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We describe two new small-bodied species of South Asian Cnemaspis from Kanyakumari District of Tamil Nadu State, India. The two new species are sister taxa, forming a well-supported, previously unsampled clade of South Asian Cnemaspis that we name the kanyakumariensis clade. This new clade is recovered with weak support as the sister taxon to the goaensis clade. Both the new species together can be easily distinguished from all other peninsular Indian clades by a combination of non-overlapping morphological characters such as small size with snout to vent length < 40 mm, femoral pores only present in males, presence of spine-like tubercles on flanks, and condition of the subcaudals. They can also be distinguished from each other by several characters such as the number of dorsal tubercles around the body, short vs long spine-like tubercles on flank, and the arrangement of keeled subcaudal scales. They also differ by uncorrected pairwise sequence divergence of 10.2 and 2.9% for ND2 and 16S, respectively. This work reveals that even the low-elevation coastal hills of southern India have ancient, endemic lineages and require protection. [ABSTRACT FROM AUTHOR]

The worship of baetyls in antiquity is well documented in the Near East and the Mediterranean, archaeologically as well as historically. While such practices were also common in South‐East Arabia, the archaeological information on it is still very limited. A boulder carved with a 'trident' (a mark familiar from local Abiel coin issues), which came to light at the site of Mleiha, has a circular cavity on the side similar to those visible on stones and on an eagle statue from contemporary ed‐Dur. This association suggests a religious context for the Mleiha petroglyph and, thus, a possible identification as a baetyl. The archaeological evidence for stone worship and associated cult practices from the SE‐Arabian Mleiha/PIR A‐C period (3rd century bce–3rd century ce) is reviewed and compared with ethnographic parallels and information from, among other sources, the Kitāb al‐aṣnām (Book of Idols) by Hishām ibn al‐Kalbī (737–819 ce). [ABSTRACT FROM AUTHOR]

The purpose of this research is to analyze the headcut propagation and downstream sediment yield as a result of a low‐head dam failure. While frameworks have been presented elsewhere to track headcut propagation from a dam failure/removal, little research has been conducted to calculate the downstream sediment yield of the resulting headcut. The sediment yield is of particular interest when a reservoir is located downstream of the headcut. This paper estimates the increased sediment yield to Tuttle Creek Lake as a result of a low‐head dam failure on the Big Blue River. From 2018 to 2022, the headcut contributed an estimated 859,000 m3 of sediment to Tuttle Creek Lake. Erosion is unlikely to continue due to the presence of natural grade control provided by boulder riffles and bedrock. [ABSTRACT FROM AUTHOR]

Schmidt hammer R‐values, which reflect the degree of rock surface weathering, can be paired with independent rock surface exposure ages to produce Schmidt hammer exposure‐age dating (SHD) calibration curves that are used to provide rapid estimations of exposure ages for undated rock surfaces. In this Letter, we lay the groundwork for later establishing a SHD calibration curve based on glacial erratics deposited by the Laurentide Ice Sheet in the North American Great Lakes region. First, we establish a reference R‐value for a calibration boulder, which may be used to facilitate direct comparison of R‐values collected by different individuals using mechanical N‐type Schmidt hammers, specifically. We then assess how no, light or heavy use of a carborundum puck to smooth rock surfaces affects resulting R‐value data. Lastly, we compare two different R‐value metrics on the same rock surface: Rmean (n = 30) versus ΔR (Rmax − Rmin of five consecutive R‐values on the same spot). In all assessments, Rmean is similar for erratic surfaces with no and light surface treatment, and both are significantly lower than Rmean of surfaces with heavy treatment. Thus, we advise against the use of heavy surface treatment in SHD applications. We observe no relationship between inferred erratic age and either Rmean or ΔR, which could arise from inferred ages of erratics being inaccurate, from inferred ages of erratics being too similar or from measuring too few erratics from each landform. [ABSTRACT FROM AUTHOR]

Introduction: Bouldering is an Olympic discipline that takes place on low-height climbing structures known as boulders. Routesetters play a critical role in bouldering; they design and set boulders to be climbed, which must be original, safe to climb and adapted to climbers' levels. Considering the critical role routesetters play to keep the present success and ensure the future development of bouldering, the purpose of this study was to profile expert routesetters by identifying relevant key skills they possess and examining specific strategies they use when designing boulders. Methods: Seventy-eight expert routesetters completed an online survey structured in eight sections that assessed the following: perceptual–cognitive skills; soft skills; motor skills; climbing skills; welfare; safety and difficulty; climbing holds and wall features; and climbing movement diversity and boulder styles. Results: Among fundamental skills experts identified, most relevant to routesetters were possessing a broad climbing movement repertoire, the ability to develop several climbing strategies for one boulder, forecasting of climbing movements, climbing-specific decision-making and creativity, self-reflection, teamwork, dealing with negative feedback, technical skills and general fitness. Furthermore, most relevant specific routesetter skills and strategies appeared to encompass the ability to design boulders that account for climbers' skill levels and safety, to adapt to the constraints of climbing gyms, to make optimal use of climbing wall features and to design versatile climbing movements. Conclusion: The expert routesetters' profile comprises fundamental and specific skills and strategies that enable them to design target-oriented boulders with versatile climbing movements for different levels whilst accounting for climbers' welfare. [ABSTRACT FROM AUTHOR]

