Composition Of Parent Material Research Articles

Evolution of desert pavements and the vesicular layer in soils of the Transantarctic Mountains

Compared to mid-latitude deserts, the properties, formation and evolution of desert pavements and the underlying vesicular layer in Antarctica are poorly understood. This study examines the desert pavements and the vesicular layer from seven soil chronosequences in the Transantarctic Mountains that have developed on two contrasting parent materials: sandstone–dolerite and granite–gneiss. The pavement density commonly ranges from 63 to 92% with a median value of 80% and does not vary significantly with time of exposure or parent material composition. The dominant size range of clasts decreases with time of exposure, ranging from 16–64 mm on Holocene and late Quaternary surfaces to 8–16 mm on surfaces of middle Quaternary and older age. The proportion of clasts with ventifaction increases progressively through time from 20% on drifts of Holocene and late Quaternary age to 35% on Miocene-aged drifts. Desert varnish forms rapidly, especially on dolerite clasts, with nearly 100% cover on surfaces of early Quaternary and older age. Macropitting occurs only on clasts that have been exposed since the Miocene. A pavement development index, based on predominant clast-size class, pavement density, and the proportion of clasts with ventifaction, varnish, and pits, readily differentiated pavements according to relative age. From these findings we judge that desert pavements initially form from a surficial concentration of boulders during till deposition followed by a short period of deflation and a longer period of progressive chemical and physical weathering of surface clasts. The vesicular layer that underlies the desert pavement averages 4 cm in thickness and is enriched in silt, which is contributed primarily by weathering rather than eolian deposition. A comparison is made between desert pavement properties in mid-latitude deserts and Antarctic deserts.

Elastomagnetic and Elastoresistive Effects in CoFe Films Produced by Femtosecond Pulsed Laser Deposition

Femtosecond pulsed laser deposition, carried out in high vacuum, leads the ablation of any target material, producing a plume of nano-drops which are deposited on a substrate as particles, preserving the parent material composition. The deposited nanoparticles (NPs) exhibit a characteristic disk-shape with a major diameter ranging from 5 nm up to 60 nm and a thickness ranging from 1 nm up to 10 nm. Also when the particles form a thick layer, they remain separated by an interface of free volume. This characteristic morphology of the deposited films gives an interplay of interparticle and intraparticle physical correlations which deeply differentiates their properties from those of similar nanogranular films deposited by other techniques. This investigation is focused on the influence of the novel structural conditions on the coupling between strain and magnetization, and/or strain and resistivity, in Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</sub> NP films deposited on Kapton substrate. Due to the NP nature of the films, these couplings are substantially different from standard magnetostrictive and piezoresistive effects. Magnetization and resistivity versus applied strain were studied, thus evidencing novel elastoresistive and elastomagnetic functionalities and evaluating their relative sensitivities. The limits and potentiality for the application of the new NP magnetic films in microelectromechanical systems (MEMS) will be briefly discussed.

Assessing heavy metal contamination in soils of the Zagreb region (Northwest Croatia) using multivariate geostatistics

The assessment of soil contamination and location of pollution sources represent a crucial issue in soil remediation. Topsoil samples were collected in the Zagreb area (Northwest Croatia) and the total contents of trace and major elements were determined. A multivariate geostatistical analysis was used to estimate soil chemical composition variability. Factorial Kriging Analysis (FKA) was used to investigate the scale-dependent correlation structure of some variables by modelling co-regionalization of ten chemical variables, co-kriging specific factors and mapping them. The FKA provided two regionalized factors at different spatial scales of variability: the first factor at shorter range for Zn, Pb, Cd, Cu and Ni indicated different sources of anthropogenic contamination, whereas Ca (mainly loading on the longer range factor) was related to the lithology and parent material composition. The methodology used has proved to be a useful tool to separate geological and anthropogenic causes of variation in soil heavy metal content and to identify common pollution sources.

