Frost Features Research Articles

Role of ice formation mechanisms occurring inside stylolite on limestone tilestone frost susceptibility

Freeze temperature and ice quantity formed inside porous media has been investigated on limestone tilestone samples by Differential Scanning Calorimetry (DSC) measurements. The aim was to determine the role of these stone frost features on limestone damage to Freeze-Thaw (FT) cycles, in relation to the presence of stylolite inside their structure. In fact, the presence of stylolite inside the structure leads to increase locally the pore rate and size, with connected pores. This implies a local increase of ice quantity formed at the surround of stylolite. Damage is thus associated to a heterogeneous nucleation, a rapid growth and ice-front propagation inside pores induced by the presence of stylolite. Specimens exhibiting an increase of quantity of ice formed inside their stylolite – of more than 30% compared to host rock – were damaged by freeze/thaw cycles. Furthermore, stones with freezing temperature lower than the minimum of FT cycles temperature are frost resistant. Finally, low-temperature calorimetry appears to be a practical and cheap method for quickly assessing frost limestone susceptibility. For example, this method can benefit some modest heritage constructions in UNESCO World Heritage site ‘Causse & Cevennes’, made by craftsmen who need to quickly know the frost resistance of the stones they use.

Analysis of late spring frost dates over Iran under current climate and future scenarios

Frost damage, especially in spring, can have profound effects on agricultural and horticultural crops so that in some years, Iranian insurance companies have to pay millions of dollars of cost to the farmers. It seems that the costs tend to change due to changing in frost features under future climate scenarios. Therefore, the purpose of the study is to investigate these changes and examining the ability of SDSM and Artificial Neural Network (ANN) to downscale AOGCM output data HadCM3 (A2 and B2 scenarios) and CGCM3 (A1B and A2 scenarios). To this end, daily minimum temperature data (Tmini ) of 50 synoptic stations all over Iran for the last 50 years (1961–2010) were collected and quality controlled. The trend analyses of Late Spring Frosts (LSF) dates during historical period showed a significant (at the confidence level of 5%) downward trend of 1.4 days per decade, especially after 1980s. Consequently, statistical tests including Wilcoxon rank-sum method, Levene’s test, and bootstrapping were applied, respectively to compare the mean and variance of LSF dates and to determine the uncertainty of LSF dates at the 95% confidence level. Results revealed that, (a) performance of both downscaling techniques in simulating averages is much better than variance, (b) SDSM simulates warmer summers and colder winters in comparison with ANN; (c) the best and worst accordance between observations (during 2001–2010) and different projections obtained from ANN_CGCM3_A2 and ANN_HadCM3_B2, respectively. Finally, different zones of average dates of LSF occurrence (0 °C or colder) and their areas at current condition and three future scenario period (2011–2040, 2041–2070, 2071–2100) were quantified and compared. According to results, SDSM simulated the probable effects of climate change on LSF more intensively compared to the ANN model.

The influence of non-sorted circles on species diversity of vascular plants, bryophytes and lichens in Sub-Arctic Tundra

Non-sorted circles (NSCs), also known as frost boils, are common soil frost features that create a small-scale mosaic of vegetation zones in periglacial landscapes. The causes of variation in plant ...

Archaeological magnetometry in an Arctic setting: a case study from Maguse Lake, Nunavut

Magnetometry has been little used on Arctic archaeological sites, but has great potential to help us understand site structure by identifying buried features and providing additional detail about the construction and use of visible surface features. In the Arctic environment, magnetometer surveys have to deal with the effects of permafrost activity on soils and the potential influence of glacial erratics of varying geological composition. Here, we present the results of magnetometer surveys of a non-cultural site with periglacial features and two archaeological sites located in the Canadian low Arctic. Despite considerable “noise” apparently caused by igneous erratics, the surveys successfully identified several frost features and a range of archaeological feature types. They also appear to have located buried archaeological features and identified activity areas within some dwellings. These preliminary results suggest that the technique is worth pursuing on northern sites.

Progressively cooler, drier interglacials in southern Russia through the Quaternary: Evidence from the Sea of Azov region

