Periglacial cover beds and soils in landslide areas of SW-Germany

At the slopes of the Jurassic cuesta scarp in SW-Germany, pedological and mineralogical investigations were carried out in landslide areas. So far, it is possible to distinguish two well-defined landslide areas, one of them belonging to the Pleistocene, the other one characterised by Holocene movements. In general, the distribution of soils and sediments is strongly linked to the age of landslide deposits. In Pleistocene landslide areas, the parent material of the studied soils is formed by periglacial cover beds of Late Pleistocene age, consisting of Jurassic, aeolian and volcanic components. The Upper Periglacial Cover Bed was recognised as the most important marker horizon in the studied slope areas. There, the existence of minerals originating from the eruption of the Laacher See volcano, dated to 12,900 yr BP, could be demonstrated for the first time. Most of the Pleistocene landforms are characterised by well-developed soils, like Clayic and Vertic Cambisols, whereas relic soils exclusively occur in the oldest parts of landslide deposits. Landslide areas affected by Holocene slope processes do not exhibit periglacial layers, as mass movements removed periglacial sediments and former soils extensively. As a consequence, the parent material is different from those of Pleistocene landslide areas. Therefore, sediments in these areas are characterised by Jurassic components and only initial soils are present.     

Soil polygenesis in the northeast part of Vladimir opolie

Soil studies in cultural landscapes of the medieval epoch within the Vladimir opolie territory on the Russian Plain suggest that virtually all automorphic soils in this area were plowed in that period. The morphology of the profiles of studied soils depends on the composition of parent materials. If the parent material represents a pedocyclith that passed through the stage of periglacial pedogenesis in the Late Pleistocene, then the soil profile developed from this material is a heterochronous body with distinct features of polygenesis. If the parent material is a relatively homogeneous sediment that was not subjected to periglacial pedogenesis in the Late Pleistocene, then the soil profile developed from this material contains only the features of the Holocene pedogenesis, even in the case when the thickness of the homogeneous substrate does not exceed 0.5 m. It is hypothesized that the Holocene pedogenesis within the humid forest and southern taiga zones in the center of the Russian Plain cannot delete the features of the pre-Holocene pedogenesis and morpholithogenesis; these features are always inherited by the profiles of modern soils. The presence of these features ensures the development of a fully developed mature soil profile.     

Quartärgeomorphologische untersuchungen im Nordteil der “Tunesischen dorsale”

Seven Quaternary profiles from the Mediterranean region of northern Tunisia are described and their geomorphological significance assessed. Fifteen radiocarbon datings permit the field observations to be arranged in a chronosequence.The results indicate that the Late Pleistocene period witnessed the production and displacement of coarse debris, a process extending down to low altitudes. Until now, however, the only evidence for this has been found in the vicinity of steep slopes or rock walls. The coarse sediments partly overlie slope deposits derived from reddish soils; to some extent they contain fine reddish pedogenic material, and in part they are covered by it.In the Holocene, the displacement of fine alluvial sediments alternated several times with the formation of humic horizons. Anthropogenic influences on landscape evolution must be admitted as a possibility as from at least three thousand years ago.The aeolian sands of the Late Pleistocene and Middle Holocene are correlated with regressions of high sea levels.     

Periglacial cover-beds on the Swiss Plateau: indicators of soil, climate and landscape evolution during the Late Quaternary

