Summit Areas Research Articles

Volumetric Changes of Mud on Mars: Evidence From Laboratory Simulations

AbstractSubtle mounds have been discovered in the source areas of Martian kilometer‐sized flows and on top of summit areas of domes. These features have been suggested to be related to subsurface sediment mobilization, opening questions regarding their formation mechanisms. Previous studies hypothesized that they mark the position of feeder vents through which mud was brought to the surface. Two theories have been proposed: (a) ascent of more viscous mud during the late stage of eruption and (b) expansion of mud within the conduit due to the instability of water under Martian conditions. Here, we present experiments performed inside a low‐pressure chamber designed to investigate whether the volume of mud changes when exposed to a Martian atmospheric pressure. Depending on the mud viscosity, we observe a volumetric increase of up to 30% at the Martian average pressure of ∼6 mbar. The reason is that the low pressure causes instability of the water within the mud, leading to the bubble formation that increases the volume of the mixture. This mechanism bears resemblance to the volumetric changes associated with the degassing of terrestrial lava or mud volcano eruptions caused by a rapid pressure drop. We conclude that the mounds associated with putative Martian sedimentary volcanoes might indeed be explained by volumetric changes in the mud. We also show that mud flows on Mars and elsewhere in the Solar System could behave differently to those found on Earth because mud dynamics are affected by the formation of bubbles in response to the different atmospheric pressures.

Modern air, englacial and permafrost temperatures at high altitude on Mt Ortles (3905 m a.s.l.), in the eastern European Alps

Abstract. The climatic response of mountain permafrost and glaciers located in high-elevation mountain areas has major implications for the stability of mountain slopes and related geomorphological hazards, water storage and supply, and preservation of palaeoclimatic archives. Despite a good knowledge of physical processes that govern the climatic response of mountain permafrost and glaciers, there is a lack of observational datasets from summit areas. This represents a crucial gap in knowledge and a serious limit for model-based projections of future behaviour of permafrost and glaciers. A new observational dataset is available for the summit area of Mt Ortles, which is the highest summit of South Tyrol, Italy. This paper presents a series of air, englacial, soil surface and rock wall temperatures collected between 2010 and 2016. Details are provided regarding instrument types and characteristics, field methods, and data quality control and assessment. The obtained data series are available through an open data repository (https://doi.org/10.5281/zenodo.8330289, Carturan et al., 2023). In the observed period, the mean annual air temperature at 3830 m a.s.l. was between −7.8 and −8.6 ∘C. The most shallow layers of snow and firn (down to a depth of about 10 m) froze during winter. However, melt water percolation restored isothermal conditions during the ablation season, and the entire firn layer was found at the melting pressure point. Glacier ice is cold, but only from about 30 m depth. Englacial temperature decreases with depth, reaching a minimum of almost −3 ∘C close to the bedrock, at 75 m depth. A small glacier located at 3470 m a.s.l., close to the summit of Mt Ortles, was also found in cold conditions down to a depth of 9.5 m. The mean annual ground surface temperature was negative for all but one monitored sites, indicating cold ground conditions and the existence of permafrost in nearly all debris-mantled slopes of the summit. Similarly, the mean annual rock wall temperature was negative at most monitored sites, except the lowest one at 3030 m a.s.l. This suggests that the rock faces of the summit are affected by permafrost at all exposures.

Decadal Monitoring of the Hydrothermal System of Stromboli Volcano, Italy

AbstractIn active volcanoes, magmatic fluids rising toward the surface may interact with shallow waters, thereby forming hydrothermal systems that record variations in magma dynamics at depth. Here, we report on a data set comprising the chemical and isotopic composition of thermal waters and dissolved gases from Stromboli Island (Aeolian Volcanic Arc, Southern Italy) that spans 14 years (2004–2018) of continuous observations. We show that the shallow thermal aquifer of Stromboli results from variable mixing between meteoric water, seawater and magmatic fluids. Gas‐water‐rock interactions occur, which induce a large spectrum of variation in both water and gas chemistry. These shallow processes do not affect the 3He/4He of helium dissolved in thermal waters, which records a magmatic signature that varies in response to changes in magma supply at depth. We show that in periods of more intense volcanic activity, the helium isotopic composition of thermal waters approaches that of the gas emitted from the magma residing at 7–10 km depth. Investigation of hydrothermal waters at active volcanoes is a promising tool to examine magmatic fluids and their shallow circulation, as well as to evaluate the state of activity of a volcano, particularly when summit areas are inaccessible.

