Valley (SW Slovenia)

Automatic landslide classification based on digital elevation models has become a powerful complementary tool to field mapping. Many studies focus on the automatic classification of landslides’ geomorphological features, such as their steep main scarps, but in many cases, the scarps and other morphological features are difficult for algorithms to detect. In this study, we performed an automatic classification of different litho-geomorphological units to differentiate slope mass movements in field maps by using Maximum Likelihood Classification. The classification was based on high-resolution lidar-derived DEM of the Vipava Valley, SW Slovenia. The results show an improvement over previous approaches as we used a blended image (VAT, which included four different raster layers with different weights) along with other common raster layers for morphometric analysis of the surface (e.g., slope, elevation, aspect, TRI, curvature, etc.). The newly created map showed better classification of the five classes we used in the study and recognizes alluvial deposits, carbonate cliffs (including landslide scarps), carbonate plateaus, flysch, and slope deposits better than previous studies. Multivariate statistics recognized the VAT layer as the most important layer with the highest eigenvalues, and when combined with Aspect and Elevation layers, it explained 90% of the total variance. The paper also discusses the correlations between the different layers and which layers are better suited for certain geomorphological surface analyses.

Recognition of whole-landscape changes due to extreme rain events in a hyperarid desert

Infrequent extreme rain events in extraordinarily dry environments can dramatically shape the landscape. Here, a change-detection method is demonstrated that uses Landsat 8 OLI scenes to document land surface modification across thousands of square kilometers due to two extreme rain events which impacted the Atacama Desert. Images for 4 dates, in 3 date-pairs, are analyzed using a Change Vector Analysis (CVA) technique which delivers a measure of the intensity of change (Intensity-CVA). In 2015, an extreme rain event affected the southern Atacama and one in 2019 affected the northern Atacama. In this work, we show with the 2015 event the efficacy of CVA to identify areas of mass transference by favorable comparison to published Interferometric Synthetic Aperture Radar (InSAR) permanent coherence loss for areas located in nearly flat terrains. The efficacy of Intensity-CVA was also demonstrated for the 2019 rain event, where it identified mass transference and mineral transformations. To clarify the physical processes behind the Intensity-CVA response, for specific areas with known types of surface materials we conducted Principal Component Analysis (PCA) on quadratic difference of Surface Reflection (SR) values of Landsat 8 OLI scenes for multiple dates and also analyzed Intensity-CVA trends. These two analyses reveal that, among locations with strong Intensity-CVA change, remotely identified changes are dominated by soil moisture variations associated with active alluvial deposits, playa lakes and evaporitic units verified by PCA even 60 Km away from the focus of the rain. Secondarily we detected salt crystals growth several months after the rain. This approach, validated in the Atacama, successfully identified the consequences of extreme rain events at the scale of the entire landscape. This result opens the possibility to use a long-lived sensor, such as Landsat, to examine geomorphological surface changes through time in arid environments in a context of climate change.

Holocene marine terraces as recorders of earthquake uplift: Insights from a rocky coast in southern Hawke's Bay, New Zealand