Soils and the stratification of their parent materials were studied on the central Swiss Plateau. This area is characterized by glacial deposits varying from Late Glacial to pre-Würmian in age. Soils of all studied sites are developed within colluvial layers, the so-called cover-beds. In relation to the underlying deposits, we find a regular spatial distribution of cover-bed types. A surficial layer (Upper Layer) with relatively constant thickness (around 50 cm independent of relief position) covers Pleistocene sediments of any age. Therefore, it was formed mainly by cryoturbation/solifluction after the final glacier retreat from the Swiss Plateau (Younger Dryas or Oldest Dryas age). Layers that originate mainly from aeolian processes (Intermediate Layers) are restricted to areas outside the recessional moraines of the Berne-Stade (BS). Hence, they were formed merely up to the late Pleniglacial. They frequently consist of two distinct layers. Outside the glaciation of the Last Glacial Maximum (LGM), cover-beds in places overlie pre-LGM palaeosol relics (probably of Eemian age or even older). These are preserved even on higher relief positions, indicating that periglacial erosion during the Pleniglacial was only marginal. The palaeosol relics also occur on till of the so-called Older Wangen-Stade, which is commonly believed to represent the LGM, whereas we consider it to be older at least partly. Eventually, the distribution of soil types and their ecological characteristics are influenced considerably by cover-beds. As these beds reflect distinct phases of the Pleistocene, colluvial sediments provide a major tool for linking modern landscape characteristics to the Late Quaternary climate evolution.     

Parent materials enriched in organic matter in the northeast of Russia

The distribution, development, and properties of the sedimentary parent materials in the northeastern sector of the Russian Arctic and Subarctic regions are discussed. Vast areas in this sector are occupied by deposits of the Ice Complex that were formed in the Late Pleistocene and have been preserved in the frozen state up to the present time. The processes of synlithogenic pedogenesis took an active part in the formation of these deposits; owing to them, the sediments are enriched in organic matter. A larger part of this organic matter is represented by fine plant detritus. In the course of the thermokarst processes and partial thawing of these deposits in the Holocene, the organic matter content in the upper part of the Ice Complex has somewhat decreased, and its qualitative composition has changed. The soil profiles developing from these deposits inherit the relict organic matter.     

Application of ground‐penetrating radar to determine the thickness of Pleistocene periglacial slope deposits

Wide areas of the mountainous regions of Germany have rock covered by Pleistocene periglacial slope deposits (PPSD), formed by gelifluction during the cold periods of the ice ages in non‐glaciated areas. The PPSD provide the parent material for soil development, and their physical characteristics affect several stabile soil properties. Because the PPSD play a significant ecological role, we studied the spatial distribution and properties of the PPSD in order to assess the distribution of the stabile soil properties. The high stone content of the PPSD greatly hinders augering and digging. Hence, we tested the use of ground‐penetrating radar (GPR) as a potentially time‐saving, non‐destructive method to determine the thickness of the PPSD. In several study areas of the Rhenish Massif, GPR investigations of single soil profiles and soil transects along an exposed gas‐pipeline ditch were carried out. The GPR images were compared to the actual thickness of the layers of the PPSD exposed in the profiles and the ditch. In the GPR images usually at least one distinct boundary could be identified, which occurs at the transition between the loose material and the hard rock, mostly ranging between 50 and 150 cm depth. In some cases, in which stone content changed abruptly between different layers of the PPSD, also the boundaries between these layers could be identified in the GPR image. On the other hand, in areas where remnants of the Mesozoic‐Tertiary weathering mantle are preserved, the boundary between the saprolite and the overlying basal layer of the PPSD is ambiguous or not at all visible.     

Chrono-toposequences of soils on the river terraces in Transylvania (Romania)

A sequence of surface soil profiles and buried soils described on the 4th, 3rd, 2nd and 1st terraces of different rivers in Transylvania is presented as part of an attempt to perform a paleopedologic interpretation of the dominant soil types of this area. Excepting the first terrace, the described soils were formed from Pleistocene slopewash deposits of Würm, or possibly of Riss age, which overlay alluvial terrace deposits. On the basis of fossil animal remains, periglacial cryostructures, prehistoric artifacts (Coţofeni culture of the transition period from the Neolithic to the Bronze Age) and Scythian graves an approximate age of different soil horizons, as well as the polycyclic nature of soils was established. There is no essential difference between a Würmian buried soil horizon and the argic Bt horizon of the surface soils; moreover, in some cases, the buried paleosols become the Bt horizon itself of the surface soils, through the thinning of the overlying deposits. Even if the possibility of formation of the argic Bt horizons during the postglacial until the end of Neolithic, cannot be excluded, from the presented situations it seems that these horizons in the Transylvanian Basin are Würmian relics, formed in the periglacial interstadials. In most of the cases Bt horizon has nothing in common genetically with the topsoil.     