Sand and clay mineralogy of soils of Garhwal Himalaya, Uttarakhand

Fine sand and clay mineralogy of selected horizons of forest soils representing various landforms of Maldeota, Satengal and Dhanaulti areas of Raipur and Jaunpur ranges of Mussoorie forest division of Garhwal Himalaya were investigated. Light minerals constituted more than 80 percent of total fine sand fractions and consisted of quartz, feldspar and mica in order of their abundance. Heavy minerals occurred in minute amounts and constitute 20 percent of the minerals and were dominated by opaque minerals followed by biotite, chlorite, chloritized mica, zircon, garnet, hornblende, tourmaline, rutile etc. Quartz is the dominant mineral in Maldeota and Satengal sites followed by Dhanaulti while feldspar and mica are abundant in Dhanaulti followed by Maldeota and Satengal. Among the heavy minerals opaque minerals, biotite and calcite are present in appreciable quantity in all the three sites viz. Maldeoata, Satengal and Dhanaulti. The other heavy minerals are present in small quantities at all the three sites. The clay fractions from the soils of Maldeota are characterized by illite as the dominant clay mineral associated with kaolinite, chlorite, vermiculite and quartz. The clays from Satengal contained mixture of illite as dominant mineral followed by mica, mixed layer minerals, vermiculite, chlorite and quartz. The soil clays from Dhanaulti indicates the presence of illite, muscovite, kaolinite, mixed layer minerals, chlorite and small traces of vermiculite, calcite and quartz. Differences in mineralogical make up were mostly associated with nature and composition of parent material and degree of weathering. The study, therefore, suggests that soils of the study area contained low to moderate amount of weatherable minerals indicating their podzolic nature.

Engineering characteristics of a glacio-lacustrine clay deposit in a semi-arid climate

Parent material composition, particle disintegration by glaciers and lacustrine environment govern the geological development and engineering characteristics of clay deposits in southern Saskatchewan. The pre-existing expansive clay minerals were preserved due to the restrained leaching in the Regina Lake and the prevalent aridity in the area. The main objective of this paper was to develop a fundamental understanding of the clay deposit for the use in the design and construction of civil infrastructure. The results indicated the presence of expansive clay minerals in the deposit, with smectite accounting for 35% of the material. The major exchangeable cation was found to be Ca2+ which accounted for more than half of the total measured cation exchange capacity of 40 (cmol(+)/kg). The most likely exchange complex governing water adsorption of the clay was determined to be Ca2+-smectite. Alongside a high initial saturation (86%), this complex resulted in moderate volume changes in the clay. The swelling pressure was fully developed within the first hour of the constant volume test. The corrected swelling pressure was determined to be 120 kPa leading to an estimated heave of 36 mm in the surface layer of the deposit. The compression index and the swelling index were found to be 0.25 and 0.08, respectively.

Soil chemistry in lithologically diverse datasets: The quartz dilution effect

Abstract National- and continental-scale soil geochemical datasets are likely to move our understanding of broad soil geochemistry patterns forward significantly. Patterns of chemistry and mineralogy delineated from these datasets are strongly influenced by the composition of the soil parent material, which itself is largely a function of lithology and particle size sorting. Such controls present a challenge by obscuring subtler patterns arising from subsequent pedogenic processes. Here the effect of quartz concentration is examined in moist-climate soils from a pilot dataset of the North American Soil Geochemical Landscapes Project. Due to variable and high quartz contents (6.2–81.7 wt.%), and its residual and inert nature in soil, quartz is demonstrated to influence broad patterns in soil chemistry. A dilution effect is observed whereby concentrations of various elements are significantly and strongly negatively correlated with quartz. Quartz content drives artificial positive correlations between concentrations of some elements and obscures negative correlations between others. Unadjusted soil data show the highly mobile base cations Ca, Mg, and Na to be often strongly positively correlated with intermediately mobile Al or Fe, and generally uncorrelated with the relatively immobile high-field-strength elements (HFS) Ti and Nb. Both patterns are contrary to broad expectations for soils being weathered and leached. After transforming bulk soil chemistry to a quartz-free basis, the base cations are generally uncorrelated with Al and Fe, and negative correlations generally emerge with the HFS elements. Quartz-free element data may be a useful tool for elucidating patterns of weathering or parent-material chemistry in large soil datasets.

