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.     

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.     

Genesis and age of mineralogical profiles of Moldavian chernozems

In chernozems developed in the autonomous positions in Moldova, the mineralogy of their silicate component has some features indicative of stronger transformations than those that could be expected for the chernozems formed by the Holocene pedogenesis. The mineralogical profiles testify to the eluvial nature of the main subtypes of chernozems. It is suggested that the revealed changes are not due to the Holocene pedogenesis. According to the probable age of the mineralogical profiles calculated from the volumes of aluminosilicates removed, these profiles originated in the early and middle Late Pleistocene, i.e., about 50 000–120 000 years ago. The effect of forest pedogenesis in the past epochs on the mineralogy of the northern subtypes of chernozems also cannot be excluded. The presented data characterize the chernozems under study as polygenetic soil formations.     

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.     

Evolution of forest pedogenesis in the south of the forest-steppe of the Central Russian Upland in the Late Holocene

The Late Holocene stage of forest pedogenesis has been studied on the interfluves along river valleys in the forest-steppe zone of the Central Russian Upland. The development of gray forest soils from the former chernozems as a result of the Late Holocene advance of forest vegetation over steppes is discussed. It is argued that the climatic conditions of the Subatlantic period were unstable, so that multiple alternation of forest and steppe vegetation communities took place. This specified a complex character of soil evolution upon contrasting substitution of forest pedogenesis for steppe pedogenesis. On the interfluves near the natural drainage network (balkas, ravines, and steep slopes of river valleys), the climate-driven dynamics of forest and steppe vegetation with corresponding changes in the character of pedogenesis could take place during the entire Holocene, which is reflected in a lower thickness of humus profiles and deeper leaching of carbonates from chernozems of the Early Iron Age in comparison with their analogues formed under steppe cenoses in central parts of the interfluves. Two variants of the evolution of gray forest soils can be suggested: the pulsating evolution typical of balkas and interfluves near river valleys and the continuous progressive evolution typical of automorphic (plakor) positions in central parts of the interfluves.     

Paleosols in depressions of the central Russian upland in the Early Valdai time

The genesis, evolution, and paleoecology of soils of the Early Valdai interstadials were investigated in the Aleksandrov quarry (Kursk oblast), a key section of the Late Pleistocene deposits in the periglacial area of the East European Plain. The soils developed in the uppermost parts of the buried hollows (investigated in 2009) were compared with the soils developed in the lower parts of the same hollows (investigated in 1988). The data obtained suggest that the soils in the upper parts of the hollows were developed under wetter and, at the same time, more percolative water regime than the soils in the lower parts of the hollows. These soils were formed in a semihumid climate under the forest-steppe vegetation. Forest groves existed in the upper parts of the erosional network amidst herbaceous meadow steppes. In general, the soil cover pattern of the Early Valdai interstadials corresponded to the modern soil cover pattern within the analogous landscapes.     

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.     

Soil development on the Crimean Peninsula in the Late Holocene

The study of soils of different ages in different physiographic regions of the Crimean Peninsula made it possible to reveal the main regularities of pedogenesis in the Late Holocene (in the past 2800 years). With respect to the average rate of the development of soil humus horizons, the main types of soils in the studied region were arranged into the following sequence: southern chernozems and dark chestnut soils > mountainous forest brown soils > gravelly cinnamonic soils. In the newly formed soils, the accumulation of humus developed at a higher rate than the increase in the thickness of humus horizons. A sharp decrease in the rates of development of soil humus profiles and humus accumulation took place in the soils with the age of 1100-1200 years. The possibility for assessing the impact of climate changes on the pedogenetic process on the basis of instrumental meteorological data was shown. The potential centennial fluctuations of the climate in the Holocene determined the possibility of pulsating shifts of soil-geographic subzones within the steppe part of the Crimea with considerable changes in the rates of the development of soil humus horizons in comparison with those in the Late Holocene.     