Lithological cycles with a repetitive pattern of sandstone overlain by limestone or shale comprise the middle Minnelusa Formation in the Black Hills region, USA. At least eight lithological cycles were observed at Boulder Canyon Road (BCR), eight at Vanocker Canyon Road (VCR) and four at Hot Brook Canyon (HBC). These rocks were deposited in a nearshore to offshore marine environment, and the shale and limestone intervals at the top of these cycles yielded conodonts. Five biostratigraphically distinct Middle to Upper Pennsylvanian conodont faunas were recovered from these marine units. An upper Desmoinesian assemblage was recovered from VCR cycle 1. Two Missourian assemblages were recovered, one indicative of the Idiognathodus cancellosus Zone from VCR cycle 3 and the other indicative of the Streptognathodus gracilis Zone from VCR cycle 6. Two Virgilian assemblages were recovered, one indicative of the Heckelina simulator Zone from VCR cycle 7, VCR cycle 8 and HBC cycle 2 and the other indicative of the lower part of the "Streptognathodus" group 4 virgilicus Zone from HBC cycle 3. Two conodont biofacies were recognized within the middle Minnelusa, the low energy, offshore, Idiognathodontidae-Idioprioniodus biofacies and the higher energy, nearshore Idiognathodontidae-Hindeodus biofacies. [ABSTRACT FROM AUTHOR]

To solve the construction difficulties of the rectangular pipe jacking in the boulder area in a complex geological environment, based on the pipe jacking project of the pedestrian passage of the Qieye Ridge in the transformation project of the Harbor Avenue in Xiangzhou District, Zhuhai City, Guangdong Province, the construction risks encountered by boulders during pipe jacking excavation were analyzed in conjunction with the actual engineering conditions. According to the size, shape, and distribution of the boulders, the advantages and disadvantages of different construction schemes when encountering boulders during pipe jacking construction process were discussed, and the engineering costs, environmental impact, construction difficulty, safety, and applicability of five obstacle handling schemes were systematically compared and analyzed. The best handling method suitable for this case project was selected to achieve the purpose of improving efficiency, reducing costs, and avoiding risks. The case project adopted the pre-treatment construction technology of the down-the-hole hammer in the casing technology to crush and remove the boulders, and successfully restored the pipe jacking excavation construction. This solution could ensure efficient, safe, and orderly clearance work and had excellent application effects. [ABSTRACT FROM AUTHOR]

The lunar surface undergoes various space weathering and impact processes, which shape the regolith and expose boulders. Using high-resolution Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera imagery and associated Digital Elevation Models, we investigate regolith thicknesses and boulder densities at the four candidate landing sites of the Emirates Lunar Mission Rashid-1 rover: the floor-fractured crater Atlas and the Sinus Iridum, Oceanus Procellarum and Lacus Somniorum maria. The regolith thickness is estimated using the small crater morphology method, by mapping 3413 central mound, flat-bottomed, concentric craters (<350 m in diameter). Boulders were counted manually and compared with LRO Diviner rock abundance and mini-RF Circular Polarisation Ratio global maps. There is no obvious correlation between the site's age, average regolith thickness and boulder density. The "Depth-Age hypothesis" is not confirmed here: Atlas (3.8 Gyr) has the thinnest regolith (median: 1.2 m), Procellarum (1.9 Gyr) and Somniorum (3.7 Gyr) have similar thicknesses (1.7 m and 1.8 m respectively), and the regolith in Iridum (3.4 Gyr) is the thickest (2.9 m). The estimated regolith thickness is highly variable laterally within the landing ellipses. Boulder fields in the landing areas are well-correlated with higher Diviner rock abundance values, and with locally thicker patches of regolith. The relatively thin regolith in Atlas could be related to its complex geology involving multiple volcanic episodes. Orbital estimates of regolith thickness and boulder distribution remain key for landing safety and trafficability assessments during mission preparations, and bring key insights into the local history of the regolith through crater morphologies. [ABSTRACT FROM AUTHOR]

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Active orogens balance tectonic rock uplift with erosion, commonly via river incision coupled to landslide denudation of “threshold” hillslopes, but sediment’s role in this feedback is unclear. We report fluvial geometry and sediment size, prevalence, and mobility across two ≤600-m-tall gneissic northern Alaska Range anticlines that sustain steep landslide-clad hillslopes but differ 10× in late Pleistocene–recent rock uplift rate. Enigmatically, the river steepens and narrows prominently across the fold experiencing slow surface uplift (∼0.5 mm/ yr) but remains low-gradient and wide downstream across the anticline undergoing rapid differential rock uplift (∼5 mm/yr). Frequent bedload mobilization across both folds implies fluvial equilibration to sediment transport despite discrepant channel forms and similarly prevalent hillslope-derived boulders. Boulder prevalence correlates significantly with channel slope and width on the slowly uplifting anticline, but weakly on the rapidly uplifting anticline. Strong correlations across the tectonically quiescent anticline may reflect local incision-suppressing boulder aggradation that forces the channel to steepen and narrow, consistent with field observations. Conversely, weak correlations across the rapidly uplifting anticline imply that boulders may modulate expected tectonic channel adjustment by preferentially aggrading to subdue slope, and deflecting frequently mobile bedload to drive lateral erosion that maintains channel width, steepens adjacent hillslopes, and perpetuates hillslope-channel coupling. Hence, hillslope-derived boulders may occupy important roles in regulating feedbacks between river incision and landslide erosion that differ fundamentally at high and low tectonic rates. [ABSTRACT FROM AUTHOR]

Natural dams are formed most often in narrow, steep valleys in high mountains. The outburst floods triggered by natural dam failures result in the topography and landforms successively being altered. Boulder bars are common natural structures that are selected here to quantitatively evaluate the impact of outburst floods on the topographical and landform variations in downstream channels. In this study, we selected the Sedongpu natural dam on the Yarlung Tsangpo River formed as a result of a landslide in 2018 as an example, and studied the geomorphological changes in a river reach located 173 km downstream of the Sedongpu natural dam. The sizes and shapes of the boulder bars in this area were statistically analyzed. The results show that there are three shape types of boulder bars in this area, i.e., sickle, bamboo leaf and oval. Furthermore, it found that the relationship between the lengths and widths of boulder bars is similar before and after outburst floods, as is the relationship between perimeters and lengths of boulder bars, which means these relationships are not affected by outburst floods. And the perimeters of boulder bars are almost twice their lengths. In addition, the relationship between the areas and lengths of boulder bars follows a power function. The most important finding is that the riverine morphological features conserved self-similarity due the influence of the outburst flood erosion triggered by a natural dam failure. This finding adds to the previous observations since dam failures introduce sudden and dominating impacts on river systems. [ABSTRACT FROM AUTHOR]