The influence of quaternary uplift on the altitude zonation of mountain soils on diabase and volcanic ash in humid parts of the Colombian andes

Results are being presented of a pedogeographic study covering a humid tropical mountaneous region (1000 – 4000m) around Cali, Colombia. The country rock is diabase, the parent material volcanis ash, ferrallitic and fersiallitic weathering products of the diabase and their respective mixtures in slope sediments Stratigraphic and mineralogical studies of these slope sediments revealed a depositional sequence which could be related to climatically and ash induced phases of geomorphic activity for which radiocarbon ages of the ash sedimentation provided a chronological frame.The submontane and lower montane zones are characterized by extensive deep alterites and old piedmont sediments which were preserved on plateaus and benches during the geologically young uplift. Their clayey ferrallitic material strongly influences the character and zonation of soils though the widespread admixture of allophanic material keeps most of the soils outside the OxisolsThe soils above 1000 m altitude are humic, acid and cryptopodzolic (Humox, Humitropept, Dystrandept, above 3200 m Cryumbrept and Cryandept). Humus accumulation and acidification increase with altitude. Allophane increases the humus content, reduces the exchangeable aluminium and favours non-crystalline (as against gibbsitic) aluminum accumulation in the subsoil. Free iron oxide tends to crystallize or recrystallize as goethite. Its translocation occurs only in conjunction with hydromorphism. The Holocene soils are compared with Middle Pleniglacial paleosols, mainly Placaquepts, and their differences in pedogenesis and environment are discussed.     

Chronology of plaggic deposits; palynology,radiocarbon and optically stimulated luminescence dating of the Posteles (NE-Netherlands)

Plaggic agriculture was the dominant land use system on Pleistocene sandy soils in Northwest Europe before the introduction of chemical fertilizers. In the today's landscape plaggic deposits are still recognizable as characteristic soils and landforms, related to this historical land use system. They are also important constituents of the soil archives in Northwest Europe. In preliminary studies of plaggic anthrosols, the reconstruction of the development of the plaggic deposits was based on palynological and historical data and radiocarbon dates. Disagreement appeared between palaeopedological and historical explanation of the evolution of plaggic anthrosols. Application of OSL dating improves the knowledge of chronology of plaggic deposits. The soil organic matrix, including pollen grains, consists of a complex mix of compounds of different ages and sources. Pollen diagrams of plaggic anthrosols show a palynological registration of the Late Holocene landscape evolution, but the palynological signal is not consequently correlated with the age of the plaggic sediments. An older soil organic matrix is suspended in the voids of a younger mineral soil skeleton.     

Clay mineralogy,chemical weathering and landscape evolution in Arctic–Alpine Sweden

The purpose of this research was to: (1) characterize the clay mineralogy of soils in and adjacent to Kärkevagge, a recently deglaciated valley in Arctic Sweden, (2) document chemical weathering in a periglacial environment and (3) use the mineralogy to help explain landscape evolution. Soil samples were analyzed from 11 sites that differ in elevation, parent material, drainage, slope and vegetation. Parent materials include residuum, alluvium, colluvium and glaciofluvial material derived from garnet–mica–schist, plus, in one locality, a till of granitic origin. X-ray diffraction (XRD) was used to characterize the clay-size fraction (<2 μm). Muscovite, chlorite and mixed-layered (ML) minerals are the predominant soil minerals identified. ML minerals indicate chemical weathering and also act as tracers used to identify source areas of soil parent materials. High concentrations of ML minerals in the soils on the alpine ridges flanking Kärkevagge indicate in situ chemical weathering. At lower elevations within the valley, their distribution indicates that the ridges contributed sediments early on in the evolution of the landscape, but more recently the source has shifted towards ML-poor supply areas from lower elevations. Soil chemistry also supports this model; the alpine soils are base-poor while the valley soils are base-rich. The higher abundance of ML minerals in the alpine zone indicates either a long period of weathering or a greater period of development. The latter explanation supports the hypothesis that the ridge crests were covered by cold-based ice during the last glaciation; remnants of which still survive at the highest elevations. Cold-based ice preserved a pre-weathered landscape that was the primary source of the ML minerals in the soils in the valley.     