Evidence for a more extensive Greenland Ice Sheet in southwestern Greenland during the Last Glacial Maximum

Abstract The maximum extent and elevation of the Greenland Ice Sheet in southwestern Greenland during the Last Glacial Maximum (LGM, 26–19.5 ka) is poorly constrained. Yet, the size of the Greenland Ice Sheet during the LGM helps to inform estimates of past ice-sheet sensitivity to climate change and provides benchmarks for ice-sheet modeling. Reconstructions of LGM ice extents vary between an inner continental shelf minimum, a mid-shelf position, and a maximum extent at the shelf break. We use three approaches to resolve LGM ice extent in the Sisimiut sector of southwestern Greenland. First, we explore the likelihood of minimum versus maximum Greenland Ice Sheet reconstructions using existing relative sea-level data. We use an empirical relationship between marine limit elevation and distance to LGM terminus established from other Northern Hemisphere Pleistocene ice sheets as context for interpreting marine limit data in southwestern Greenland. Our analysis supports a maximum regional Greenland Ice Sheet extent to the shelf break during the LGM. Second, we apply a simple 1-D crustal rebound model to simulate relative sea-level curves for contrasting ice-sheet sizes and compare these simulated curves with existing relative sea-level data. The only realistic ice-sheet configuration resulting in relative sea-level model-data fit suggests that the Greenland Ice Sheet terminated at the shelf break during the LGM. Lastly, we constrain the LGM ice-sheet thickness using cosmogenic 10Be, 26Al, and 14C exposure dating from two summit areas, one at 381 m above sea level at the coast, and another at 798 m asl 32 km inland. Twenty-four cosmogenic radionuclide measurements, combined with results of our first two approaches, reveal that our targeted summits were likely ice-covered during the LGM and became deglaciated at ca. 11.6 ka. Inventories of in situ 14C in bedrock at one summit point to a small degree of inherited 14C and suggest that the Greenland Ice Sheet advanced to its maximum late Pleistocene extent at 17.1 ± 2.5 ka. Our results point to a configuration where the southwestern part of the Greenland Ice Sheet reached its maximum LGM extent at the continental shelf break.

Sediment accumulation rates and particle mixing at northwestern Pacific seamounts

Cobalt-rich ferromanganese crusts are present on seamount summits throughout the northwestern Pacific at water depths of approximately 1000 to 2500 m, where they are often associated with unconsolidated sediments. Sedimentation rates at the summits of seamounts calculated from ages 14 C were 0.61 to 2.05 cm kyr −1 , higher than those of the surrounding abyssal plain. Sediments at seamount summits consist almost entirely of carbonate, which may contribute to higher sedimentation rates at summits than at seamount feet, which are below the carbonate compensation depth. The shallowest mixing layer depth and the smallest particle mixing coefficient (estimated from 210 Pb data) at the summit areas than at the foot of seamounts; suggest a weak bioturbation activity in the peaks. The difference in bottom-water dissolved oxygen and particulate organic matter concentrations between the summits and feet of the seamounts in the northwestern Pacific may contribute to this difference in bioturbation activity. • Sediment cores were collected from three guyots in the northwestern Pacific • Sediment accumulation rates on seamount summits were 0.61–2.05 cm kyr −1 • Mixing layer depth/particle mixing coefficients imply weak bioturbation on summits • Dissolved oxygen and particulate organic matter may markedly influence bioturbation