This study reports the presence of Percnon gibbesi in the North Adriatic Sea, specifically at Cape Kamenjak, Croatia. The species was first observed in the Mediterranean in 1999, and has rapidly proliferated across the region, with Cape Kamenjak now representing its northernmost finding. Seven individuals were identified during free-diving activities in Pinižule Bay in December 2023. Follow-up surveys in January 2024 revealed their presence approximately 15 meters from the shore, under large boulders, at depths ranging from 2.6 to 3.6 meters, with water temperatures ranging from 13 to 15 °C. Morphological examinations confirmed the specimen as male P. gibbesi, with a carapace length of 15 mm, carapace width of 14.3 mm, and a weight of 1.87 g. Shipping was identified as a primary vector of introduction due to the proximity of Cape Kamenjak to major Mediterranean ports. This research provides insights into the invasion dynamics of P. gibbesi in the northern Adriatic, urging proactive management strategies and collaborative efforts in monitoring programs. [ABSTRACT FROM AUTHOR]

In subway construction, the presence of boulders can significantly impact excavation and tunneling processes. However, despite these challenges, an effective and reliable method for detecting boulders in advance has not yet been established. This paper presents a novel method for detecting and characterizing boulders using 3D cross-hole electrical resistivity tomography (ERT). The proposed technique involves the strategic deployment of multiple borehole electrodes, which work together to create a comprehensive three-dimensional resistivity model of the subsurface. This model allows for the identification and characterization of boulders, providing crucial information about their location and size. We demonstrate the efficacy of this approach in a physical flume experiment and a case study of subway construction, The findings from both the laboratory and field studies indicate that the 3D cross-hole ERT method is not only effective in detecting boulders and providing detailed information about their size and spatial distribution but also optimizes construction planning, reduces unexpected disruptions and additional costs, and enhances overall construction safety. The results highlight the potential of 3D cross-hole ERT as a valuable tool for geological assessments during infrastructure development. [ABSTRACT FROM AUTHOR]

The bearing capacity - the ability of a surface to support applied loads - is an important parameter for understanding and predicting the response of a surface. Previous work has inferred the bearing capacity and trafficability of specific regions of the Moon using orbital imagery and measurements of the boulder tracks visible on its surface. Here, we estimate the bearing capacity of the surface of an asteroid for the first time using DART/DRACO images of suspected boulder tracks on the surface of asteroid (65803) Didymos. Given the extremely low surface gravity environment, special attention is paid to the underlying assumptions of the geotechnical approach. The detailed analysis of the boulder tracks indicates that the boulders move from high to low gravitational potential, and provides constraints on whether the boulders may have ended their surface motion by entering a ballistic phase. From the 9 tracks identified with sufficient resolution to estimate their dimensions, we find an average boulder track width and length of 8.9 ± 1.5 m and 51.6 ± 13.3 m, respectively. From the track widths, the mean bearing capacity of Didymos is estimated to be 70 N/m2, implying that every 1 m2 of Didymos' surface at the track location can support only ~70 N of force before experiencing general shear failure. This value is at least 3 orders of magnitude less than the bearing capacity of dry sand on Earth, or lunar regolith. Bearing capacity, the ability of a surface to support applied loads, is a critical property in planetary exploration to understand a surface's response to landing or roving. Here, the bearing capacity of the asteroid Didymos is estimated using DART images of suspected boulder tracks on its surface. [ABSTRACT FROM AUTHOR]

Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in the catastrophic disruption of parent bodies. Ground-based observations reveal that some of these asteroids are today binary systems, in which a smaller secondary orbits a larger primary asteroid. However, how these asteroids became binary systems remains unclear. Here, we report the analysis of boulders on the surface of the stony asteroid (65803) Didymos and its moonlet, Dimorphos, from data collected by the NASA DART mission. The size-frequency distribution of boulders larger than 5 m on Dimorphos and larger than 22.8 m on Didymos confirms that both asteroids are piles of fragments produced in the catastrophic disruption of their progenitors. Dimorphos boulders smaller than 5 m have size best-fit by a Weibull distribution, which we attribute to a multi-phase fragmentation process either occurring during coalescence or during surface evolution. The density per km2 of Dimorphos boulders ≥1 m is 2.3x with respect to the one obtained for (101955) Bennu, while it is 3.0x with respect to (162173) Ryugu. Such values increase once Dimorphos boulders ≥5 m are compared with Bennu (3.5x), Ryugu (3.9x) and (25143) Itokawa (5.1x). This is of interest in the context of asteroid studies because it means that contrarily to the single bodies visited so far, binary systems might be affected by subsequential fragmentation processes that largely increase their block density per km2. Direct comparison between the surface distribution and shapes of the boulders on Didymos and Dimorphos suggest that the latter inherited its material from the former. This finding supports the hypothesis that some asteroid binary systems form through the spin up and mass shedding of a fraction of the primary asteroid. By comparing boulders' surface distribution and shapes on the binary asteroid system, Didymos, authors show that both bodies are rubble piles produced in their progenitor catastrophic disruption and that the secondary, Dimorphos, likely inherited its material from the primary through spin up and mass shedding. [ABSTRACT FROM AUTHOR]