Phosphorus sorption–desorption in alluvial soils of a young weathering sequence at the Danube River

Soil parameters change continuously over time and the duration of pedogenesis may significantly affect a soils' sorption capacity for nutrients and contaminants. In former studies, we showed that progressing pedogenic development had increased the retention capacities for Cu and Cd in young alluvial soils at the Danube River (Austria). The present study was conducted to evaluate the impact of pedogenesis on phosphorus (P) retention in these soils, which represent a weathering sequence covering an age gradient from < 20 yr to < 500 yr. We performed batch sorption experiments followed by three subsequent desorption steps. Phosphorus retention differed strongly among the studied soils and ranged from 11 to 40% when 1000 mg phosphate — P kg − 1 was added. The subsequent desorption experiments with 0.01 m KCl solution revealed a high mobility (up to 89%) of this recently added P. Correlation analyses showed that P retention in the studied samples was positively correlated to dithionite-extractable Al, Mn and Fe, oxalate-extractable Mn and clay content. The present study revealed that P sorption was not influenced by soil development. The composition of the soil parent material, as affected by differences in sedimentation conditions across the studied floodplain, had a stronger impact on P sorption than the changes induced by 500 yr of pedogenesis under the continental climate of Central Europe.

Differential response of mineral-associated organic matter in tropical soils formed in volcanic ashes and marine Tertiary sediment to treatment with HCl, NaOCl, and Na 4P 2O 7

Quantitative knowledge of the amount and stability of soil organic matter (SOM) is necessary to understand and predict the role of soils in the global carbon cycle. At present little is known about the influence of soil type on the storage and stability of SOM, especially in the tropics. We compared the amount of mineral-associated SOM resistant to different chemical treatments in soils of different parent material and mineralogical composition (volcanic ashes – dominated by short-range-order aluminosilicates and marine Tertiary sediments – dominated by smectite) in the humid tropics of Northwest Ecuador. Using 13C isotope analyses we traced the origin of soil organic carbon (SOC) in mineral-associated soil fractions resistant to treatment with HCl, NaOCl, and Na 4P 2O 7 under pasture (C 4) and secondary forest (C 3). Prior to chemical treatments, particulate organic matter was removed by density fractionation (cut-off: 1.6 g cm − 3). Our results show that: (1) independent of soil mineralogical composition, about 45% of mineral-associated SOC was resistant to acid hydrolysis, suggesting a comparable SOM composition for the investigated soils; (2) oxidation by NaOCl isolated a SOM fraction with enhanced stability of mineral-bound SOM in soils developed from volcanic ashes; while Na 4P 2O 7 extracted more SOC, indicating the importance of Al-humus complexes in these soils; and (3) recently incorporated SOM was not stabilized after land use change in soils developed from volcanic ashes but was partly stabilized in soils rich in smectites. Together these results show that the employed methods were not able to isolate a SOM fraction which is protected against microbial decay under field conditions and that the outcome of these methods is sensitive to soil type which makes interpretation challenging and generalisations to other soils types or climates impossible.

How does forest harvest influence carbon dioxide fluxes of black spruce ecosystems in eastern North America?

Forest harvest is a major disturbance in the boreal forest of eastern North America and should significantly impact biosphere–atmosphere interactions at the regional scale. During a cooler, wetter year (2004) and a warmer, drier year (2005), we compared carbon dioxide (CO 2) fluxes over a mature black spruce stand (EOBS) with a site that was harvested in 2000 (HBS00) and that had similar soil parent material, site fertility, climate, and pre-harvest species composition. During the study period, EOBS was C neutral (0–6 g C m −2 year −1), while HBS00 was a fairly strong C source (119–167 g C m −2 year −1). Averaged over both years, gross ecosystem productivity (GEP) was 101% higher at EOBS compared to HBS00 (636 g C m −2 year −1 versus 316 g C m −2 year −1), while ecosystem respiration ( R) was 37% higher at EOBS (633 g C m −2 year −1 versus 462 g C m −2 year −1). The mean between-site difference in annual NEP was six times greater than was the mean between-year difference, thus suggesting that the C budget of boreal black spruce forests is much more affected by developmental stage (i.e., stand age) than by between-year climate variability. Relative to the mature site, the harvested site had a more dynamic structure due to plant regrowth that induced greater between- and within-year variability in the response of GEP and R to environmental conditions over the 2-year study period. For example, maximum photosynthetic capacity was stable between years at EOBS (12.5 μmol m −2 s −1), whereas it increased from 4.7 to 7.3 μmol m −2 s −1 from 2004 to 2005 at HBS00. The photosynthetically active growing season started about a week later and finished a week earlier at HBS00 relative to EOBS. The earlier snowmelt at the harvested site did not promote an earlier start of the growing season at this site compared to the mature site. Although environmental conditions in spring have a significant influence on the annual C budget of mature sites, this does not seem to be the case for disturbed sites where mid-summer conditions are more important to the annual C balance.