Periglacial landforms of Dartmoor: an automated mapping approach to characterizing cold climate geomorphology

ABSTRACT A systematic mapping approach characterizes Dartmoor periglacial landform signatures using the geomorphology of nine summit areas displaying well developed tor and blockfield landforms. This combines manual vectorisation with automatic classification and surface boulder identification, using spectral signatures to reveal patterns and distribution. Tors were classified using a three-fold scheme: T0 - summits with no tors; T1 - summits with castellated and high relief tors; T2 - summits with subdued or low relief tors. Clitter (blockfield and blockstream) features identified by automated mapping include boulder lobes and stripes and boulder-fronted lobes and terraces, arranged according to distance downslope from parent tors. This zonation of periglacial landforms is proposed as a landsystem signature for areas exposed to periglacial and permafrost processes for significant time during the Quaternary. It represents a process-form regime in which cold climate processes, acting on partially deeply weathered and pneumatolysised granite, produce castellated tors, cryoplanation benches and autochthonous blockfield (clitter), and permafrost creep develops boulder lobes that elongate and evolve downslope as allochthonous blockslopes with boulder stripes and boulder-fronted lobes and terraces. This demonstrates that automated mapping can be applied to areas of upland periglacial landforms to rapidly and systematically compile quantifiable patterns of landform assemblages.

The Extensive Parameters as a Tool to Monitoring the Volcanic Activity: The Case Study of Vulcano Island (Italy)

On Vulcano Island (Italy), many geochemical crises have occurred during the last 130 years of solfataric activity. The main crises occurred in 1978–1980, 1988–1991, 1996, 2004–2007, 2009–2010 and the ongoing 2021 anomalous degassing activity. These crises have been characterized by early signals of resuming degassing activity, measurable by the increase of volatiles and energy output emitted from the summit areas of the active cone, and particularly by increases of gas/water ratios in the fumarolic area at the summit. In any case, a direct rather than linear correspondence has been observed among the observed increase in the fluid output, seismic release and ground deformation, and is still a subject of study. We present here the results obtained by the long-term monitoring (over 13 years of observations) of three extensive parameters: the SO2 flux monitored in the volcanic plume, the soil CO2 flux and the local heat flux, monitored in the mild thermal anomaly located to the east of the high-temperature fumarole. The time variations of these parameters showed cyclicity in the volcanic degassing and a general increase in the trend in the last period. In particular, we focused on the changes in the mass and energy output registered in the period of June–December 2021, to offer in near-real-time the first evaluation of the level and duration of the actual exhalative crisis affecting Vulcano Island. In this last event, a clear change in degassing style was recorded for the volatiles emitted by the magma. For example, the flux of diffused CO2 from the soils reached the maximum never-before-recorded value of 34,000 g m−2 d−1 and the flux of SO2 of the plume emitted by the fumarolic field on the summit crater area reached values higher than 200 t d−1. The interpretation of the behavior of this volcanic system, resulting from the detailed analyses of these continuous monitoring data, will complete the framework of observations and help in defining and possibly forecasting the next evolution of the actual exhaling crisis.

Forest Dynamic in the Italian Apennines

In recent decades, many mountain areas of the Mediterranean countries show spontaneous reforestation or densification due to depopulation and the consequent abandonment of traditional agricultural and pastoral activities, leading to the loss of open habitats. In this paper, dynamics of natural and semi-natural areas in the summit areas of the Abruzzo, Lazio e Molise National Park are investigated, highlighting changes that occurred from 1954 to present days. Historic Land cover maps have been produced by photo interpretation. A quantitative description of changes and habitats loss in relation to the socio-economic changes is provided. As expected, a forest surface expansion and an open areas decrease are observed similarly to many marginal mountains, where land abandonment and general forest/shrub recovery are the inevitable tendencies. An intense debate is still ongoing regarding the opportunity of rewilding, allowing the natural reforestation processes, versus the management of some areas, in order to preserve habitats and cultural traditional landscapes. For the EU biodiversity conservation policy to be effective, proper planning and management of interventions as well as public support and funding, become crucial when traditional activities are no longer profitable and viable for local inhabitants.