Planetary defense efforts rely on estimates of the mechanical properties of asteroids, which are difficult to constrain accurately from Earth. The mechanical properties of asteroid material are also important in the interpretation of the Double Asteroid Redirection Test (DART) impact. Here we perform a detailed morphological analysis of the surface boulders on Dimorphos using images, the primary data set available from the DART mission. We estimate the bulk angle of internal friction of the boulders to be 32.7 ± 2. 5° from our measurements of the roundness of the 34 best-resolved boulders ranging in size from 1.67–6.64 m. The elongated nature of the boulders around the DART impact site implies that they were likely formed through impact processing. Finally, we find striking similarities in the morphology of the boulders on Dimorphos with those on other rubble pile asteroids (Itokawa, Ryugu and Bennu). This leads to very similar internal friction angles across the four bodies and suggests that a common formation mechanism has shaped the boulders. Our results provide key inputs for understanding the DART impact and for improving our knowledge about the physical properties, the formation and the evolution of both near-Earth rubble-pile and binary asteroids. Planetary Defense efforts rely on estimates of asteroids' mechanical properties, which are difficult to obtain accurately from Earth. Here, authors compare images from space missions to the rubble-pile asteroids Dimorphos, Itokawa, Ryugu, and Bennu and study such properties through boulders on their surface. [ABSTRACT FROM AUTHOR]

Images collected during NASA's Double Asteroid Redirection Test (DART) mission provide the first resolved views of the Didymos binary asteroid system. These images reveal that the primary asteroid, Didymos, is flattened and has plausible undulations along its equatorial perimeter. At high elevations, its surface is rough and contains large boulders and craters; at low elevations its surface is smooth and possesses fewer large boulders and craters. Didymos' moon, Dimorphos, possesses an intimate mixture of boulders, several asteroid-wide lineaments, and a handful of craters. The surfaces of both asteroids include boulders that are large relative to their host body, suggesting that both asteroids are rubble piles. Based on these observations, our models indicate that Didymos has a surface cohesion ≤ 1 Pa and an interior cohesion of ∼10 Pa, while Dimorphos has a surface cohesion of <0.9 Pa. Crater size-frequency analyzes indicate the surface age of Didymos is 40–130 times older than Dimorphos, with likely absolute ages of ~ 12.5 Myr and <0.3 Myr, respectively. Solar radiation could have increased Didymos' spin rate leading to internal deformation and surface mass shedding, which likely created Dimorphos. Images collected during NASA's DART mission of the asteroid Didymos and its moon, Dimorphos, are used to explore the origin and evolution of the binary system. Authors analysis indicate that both asteroids are weak rubble piles and that Didymos' surface should be about 40 to 130 times older than Dimorphos. [ABSTRACT FROM AUTHOR]

The calving of glaciers regularly produces tsunami‐like waves that pose a serious threat to coastal environments. Those strong waves are not only able to move ice mélange and redistribute icebergs, growlers, or sea ice across a fjord but also flood and remodel neighbouring cliffs and beaches. Here, we analyze over 90 years (1929–2023) of coastal zone changes that occurred in front of Eqip Sermia. We show that calving waves play a dominant role in transforming the lateral moraine and forming a beach and spit system south of the glacier front. Part of the former moraine has transformed into a boulder‐dominated spit, which closed the lagoon over the years. By multidecadal analysis, we also detected a significant erosion of unconsolidated cliffs located on the opposite side of the bay (~0.53 m per year between 1985 and 2023). In addition, we demonstrate that even a single event (one calving wave) can remodel a beach surface by entrainment of up to 1.8‐m‐diameter boulders and the erosion of the beach surface by washing away sand and gravel from rocky outcrops. Our study constitutes important progress toward modes of paraglacial coastal evolution in regions characterized by rapidly retreating calving glaciers. [ABSTRACT FROM AUTHOR]

The present review paper offers the learning of steep boulder beds, and other dynamic topographic conditions, for deep understanding of scour catastrophes and recognizing absolute measures to link this key research gap. Though many models exist for silt, sand, and small size coarser bed materials, but no certain model is available universally for scour estimation in bed material above this size. This review paper claims for amplified research into boulder beds, steep bed slopes and dynamic river and stream conditions. Also, the present work highlights the requirement for evolving absolute criteria for such geographical weaknesses. The importance of taking into account complex and dynamic environments in the study of scour failures is also emphasized. Besides, the instant review paper discusses the scientific advancement for more precise and safe predictive models for scour, to discover a guiding tool to a strategy that augments well for the health of hydraulic structures to synchronize with the fundamental philosophies of long-term safety, economy, and functionality. [ABSTRACT FROM AUTHOR]

Boulders are globally widespread and influence processes across many landscapes including hillslopes, coasts, rivers and extra‐terrestrial settings. Boulders are described as particles, sufficiently large, that they have a disproportionate effect on the surrounding landscape. Moving beyond this conceptual definition, however, requires a somewhat arbitrary decision of how to define a minimum boulder size. The implications of boulder definition on study findings are rarely considered. We investigate the suitability of five boulder definitions, two based on fixed sizes: (1) 0.26 m and (2) 1 m, and three definitions which vary based on system characteristics: (3) grain mobility, (4) grain protrusion and (5) surface grain size distribution (> 84th percentile, D84). We consider the impact of definition on calculated boulder metrics, and, for the >1m and >D84 definitions, their association with channel and catchment characteristics across 20 boulder‐bed streams in northern Sweden. We also surveyed river managers responsible for restoring these rivers, to gain a practitioner insight on boulder size definition. We found that boulder definition matters; for metrics relating to the number or density of boulders, the >D84 and >1m size definitions were negatively correlated. Surveys indicated the importance of communicating boulder definition. We conclude that, whilst the best choice of boulder size definition will vary based on the questions of interest and techniques employed, evaluating the implications of the chosen boulder size definition and communicating the reasoning behind boulder definition choice is crucial. [ABSTRACT FROM AUTHOR]