AbstractOn rocky tectonic coasts, data from Holocene marine terraces may constrain the timing of coseismic uplift and help identify the causative faults. Challenges in marine terrace investigations include: (1) identifying the uplift datums; (2) obtaining ages that tightly constrain the timing of uplift; (3) distinguishing tsunami deposits from beach deposits on terraces; and (4) identifying missing terraces and hence earthquakes. We address some of these challenges through comparing modern beach sediments and radiocarbon ages with those from a trench excavated across three terraces at Aramoana, central Hikurangi Subduction Margin, New Zealand. Sedimentary analyses identified beach and dune deposits on terraces but could not differentiate specific environments within them. Modern beach shells yielded modern radiocarbon ages, regardless of position or species, showing age inheritance and habitat is likely not an issue when dating shells on these terraces. By integrating terrace mapping, stratigraphy, morphology, and radiocarbon ages we develop a conceptual model of coastal uplift and terrace formation following at least two, possibly three, earthquakes at 5490–5070, 2620–2180, and 950–650 cal. yr bp. A high step and time gap between the upper two terraces raises the possibility that at least one intervening terrace is completely eroded. The trench exposure also showed that terrace stratigraphy may differ from that inferred from surface geomorphology, with apparent beach ridges being of composite origin and draping of younger beach deposits on the outer edge of a previous terrace. Dislocation modelling and comparison of marine terrace and earthquake ages from ~4 km south and ≤ 73 km north confirms that the most likely earthquake source is the nearshore, landward‐dipping, Kairakau Fault. Alternative sources, such as multi‐fault ruptures of the Kairakau‐Waimārama faults or Hikurangi subduction earthquakes, and/or a combination of the two are also possible and should be examined in future studies.

Constraining the age of Quaternary megafloods in the Altai Mountains (Russia) using luminescence

Some of the largest catastrophic outbursts of periglacial lakes known in the geological history of the Earth have been identified in the Altai Mountains. Traces of these events are recorded in the form of large terraces, predominantly composed of gravel material with numerous horizons of large boulders and blocks. Determining the age of these large-scale events is difficult due to the lack of suitable material (e.g. organics, well-bleached sand) and the specific genesis of these sediments. The results of cosmogenic radionuclide dating suggest a post-LGM age both for the source of the flood water and for different elements of the catafluvial terraces in the Chuya and Katun river valleys. Nevertheless, the age(s) of catastrophic breakthrough remains controversial. On the basis of a few IRSL ages, and geological and other evidence, some view the event as occurring around MIS 5. In this study, we investigate loess-like loams overlying the catafluvial sediments on the surface of the highest level terrace, ∼200 m above present river level. A total of 24 samples for luminescence dating were obtained, for which the OSL, IR 50 , and pIRIR 50,290 signals were measured to control the degree of signal zeroing and the dating reliability. The age of the loess in all three pits was from 0.5 ka at the top to 23 ka at the base of the loess strata. From a sand layer in the top of the catafluvial deposits, two ages of ∼85–90 ka were obtained from feldspar pIRIR 50,290 . These results provide a minimum pre-LGM age for the geomorphological surface of a major catafluvial terrace in the Altai Mountains.

Reconstruction of Land and Marine Features by Seismic and Surface Geomorphology Techniques

Seismic reflection utilizes sound waves transmitted into the subsurface, reflected at rock boundaries, and recorded at the surface. Interpretation of their travel times and amplitudes are the key for reconstructing various geomorphological features across geological time (e.g., reefs, dunes, and channels). Furthermore, the integration of surface geomorphology technique mapping, such as digital elevation models, with seismic geomorphology can increase land and marine feature modelling and reduce data uncertainty, as well. This paper presents an overview of seismic and surface geomorphology techniques and proposes an integrated workflow for better geological mapping, 3D surface imaging, and reconstruction. We intend to identify which techniques are more often used and which approaches are more appropriate for better output results. We noticed that an integration of surface and subsurface geomorphology techniques could be beneficial for society in landscape mapping, reservoir characterization, and city/regional planning.