Zur Darstellung von Schichtwechseln in periglazialen Decklagen des Bayerischen Waldes unter besonderer Berücksichtigung der Mittellage und ihrer Eigenschaften

On the presentation of layering in periglacial slope deposits Methods are discussed that appear suitable for more precisely subdividing periglacial slope deposits and their material composition beyond the level of field observation. The study area is the Bavarian Forest region and its surroundings in eastern Bavaria. As a first step significant information concerning layer changes and material characteristics is derived from grain-size distribution. For methodological reasons a further mathematical abstraction in the sense of layering coefficients is not feasible, however. Heavy mineral spectra allow the distinction of layers with eolian influence from loess-free layers and point out material relationships. In addition they characterize the degree of weathering of both the periglacial deposits and the underlying bedrock. The Laacher See tephra as a means of dating is unfortunately absent in the study area. Principal and trace elements of the fine soil fraction are sensitive indicators of material change. The study of pedogenic oxides of various fractions reveal that the substrate of the periglacial slope deposits is composed of material modified by soil-forming processes prior to sedimentation. This is especially true for the middle layer, the analysis and origin of which stand at the center of this contribution. X-ray diffraction analysis of the clay fraction helps differentiate pedogenic transformations and sedimentary characteristics. It equally supplies evidence of considerable eolian influx of clay and silt in the main and the middle layer. The diagnostic characteristics of the individual layers are presented; peculiarities of the middle layer as well as divergencies from the criteria found in the literature are dicussed.     

Pedostratigraphy of Terra Rossa and Quaternary geological evolution of a lacustrine limestone plateau in central Italy

Pedostratigraphic levels (PLs) are typical assemblages of soil‐genetic horizons, formed by materials having the same degree of weathering. The pedostratigraphic approach can be very useful to comprehend the formation of the Quaternary soil cover, the environmental evolution of a territory, and to estimate the age of paleosols. A pedostratigraphic study of a Terra Rossa was carried out to understand the soil–parent material origin and to estimate the time of the beginning of pedogenesis. Besides soil and geomorphological survey, the Terra Rossa was analyzed for Fe forms, geochemistry, clay mineralogy, micromorphology, and with scanning electron microscope. Optical dating was applied to obtain age estimates for the deposition of the parent material of soil formation. The insoluble residue of limestone was obtained and analyzed for geochemistry and clay mineralogy. The bedrock is constituted by Quaternary lacustrine limestone, showing pronounced karst landforms. The soil profile is situated in a little dissolution doline and was divided into three PLs: PL1 (0–110 cm) is constituted by cambic and ochric horizons, formed during Holocene in a mixture of colluvial soil sediments and fresh limestone, with aeolian components; PL2 (110–290 cm) includes two argic horizons, which began to form during Late‐Middle Pleistocene in colluvial soil sediments, with few aeolian additions; PL3 (290–330 cm) is constituted by a red argic horizon, with nitic properties, which developed from the insoluble residue of the limestone. The age of PL3 was calculated through a mass balance and an estimation of the limestone‐dissolution rate during the Quaternary, which led to an approximate age of Middle Pleistocene, between 250 and 500 ky BP. The time of the beginning of pedogenesis on limestone can be used as a reference for the tectonic uplifting of the area and emersion of the plateau.     

Thermoluminescence dating of soils developed in Late Devensian loess at Pegwell Bay, Kent

Thermoluminescence (TL) measurements on the present organic surface soil and two buried soils in loess and colluvium derived from loess at Pegwell Bay, Kent, suggest that the signal is almost completely zeroed during soil development, mainly by optical bleaching. The technique may therefore be used to date buried soils developed in loess and possibly other terrestrial sediments. Decalcification, gleying and other soil-forming processes may also affect the TL signal of the soil parent material, and seem to be the main reasons why the Btg horizons of the Early Holocene buried soil at Pegwell Bay give more recent TL dates than the parent calcareous loess.     