Loess-palaeosol exposures along Taganrog Bay, Sea of Azov, in southern Russia, reveal a complex succession of Quaternary palaeoenvironments over the past 0.7 million years. The deposits overlie marine sediments of Tiraspolian (Cromerian) age. At the key section of Semibalki-1, four palaeosol complexes are identified within the series. The earliest palaeosol complex in the Semibalki-1 section is correlated with the late Muchkap Interglacial (the Vorona palaeosol). The soil type resembled modern subtropical Mediterranean region soils. The later Middle Pleistocene palaeosols bear evidence of soil-forming processes typical of various temperate zone environments, with a gradual transition to increasingly cooler, drier conditions. Soils suggesting transitional development between kastenozems and chernozems developed during the Likhvin Interglacial (Inzhavino PC). PC 2 (Kamenka Interglacial) is typified by eluviated Luvic Chernozemic soils, possibly formed under prairie parkland conditions. Finally, the Mikulino Integlacial of the Late Pleistocene (Mezin PC) is represented by chernozems similar to the modern (Holocene) soils of the region, but showing enhanced podzolization and fewer seasonal frost features. A succession of environmental changes has been traced in the study region, from semi-humid subtropical environments at the end of the Early Pleistocene to prairie environments, then to boreal-mild temperate during the Middle Pleistocene, and finally towards landscapes with typical steppe soils in the Late Pleistocene and Holocene. The sequence indicates that moisture supply and temperatures during successive interglacials shifted progressively towards increasingly cooler, somewhat drier climates, influencing soil formation.

Frost and soils: implications for paleosols, paleoclimates and stratigraphy

Frost is a pedogenetic agent. This paper describes the use of frost features in soil for paleoclimatic and stratigraphic interpretation. It is possible to differentiate periods of frost activity from those of temperate pedogenesis by macroscopic and microscopic criteria and to distinguish between soils with pre-, syn- and epigenetic frost effects. An experimental approach is necessary to determine initial frost effects because they are usually difficult to observe at natural active sites. Work with ecologists also clarifies the evolution of frost-affected soils under climatic and vegetational constraints. Vegetation has important effects on the thermal and hydraulic regimes of soils and on erosion susceptibility. The recognition of fossil cryosoils often allows the reconstruction of sequences of paleoclimatic events in periods or environments with little or no micropaleontological evidence. The interrelations between frost and other pedogenetic processes allow a better understanding of climatic evolution and deterioration throughout the Neogene and especially during the Quaternary and the Holocene. Most of the inherited frost features in European soils are younger than 480 ka BP. The differentiation between frost and tectonic perturbations is very important for calculation of soil erosional budgets.

Recent work on Quaternary paleosols in Britain

Abstract Apart from observations of isolated exposures of buried paleosols, most of the early paleopedological work in Britain was concerned with surface (non-buried) paleosols, principally the paleo-argillic soils of the current system of soil classification for England and Wales. Within the last 20 years more extensive buried interglacial soils have been discovered in parts of East Anglia and the Lake District. Those on a sequence of buried pre-Anglian terraces of the proto-Thames in East Anglia strongly resemble the surface paleo-argillic soils. Comparison of the two would show whether the paleo-argillic soils should be subdivided in any way, and could clarify diagenetic processes affecting buried soils and the extent to which early soil features are lost by continuing pedogenesis. Buried arctic structure soils were formed in many different periods, including the Dimlington and Loch Lomond Stadials of the Late Devensian (since 26,000 BP). If these can be correlated with the frost features that occur widely in paleo-argillic and other surface soils, they will also clarify the pedogenetic histories and improve the classification of British surface soils. Buried Late Devensian interstadial soils are also widespread, and provide evidence for the ecological effects of the rapid climatic changes occurring (between 13,000 and 10,000 BP). Those exposed in recent excavations related to the Channel Tunnel provide the first evidence for clay illuviation at this time in Britain.

Subalpine heaths as an indicator of a periglacial environment

Subalpine heaths in Abisko Valley, northern Sweden, are considered an indicator of a periglacial environment. Geomorphological frost features such as active nonsorted circles, stone pits and frost-heaved stones and boulders are found on subalpine heaths. Soil studies indicate that cryoturbation and solifluction have been and are currently active on subalpine heaths. Temperature measurements show that in years with low precipitation and cold winters, ground temperature docs not rise above 0° 200 cm depth on vegetation covered sites on wet subalpine heaths. Seasonal frost processes are reinforced by local climatic factors and edaphic conditions resulting in the development and maintenance of periglacial features in environments below the tree-line.

Alpine Vegetation and Active Frost Features of Pellisier Flats, White Mountains, California