Taraxacum sect. Erythrocarpa in Europe in the Alps and eastwards: A revision of a precursor group of relicts

A taxonomic revision of Taraxacum sect. Erythrocarpa in the eastern part of Europe and in the Alps is presented. Seventeen species are recognized, nine of them are described as new. Most species occupy relatively restricted geographical ranges, the most characteristic habitats being limestone cliffs and mountain summit areas. The highest species diversity of this section is situated in the mountain ranges of Greece and the adjacent regions of Bulgaria and North Macedonia; only two species are known from the Alps, and a new species is described also from Crimea, Ukraine. Taraxacum pindicola is the only sexual diploid among the taxa studied, the other taxa exhibit agamospermy. The name T. pindicola is newly lectotypified. The northernmost representative of T. sect. Erythrocarpa, T. pieninicum (S. Poland), is conspecific with T. erythrocarpum of the western Slovakia. The names T. albomarginatum A.J. Richards and T. voricola A.J. Richards are later synonyms of T. olympophilum Sonck. Taraxacum sect. Erythrocarpa is characterized and, for each species, nomenclature, typification, a detailed description or a reference to it, diagnostic notes, distribution and habitat, and a list of herbarium specimens studied are given. Most species are illustrated, and for selected ones, distribution maps are provided.

Картографирование геолого-геоморфологической основы ландшафтов для управления экологическими рисками в условиях ярусного строения рельефа южной криолитозоны

The article considers the experience of large-scale mapping of the geological and geomorphological framework of landscapes, taking into account the layered structure of the relief. The key study site represented a 25 km² area, in the northern part of the Yenisei Ridge. This territory is located in the southern cryolithozone. In the course of field work, over a dozen transects were established. They reflected various structural levels of the relief, i.e., the products of its cyclic development. Surface deposits were studied using borehole cores, occasional natural outcrops, and soil pits. These data were supplemented with extrapolations from the analogous areas of the Yenisei Ridge. The collected material on relief features provided the basis for the development of landscape subdivisions’ hierarchy applicable for landscape mapping of territories with leveled denudation relief: the Yenisei Ridge, the west of the Central Siberian Plateau, and other regions with a similar history of development. The compiled map’s legend reflects the relief stratification and the main features of cover sediments. Two levels of planation surface and a complex of surfaces with superimposed planation and differentiation (three different landscapes) were identified. Periglacial processes in the Neo-Pleistocene (Q₂₋₃) glacial epochs and partially in the Holocene (Q₄) played the key role in the formation of the sedimentary cover. The main types of periglacial formations, wide spread within the study territory, were identified and included eluvial-desorption deposits (on summit areas), solifluction-desorption deposits (on slopes and ravine floors), and colluvium-alluvial deposits (on glacis floodplains). We have demonstrated that these types of surface deposits have differentiated influence on the distribution of permafrost geosystems. Analysis of the data on genesis of cover sediments and their relation to relief allowed us to extrapolate the results of the field studies and to map permafrost landscapes—the most susceptible to external impacts natural complexes that require targeted environmental policies.

Vulnerability of the Permafrost Landscapes in the Eastern Chukotka Coastal Plains to Human Impact and Climate Change

Permafrost landscapes are particularly susceptible to the observed climate change due to the presence of ice in the ground. This paper presents the results of the mapping and assessment of landscapes and their vulnerability to potential human impact and further climate change in the remote region of Eastern Chukotka. The combination of field studies and remote sensing data analysis allowed us to identify the distribution of landscapes within the study polygon, reveal the factors determining their stability, and classify them by vulnerability to the external impacts using a hazard index, H. In total, 33 landscapes characterized by unique combinations of vegetation cover, soil type, relief, and ground composition were detected within the 172 km2 study polygon. The most stable landscapes of the study polygon occupy 31.7% of the polygon area; they are the slopes and tops of mountains covered with stony-lichen tundra, alpine meadows, and the leveled summit areas of the fourth glacial-marine terrace. The most unstable areas cover 19.2% of the study area and are represented by depressions, drainage hollows, waterlogged areas, and places of caterpillar vehicle passage within the terraces and water-glacial plain. The methods of assessment and mapping of the landscape vulnerability presented in this study are quite flexible and can be adapted to other permafrost regions.