Late Pleistocene ‐ Holocene palaeosols in the north of Sonora,Mexico: chronostratigraphy,pedogenesis and implications for environmental history

Red palaeosols of the late Pleistocene‐early Holocene, both buried and non‐buried, were studied recently in Sonora (NW Mexico) to reconstruct their pedogenesis as well as the palaeoenvironmental conditions. The alluvial palaeosol‐sedimentary sequence of the La Playa archaeological site is a key locality for the buried San Rafael palaeosol, which exhibits a 2Ah‐2Bw‐2BCk‐3Bgk profile and was defined as a Chromic Cambisol. Radiocarbon dates from pedogenic carbonates and charcoal set the soil formation interval between > 18 000 and 4300 calibrated years before present (cal. year BP). Micro‐morphological observations together with profile distribution of clay, carbonates, organic carbon, pedogenic iron oxides and rock magnetic properties indicated a strong eluvial‐illuvial redistribution of carbonates, moderate silicate weathering and gleying in the lower horizon. Although this soil was much more developed than the overlying syn‐sedimentary late Holocene Fluvisols, clay mineral composition and stable carbon isotope signatures of humus and carbonates were similar in both soils. We suggest that pedogenesis of the San Rafael palaeosol took place under a slightly more humid climate and relative geomorphic stability. This agrees with the regional palaeoclimate reconstruction, which indicates a moister climate during the Late Wisconsin glaciation (MIS 2). An abrupt termination of the San Rafael pedogenesis marked by disturbance and aridization features in the Ap horizon of the palaeosol could be linked to a global drought around 4200 years cal. year BP. Surface Chromic Cambisols in northern Sonora show similar pedogenetic characteristics to the buried red palaeosols of La Playa. They appear to be a relict component of the present day soil mantle.     

Geochemical characterization of loess-soil complexes on the Terek-Kuma Plain and the Azov-Kuban’ Lowland

The changes in the material composition of the buried soils and loesses in relation to the dynamics of the climate and sediment accumulation were studied for revealing the pedogenetic features and assessing the natural conditions in the steppe zone of the southern Russian Plain. A comparative analysis of the chemical compositions of the different-aged Pleistocene loess-soil complexes (the Otkaznoe, Port-Katon, and Shabel’skoe profiles) on the Terek-Kuma Plain and the Azov-Kuban’ Lowland was performed. An increase in the concentrations of Fe and Mn, which are intensively involved in the biological cycle, and Rb, which is accumulated due to the activation of weathering processes, was observed in the paleosols that developed in interglacial periods of activation of pedogenesis. Increased coefficients of weathering (chemical index of alteration (CIA)) = [Al/(Al + Ca + Na + K)] 100, Al/(Al + Ca + Na + Mg), Rb/Sr, and Mn/Sr), leaching (Ba/Sr), and biological activity and bioproductivity (Mn/Fe, Mn/Al) were also noted for the paleosol horizons as compared with the loess horizons. It is argued that geochemical coefficients can be used as an efficient tool in the soil and paleogeographic studies aimed at the reconstruction and refinement of the schemes of changes in the bioclimatic conditions during the Pleistocene.     

Humus pedorelicts in soddy calcareous soils of the Vyatka-Kama interfluve

A plowed soddy-calcareous soil with relict features developed from Permian clayey calcareous soil was described for the first time in the area of soddy-podzolic and gray forest soils of mixed forests in the middle and lower riches of the Vyatka River. This soil was thoroughly examined by physical, chemical, biochemical, radioisotope, and physicochemical methods. A second humus horizon enriched in calcium humates was described in this soil. Its age was determined at about 7200 yrs. This horizon attests to the presence of in situ postcarbonate pedorelicts in the soil cover of the eastern Russian Plain. The studied soil was formed during the Atlantic optimum of the Holocene under conditions more favorable to humus-accumulative processes as compared with those during the subsequent period. The soil evolution in the second part of the Holocene was characterized by the partial preservation of the previously formed features with the development of eluviation features under colder and wetter climatic conditions. This intrazonal soil is genetically close to gray forest and soddy-podzolic soils with residual second humus horizons that are widespread on the Vyatka-Kama interfluve. The evolution of the latter soils in the second part of the Holocene has been driven by eluviation processes that gradually eliminate the features of the second humus horizon from the soil profiles.     