Active, polar-type frost features are described from a high plateau in the White Mountains, a range which flanks the Great Basin along the California-Nevada state line. Observations of unusual vegetation patterns and of plant remains in overridden turf banks are presented; these, as well as other data support the idea that a current, annual, freeze-thaw cycle contributes to soil heaving and instability on the large solifluction terraces of the region. The flora of Pellisier Flats is listed for the first time, and the distribution of species is presented in tabular form to show the relationships of the floral components to frost scars and the gross topography of this remote area. INTRODUCTION Pellisier Flats is the gently rolling, north-trending plateau that forms the crest of California's White Mountains in the region near the Nevada state line (Fig. 1). This nearly inaccessible2 eight-squaremile surface ranges from 12,500 to 13,500 ft (4100-4430 m) in altitude. It lies 8,000 ft ablove the flanking desert basins and 1,000 to 2,000 ft above upiper tree line. The plateau (Fig. 2) is bounded on the west by precipitous canyons, which drain into the Owens Vallev, and on the east by sheer-walled glacial cirques, which expand into broad valleys. During the summer of 1964 the authors traversed Pellisier Flats to collect and catalogue the flora and to make geological observations; the presence of apparently active frost features and corresponding zonation of the vegetation led to subsequent investigations. CLIMATE The climate at 12,500 ft (4100 m) in the White Mountains is cold and semiarid (K6ppen Bsk) as indicated by the weather records of the Barcroft Laboratory of the White Mountain Research Station, located 10 miles south of the flats (Pace, 1963). Yearly precipitation is 15.5 inches, the mean annual temperature 28 F. Although precipitation is mostly in the form of winter snows, occasional summer thunderstorms, bring heavy rains. The habitat classification appropriate for most of the flats is that of alpine fell-field. 1 Two of the authors (Lloyd and Mitchell) were employed by the White Mountain Research Laboratories of the University of California during the summers of 1963-1965 to engage in a study of the White Mountains flora. 2 Helicopter service was furnished by the White Mountain Research Station. 516 This content downloaded from 207.46.13.111 on Sat, 08 Apr 2017 19:50:16 UTC All use subject to http://about.jstor.org/terms 1966 MITCHELL ET AL.: PELLISIER FLATS 517 Boundory P44k a 13140 fISH

Glacial deposits in southeastern Norway

The types of deposits distinguished are those of active glaciers, now represented by uplifted marine sediments, ground moraine, and terminal moraine, and those of stagnant glaciers, now represented by fluvioglacial sediments and ablation drift in valleys, stagnant ice deposits on plateaus and along the ice divide, and thin drift, characterized by frost features, in mountainous areas.

Late Pleistocene Climate of Europe: A Review

The Pleistocene periglacial environment of Europe is believed to have been marked by intensive frost action and wind action and by the spread of arctic and subarctic plants and animals south to the Alps. The frost action is recorded by ice-wedge casts, involutions, solifluction deposits, block fields, and related deposits, some of which may record permafrost. The occurrence of extensive sand dunes and loess deposits may be related to the distribution of glaciofluvial plains, strong winds, and the absence of forest cover. The occurrence of a tundra zone in the basal levels of Late-glacial pollen sequences in central Europe indicates a frigid climate, and molluscan and mammalian faunas provide similar information. Poser and Budel have separately attempted to represent the Pleistocene climatic-vegetational zones of Europe on maps. Poser located the southern limit of permafrost according to the distribution of ice-wedge casts and involutions, and the northern limit of forest from pollen-analytical evidence summarized by Firbas. These two map lines were then used to help delineate several vegetational-climatic provinces. An additional study on the Late-glacial sand dunes led to the presentation of a map of mean summer air pressure for Europe. Budel located the Pleistocene frost limit on the basis of its presumed relation to the 1000-m snow line, which is identifiable in the mountains of central Europe. His representation differs from Poser9s chiefly for Hungary and France, where there is a dearth of pollen studies from which vegetational relations can be inferred. Budel distinguishes several vegetational zones throughout Europe on the basis of loess distribution and also from pollen diagrams where available. Budel believes that the ice sheet had only a minor effect on the climatic zonation of Europe during the Pleistocene. Although exception is taken to many details of the criteria used by Poser and Budel for vegetational zonation, the maps are considered useful as a basis for discussion of Pleistocene atmospheric circulation patterns. The sequence of climatic changes for the last cold period is inferred largely from the stratigraphy of periglacial loesses and intercalated soils, and from their correlation with the Alpine glacial sequence. The controversy concerning the classification of the Wurm period as single (following Penck) or as multiple (following Soergel) is reviewed; the validity of the Gottweig interstadial is questioned on the basis of recent field studies and radiocarbon dates in Austria and adjacent areas. The reduction of mean annual temperature during the late Pleistocene, as inferred from the snowline depression in the mountains, amounted to 5°–8°C under the general assumption of a 0.5°–0.7°C/100 m vertical temperature gradient (lapse rate) in the atmosphere. Calculations based on the occurrence of frost features and fossil plants in lowlands, however, suggest a temperature depression of 10°–12° C. The discrepancy may result from different lapse rates over mountains and over lowlands, according to Mortensen. Studies of modern lapse rates in arctic, subarctic, and subtropical regions are reviewed in order to evaluate this hypothesis. Maps of mean atmospheric pressure and circulation patterns are commonly based on extrapolation from those modern patterns that are related to snowy winters, cool summers, and other conditions favorable to glaciation, on the assumption that the Pleistocene climate was marked primarily by a different frequency of certain air-mass movements and related storm tracks compared to today. Possible causes for circulation changes are still highly speculative, although much recent interest is centered on variations in solar radiation such as are exhibited in sunspots.