The influence of natural fire and cultural practices on island ecosystems: Insights from a 4,800 year record from Gran Canaria, Canary Islands

AbstractAimLong‐term ecological data provide a stepped frame of island ecosystem transformation after successive waves of human colonization, essential to determine conservation and management baselines. However, the timing and ecological impact of initial human settlement on many islands is still poorly known. Here, we report analyses from a 4800‐year sedimentary sequence from Gran Canaria (Canary Islands), with the goal of disentangling forest responses to natural fire from early human pressure on the island.LocationLa Calderilla, a volcanic maar caldera at 1,770 m a.s.l. on Gran Canaria.TaxonPlants and fungi.MethodsA core from the caldera infill was analysed for sediment properties, pollen, micro‐ and macrocharcoal, with radiocarbon and biochronology dating. Fossil data were statistically zoned and interpreted with the help of cross‐correlation and ordination analyses. Surface samples and a pollen–vegetation training set were used as modern analogues for vegetation reconstruction.ResultsBefore human settlement (4,800–2,000 cal. yr bp), pine (Pinus canariensis) pollen dominated. Extensive dry pine forests characterized the highlands, although with temporary declining phases, followed by prompt (sub‐centennial scale) recovery. Towards 2,280 cal. yr bp there was a shift to open vegetation, marked by an increase in coprophilous spores. Coincidental with independent evidence of human settlement in the pine belt (2,000–470 cal. yr bp) there was a decline of pine and a peak in charcoal. Following historic settlement (470–0 cal. yr bp), pollen producers from anthropogenic habitats, secondary vegetation and coprophilous fungi increased in abundance, reflecting higher pressure of animal husbandry and farming. Modern moss polsters reflect extensive reforestation since 1950 ce (Common Era).Main conclusionsFrom 4,800 cal. yr bp, the pristine vegetation covering the Gran Canaria highlands was a mosaic of dry pine forests and open vegetation. The pine forests sustained intense fires, which may well have promoted habitat diversity. Human interference was initiated around 2,280 cal. yr bp probably by recurrent cultural firing and animal husbandry, triggering a steady trend of forest withdrawal and expansion of grasses and scrubs, until the final disappearance of the pine forest locally in the 20th century. Grasslands were found to be of ancient cultural origin in the summit areas of Gran Canaria, although they underwent an expansion after the Castilian Conquest.

Climate warming accelerates forest encroachment triggered by land use change: A case study in the Italian Prealps (Triangolo Lariano, Italy)

During the past decades, the montane and subalpine belts of many European mountains experienced agricultural land abandonment followed by spontaneous recolonization of trees and shrubs on semi-natural mountain grasslands, potentially leading to severe losses in biodiversity.Here we analyse the spatial and temporal patterns of forest encroachment of a Prealpine study site in Northern Italy (Triangolo Lariano, Como) since 1954 in response to land use change and aim to assess whether this process has been accelerated by recent climate warming and atmospheric CO2 increase.To achieve a detailed reconstruction of forest encroachment dynamics, we adopted a multidisciplinary integrated approach, involving dendrochronological and phytosociological analyses, and vegetation mapping. Available maps updated with aerial photographs allowed the delineation of the forest distribution and changes of forest boundaries. Accordingly, along nine elevational transects, 60 plots were set within different forest-grassland successional stages in order to integrate vegetation mapping with phytosociological analyses and reconstruct the recruitment rates through dendrochronological analyses.Since 1954, the forest encroachment process occurred across an elevation range of 185 m, at a mean rate of 29 m per decade, although with uneven temporal and spatial trends. The forest encroachment rates increased progressively with time, from +0.8%/y (1954–1993) to +2.4%/y (1993–2015) to +4.9%/y (2015–2018). The air warming exhibited an increasing trend too, especially in the last twenty years. Betula pendula was the most abundant species responsible for this process (the only one presenting seedlings and saplings settling along the summit areas) and showed two recruitment peaks: the first in concomitance with the abandonment of the agro-silvo-pastoral practices (1950/60s), but the largest recruitment was detected with the increased air warming since early 2000s. The correlation analysis confirmed that forest encroachment was related to air warming (in particular summer warming), land use change and increase of atmospheric CO2 and that it was further accelerated in concomitance with further air warming in the recent decades.The forest encroachment process on semi-natural grasslands triggered by land use change on European mountains and its recent acceleration in response to climate warming represent an increasing threat to biodiversity, leading to potential habitat and species loss, especially of the most vulnerable habitats.