PAGURIZED GASTROPOD SHELLS IN A NORTHEAST BRAZILIAN COASTAL LAGOON AT THE SEA-ESTUARY INTERFACE

Gastropods are known for the presence of calcareous shells, even after their death. The diversity of this resource can be reflected in the local diversity of living gastropods. These shells are used by hermit crabs as protection and against desiccation. Coastal lagoons are biodiversity hotspots and the site of recruitment of continent-sea connectivity, and their diversity is sometimes altered by connectivity events with adjacent areas. Therefore, we sought to make a list that evaluates the seasonal variation of diversity and demonstrates the pattern of shell use by hermit crab species. The samplings were standardized in six monthly repeated transects from February 2013 to January 2014, using a fishing net trawl. The shells were identified to species level and quantified. Diversity indexes were calculated, seasonally, for the assemblage of used shells. Hermit crabs used 14 species of gastropod shells, of which Vitta virginea and Phrontis vibex were the most abundant and frequent. The diversity indexes indicated a temporal variation of the shells, with April the month showing the highest difference in diversity. A reflection of the change in surface geomorphology, caused by the King Tide, it’s discharge and carrying of empty gastropod shells to the open sea. The usage patterns of these biogenic remains can reveal strategies of decreased intra/interspecific competition. Furthermore, we described the first record in the Brazilian Northeast of the hermit crab C. symmetricus, after its taxonomic resurgence.

Miocene-Holocene river drainage evolution in Southland, New Zealand, deduced from fish genetics, detrital gold and geology

ABSTRACT We integrate multidisciplinary observations to provide a regional-scale synthesis of river drainage reconfiguration in Southland (New Zealand) between the Miocene and the Holocene. Distributions of sedimentary clasts, including alluvial gold, garnets and chromite, are combined with freshwater fish genetics, surface geomorphology, and basement geology to constrain river drainage directions and interconnections through time. River evolution in much of the South Island has been dominated by localised tectonic uplift linked to distant Alpine Fault tectonism. In the southeast, the rise of ranges between Central Otago and Southland severed initial long-distance southward drainage and gold transport and isolated fish species. Plio-Pleistocene range uplift caused the recycling of older alluvial gold deposits into the new Southland river systems. The most significant Southland drainage reorientations have occurred through the Pleistocene, in parallel with similar processes in Central Otago. In particular, the Pomahaka River has evolved geomorphologically from a Southland-linked catchment to become a major tributary of the Clutha catchment, with associated biological evolution of distinctive endemic freshwater fish.

Moraines in the Austrian Alps record repeated phases of glacier stabilization through the Late Glacial and the Early Holocene

Climate is currently warming due to anthropogenic impact on the Earth’s atmosphere. To better understand the processes and feedbacks within the climate system that underlie this accelerating warming trend, it is useful to examine past periods of abrupt climate change that were driven by natural forcings. Glaciers provide an excellent natural laboratory for reconstructing the climate of the past as they respond sensitively to climate oscillations. Therefore, we study glacier systems and their behavior during the transition from colder to warmer climate phases, focusing on the period between 15 and 10 ka. Using a combination of geomorphological mapping and beryllium-10 surface exposure dating, we reconstruct ice extents in two glaciated valleys of the Silvretta Massif in the Austrian Alps. The mountain glacier record shows that general deglaciation after the Last Glacial Maximum (LGM) was repeatedly interrupted by glacier stabilization or readvance, perhaps during the Oldest Dryas to Bølling transition (landform age: 14.4 ± 1.0 ka) and certainly during the Younger Dryas (YD; 12.9–11.7 ka) and the Early Holocene (EH; 12–10 ka). The oldest landform age indicates a lateral ice margin that postdates the ‘Gschnitz’ stadial (ca. 17–16 ka) and predates the YD. It shows that local inner-alpine glaciers were more extensive until the onset of the Bølling warm phase (ca. 14.6 ka), or possibly even into the Bølling than during the subsequent YD. The second age group, ca. 80 m below the (pre-)Bølling ice margin, indicates glacier extents during the YD cold phase and captures the spatial and temporal fine structure of glacier retreat during this period. The ice surface lowered approximately 50–60 m through the YD, which is indicative of milder climate conditions at the end of the YD compared to its beginning. Finally, the third age group falls into a period of more substantial warming, the YD–EH transition, and shows discontinuous glacier retreat during the glacial to interglacial transition. The new geochronologies synthesized with pre-existing moraine records from the Silvretta Massif evidence multiple cold phases that punctuated the general post-LGM warming trend and illustrate the sensitive response of Silvretta glaciers to abrupt climate oscillations in the past.