Saturated hydraulic conductivity of soils in the Southern Piedmont of Georgia, USA: Field evaluation and relation to horizon and landscape properties

Abstract Saturated hydraulic conductivity ( K s ) is one of the soil properties used most often to predict soil behavior and suitability for a variety of uses. Because of the difficulty in K s measurement and its variability with depth and across the landscape, K s is commonly predicted from other more easily evaluated properties including texture, clay mineralogy, bulk density, pedogenic structure and cementation. Of these, texture and pedogenic structure are most commonly used to estimate K s , but the reliability of these estimates has not been evaluated for common soils in the Southern Piedmont of Georgia. Thus, the objectives of this study were to evaluate K s for major horizons in soils and landscapes in the Georgia Piedmont and to relate K s to morphological properties of these horizons. Ten sites across the region were selected, and 21 pedons arranged in three transects were described from auger holes and pits. For each pedon, K s was measured in upper Bt horizons, at 140 cm below the surface (Bt, BC, or C horizon), and at a depth intermediate between the shallow and deep measurements (Bt, BC, or C horizon) with a constant head permeameter. The K s of individual horizons ranged from 1 × 10 − 8 to 2 × 10 − 5 m s − 1 . At six of 10 sites evaluated, clayey upper Bt horizons had higher K s than deeper horizons with less clay. This difference was attributed to weaker structure in the deeper BC horizons. Structural differences did not explain all variation in K s with depth, however. Other soil and landscape properties including parent material composition, colluvium on lower slope positions, C horizon cementation, and depth of soil development also affected K s of horizons in these soils and should be used to better estimate K s .

Effect of Agricultural Practices on Trace‐Element Distribution in Soil

The impact of agricultural practices on the spatial distribution of trace elements (TEs) in the surface horizon of Albeluvisols was studied by comparing three types of situation with an increasing anthropogenic gradient: a forest soil, considered as a reference, and cultivated soils with and without spreading of sewage sludge. Total cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) were determined in soil surface horizons. The quantity of particles finer than 2 µm, organic carbon (OC), iron (Fe), manganese (Mn), and calcium (Ca) contents were also measured and used as tracers of soil components that may have contained TEs. Governing factors of the spatial variability of TEs were searched for through comparison of the descriptive statistics (mean and coefficient of variation) and the determination of the best multivariate model predicting TE contents. Nickel and Cr distributions seem to be mainly linked to variability of the parent material composition, whereas that of Co is related to redox pedological processes. In addition, agricultural practices play a role in TE distribution, through the input of TEs, mostly Cd, Cu, and Zn, via sewage sludge spreading and liming amendments, and lateral (homogenization) and vertical (mixing of horizons) redistribution through tilling the soil.