Quantifying wind erosion at landscape scale in a temperate grassland: Nonignorable influence of topography

Revised wind erosion equation (RWEQ) is widely applied to determining wind erosion and achieves reliable results. However, the spatial variability of wind erosivity and wind erosion has not been sufficiently investigated in previous studies. In this paper, RWEQ was used to determine wind erosion and its spatial variation at the landscape scale in the Xilingele grassland, which is a typical temperate grassland in North China suffering from increasing wind erosion problems. Based on field investigation and laboratory measurement, land-surface parameter data were obtained. Computational fluid dynamics (CFD) wind modelling was integrated to acquire the spatial variation of wind data, which considers the influence of topography and land use. These data were used to determine the five factors of RWEQ and wind erosion modulus. Results showed that the mean wind erosion modulus was 5.33 t ha−1 yr−1, and 97.16% of the area had light or no wind erosion, which was mostly distributed in the low plains and the leeward areas. However, there were hotspots of wind erosion which were mainly distributed in the windward slopes and the summit areas. There were no significant differences among the wind erosion moduli of different land uses, but land use affected the influence of topography on wind erosion. The maximum modulus varied greatly from 0 to 259.41 t ha−1 yr−1 for different land uses, and the most severe wind erosion occurred in moderately grazed grassland (MG), followed by heavily grazed grassland (HG), arable land (AL), lightly grazed grassland (LG) and ungrazed grassland (UG). Statistical tests indicated that topography had a significant influence on wind erosion, which was not detected in previous studies due to the lack of high-resolution topography and wind data. The combination of RWEQ and CFD wind modelling suggests that future wind erosion studies should further consider the important influence of topography. To achieve sustainable development in temperate grassland, rational grazing is critical, and special attention should be paid to windward slopes and high elevation areas.

Glacier and climate evolution in the Pariacacá Mountains, Peru

Glaciers in Peru play a major role in water availability and they also have direct implications on natural hazards such as glacial lake outburst floods (GLOFs) and/or ice avalanches, which have caused a high number of fatalities and damage to infrastructure in the last decades. Despite a noticeable effort to quantify and understand the shrinking and thawing of glaciers in Peru, there are still regions where detailed assessment is still missing.In this work, a set of remote sensing images were used to map, for the first time, the evolution of the glaciated area (from 1970 to 2018) in the Pariacacá Mountains (11º5’ S, 76º0’ W) in the Cordillera Central of Peru. The results evidenced a marked decrease of the glaciated surface, with 55.3% shrinkage since 1970 and 40% since 1987. Faster glacier retreat occurred between 1985 and the end of the 1990s, and this period was followed by a significant slowdown in shrinking rates. The differential loss of ice, depending on elevation and exposure to incoming radiation, has led to changes in spatial distribution of the glaciers. Currently, they have almost completely thawed below 5000 m a.s.l. They are mostly located in south- to west-facing aspects. Ice melting in the last decades has even affected the summit areas. Finally, the development of ablation hollows has been identified as an important driver of glacier thaw. These features are formed mainly in gentle slopes and highly irradiated zones between 5000 and 5400 m a.s.l.