A mid–late Holocene flood record from the alluvial reach of the Mahi River, Western India

Flooding of rivers in India is linked with the peak monsoons. Investigating the linkage between monsoonal patterns and flood history of various rivers is therefore of fundamental importance in the Indian context. In the present study, the slackwater deposits in the alluvial reaches of the Mahi river basin, western India have been documented. These occur in the ravines incised during the early Holocene on an alluvial surface comprising sediments of Late Pleistocene age. The slackwater deposits occur at elevations up to 20 m from the present river level and extend to about 500 m inland. The carbonate rich sediments forming the ravine cliffs have provided bank stability and the dissections in the ravines have helped in the accumulation of slackwater deposits due to backflooding of the floodwater from the main channel. Recent gullies have incised the sediments and exposed deposits related to major flood events. The best exposures of slackwater deposits have been observed at Dodka. The sediment succession of the slackwater deposits is dominated by bedsets and laminasets of silt and sand separated by colluvial sediments. Four events of flood deposition occurred during the mid to late Holocene. Two units of slackwater deposits, SWD 2 and 4 have been dated by IRSL at 4.6 ± 1 ka and 1.7 ± 0.5 ka. The stratigraphy of these deposits indicates that the first two slackwater units (SWD1 and SWD2) have resulted due to flooding in a regime of intense monsoon. The other two units, however, represent extreme high magnitude floods in a period of low average precipitation.     

Holocene evolution of floodplain soils and landscapes in the Kulikovo field area

The lithostratigraphic, radiocarbon, macro- and micromorphological, particle-size, and other analyses have been applied to reconstruct the Holocene evolution of soils and landscapes on the high- and mediumlevel floodplains of the Nepryadva River in the Kulikovo field area. It is shown that the soils buried within the thickness of alluvial sediments on the high- and medium-level floodplains were formed in different times and had their own evolution patterns; the polygenetic nature of these soils is demonstrated. The development of floodplain landscapes in the Holocene was affected by the long-term climatic fluctuations. The bed of the high floodplain was formed during the Late Valdai glacial stage. The beginning of the development of an intricate sequence of buried soils and sediments of the floodplain dates back to the Boreal period. This pedosedimentary sequence in the studied area can be referred to as the Kulikovo sequence. In the course of its formation, the pedogenic stages with a predominant development of soils alternated with the lithogenic stages of active alluviation and deposition of colluvial deposits from adjacent slopes on the floodplain.     

Soil catenas to estimate ages of movements on normal fault scarps, with an example from the Wasatch fault zone, Utah, USA

Trenches excavated across fault scarps on a 13 ka delta surface at Brigham City, Utah, USA, document four types of soil-catena phenomena. First, the relict summit soil is eroded at the scarp crest, and its components incorporated into the accumulating colluvial wedge at the scarp base. Second, the pre-faulting soil weakens laterally as it is traced scarpward beneath the colluvial wedge from a relict position beyond the scarp toe. Third, soils developed on individual colluvial wedges and on the underlying, pre-faulting surface merge downslope to form a cumulative soil profile at the scarp toeslope. Fourth, soil horizons thicken downslope, probably due to the combined affect of more available moisture, water infiltration, and sediment accumulation.Two soil catenas were used to evaluate the applicability of a continuity approach to paleoearthquake dating, by which percentages of total development time represented by each soil at a fault scarp footslope could be estimated. The continuity approach sets total soil development at the scarp footslope, including any buried pre-faulting soil plus the sum development of all colluvial wedge soils corrected by a slope factor (F), equal to total soil development at the scarp summit. Soil development was characterized by Profile Development Index (PDI) and pedogenic clay parameters, using facies models to estimate parent material values for genetically-different colluvial units, and recognizing inherited soil components in colluvial wedges as parent material properties. The F slope factor, used to correct colluvial wedge soils for development attributable to slope position rather than age, was checked by using a nearby fluvial scarp as an independent control. Our soil data, when compared to independent age estimates, imply that rates of soil development have not been constant over the last 13 ka at Brigham City, but rather were considerably higher than average between 13 ka and 8.3 ka. Higher rates are probably due to a relatively high influx of eolian dust during the late Pleistocene to early Holocene following the lowering of Lake Bonneville, a large paleolake in the western USA. These variable rates of soil development preclude using the continuity approach for paleoearthquake dating at Brigham City. However, promising results showing that generally consistent F factors can be calculated for fault and fluvial scarps leave open the possibility that in areas where soil development rates have been relatively constant over the time period in question, the continuity approach may be a broadly applicable method for paleoearthquake dating.     