Properties of red Oxisols on calcareous sedimentary rocks in Thailand

An analysis of properties of red Oxisols on calcareous sedimentary rocks under different climatic regimes in Thailand was carried out to ascertain their similarities and differences. These soils are Kandiustox in Northeast Plateau and Kandiudox in Peninsular Thailand and have characteristics typical of highly weathered soils. They are very deep (> 2 m depth), are generally acidic (pH 5–6), clayey, have low cation exchange capacity and negative ΔpH values. Their profile development illustrates some differences being Ap(A)–Bt–Bto for Kandiustox and Ap–Bto or Ap–Bto–Bo for the Kandiudox which can be due to differences in leaching conditions under different moisture regimes and a more favourable natural condition for iron oxide accumulation in the Kandiudox. These soils generally have low bulk densities (0.77–1.36 Mg m − 3 ) and low available water for plants (5.0–9.3 wt.%). The fabric of the soils indicates that there are more well rounded micropeds in Kandiudox than in Kandiustox and the sizes of microaggregates in these soils are somewhat different ranging from 10 to 1000 μm in Kandiustox and 50–1400 μm in Kandiudox. The iron oxide concentration in microaggregates is more variable in the Kandiudox possibly indicating a more complex pedogenesis in these soils as compared to the Kandiustox. Kaolin, quartz and hematite are the dominant minerals in all these Oxisols, gibbsite and goethite are major minerals only in the Kandiudox and boehmite occurred in only one Kandiudox in tropical rainforest environment. Differences in mineralogy also indicate the influence of parent material composition. Soil properties that relate to soil fertility status particularly organic matter concentration (2.1–34.5 g kg − 1 ), available phosphorus (0.3–47.5 mg kg − 1 ) and available potassium (5–233 mg kg − 1 ) are poor and similar for the Kandiustox and Kandiudox profiles. Both groups of Oxisols have low values of cation exchange capacity which is in consistent with the dominance of low activity clays (kaolin, sesquioxides) with the Kandiudox profiles having lower mean CEC (6.7–10.2 cmol kg − 1 ) than the Kandiustox (11.5–16.3 cmol kg − 1 ) profiles.

Using chemical tracers in hillslope soils to estimate the importance of chemical denudation under conditions of downslope sediment transport

We present a model of hillslope soils that couples the evolution of topography, soil thickness, and the concentration of constituent soil phases, defined as unique components of the soil with collective mass equal to the total soil mass. The model includes both sediment transport and chemical denudation. A simplified two‐phase model is developed; the two phases are a chemically immobile phase, which has far lower solubility than the bulk soil and is not removed through chemical weathering (for example, zircon grains), and a chemically mobile phase that may be removed from the system through chemical weathering. Chemical denudation rates in hillslope soils can be measured using the concentration of immobile elements, but the enrichment of these immobile elements is influenced by spatial variations in chemical denudation rates and spatial variations in the chemical composition of a soil's parent material. These considerations cloud the use of elemental depletion factors and cosmogenic nuclide‐based total denudation rates used to identify the relationship between physical erosion and chemical weathering if these techniques do not account for downslope sediment transport. On hillslopes where chemical denudation rates vary in space, estimates of chemical denudation using techniques that do not account for downslope sediment transport and spatial variations in chemical denudation rates may be adequate where the chemical denudation rate is a significant fraction of the total denudation rate but are inadequate in regions where chemical weathering rates are small compared to the total denudation rate. We also examine relationships between transient mechanical and chemical denudation rates. Soil particle residence times may affect chemical weathering rates, and the relationship between total landscape‐lowering rates and soil particle residence times can thus be quantified.

Relationships Between Permeability and Erodibility of Cultivated Acrisols and Cambisols in Subtropical China

The relationships between soil erodibility factor (K) and soil saturated permeability (K(subscript fs) for cultivated Acrisols derived from Quaternary red clay and Cambisols derived from red sandstone were studied and quantified using a rainfall simulator and Guelph permeameter in a hilly area of subtropical China. A negative correlation existed between K(subscript fs) of the topsoil (0-5 cm) and K. The empirical expression K≈a×K(superscript -b subscript fs)+c, where a, b and c are the structural coefficients related to soil properties, such as soil type, soil parent material, organic matter, pH and mechanical composition, best described the relationship between soil saturated permeability and soil erodibility.