A spherical weathering body, also called a boulder, is an element of complex geological strata and presents a significant challenge to tunnelling by a tunnel-boring machine (TBM). In this study, ground-based drilling and blasting were used to precondition boulders. To determine the specific charge needed for preconditioning blasting, model blasts were conducted, and the relationships among the specific charge, fragment size, and overburden depth in the model blasts were investigated. The determined specific charge from the model blasts was then modified by considering the overburden depth and used to precondition the boulders for practical TBM tunnelling. The results indicate the following: (1) model blasts were effective in determining the correct specific charge and predicting boulder fragment sizes resulting from blasting; (2) the boulders met in practical TBM tunnelling were successfully preconditioned by using the determined specific charge; (3) the determined specific charge was 3.26 kg/m3, corresponding to an average fragment size 4.5 cm with an overburden of zero and increased with increasing overburden; (4) fragment sizes were dependent on both the specific charge and overburden depth. Our conclusions can be used to accurately determine the specific charge instead of empirical formulas. [ABSTRACT FROM AUTHOR]

The aim is to recognise the importance and role of geodiscovery as part of a wider sustainable local development strategy to benefit residents and tourists alike. The research was conducted on a massive erratic boulder discovered in February 2024, in NW Poland. The study included the collection of data on dimensions, petrographic type, erratic boulder type and specific microforms indicating the influence of morphogenetic processes from subglacial, periglacial and modern environments on the erratic boulder. The Jarosik Boulder in northwest Poland is crucial for advancing earth sciences, ecological awareness, and regional economic development. Residents of Grabowo and Kamień Pomorski value and monitor the area's geo-diversity to anticipate environmental changes. The boulder has a strong emotional connection with locals, who actively engage in its preservation and online discussions. Promoting the boulder can enhance the region's environment, culture, and well-being, contributing to sustainable development. Local initiatives and effective promotion through media and community events are essential for boosting geotourism and benefiting both residents and visitors. Recognised as a cultural asset, Jarosik Boulder can realise its full potential through the commitment of local authorities to improving the community. As a unique aspect of geodiversity in NW Poland, Jarosik Boulder serves as a catalyst to promote geological science, support environmental education efforts, and foster sustainable economic and regional development. [ABSTRACT FROM AUTHOR]

Significant infrastructure is required to establish a long-term presence of humans on the lunar surface. In-situ resource utilization (ISRU) is a fundamental approach to ensure the viability of such construction. Here, we investigate the feasibility of constructing blast shields as one example of lunar infrastructure using unprocessed lunar boulders and an autonomous robotic excavator. First, we estimate the volume of unprocessed material required for the construction of blast shield segments. Secondly, we quantify the amount of available boulders in two exploration zones (located at the Shackleton-Henson Connecting Ridge and the Aristarchus Plateau pyroclastic deposit) using LRO NAC images and boulder size-frequency distribution laws. In addition, we showcase an alternative approach that relies on Diviner rock abundance data. Thirdly, we use a path planning algorithm to derive the distance, energy, and time required to collect local material and construct blast shield elements. Our results show that our construction method requires two orders of magnitudes less energy than alternative ISRU construction methods, while maintaining realistic mission time and payload capacity margins. [ABSTRACT FROM AUTHOR]

A search for long-term trends in the F 2 layer critical frequency foF 2 is performed based on vertical sounding observations at three stations of the Northern Hemisphere (Juliusruh, Boulder, and Moscow) and three stations of the Southern Hemisphere (Townsville, Hobart, and Canberra). A method developed and extensively described by the authors is used. The data for two winter months in each hemisphere for five near-noon LT moments were analyzed. Three solar activity (SA) proxies (F 30, Ly-α, and MgII) were used to eliminate SA effects. Negative trends are obtained for all considered situations (station, month, LT moment, SA proxy). The trends agree well with each other both if stations of the Northern and Southern hemispheres are compared individually or in aggregate. [ABSTRACT FROM AUTHOR]

Mountain streams with rocky substrates and high turbulence are generally characterized by bryophytes rather than vascular plants. Conocephalum salebrosum (Snakeskin Liverwort) is a thallose bryophyte that occurs in damp soil along streambanks as well as on rocks and boulders in stream channels. Our objectives were to determine its prevalence on boulders in western North Carolina streams and characterize its habitat and chlorophyll levels. We documented Snakeskin Liverwort in 11 streams across 6 counties and 3 river basins; all had a circumneutral pH and low conductivity. We found patches of Snakeskin Liverwort in a variety of light conditions, but overall, patches were situated on boulders that received significantly less sunlight than nearby random boulders. Within channels, patches occurred more often along the edges of streams than in the center. Chlorophyll concentrations in thalli collected from 2 streams at different elevations and river basins did not differ significantly, suggesting similar photosynthetic potential. Mosses were present on ≥92% of boulders supporting Snakeskin Liverwort and on ≥90% of nearby random boulders. Vascular plants occurred in 50–93% of Snakeskin Liverwort patches, compared with 10–28% of random boulders. Graminoids (sedges and grasses) were the most common vascular plants aasociated with liverwort patches, followed by forbs. Our results suggest the thallose mats of Snakeskin Liverwort facilitate the establishment of rooted plants on boulders, which could enhance overall primary production in mountain streams. [ABSTRACT FROM AUTHOR]

The article provides a detailed account of the Solar Section's observations in February and March 2024. It highlights the decline in sunspot activity in the southern hemisphere but notes that multiple groups were still present daily. The article also mentions the eruption of a prominence from AR13615 on March 30, 2024. Various sunspot groups, filaments, prominences, and flares were observed during this period, with some showing growth and complexity while others underwent changes in shape and size. The text concludes with a reminder to observe the fading eruption of T CrB before it becomes invisible to the naked eye. [Extracted from the article]

