Earth Hummocks Research Articles

CHEMISTRY OF HUMIC SUBSTANCES EXTRACTED FROM AN ARCTIC SOIL

A humic and a fulvic acid, extracted from the Ahb horizon of an earth hummock occurring on an Alpine Tundra (Brunic Turbic Cryosol) in the northern part of the Mackenzie river in the Northwest Territories, were characterized by elementary and functional group analyses and by optical measurements. To obtain more detailed structural information, the humic acid, the major organic fraction in the soil extract, was degraded by alkaline permanganate and alkaline cupric oxide oxidation. The degradation products were identified on a gas chromatographic–mass spectrometric–computer system. The analytical characteristics of the Arctic humic and fulvic acids were similar to those reported in the literature for humic and fulvic acids from more moderate climates. However, effects of near-surface permafrost and harsh Arctic climatic conditions manifested themselves in the degradation data. Compared to humic acids from warmer climates, the Arctic humic acid appeared to be poorly developed, exhibiting a low degree of condensation and aromaticity, a low resistance to mild chemical oxidants, yielding only very small amounts of benzenepolycarboxylic acids higher than the di-forms, but relatively large quantities of aliphatic carboxylic acids, especially the n-C16 and n-C18 fatty acids.

Tree Ring Record of Soil Movements on Permafrost

Trees growing on severely cryoturbed soils on of high activity and quiescence in the last 160 permafrost terrain produce reaction wood in years. Such periods can be matched in two areas response to tilting of trees by ground heave 450 km apart, but occur two years earlier in the movements. A total of 157 tree disks taken from north than in the south. Above-average levels 59 different earth hummocks show multiple tilt- of activity are indicated for the period 1847 to ing and recovery. The direction of tilt is general- 1943, and low levels of activity during the last ly away from the center of active hummocks. two decades. There are indications that high The chronology of ground heave movements as levels of activity are related to higher than norrecorded by reaction wood shows brief periods mal fall temperatures and precipitation.

Paleoclimatic Significance of Fossil Periglacial Phenomena in Hokkaidô, Northern Japan

In present paper some fossil forms of frozen ground phenomena such as earth hummocks (Fig. 1), sorted patterned grounds (Figs. 3 & 4), festoon: vertical stones (Figs. 4 & 5), involutions (Figs. 7 & 8), and ice-wedge casts (Fig. 6) are described.The zonal distribution of active frozen ground phenomena and related environments are tabulated from some literatures as well as the results of our own survey on them in Japan (Table 1). Paleoclimate of the last glacial period in the esatern part of Hokkaido is considered after distribution of fossil frozen ground phenomena comparing with distribution of active ones. Volcanic ash layers and river terraces are surveyed to determine tephorochronologically the age of phenomena.The main results are as follows. All kinds of frozen ground phenomena, even earth hummocks, carry involution structures in cross section (Fig. 2). Stratified sediments such as volcanic ash layers clarify involution structures. In Japan, the southern limit of active earth hummocks coincedes approximately with +6°C mean annual isotherm. Therefore, buried earth hummocks and small-scale involutions do not indicate ancient cold climate in eastern Hokkaido where present mean annual temerature is nearly+6°C.Festoon, a kind of involution, can easily be found in fine sediments overlying river terrace gravels. Because of prevention of dense vegetation cover gravels do not reach the ground surface to form sorted patterned ground in most cases although some fossil sorted patterned grounds are found. Vegetation profited by warmth in summer sets the limit of sorted patterned grounds on nearly 0°C mean annual isotherm in central Japan and on a isotherm of somewhat lower than 0°C in Hokkaido.Some large-scale involutions (Fig. 8) may be cross sectios of palsas. Ice-wedge casts, indicators of ancient permafrost, are also found in the lowlands of eastern Hokkaido. Based on Pewe's observation decreasing of temperature at the time should be estimated as 12°-14°C.In this region ice-wedge casts indicating the maximum coldness are buried by a markable layer (Erimo Volcanic Sand: Spfa; 32, 200 14C yr.B.P.). It is, therefore, concluded from chronological studies of river terraces and volcanic ash layers that in this region the maximum decreasing of temperature precedes the maximum lowering of sea level observed all over the world in 18, 000-20, 000yr.B.P.

Frost Cracks and Earth Hummocks at Kosciusko, Snowy Mountains, Australia

Frost cracks and earth hummocks are described from wet, peaty flats underlain by gravels in the Kosciusko area. Their dimensions in relation to the relatively mild climate and insulating snowcover ...