The effect of subsoil cracking on moisture deficits of Pleistocene and Holocene fluvial clay soils in the Netherlands

Computer simulation of the soil water regime was used to calculate moisture deficits for Pleistocene and fluvial Holocene clay soils for a 30-year period. Hydraulic conductivity (K-h) and moisture retention (h-θ) data were derived for major horizons in both soils as well as functions to characterize bypass flow and effects of horizontal planar voids on upward unsaturated flow of water from the water-table to the root zone. Calculated moisture deficits in Holocene soils occurred earlier during the year and were more pronounced during the summer period. Differences between the two soils could be attributed to more pronounced formation of horizontal planar voids in the Holocene soil, which was associated with more pronounced swelling and shrinkage of the undisturbed soil material. The relatively low swelling and shrinkage of the undisturbed Pleistocene soil material was attributed to very dense packing of the elementary soil particles.     

Specificity of the morphology of interglacial and interstadial paleosol complexes of the middle and late Pleistocene in the center of the East European Plain

Paleosol studies were conducted on the Moskva-Oka interfluve in the center of the East European Plain. Three paleosol complexes were distinguished in the sequence of soil-loess deposits: the Mezin complex of the Late Pleistocene age and the Kamensk and Inzhavin complexes of the Middle Pleistocene. Each of them consisted of the paleosols of two phases: the earlier interglacial phase and the later interstadial phase. In some cases, the paleosols of these two phases were separated by a thin layer of sediments with distinct features of cryoturbation. Paleosols of the interstadial phases are represented by the dark-colored humus-rich meadowchernozemic and chernozem-like prairie soils. During the interglacial periods in the Middle and Late Pleistocene, the soils with pronounced eluvial-illuvial differentiation of their profiles were developed under forest cenoses. Data on the morphology of paleosols; their physical, chemical, and physicochemical properties (particle-size distribution, pH, humus, carbonates, amorphous and crystallized iron oxides, etc.); and their micro-morphological features studied in thin sections prepared from undisturbed soil monoliths make it possible to judge the character of the pedogenesis during different epochs.     

The influence of parent material on soil fertility degradation in the coastal plain of Tanzania

Differences in the vulnerability of soils to fertility degradation are compared for two major soil groups located in the coastal plain of Tanzania and cropped with sisal (Agave sisalana). Ferralsols derived from intermediate gneiss of Precambrian age and Cambisols developed in Jurassic and Neogene limestones partly covered with Quaternary deposits were selected for comparison. A clear influence of parent material was apparent when soils were continuously cropped with sisal and no fertilizers were applied. Serious soil fertility decline occurs in Ferralsols, but Cambisols are resilient to chemical degradation and the fertility decline in these soils was very limited. The differences in degradation rates are explained by the lower initial fertility and low nutrient reserve of Ferralsols, while the Cambisols had higher initial fertility levels and nutrients removed by the sisal crop are replenished by the weathering of the underlying parent material. Sustainable soil fertility management of Cambisols includes only NPK fertilization, but heavy dressings of lime, organic manures and/or chemical fertilizers are required to improve the fertility status of the Ferralsols and to produce crops in a sustainable manner.