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.     

Modeling of the evolution of steppe chernozems and development of the method of pedogenetic chronology

Geoarchaeological methods were used to study chronosequences of surface soils in the steppe zone and to trace soil evolution during the Late Holocene in northwestern Crimea. It was found that the morphological and functional “maturity” of the humus horizons in steppe chernozems of the Late Holocene was reached in about 1600–1800 yrs. After this, their development decelerated irreversibly. The maximum concentration of trace elements accumulated in these horizons in the course of pedogenesis was reached in 1400 yrs. A new method of pedogenetic chronology based on the model chronofunction of the development of irreversible results of pedogenesis over time is suggested. Original pedochronological data and growth functions—the most suitable models for simulating pedogenesis over the past three thousand years—suggest that the development of morphological features of soil as an organomineral natural body follows growth patterns established for biological systems.     

南极半岛海洋气候区的土壤Ⅴ.气候变化响应

气候变化导致南极海洋气候区冰川消退、多年积雪融化,为新的土壤形成与分布提供了潜在的母质基础与发展空间;地表和土壤内部水分活动在时间和空间上的加强促进了以自由水为基础的土壤过程和冰缘地貌过程;由气候变化引发的低等植物生境、群落结构变化、初级生产力与生物量的提高、海洋脊椎动物迁徙和栖息地的变迁,影响了本区土壤有机质积累过程以及土壤有机质结构与性状。已有的证据表明,气候变化正对南极海洋气候区土壤发生、发育及演变产生重要影响。     

海南岛北部玄武岩区土壤母质均一性及相对年龄判定

【目的】时间序列法是定量研究土壤发生过程、演变速率及其变化阈值的重要手段,构建可靠的土壤时间序列需对土壤母质均一性和相对年龄进行判定。【方法】以海南岛北部不同喷发期玄武岩发育土壤所构成的成土时间序列（0.09、0.146、0.64、1.12、1.81、2.30 Ma B. P.）为对象,利用各种土壤属性参数（包括剖面形态、颗粒组成、稳定元素含量、风化发育指数和元素变化率等）对该时间序列母质均一性和土壤相对年龄进行判定。【结果】各剖面颜色、质地、结构等形态总体呈均一、渐变的特征,去除黏粒后的粗粉粒含量、稳定元素Ti/Zr比值在剖面内和剖面间变化均较小,表明时间序列土壤的起源母质相同。随着成土年龄的增加,黏粒含量和剖面发育指数呈线性增加的趋势,土壤风化强度指标（B指数、CIW指数、CIA指数和ba值）服从对数函数变化规律,在土壤相对年龄的判定中具有较好的指示意义。【结论】研究区土壤母质来源相同,土壤相对年龄可通过相关土壤属性体现出来,为定量研究土壤发生阈值奠定了基础。     

Nature of an overlapped paleosol and its significance in pedogenesis and paleogeography in North Huai region, China

An overlapped paleosol (albic Paleudalf) in North Huai region was studied by means of sand and clay mineralogy, elemental geochemistry, particle size distribution, observation of quartz sand surface structure under SEM, micromorphology, pollen analysis as well as soil dating. These albic soils are very extensive on uplands in this region and the profiles have developed on two individual formations rather than being differentiated by the homogenous eluvium of gneiss. It was also indicated that the soil evolution in this region proceeded from dessication and kaolinization during the middle Pleistocene to accumulation of bases and predominance of fragmental minerals in the early Holocene. The pedogenesis was further related to climate-landscape events in this region during the Quaternary. This study advocated that awareness of soil-landscape evolution was necessary in advance of pedogenesis research and a single soil-forming process could not account perfectly for soil formation with delicate evolution history.     