Recent Evolution of Glaciers in the Manaslu Region of Nepal From Satellite Imagery and UAV Data (1970–2019)

Glacierized mountain ranges such as the Himalaya comprise a variety of glacier types, including clean and debris-covered glaciers. Monitoring their behaviour over time requires an assessment of changes in area and elevation along with surface features and geomorphology. In this paper we quantify the surface evolution of glacier systems in the Manaslu region of Nepal over the last five decades using 2013/2019 multi-sensor imagery and elevation data constructed from 1970 declassified Corona imagery and 1970 declassified Corona imagery. We investigate area changes, glacier thickness, geodetic glacier mass balance and surface velocity changes at regional scales and focus on the Ponkar Glacier and Thulagi Glacier and Lake for an in-depth assessment of surface geomorphology and surface feature dynamics (ponds, vegetation and ice cliffs). The time series of surface elevation changes for the lower ablation area of Ponkar Glacier is extended using 2019 UAV-based imagery and field-based ablation rates measured over the period 2016–2019. Glaciers in the Manaslu region experienced a mean area loss of −0.26 ± 0.0001% a−1 between 1970 and 2019. The mean surface lowering was −0.20 ± 0.02 ma−1 over the period 1970 to 2013, corresponding to a regional geodetic mass balance of −0.17 ± 0.03 m w. e.a−1. Overall, debris-covered glaciers had slightly higher thinning rates compared to clean ice glaciers; lake-terminating glaciers had double thinning rates compared to land-terminating glaciers. Individual glacier mass balance was negatively controlled by glacier slope and mean glacier elevation. During the period 1970 to 2013, Ponkar Glacier had a geodetic mass balance of −0.06 ± 0.01 m w. e.a−1, inversely correlated with parts of the central trunk thickening. Between 2013 and 2019 there was a nine-fold increase in the thinning rates over the lower parts of the glacier tongue relative to the period 1970–2013. Ice-surface morphology changes between 1970 and 2019 on Ponkar Glacier include a decrease in ogives and open crevasses, an increase in ice cliffs and ponds and the expansion of the supraglacial debris and ice-surface vegetation. These changes point to reduced ice-dynamic activity and are commensurate with the observed recession and negative glacier mass balance over the last five decades.

Site selection of check dams using geospatial techniques in Debre Berhan region, Ethiopia — water management perspective

Remote sensing and GIS technology were very helpful to determine an appropriate location of freshwater storage in Amhara, Ethiopia. The techniques were used to investigate the impact of lithology, surface geomorphology, slope parameters, drainage flow, drainage density, lineament density, land cover parameters on relief, and aerial and linear features and to understand their interrelationships. Morphometric parameters such as mean stream length (Lsm), stream length ratio (RL), bifurcation ratio (Rb), mean bifurcation ratio (Rbm), relief ratio (Rh), drainage density (Dd), stream frequency (Fs), drainage texture (Rt), form factor (Rf), circularity ratio (Rc), and elongation ratio (Re) were calculated. Spatial maps of morphometric parameters were produced by using AHP (analytical hierarchy process) of ArcGIS 10.3. Final priority map was generated by the overlay of those parameters with five categories of poor (16.6%), low (41.63%), moderate (29.61%), high (8.88%), and very high (3.28%) storage locations. The map showed that this study area belonged to the low to moderate storage location. The results exhibit precision-based assessment of the suitability for the dam construction sites of 6, 7, and 9 sub-basin zones. The outcome of this study strengthens the knowledge of geospatial analysis for water resources vulnerability and also allows policymakers in this drought-prone area to sustainably manage water supplies.