Interplay between soil formation and geomorphic processes along a soil catena in a Mediterranean mountain landscape: an integrated pedological and geophysical approach

Soil spatial distribution often shows high variability because of geo-environmental settings affecting soil formation and geomorphic processes. The paper describes a combined pedological–geophysical approach for investigating the interplay among soil-forming processes, geomorphic dynamics and physico-chemical soil properties in a soil catena in a Mediterranean mountain landscape (southern Italy). Stocks of soil organic carbon (SOC) and total nitrogen (STN) were determined and their interactions with slope position analyzed. Five slope units were defined along the soil catena (summit, shoulder, back, foot, and toe slopes), and in each of them, a soil profile was dug and analyzed. Thickness of soil horizons and contact between soil and parent material were determined by a 2D-electrical resistivity tomography survey. Results showed granitic bedrock is characterized by vary weathering degrees strongly affecting soil type development. Moreover, soil properties variation is related to topographic features and water erosion processes. Soil chemical composition showed high values of SiO2 and Al2O3, probably due to inheritance from underlying granitic parent material. Particularly, Fe2O3 content increased with weathering conditions as shown by chemical index of alteration values. Along foot and toe slopes, reworking and accumulation of colluvial soil lead to the formation of thicker accretionary A horizon. Consequently, summit areas, together with foot and toe slopes had greater SOC and STN stocks than back and shoulder slopes. That because soils are thicker and richer in SOC on summit and valley bottom than in shoulder and back-slope positions. The proposed approach has showed the benefit of an integrated methodology for investigating spatial variations along soil catenas.

Variation in chewing efficiency of Yakushima Japanese macaque (Macaca fuscata yakui).

Chewing efficiency plays an important role in the survival and distribution of primates. Yet, little is known about the intra-specific variation of chewing efficiency. The purpose of this study is to report the pattern of seasonal and regional variation in chewing efficiency among Yakushima Japanese macaques (Macaca fuscata yakui). Fecal samples of Yakushima Japanese macaques were collected from lowland, highland and summit areas in Yakushima between July 2015 and March 2016 (n = 236). Using sieving analysis, we compared fecal particle size (dMEAN) and proportion of finest particles p(0) between different geographical areas and seasons. Seasonally, in the lowland zone, there was a non-significant decrease in dMEAN during spring, while p(0) was significantly higher during summer than it was during winter and spring. Regionally, dMEAN was higher in the summit zone than it was in other areas during autumn, while p(0) was also higher in the summit zone. While seasonal variation in dMEAN can be explained by the reported difference in the proportions of food categories in diet between seasons, its influence is mitigated, possibly by the selective feeding of less mechanically challenging parts in each category. Regional variation in dMEAN and p(0) may be the results of bamboo consumption in this area. Combining our data with studies that focus on seasonal and regional variations of food properties or gut microbes might provide a better understanding of the relation between diet, chewing and digestion in Yakushima macaques.

Genetic evidence in support of the recognition of the Kaputar Rock Skink, one of New South Wales’ most range-restricted vertebrate species

The existence of the Kaputar Rock Skink, a morphologically distinct Egernia population restricted to the Nandewar Ranges in northern New South Wales, has been known for decades. However, no comprehensive description or diagnosis of the taxon has been published in the scientific literature, and its distinctiveness largely assumed. As part of a study investigating the genetic differentiation of faunal populations on the Nandewar Range, comparisons between the Kaputar Rock Skink and east Australian Egernia striolata-group species were undertaken. The results indicate that the Kaputar Rock Skink is a distinct genetic lineage, showing species-level divergence from other Egernia species. Field studies suggest the Kaputar Rock Skink is restricted to an extremely narrow band of rock habitat above 1000 m or more in elevation, and only occupies retreat and sheltering sites near cliff edges or in areas of extensive outcropping rock. It now appears to be a cool-adapted species constrained to high elevation habitat by niche conservatism. Field studies suggest the availability of suitable habitat on the summit areas of the Nandewar Ranges is highly limited, making it vulnerable to several potentially threatening processes, including anthropogenic climate change. The name Contundo roomi was erected for the Kaputar Rock Skink by Wells & Wellington in 1985, and we recommend Egernia roomi (Wells & Wellington, 1985) as the name for the Kaputar Rock Skink.