Boulders are ubiquitous on rocky planets and provide valuable information about planetary processes. The abundance, size, and distribution of boulders offer insights into the primary processes that form them and the secondary processes that modify their position and size. However, the roles of varying environmental processes, including cryospheric processes, are poorly known. In this study, we analyze over 20 million boulders in the northern lowlands of Mars (50–70°N) to evaluate their distribution and identify environmental factors that might influence their clustering. We used spatial statistics to quantify the degree of boulder clustering across the northern plains. We found two latitudinal trends: overall decreasing clustering with increasing latitude (50–70°N) and a sub‐trend of increased clustering at higher latitudes (65–70°N). Our findings suggest that boulder distribution patterns are linked to the latitude‐dependent mantle (LDM) and subsurface ice. Boulders exhibit higher spatial clustering at higher latitudes, where the ice is thick and continuously present, and the LDM is more pristine. Lower clustering occurs at lower latitudes or regions where the ice loss is likely during interglacial periods, and the LDM degrades, exposing more boulders of varying sizes. We also discovered an anomalous region where boulder clustering is nearly random, located on the edge of the Alba Mons Patera. This area displays distinct geophysical characteristics compared to the rest of the lowlands. Although these characteristics do not indicate a specific process for the variation of boulder distribution in this study, the data suggest a coupling between cryospheric processes and boulder evolution, warranting further research. Plain Language Summary: Boulders are common on rocky planets and can provide important information about boulder‐forming processes and displacement. We studied over 20 million boulders on the northern plains of Mars to learn more about how they are distributed across the planet and what factors might influence their placement. We found that boulders are more likely clustered in areas with more ice below the surface. We also discovered an area north of Alba Mons where boulders seem to be scattered randomly, and the surface properties are different than elsewhere in the northern plains. This may be due to the repeated deposition and removal of ice in this area, but more research is needed to fully understand these patterns. Key Points: The level of boulder clustering follows latitudinally varying mantle distribution and degradation statesThe topographic, geophysical, and surface characteristics of northern Alba Patera indicate a higher presence of subsurface iceLandscape ages across the Martian northern lowlands may affect variations in boulder distributions [ABSTRACT FROM AUTHOR]

The boulder impact force in debris flow is generally calculated by static methods such as the cantilever beam models. However, these methods cannot describe the dynamic scenario of boulder collision on structures, so the inertia and damping effects of the structures are not involved causing an overestimation on the boulder impact force. In order to address this issue, a dynamic-based model for calculating the boulder impact force of a debris flow was proposed in this study, and the dynamic characteristics of a cantilever beam with multiple degrees of freedom under boulder collision were investigated. By using the drop-weight method to simulate boulders within debris flow, seven experiments of drop-weight impacting the cantilever beam were used to calibrate the error of the dynamic-based model. Results indicate that the dynamic-based model is able to reconstruct the impact force history on the cantilever beam during impact time and the error of dynamic-based model is 15.3% in calculating boulder impact force, significantly outperforming the cantilever beam model's error of 285%. Therefore, the dynamic-based model can overcome the drawbacks of the static-based models and provide a more reliable theoretical foundation for the engineering design of debris flow control structures. [ABSTRACT FROM AUTHOR]

Relative submergence of macroroughness elements such as boulders and bedrock outcrops, or large bed elements (LBEs), collectively, is a primary control on hydraulics and morphodynamics in steep, coarse-bedded rivers. However, in practice, the property is typically represented by singular, often reach- or cross-section-averaged values that mask bed-surface heterogeneity and joint distributions of local flow depths. By coupling sub-meter resolution two-dimensional (2D) hydrodynamic modeling with spatially explicit mapping of LBEs from a 13.2 km segment of a boulder-bedded mountain river, we present complete distributions of LBE relative submergences at multiple spatial scales and explore their dynamism across discharges. Through distribution fitting and statistical analysis of resultant discharge-dependent LBE relative submergence datasets, it was confirmed that segment- and reach-scale datasets exhibited similar statistical properties and were able to be drawn from the same type of distribution. Further, the rate at which statistical and parametric properties changed between discharge-dependent datasets were statistically equivalent between spatial domains, which we term “process-based similarity”. Commonality in distribution type and the uniform between discharge–scaling relationships suggest mutual self-organizing processes associated with the size-frequency distribution, spatial arrangement, and submergence of LBEs were present between most domains.

Zebrafish are an established and widely used animal model, yet there is limited understanding of their welfare needs. Despite an increasing number of studies on zebrafish enrichment, in-tank environmental enrichment remains unpopular among researchers. This is due to perceived concerns over health/hygiene when it comes to introducing enrichment into the tank, although actual evidence for this is sparse. To accommodate this belief, regardless of veracity, we tested the potential benefits of enrichments presented outside the tank. Thus, we investigated the preferences and physiological stress of zebrafish with pictures of pebbles placed underneath the tank. We hypothesized that zebrafish would show a preference for enriched environments and have lower stress levels than barren housed zebrafish. In our first experiment, we housed zebrafish in a standard rack system and recorded their preference for visual access to a pebble picture, with two positive controls: visual access to conspecifics, and group housing. Using a crossover repeated-measures factorial design, we tested if the preference for visual access to pebbles was as strong as the preference for social contact. Zebrafish showed a strong preference for visual access to pebbles, equivalent to that for conspecifics. Then, in a second experiment, tank water cortisol was measured to assess chronic stress levels of zebrafish housed with or without a pebble picture under their tank, with group housing as a positive control. Cortisol levels were significantly reduced in zebrafish housed with pebble pictures, as were cortisol levels in group housed zebrafish. In fact, single housed zebrafish with pebble pictures showed the same cortisol levels as group housed zebrafish without pebble pictures. Thus, the use of an under-tank pebble picture was as beneficial as being group housed, effectively compensating for the stress of single housing. Pebble picture enrichment had an additive effect with group housing, where group housed zebrafish with pebble pictures had the lowest cortisol levels of any treatment group. [ABSTRACT FROM AUTHOR]