Workflow for capturing information and characterizing difficult-to-access geological outcrops using unmanned aerial vehicle-based digital photogrammetric data

This paper aims to present a methodological approach for capturing information and characterizing difficult-to-access geological outcrops using unmanned aerial vehicle-based digital photogrammetric data, which has been growing in importance as a three-dimensional modeling method along with the use of 3D geomodelling, geological, stratigraphic and structural software packages, and specialized programmed algorithms in complex geological cases. In this way, it is possible to document rock outcrops, geological structures, stratification or foliation plans, geometry of outcropping lithologies, underground and surface mining works, karst systems, etc. The data obtained will then serve as a basis for the geomodelling of the geological structure of mineral deposits and oil and gas. Traditionally, the photogrammetry technique in Geosciences has been limited to simplifying and improving the work of surface mapping, topography, cartography, interferometry patterns, surface geomorphology and spectral analysis of high-resolution satellite images. However, currently, the evaluation of the discontinuities of a rock massif can be carried out, the structural domains with high precision, in a short time and in a complete way remotely, taking the information gathered in outcrops to other scenarios so that the work be interactive.

Was Venus Ever Habitable? Constraints from a Coupled Interior–Atmosphere–Redox Evolution Model

Abstract Venus’s past climate evolution is uncertain. General circulation model simulations permit a habitable climate as late as ∼0.7 Ga, and there is suggestive—albeit inconclusive—evidence for previous liquid water from surface geomorphology and mineralogy. However, it is unclear whether a habitable past can be reconciled with Venus’s inferred atmospheric evolution. In particular, the lack of leftover atmospheric oxygen argues against recent water loss. Here, we apply a fully coupled model of Venus’s atmospheric–interior–climate evolution from post-accretion magma ocean to present. The model self-consistently tracks C-, H-, and O-bearing volatiles and surface climate through the entirety of Venus’s history. Atmospheric escape, mantle convection, melt production, outgassing, deep water cycling, and carbon cycling are explicitly coupled to climate and redox evolution. Plate tectonic and stagnant lid histories are considered. Using this coupled model, we conclude that both a habitable Venusian past and one where Venus never possessed liquid surface water can be reconciled with known constraints. Specifically, either scenario can reproduce bulk atmospheric composition, inferred surface heat flow, and observed 40Ar and 4He. Moreover, the model suggests that Venus could have been habitable with a ∼100 m global ocean as late as 1 Ga, without violating any known constraints. In fact, if diffusion-limited water loss is throttled by a cool, CO2-dominated upper atmosphere, then a habitable past is tentatively favored by our model. This escape throttling makes it difficult to simultaneously recover negligible water vapor and ∼90 bar CO2 in the modern atmosphere without temporarily sequestering carbon in the interior via silicate weathering to enhance H escape.

Comment on “Fragmentation of the Adriatic Promontory: New Chronological Constraints From Neogene Shortening Rates Across the Southern Alps (NE Italy)” by Moulin & Benedetti

AbstractMoulin and Benedetti (2018),https://doi.org/10.1029/2018TC004958present a new interpretation of the Neogene‐Quaternary tectonic evolution of the Eastern Southern Alps (ESA) in Veneto‐Friuli. After the reinterpretation of literature field data by means of remote sensing analysis (Digital Elevation Model interpretation), they calculated deformation rates of the tectonic structures through age interpretation of geomorphological surfaces of the Veneto‐Friuli piedmont plain. The authors linked the result of surface analysis to the thrust and fold architecture of the ESA basing on the Castellarin et al. (2006),https://doi.org/10.1016/j.tecto.2005.10.013interpretation of TRANSALP project and the Friuli geological map at the scale 1:150,000 (Carulli, 2006). Discussing their new architecture of the ESA, the authors finally yielded rates of Europe‐Adria plates convergence and suggested fragmentation of Adria over the last 1–2 Ma. The present comment is aimed at discussing several critical points concerning: the use of the geomorphological and chronological data; the misinterpretation of the Digital Terrain Model; the reconstruction of the balanced geological cross section. Moreover, the application of a structural model defined in a certain area to another without considering peculiar structural complexities available in the literature results is geologically and methodologically questionable.