40Ar-39Ar geochronology of the active phonolitic Cadamosto Seamount, Cape Verde

Cadamosto Seamount is located in the SW of the Cape Verde Archipelago in the central Atlantic Ocean off the west coast of Africa. Many radiometric dates exist for the islands in the archipelago, however, no geochronological information has been obtained from the numerous seamounts. The timescales for igneous processes in the submarine realm are thus poorly understood.In this study, we investigated five lavas that were sampled by dredging and ROV (remotely operated vehicle) from the flanks and summit areas of the largely phonolitic Cadamosto Seamount during two different research cruises. Chemical zonation patterns of minerals were determined by electron microprobe, and radiometric ages were obtained from single-crystal total-fusion and single−/multi-grain step-heating 40Ar-39Ar analyses of sanidine, nepheline and sodalite-group minerals.Our 40Ar-39Ar results reveal young sanidine eruption ages (all <100 ka) at Cadamosto Seamount: (1) Three western flank/summit lavas have a relatively simple petrology dominated by phenocrysts, and overlap with mean sanidine ages of 20.98 ± 0.87 ka, 21.44 ± 0.80 ka and 22.3 ± 2.0 ka, with a combined mean age of 21.04 ± 0.62 ka from the three samples (all uncertainties are quoted at 2σ). (2) The remaining two samples from the summit/NE flank are dominated by complex zoned sanidines with resorbed antecrystic cores and phenocrystic rims. These samples yield older sanidine ages of 51.8 ± 2.4 ka and 97 ± 14 ka, which are interpreted to be maximum eruption ages. This is due to the dominance of antecrysts in these two samples and the possibility that the analyzed sanidine grains may be a mixture of older antecrystic cores and younger phenocrystic rims.The older 40Ar-39Ar ages of many sanidine and nepheline antecrysts also give us clues regarding older magmatic events at Cadamosto Seamount, despite these grains having undergone resorption and phenocrystic rim overgrowths, resulting in some radiogenic 40Ar loss during entrainment in the subsequent magmas. The antecrysts minimum ages extend back to 1.5215 ± 0.0083 Ma, which supports the age progression of magmatism observed in the southern islands chain of the Cape Verde Archipelago.The youngest volcanic eruption period (21.14 ± 0.62 ka) occurred during the Last Glacial Maximum, a period of global sea level lowstands. We suggest that the comparatively rapid crust unloading leading up to the lowstand may have reduced pressure conditions within the Cadamosto Seamount magma plumbing system, and thus led to enhanced submarine eruption activity.

Patterned ground above the alpine timberline in the High Sudetes, Central Europe

ABSTRACT Patterned ground in mountainous areas has a high palaeogeographic significance as it is associated with cold environments and frequently with permafrost conditions. Most patterned ground (i.e. sorted polygons, sorted nets, sorted stripes) in the High Sudetes is overgrown by vegetation and is relict. However, wind-blown summit areas with low snow cover allow for the activity of sorted circles, earth and peat hummocks, and some non-sorted stripes. The extent of patterned ground above the alpine timberline in the High Sudetes presented here is based on detailed field geomorphologic mapping. Patterned ground occurs on summit planation surfaces and surrounding gently sloping terrain, and covers 5.23 km2. Sorted polygons are the highest-elevated patterned-ground type. The spatial distribution of patterned ground is shown in the map, which could be helpful for future research of the Quaternary geomorphologic evolution of the mountain landscape and for nature protection planning in the High Sudetes.