Polygenesis of volcanic paleosols in Armenia and Mexico: Micromorphological records of climate variations in the quaternary period

The Pleistocene volcanic paleosols of Armenia and Mexico combine the features of both arid and humid pedogeneses. They were studied in order to reconstruct the environmental conditions during the period of the initial settlement of humans in these areas. The main attention was paid to the micromorphological analysis of the pedogenic features. The pedocomplexes studied in Armenia have been forming since the Early Pleistocene. They bear evidences of humid (weathering, clay illuviation, and gleying) and arid (calcification) pedogeneses alternating in different soil layers and pointing to climatic cycles. The nonuniform lithology of the soil profiles is related to pulsating volcanic activity. Mexican paleosols of the Late Pleistocene period are similar to the lower layers of the soils in Armenia with respect to the features characteristic of the humid and arid phases of pedogenesis. This allows us to suggest that the early stages of the formation of the Armenian pedocomplex proceeded under warmer paleoclimatic conditions similar to those of a tropical climate. It is shown that the arid pedogenesis may erase the features produced during the previous stage of humid pedogenesis. The studied paleosols are characterized by the destruction of the features inherited from the humid phase (the clayey groundmass and illuviation coatings) by the newly forming calcite. Paleopedological records point to the fact that the paleoenvironmental conditions during the periods of the initial settlement of humans in both regions differed significantly from the modern environmental conditions in these regions.     

Genesis of the silty sands and loams within the periglacial zone in the center of the Russian Plain and the properties of soils developed from them

The genesis and spatial differentiation of the silty sands and loams deposited during the Late Valdai glaciation have been studied in the central part of the Russian Plain within the Mologa-Sheksna Lowland and on terraced slopes of the Ovinishchensk Upland (Yaroslavl oblast). The stratigraphy of these sediments on different elements of the local topography and data on their particle-size distribution suggest that they belong to the same paragenetic group. Some differences in the particle-size distribution can be explained by the specificity of sedimentation in periglacial lakes found at different geomorphic levels (from 102 to 180 m a.s.l.) during the Ostashkov phase of the Valdai glaciation. For the first time, statistically significant differences in the properties of Holocene soils developed at different hypsometric levels have been revealed. The degree of textural differentiation of the soils developed from silty loams increases with an increase in the absolute height of the surface. The analysis of factual materials makes it possible to suggest that a system of impounded lakes existed in this area during the Ostashkov (maximum) phase of the Valdai cryochron; the water level in these lakes reached a maximum height of 180 m a.s.l.     

Systematization of Organo-Clay combinations in soils of the center of the Russian Plain

A systematization of organo-clay combinations in zonal soils of the center of the Russian Plain is suggested. This systematization adequately reflects the zonal features of pedogenesis and agrees with traditional estimates of the ecological state of the soils and their tolerance toward the agrogenic degradation. The four types of organo-clay combinations are characterized by different degrees of humification, aggregation, tolerance toward soil compaction, and tolerance toward soil degradation.     

Stages of development and palaeogeographical inheritance of the recent soils features in the center of the Russian plain

In the article an attempt was undertaken to make palaeogeographical analysis of the history of development of the present soils in the center of the Russian plain on the basis of the soils study in a series of sections, located in different microrelief elements of the cryogenic genesis in the Bryansk region. The analysis of the data on soil morphology, chemical and mechanical composition of soils, and peculiarities of microstructure made it possible to determine that the appearance of certain features in the soils structure was predetermined as far back as during the Late Pleistocene cryogenic period; i.e. before the beginning of the Holocene (up to 10 000 y. B.P.). The studied soils are considered as polygenetic formations. Six stages of their formation were singled out.