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result(s) for
"Periglacial processes."
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Influences Driving and Limiting the Efficacy of Ice Segregation in Alpine Rocks
by
Draebing, D.
,
Mayer, T.
,
Eppes, M.
in
Acoustic emission
,
Alpine environments
,
Cracking (fracturing)
2023
Rockwall erosion by rockfall is largely controlled by frost weathering in high alpine environments. As alpine rock types are characterized by crack‐dominated porosity and high rock strength, frost cracking observations from low strength and grain supported pore‐space rocks cannot be transferred. Here, we conducted laboratory experiments on Wetterstein limestone samples with different initial crack density and saturation to test their influence on frost cracking efficacy. We exposed rocks to real‐rockwall freezing conditions and monitored acoustic emissions as a proxy for cracking. To differentiate triggers of observed cracking, we modeled ice pressure and thermal stresses. Our results show initial full saturation is not a singular prerequisite for frost cracking. We also observe higher cracking rates in less‐fractured rock. Finally, we find that the temperature threshold for frost cracking in alpine rocks falls below −7°C. Thus, colder, north‐exposed rock faces in the Alps likely experience more frost cracking than southern‐facing counterparts. Plain Language Summary Freezing results in the formation of ice that exerts stresses on fracture walls and draws in additional moisture to supply further growth and break down rocks, a process termed frost cracking. Frost cracking drives much erosion and rockfall in alpine environments. Here we test hypotheses from prior work about how frost cracking is impacted by saturation and rock properties. We exposed rock samples of different strength and saturation to identical freezing conditions in laboratory experiments. We monitored rock temperature and acoustic emissions (AE), assuming frost cracking produces the recorded AE hits. We find that initial full saturation is not required for frost cracking, as water transport is enhanced by fractures in alpine rocks. Furthermore, rock with initial higher short‐term strength showed more frost cracking because, we infer, of stiffness properties that make these rocks more brittle compared to lower strength rocks. Frost cracking occurred at a wide range of temperatures below freezing and was highest between −9 and −7°C. We thus conclude that frost cracking is most impacted by temperature and rock short‐term strength. In Alpine environments, this may result in more frost cracking and rockfall on colder north‐facing rockwalls than warmer southern exposures. Key Points Initial saturation levels do not limit the efficacy of ice segregation in fractured alpine rocks Rock initial crack density impacts rock stiffness and thermal properties and thus frost cracking efficacy The “frost cracking window” temperature range is dependent on rock strength and crack‐controlled porosity in alpine rocks
Journal Article
Periglacial landforms and deposits from the Last Glacial Maximum to the Holocene in the Visogno and Spluga valleys (Central Italian Alps)
by
Zerboni, Andrea
,
Tantardini, Davide
,
Pezzotta, Andrea
in
Central Alps
,
Geomorphology
,
Last Glacial Maximum
2026
We present the geomorphological mapping of the Visogno and Spluga valleys in the Central Italian Alps, including the morphometric and activity analysis of local rock glaciers, aimed at understanding the response to ongoing climate change. The onset of geomorphic processes controlling the evolution of local landscape dates to the Last Glacial Maximum, under glacial conditions, and continued under warmer conditions in the Holocene. The latter phase promoted glacial retreat and favoured the onset of periglacial and paraglacial processes. Our survey identifies 19 rock glaciers, predominantly SE-facing aspects, 11 relict and 8 transitional occurring above the 2200 m threshold suggested in regional inventories as the altitude limit for permafrost. These results highlight the importance of transitional rock glaciers as potential freshwater reservoirs under ongoing climate warming, emphasising the need for their monitoring as these features are out of equilibrium in the extant climate and likely to undergo rapid changes soon.
Journal Article
Quaternary Glaciations - Extent and Chronology
2011
The book presents an up-to-date, detailed overview of the Quaternary glaciations all over the world, not only with regard to stratigraphy but also with regard to major glacial landforms and the extent of the respective ice sheets.The locations of key sites are included.