Flexible ring nets exhibit complex nonlinear mechanical behaviour when subjected to static and dynamic impact loads. This research presents the development of an efficient numerical model for assessing the performance of flexible netting barriers used in debris flow and rockfall risk mitigation. The model is calibrated through benchmark analyses and based on the equivalent stiffness method. The results demonstrate that the proposed numerical approach offers a significant computational cost reduction of 80% compared to complex numerical models while maintaining high accuracy. The coupled Eulerian–Lagrangian finite element method (CEL) is employed to simulate fluid–debris–structure interaction, showing damage characteristics consistent with flexible ring net barriers. The model is suitable for accurately determining the impact forces acting on the barrier and presents the debris behaviour and movement at various flow velocities. Notably, the results confirm that the presented model is capable of evaluating the interaction between the flexible barrier and debris flow with boulders and is an efficient approach to estimating the performance of flexible protection subjected to impacts. [ABSTRACT FROM AUTHOR]

Landward displacements of coastal boulders are geomorphological signatures of sea flooding and erosion processes. In this study, using open-access resources that do not require the integration of specialist software, the 2017 to 2021 annual mobility of medium, coarse, and very coarse boulders spread over about 100 km of the eastern coast of the Gulf of Taranto (Italy, Mediterranean Sea) was explored. The boulder displacement data obtained from remote sensing imagery were verified and refined by means of geomorphological field investigation. The main results are the following: (1) A large interannual variability in the boulder mobility was found; (2) storm Detlef, which crossed over the Mediterranean during 11–13 November 2019, was recognized as the cause of a massive displacement phenomenon; and (3) the marine weather conditions driving the investigated morphodynamic process were inferred. [ABSTRACT FROM AUTHOR]

The process by which debris flows shift from an active channel and branch out into new transport or depositional areas is termed "avulsion." They pose serious risks for structures and populations on debris-flow fans, yet avulsion mechanisms are relatively unknown and unaccounted for in hazard assessments, as compared to avulsions of rivers and streams, which are better understood. This study analyzes six debris-flow fans in the White Mountains of California and Nevada to identify relationships between avulsion locations and channel characteristics, constrain the controlling factors on avulsion, assess the probability that avulsion will occur at specified locations, and develop a method to predict avulsion locations. A database of avulsion locations and their channel characteristics was compiled in the field. These were compared to the characteristics of other positions on the fan surface that show evidence of debris flows that did not avulse through stepwise, binary logistic regression. Results indicate that two-thirds of avulsion likelihood can be attributed to the percentage of boulders at the site, slope angle, channel width, and the ratio between flow thickness and average slope at the avulsion location. The accuracy of this model can be improved when it accounts for the presence of a coarse channel plug, which increases the likelihood of avulsion. Application of the model is demonstrated by runout simulations with forced avulsions from modeled channel plugs. [ABSTRACT FROM AUTHOR]

Granite rocks are subjected to exogenic forces, such as tectonic stress and chemical weathering, which cause them to weather differentially, forming boulders that are common in temperate and humid regions. The presence of a large boulder on a slope can significantly impact slope stability, resulting in the formation of what is known as a solitary boulder slope. This study is dedicated to investigate the large-deformation instability characteristics of such slopes. In pursuit of this objective, our study first validates an adapted material point method through laboratory experiments. Subsequently, utilizing the inverse discrete Fourier transform theory, boulders with varying shapes were synthesized and further transformed into material point method models. Finally, the material point method was employed to analyse the impact of boulder position, shape, and incline on the large deformation characteristics of the slope. The results show that: (1) The closer a boulder is to the plastic zone of the slope, the stronger its reinforcement effect on the slope. (2) As the shape of boulders becomes more complex, the run-out distance of the slope tends to decrease, but the variability in run-out distances increases. (3) The slope plastic zone moves around the boulder, and its distribution undergoes alterations based on the boulder's shape. This study investigates the instability characteristics of large deformation in boulder slopes with varying boulder shapes, which provides a reference for the stability assessment of solitary boulder slopes. [ABSTRACT FROM AUTHOR]

Landscapes varied throughout human history, some offering more fitness benefits than others. Therefore, natural selection has likely designed in us landscape preferences that motivated us to seek some environments over others (Orians, 1980). These evolved landscape preferences may influence several aspects of modern-day society, including how we manipulate our urban environment. In Study 1, we conducted a content analysis of the naming conventions of apartment buildings and residential neighborhoods. We hypothesized that there would be more nature words (e.g., valley, river, arbor) in apartment and neighborhood names than nonnature words (e.g., 4th Street; Renaissance, Washington). Names of 2,980 apartment buildings and neighborhoods were collected with a program that uses Google Maps from each of the 48 contiguous United States. Results strongly supported our hypothesis; There were 52% more nature words than nonnature words in the names of apartment buildings and residential neighborhoods. Study 2 used a mixed-subjects experimental design to determine if apartments and neighborhoods with nature names were perceived as more valuable than those without nature names. Participants rated five photographs of apartments and five photographs of neighborhoods photoshopped to display nature or nonnature names for their price (in monthly rent or home's mortgage) and perceived rate of vacancy. Apartments and neighborhoods with manipulated nature names were rated as statistically more expensive. There were no statistical differences between perceived vacancy rates in apartments or neighborhoods named after nature compared with those not named after nature. The current preregistered studies are the first to document that our evolved landscape preferences may affect how developers name our homesteads, further exploiting biophilia. [ABSTRACT FROM AUTHOR]