THE UPTAKE OF AMINO ACIDS BY MICROBES AND TREES IN THREE COLD-TEMPERATE FORESTS

Amino acids are emerging as a critical component of the terrestrial N cycle, yet there is little understanding of amino acid cycling in temperate forests. This research studied the uptake and turnover of amino acid N by soil microbes and the capacity of forest trees to take up the amino acid glycine in comparison to NH4+ and NO3-. This research was conducted in three temperate forests located in northwest Connecticut, USA. The three forests differed in soil parent material and canopy tree species composition. At all three sites, amino acids were released from soil organic matter through the activity of proteolytic enzymes resulting in a pool of free amino acids in soil. Free amino acids were rapidly immobilized by soil microbes. A '5N-enriched-glycine-addition experiment also showed that a significant fraction of the amino acid N taken up by soil microbes was mineralized to NH4+ with substantial nitrification at one site. Tree species from all three sites had the physiological capacity to absorb the amino acid glycine but took up amino acid N, NH4+, and NO3- in proportion to their availability in the soil. At the site with the highest gross fluxes of N, nearly all the N in amino acids was mineralized, and fine roots assimilated inorganic N much more rapidly than amino acid N. At the two sites with slower rates of gross amino acid production, the pool of free amino acids was larger, and fine roots assim- ilated amino acid N almost as fast as inorganic N. This study demonstrates that amino acids are an important component of the N cycle in temperate forests.

An evaluation of acid deposition on cation leaching and weathering rates of an Andosol and a Cambisol

An evaluation of the response of an Andosol and a Cambisol to acid deposition and weathering rates was studied by using a controlled laboratory leaching experiment. Both soils where derived from mafic parent material, a Histic Andosol from Western Iceland and a Cambisol from North East Scotland. De-ionized water and water acidified with H 2SO 4 (pH 3) was leached through reconstructed soil columns to simulate 34 years of precipitation. Acidic input increased cation leaching and weathering rates in both soil types and reduced pH levels. The Andosol proved generally to have higher weathering rates, leaching potential, ion exchange and acid-buffering capacity as well as maintaining a relatively steady pH despite intense acidic input. This was due to differences in parent material and mineral composition. The Andosol was developed from basaltic volcanic tephra, which had higher dissolution rates due to its amorphous mineral structures. The Cambisol was developed from gabbro with more stable mineral structures.

Amino acid cycling in three cold-temperate forests of the northeastern USA

Amino acids play a critical role in soil-N cycling. Much of the current research on amino acid cycling has been conducted in arctic, alpine, boreal, and temperate grassland ecosystems. There are no comparable data for temperate forests. We quantified the concentration and production of amino acid N and inorganic N in three forests varying in parent material and tree species composition in Connecticut, USA. Soil samples were collected on three sample dates in 2001 and 2002. At all three sites, a pool of free amino acids was present in soil on all sample dates. Among-site differences in the production of amino acids were related to variations in the activity of proteolytic enzymes, the sensitivity of proteolytic enzymes to the availability of protein substrate, and the presence or absence of a surface organic horizon. Among-site differences in amino acid turnover appeared to be at least partially related to soil C-to-N ratios and their effect on C vs. N limitation to microbial function. Amino acid concentrations in the top 15 cm of mineral soil in these study sites fell within the range of reported values for ecosystems spanning a wide latitudinal gradient, including ecosystems in which amino acids are thought to contribute substantively to plant-N nutrition. The concentration of amino acid N in the organic horizons of these study sites was considerably higher than those reported in the literature. The implications of the results for N capture by temperate forest trees are discussed.

Soil–landform development of a part of the fold belt along the eastern coast of Bangladesh

The evolution of landforms and soils from the Jaldi and Maiskhali anticlines and adjoining areas in a part of the coastal region of the north–south trending fold belt of Bangladesh during the Late Quaternary Period has been investigated. Based on the degree of soil development and luminescence dating, eight soil geomorphic units have been deciphered and grouped into four members (I–IV) of a morphostratigraphic sequence for the study area. Various soil geomorphic units included in different member/sub-members are: Member I—river floodplains and active tidal flats (< 500 years); Member II—distal Piedmont Plains and old tidal flats (0.5–2 ka); Member III—proximal Piedmont Plains (6–10 ka); and Member IV—Mainland Higher and Lower Hillocks and Island Hillocks (> 15 ka). Member IV is further subdivided into Sub-member IVa—Island Hillocks (15–18 ka); Sub-member IVb—Mainland Lower Hillocks (23–25 ka); and Sub-member IVc—Mainland Higher Hillocks (30–35 ka). The youngest and poorly developed soils of Member I show features related to hydromorphism. Moderately developed soils of Members II and III show a fersiallitisation stage of pedogenesis. Member IV includes ‘strongly developed soils’ with a ferrugination stage of pedogenesis. These soils also exhibit degradation and poor birefringence of argillans and ferriargillans, indicating a significant change in conditions of pedogenesis, probably related to a paleoclimatic change from a subhumid to semiarid phase (40 ka to about 16 ka) to a hot humid to subhumid phase (16 ka–present). Parent material composition and physiography also have affected the pedogenesis in the area. Based on ages and heights above the mean sea level for the five terraces recognized in the study area, the overall base-level rise rates calculated are about 3.6 mm/year (18 ka–present) for the Maiskhali Island and 2.86 mm/year (35 ka–present) for the mainland (Jaldi anticline). These base level changes represent combined effects of eustatic sea level and tectonic uplift due to folding.