Periglacial Phenomena on the South Hakkôda Mountains

The author and his collaborators have been studying moors and other features seen on the South Hakkôda Mountains, Aomori Prefecture.In this paper, the author reports some periglacial and nival morphology there.1. Such characteristic features are densely developed on the swampy slope (photo 1) along a ridge extending to the south-east from the top of Kushigamine, the highest peak within the mountains.2. At the highest part of the swampy slope, undulating landforms (photo 2) are distributed; they may be earth hummocks. A C-14 date suggests the ages of two volcanic ash layers underlying the surface are about 1, 400yrs. B. P. and 3, 000yrs. B. P. respectively.3. Below the just-mentioned part, a nivation niche is developed. Stone-banked terraces are formed within the niche (photo 3).

Stenströmmar och utdragna polygoner på Gotland

Abstract Frost phenomena occur in thin layers of weathered material covering the Ordovician and Silurian sedimentary rocks om the islands of Oland and Gotland in the Baltic. Stone pits, sorted nets, and earth hummocks from flat areas of the islands have been described earlier (Hesselman 1908 and 1915, Sterner 1926, and Rydquist 1960). The present paper shows an example of elongated polygons and sorted stripes in gentle slopes on the northwestern coast of Gotland. They are considered mainly as frost phenomena.

ETUDES PERIGLACIAIRES MONDIALES EN 1964

Since the establishment of the Commission on Periglacial Geomorphology in 1949 and of the Biuletyn Peryglacjalny (Lodz, Poland) five years later, periglacial research has made considerable progress in many countries. Unfortunately, nobody has the data needed to prepare a complete statement of all that has occurred in the fields of teaching, individual research, joint undertakings, and the general organization of periglaciology. However, the present note summarizes various preceding reports which were similarly intended to spread the knowledge of activities in periglaciology. In 1964, the International Commission of Periglacial Morphology held several meetings in Hungary, Austria, and Great Britain. Both thematic and regional periglacial morphology were discussed. In Hungary-Austria, the topics studied dealt with loess accumulation, gelivation valleys, thermokarst, injection-ice deposits, frost wedges (ice or sand), cryoturbation solifluction sheets, and lobes. In Great Britain, two symposiums brought the participants in the field to study tors, heads, steps, vegetation patterns, earth hummocks, and Quaternary chronology. During the meetings in London, more than fifty papers were presented, and many kinds of periglacial phenomena from several countries were discussed. Poland has published number 14 of the Biuletyn Peryglacjalny that contains nine national periglacial reports; one comes from Canada (Frank A. Cook's text). Two other papers deal with general periglacial terminology. The next meeting of the commission will be in the United States during 1965.

Patterned Grounds of Numano-taira, Mt. Bantai

In a depression named Numano-taira, 1, 380m above the sea-level, situated in Mt Bantai, one can see earth hummocks in its floor, stone-stripe-like linear banks and turf-banked benches on the side slope, 4° in maximum angle, surrounding its floor.The structure of linear bank (Fig.) does not show the properties of true stone stripe; the distribution of breccia at the intermediate part between such linear banks (Photo.) exhibits the characteristics of typical polygon.

BASALTIC SOILS OF SOUTH‐WEST ICELAND. I

SummaryA preselected grid of sixty‐five randomly arranged sampling sites was the basis for a preliminary soil survey in south‐west Iceland.The soils were divided into freely drained soils and poorly drained soils, the larger group being freely drained, of which many were shallow lithosols and regosols varying in depth from a few cm. to 1–2 m.Visible soil characteristics result mainly from physical effects of climate and recent age of the soil parent material. The combined processes of alternate freeze and thaw and wind deposition have disrupted orderly soil morphology. Colour differences, usually varying shades of brown, are therefore minimized, and the mineral matter shows little sign of horizon differentiation, apart from bands of wind‐deposited volcanic ash. The poorly drained soils are mucky in appearance with a non‐indurated layer of bog iron above the permanent water‐table. Waterlogged conditions do not always lead to general gleying.Under the prevailing sub‐arctic climatic conditions grasses and most other species are shallow‐rooted, forming a surface mat 5–7 cm. thick.Field texture of freely drained surface soils is usually loamy, but may be extensively conditioned by high organic matter contents. Structure is weak platy, changing to block‐like and/or to single‐grained structure. On drying, soil aggregates usually disintegrate at the least pressure applied.Many surface features, normally related to frost action, occur, including earth hummocks, scars, V‐shaped gullies, polygons, and stone stripes. Perma‐frost is absent.