Age and development of active cryoplanation terraces in the alpine permafrost zone at Svartkampan, Jotunheimen, southern Norway
2019
Schmidt-hammer exposure-age dating (SHD) of boulders on cryoplanation terrace treads and associated bedrock cliff faces revealed Holocene ages ranging from 0 ± 825 to 8890 ± 1185 yr. The cliffs were significantly younger than the inner treads, which tended to be younger than the outer treads. Radiocarbon dates from the regolith of 3854 to 4821 cal yr BP (2σ range) indicated maximum rates of cliff recession of ~0.1 mm/yr, which suggests the onset of terrace formation before the last glacial maximum. Age, angularity, and size of clasts, together with planation across bedrock structures and the seepage of groundwater from the cliff foot, all support a process-based conceptual model of cryoplanation terrace development in which frost weathering leads to parallel cliff recession and, hence, terrace extension. The availability of groundwater during autumn freezeback is viewed as critical for frost wedging and/or the growth of segregation ice during prolonged winter frost penetration. Permafrost promotes cryoplanation by providing an impermeable frost table beneath the active layer, focusing groundwater flow, and supplying water for sediment transport by solifluction across the tread. Snow beds are considered an effect rather than a cause of cryoplanation terraces, and cryoplanation is seen as distinct from nivation.
Journal Article
Thermokarst in Siberian ice-rich permafrost: Comparison to asymmetric scalloped depressions on Mars
2010
On Earth, the thawing of permafrost deposits with high‐ground ice content results in massive surface subsidence and the formation of characteristic large thermokarst depressions. Slope asymmetries within thermokarst depressions suggest lateral growth, which occurs due to thermoerosion and gravimetric mass wasting along these slopes. It has been proposed that rimless, asymmetrically shaped depressions (called scalloped depressions) on Mars were formed by insolation‐driven ground ice sublimation. We investigated a large thermokarst depression in ice complex deposits in the Siberian Arctic as a terrestrial analogue for scalloped depressions in Martian volatile‐rich mantle deposits. Our results from field studies, insolation modeling, and geomorphometric analyses suggest lateral thermokarst development in a northern direction. This conclusion is obvious due to steeper slope angles of the south facing slopes. Insolation and surface temperatures are crucial factors directly influencing thermokarst slope stability and steepness. Comparative analyses of Martian scalloped depressions in Utopia Planitia were conducted using high‐resolution (High‐Resolution Imaging Science Experiment, Context Camera) and thermal infrared (Thermal Emission Imaging System) satellite data. By direct analogy, we propose that the lateral scalloped depression development on Mars was primarily forced on the steep pole‐facing slopes in the equator‐ward direction. Insolation modeling confirms that this must have happened in the last 10 Ma during an orbital configuration of higher obliquity than today. Development would have been maximized if the orbit was both highly oblique and highly eccentric, and/or the Martian summer coincided with perihelion. Relatively short events of increasing sublimation or even thawing of ground ice led to fast slumping processes on the steep pole‐facing slopes.
Journal Article
Morphometry of the cold-climate Bory Stobrawskie Dune Field (SW Poland): Evidence for multi-phase Lateglacial aeolian activity within the European Sand Belt
2023
Aeolian dunes have been widely identified in the European Sand Belt, which was formed during the Pleniglacial and Late Glacial when cold and dry climatic conditions were favorable for intense Aeolian processes. In this study, we mapped and analyzed the fixed Bory Stobrawskie Dune Field (SW Poland) to determine factors that drive the evolution of dunes, expressed by the occurrence of different dune types and their spatial patterns. The study identified the longitudinal zonation within the dune field, as shown by the changeable proportion of specific dune types comparable to low-latitude dune fields. However, climatically controlled periodic and low sand supply combined with a changing vegetation cover caused the non-continuous and multi-phase evolution of the dune field. Additionally, we found that a dense pattern of streams has controlled the extent of the dune field. The trapping of sand by rivers led to a limitation of the dune field expansion; on the other hand, the supply of sand into rivers led to overloading of the fluvial system, affecting their transformation into braided rivers.
Journal Article
Evaluation of periglacial landforms and formation of soil properties on the Mount Honaz, SW Türkiye
by
Serın, Soner
,
Türkeş, Murat
,
Uncu, Levent
in
Climatic data
,
Correlation coefficient
,
Correlation coefficients
2024
The main aim of this study is to explain periglacial processes on the summits of Mount Honaz (2571 m a.s.l.), define periglacial landforms, and determine the relationships between morphometric features and topographic factors. Mud circles, stony earth circles, non sorted steps, and non sorted stripes were identified on the summits of Mount Honaz. Pearson’s correlation coefficient (
r
) and linear regression analyses were performed by taking metric measurements from 125 periglacial landforms to describe their morphometric features (length, width, height) of periglacial landforms and explain the relationships between them and topographic factors (elevation, slope). To explain the relationships between periglacial landforms and soil properties, soil samples from 11 periglacial landforms were taken and analysed. Periglacial landforms, which continue to develop on the summits of Mount Honaz today, have been evaluated with present climate data. Analysis of soil samples indicates a notable impact of parent material on the genesis of periglacial landforms. The high ratio of organic matter in mud circle and non sorted step landforms and the high lime ratio in stony earth circle landforms prove a strong relationship between the formation mechanisms of landforms and the soil properties. Furthermore, it is consistent with the findings obtained from the analysis that severe periglacial processes and washing and scavenging events are experienced more on the northern slopes.