By using recent observations of the Dydimos−Dimorphos system from the Hubble Space Telescope , 37 boulders with a size of 4 to 7 m ejected from the system during the impact with the DART spacecraft were identified. In this work, we studied the orbital evolution of a swarm of boulders with a similar size to that of the detected ones. By using recent estimates for the ejection velocity of the boulders, we numerically propagated the dynamics of the swarm for 20 kyr in the future. We found that the ejection velocities and the non-gravitational effects are not strong enough to change the secular evolution significantly. The minimum orbit intersection distance (MOID) with the Earth will be reached in about 2.5 kyr, but it will not fall below 0.02 au. On the contrary, the Mars MOID will be very small in four instances, two near 6 kyr and the other two near 15 kyr. Therefore, there may be a chance for them to impact Mars in the future. Given the rarefaction of the Martian atmosphere, we expect the boulders to arrive intact on the ground and excavate a small impact crater. The results presented here provide a further indication that some meteorites found on Earth originated in collisions of ∼100 m near-Earth asteroids with projectiles of ∼1 m in size. [ABSTRACT FROM AUTHOR]

An archaeological excavation of a prehistoric roundhouse was carried out at Mullans Wood, Kilcoy, Inverness-shire by AOC Archaeology in March 2018 in advance of woodland replanting. Approximately one half of the roundhouse was investigated, revealing that the structure comprised a rubble bank supported by large boulders with evidence for an internal ring of post-holes. A small perforated stone disc was recovered from interior deposits along with a very limited charcoal/macroplant assemblage. A sample submitted for radiocarbon dating produced a date that suggested occupation of the site between the 8th and 5th centuries cal BC. [ABSTRACT FROM AUTHOR]

Early observations from the Perseverance rover suggested a deltaic origin for the western fan of Jezero crater only from images of the Kodiak butte. Here, we use images from the SuperCam Remote Micro‐Imager and the Mastcam‐Z camera to analyze the western fan front along the rover traverse, and further assess its depositional origin. Outcrops in the middle to lower half of the hillslopes comprise planar and inclined beds of sandstone that are interpreted as foresets of deltaic deposits. Foresets are locally structured in ∼20–25 m thick, ∼80–100 m long, antiformal structures interpreted as deltaic mouth bars. Above these foresets, interbedded sandstones and boulder conglomerates are interpreted as fluvial topset beds. One well‐preserved lens of boulder conglomerate displays rounded clasts within well‐sorted sediment deposited in overall fining upward beds. We interpret these deposits as resulting from lateral accretion within fluvial channels. Estimations of peak discharge rates give a range between ∼100 and ∼500 m3 s−1. By contrast, boulder conglomerates exposed in the uppermost part of hillslopes are poorly sorted and truncate the underlying beds. The presence of these boulder deposits suggests that intense sediment‐laden flood episodes occurred after the deltaic foreset and topset beds were deposited, although the origin, timing, and relationship of these boulder deposits to the ancient lake that once filled Jezero crater remains undetermined. Overall, these observations confirm the deltaic nature of the fan front, and suggest a highly variable fluvial input. Plain Language Summary: Early observations from the Perseverance rover of the Kodiak butte suggested a deltaic origin for the western fan of Jezero crater. Here, we use images from the SuperCam Remote Micro‐Imager and the Mastcam‐Z camera to analyze the western fan front along the rover traverse, and further assess its origin. We observe strata in the lower part of the fan front that we interpret as deltaic deposits formed below water in a lake. The strata of the upper part of the fan front contain sediments interpreted as fluvial deposits formed under various fluvial regimes, with some of them being deposited by the rivers that also fed the Jezero paleolake. Overall, these observations confirm the deltaic nature of the fan front, and suggest a highly variable fluvial input. Key Points: New observations from the Perseverance rover of the western fan front confirm a deltaic originDeltaic foresets in the lower fan front are organized as antiformal structures interpreted as delta mouth barsSandstones and conglomerates in the upper part of the fan front suggest a highly variable fluvial input [ABSTRACT FROM AUTHOR]

Macro-roughness elements such as boulders and bedrock outcrops, collectively referred to as large bed elements (LBEs), are key features influencing hydrodynamics and morphodynamics in mountain rivers. Where LBEs are abundant and account for a substantial portion of total flow resistance, existing geomorphic theory, previous physical experiments, and limited field observations support the theory that LBE configurations adjust to maximize flow resistance. However, methods to explicitly map individual features along entire river segments are lacking, thus limiting analysis of LBE spatial structure in boulder-bedded rivers. In addressing these gaps, this study sought to develop a procedure for mapping LBEs from 3D point-clouds, explore LBE spatial structure in a real boulder-bedded river, and test the hypothesis that LBE configurations were organized to maximize flow resistance. The mapping procedure applied a ground classification algorithm to produce a roughness surface model, from which LBEs were extracted by a marker controlled watershed algorithm. Implementing the procedure, 42,176 LBEs were mapped in 13.2-km of the mountainous Yuba River (Northern California). Scale and discharge-dependent LBE concentration and spacing metrics were quantified for multiple laterally and/or hierarchically nested spatial domains and classified to differentiate three flow-resistance based hydrodynamic regimes: isolated roughness, wake interference, and skimming flow. Of these regimes, wake interference corresponds to a state of maximum resistance, so hypothesis testing involved determining if this regime was dominant. Results confirmed 25 of 28 segment- and reach-scale LBE concentrations were in the wake interference regime. However, spacing metrics classified 24 of these same spatial domains in the skimming flow regime. Concentration metrics, which quantify LBE density in a given spatial area, differ from spacing metrics, which represent LBE proximity to one another. While comparison of segment and reach-scale regime classifications by each metric concluded concentration was superior to spacing for regime classification purposes, these disparities leave open questions about this extremal model of geomorphic adjustment. Lastly, lateral variability of metrics across the river corridor had implications for discharge-dependent resistance.