Spatial and Temporal Observations of Seasonal Thaw in the Northern Kolyma Lowland

Observations carried out in 1996-2002 in the northern part of the Kolyma Lowland reveal spatial and temporal regularities in the seasonal thawing of tundra and northern taiga soils. The main factor determining differences in active-layer thickness in zonal tundra landscapes is the texture (mechanical composition) of soil parent material. Summer thaw in sandy soils is 2-3 times deeper than in loamy soils. The distribution of maximum seasonal thaw depth in watersheds and on hillslopes with loamy soils is influenced strongly by climatic zonality, which manifests itself through an increase in the depth of thaw from the arctic tundra to northern taiga. River floodplains, thermokarst depressions (alasy), and polygonal bogs have thinner active layers than adjoining watersheds. A direct correlation exists between seasonal thaw depth and mean summer air temperature in most zonal landscapes. In many cases a tendency for increased thaw depth was observed in the warm summer of 2000-2002. An inverse correlation between seasonal thaw depth and total summer precipitation occurs in most zonal biogeocenoses with loamy soils and intrazonal landscapes. This relationship was not found in well-drained zonal tundra and taiga biogeocenoses with sandy soils or in the most waterlogged alas we examined.

Classification of anthrosols with vitric/andic properties derived from lignite ash

To test the applicability of the Soil Reference Base of Soil Resources (ISSS/ISRIC/FAO, 1998. World Reference Base for Soil Resources, World Soil Resources Report 84, FAO, Rome) for soils derived from anthropogenic substrates, soils developed on lignite ashes in Germany which have some similarities with andosols were compared with natural volcanic soils from different countries. Soil parameters used for comparison were bulk density, clay content, Al o+0.5 Fe o, and P-retention, as they serve as diagnostic criteria to define either vitric or andic horizons. For Al o+0.5 Fe o, and P-retention, there was no statistically significant difference between both soil groups, the bulk densities of the lignite ash-derived soils were even significantly lower than those of the natural volcanic soils. Moreover, pH, total organic carbon, cation exchange capacity as well as the contents of carbonates and gypsum were collated and differences emerged between both soil groups concerning the contents of carbonates, gypsum and total organic carbon. In case of the lignite ash-derived soils, these parameters as well as the contents of oxalate soluble oxides were strongly influenced by the composition of the anthropogenic parent material. Up to now, such soil materials are not included as soil-forming materials in the World Reference Base for Soil Resources. We therefore suggested the introduction of a new diagnostic soil material, the so-called technogenic soil material into the anthropogeomorphic soil materials and to introduce “technogenic anthrosols” as a new reference subunit. In our proposition, technogenic materials are defined as anthropogeomorphic materials which are formed by technical processes including a distinct degree of transformation and/or new formation of soil-forming materials. Soil materials are categorised as “technogenic” when they consist of more than 70% (by volume) of soil material derived from technical processes like, e.g. combustion products of fossil energy sources, sewage sludges, blast furnace slags, etc. To include as much information as possible into the name of a soil, we developed a concept of reference soil series for the WRB combining pedogenetic and lithogenic information. Within this concept, these soils should be considered to be a subunit of anthrosols (vitri- or andi-technogenic anthrosols) and the specific properties of the soil-forming material (coaly, calcaric, gypsiric) should be given as additional information as Reference Soil Series as well as texture and kind of parent material.