Journal Article
Southern Carpathian Periglaciation in Transition: The Role of Ground Thermal Regimes in a Warming Climate
2025
This study examines ground surface and air temperatures and their implications for periglacial activity in the Țarcu Massif, Southern Carpathians, where data on current dynamics and climate responses remain scarce despite widespread periglacial landforms. To address this, we deployed seven temperature loggers between 2018 and 2024 across a range of periglacial landforms, including non-sorted patterned ground, a periglacial hummock, protalus rampart, block stream, periglacial tor, ploughing boulder, and nival niche. We analyzed key thermal indicators such as freeze–thaw cycles, freezing and thawing degree days, frost weathering intervals, frost days, and winter equilibrium temperatures—in relation to long-term air temperature records (1961–2023), snow cover dynamics, and local topographic and substrate conditions. Results reveal a marked warming trend at the Țarcu meteorological station, particularly after 1995, along with a shift in net thermal balance beginning in the late 1990s. Since then, climatic conditions at this site have no longer been favorable for the persistence of sporadic permafrost. Ground thermal conditions varied spatially, with coarse debris sites and rock wall maintaining the lowest MAGST values—typically with 1 to 2.5 °C cooler than fine-grained sediments—and the highest potential for frost-related weathering. Despite low and variable freeze–thaw cycle frequency, the high number of frost days (around 200 per year) and sustained frost weathering potential—exceeding 50 days annually at key sites—indicate that periglacial conditions remain active for nearly half the year around 2000 m in the Southern Carpathians. Snow cover dynamics proved to be a major control on ground thermal behavior, with earlier melting and delayed onset shortening its duration but amplifying early winter cooling. These findings indicate that the Țarcu Massif is a transitional periglacial environment, where active and relict features coexist under growing climatic pressure. The ongoing decline in frost-driven processes highlights the vulnerability of mid-latitude mountain periglacial systems to climate warming and underscores the need for continued monitoring to better understand future landscape evolution in the Southern Carpathians.
Journal Article
Effects of Periglacial Landforms on Soil Erosion Sensitivity Factors and Predicted by Artificial Intelligence Approach in Mount Cin, NE Turkey
by
Dede, V
,
Pacci, S
,
Serin, S
in
Artificial intelligence
,
Artificial neural networks
,
Chemical properties
2022
AbstractIn this study, the differences in soil properties formed on various periglacial landforms located on slope land and high elevation so, this case create main problem against to soil erosion. The main aims of the study are to determine the physico-chemical properties and some soil erosion sensitivity parameters of the soils formed on the different periglacial landforms of Mount Cin and to predict those soil erosion sensitivity factor using artificial neural network (ANN). It was detected three different periglacial landforms on the Mount Cin. Stony earth circles spread over Cin Hill which is on the summit plain of Mount Cin, while non-sorted steps are located on the northern slopes of Cin Hill and Topkaya Hill. In addition, mud circle landforms spread to the south of Karaçakrak Hill. 25 soil samples were taken from the periglacial landforms in the study area. Afterwards, the physico-chemical properties of the samples were analysed in the laboratory. According to soil analysis from various periglacial landforms, the dominant soil texture is sandy loam: clay ranges from 5.61 to 16.79%, and sand from 48.61 to 76.72%. Also, the average soil erosion sensitivity factors, namely structure stability index (SSI), dispersion rate (DR), and crust formation (CF), were calculated at 29.65, 28.36, and 40.72%, respectively. Moreover, ANN is a model that can operate directly like the human brain. ANN uses the data of the current problem to make predictions. According to regression results of soil erosion sensitivity factors using ANN, the highest prediction rate was obtained for SSI (78%) and the lowest for DR (57%).
Journal Article