Buried Soil Profiles Research Articles

Soils in Karst Sinkholes Record the Holocene History of Local Forest Fires at the North of European Russia

Despite the abundance of charcoal material entrapped in soils, they remain relatively less studied pyrogenic archives in comparison to the sedimentary paleofire records (e.g., lacustrine and peat deposits), and that is especially the case in most of Russia’s territory. We report here on the deep soil archives of the Holocene forest fires from the Pinega District of the Arkhangelsk region (64.747° N, 43.387° E). Series of buried soil profiles separated by charcoal layers and clusters were revealed in specific geomorphological traps represented by the active and paleokarst subsidence sinkholes on sulfate rocks overlaid by glacial and fluvial deposits. We combine the study of soil morphology and stratigraphy with a set of radiocarbon data on charcoal and soil organic matter, as well as the anthracomass analysis, to extract a set of paleoenvironmental data. A total of 45 radiocarbon dates were obtained for the macrocharcoal material and the soil organic matter. The maximum temporal “depth” of archives estimated from the radiocarbon dating of macrocharcoal reached 10,260 ± 35 cal yr BP. Soil formation with Podzols established at the inter-pyrogenic stages repeatedly reproduced within the period of ten thousand years, while the dominant tree species was Pinus sp. According to the macrocharcoal data, the intervals between fires have shortened in the last thousand years. Dendrochronological estimates suggest the occurrence of fires in almost every decade of the 20th and early 21st centuries. This is the first study of the millennia-scale soil record of forest fires in this particular region of Russia.

A comparison of Quaternary soil chronosequences from the Ionian and Tyrrhenian coasts of Calabria, southern Italy: Rates of soil development and geomorphic dynamics

Soil development during the Quaternary was investigated, by comparing and integrating analytical datasets of three soil chronosequences developed on different terrace staircases along the Tyrrhenian (western) and Ionian (eastern) coasts of northern Calabria, southern Italy. Two of these soil chronosequences developed on early to late Pleistocene marine terraces in two sectors of the Praia area (western coast), whereas the third one developed on fluvial terraces in the Rossano area (eastern coast) spanning from middle to late Pleistocene ages, respectively. We present and discuss both novel results and already published data related to selected morphological, physical, chemical, mineralogical and SEM analyses from the two coastal sectors. We explored the effects of time on soil development, trying to unravel the role of soil-forming processes, parent material and geomorphic dynamics on direction and rates of pedogenesis. A complex nature of parent materials was indicated by the geochemical signature, coupling certain similarities with some heterogeneity between the two study sectors but also across single soil profiles, as a response to morphodynamic processes (soil reworking, aggradation, burial and/or erosion), in turn promoting soil ageing and/or rejuvenation. These processes and lithological discontinuities were also responsible for some data scattering from calculated soil chronofunctions for peculiar soil properties and pedogenic indices plotted against estimated soil ages. Among the main outcomes, good positive correlations were obtained for the (Fed–Feo)/Fet and Fed/Fet indices, weighted on the basis of total soil profile and single horizon thicknesses to minimize the effects of soil truncation by erosion processes. Our results confirm the reliability of these indices as soil development indicators. Moreover, they suggest that: (i) rates of soil development did not change significantly over ca. 100–800 ka, despite the cyclical alternation of Pleistocene climate changes; (ii) dominant soil-forming processes tend to minimize original differences of pedogenic substrata and local (pedo)climatic conditions through time. In addition, soil chronofunctions permitted to estimate the unknown age (the time range of soil development before burial, about 200 ky) of a buried soil profile in the Rossano area, not correlated to any terrace surface of known age. The occurrence of etched quartz grains in soils of different ages for the two study sectors clearly indicates different rates of silica dissolution in the Tyrrhenian and Ionian coasts of Calabria, promoted by different climatic and pedoenvironmental conditions.

Short chronosequences of paleosols from the Skvortsovka kurgans in the Buzuluk River valley of Orenburg oblast

Paleosols buried under kurgans of the Yamnaya (the third millennium BC) and Srubnaya (the 18th–17th centuries BC) cultures within the Skvortsovka group of kurgans in the Buzuluk River valley in Orenburg oblast have been studied. This is the area of the dry steppe zone. The changes in the paleosol properties make it possible to distinguish between relatively short-term chronointervals separately for the Yamnaya and Srubnaya cultures. The paleosol data and radiocarbon dating have been used for revealing the relative order of the construction of the kurgans within these chronointervals and for the paleoclimatic reconstruction. Quite definite changes took place in the soil formation from the beginning to the end of the particular chronointervals: the contents of humus and exchangeable bases and the portion of calcium ions in the composition of the exchangeable cations increased in parallel with the enhanced leaching of carbonates and the enhanced biological activity. These changes attest to the increasing amount of precipitation. In general, the climate of the Srubnaya cultural epoch was less continental, whereas the climate of the Yamnaya cultural epoch was relatively close to the modern climate. The 14C dates of the pedogenic carbonates in the upper meter of the paleosol profiles have been used as auxiliary data to confirm the sequence of the soil’s burial during the short chronointervals corresponding to the humid stages of the paleosol’s evolution, and the 14C dates of the diagenetic carbonates have been used to determine the dates of construction of the kurgans with due account for some time gap between the construction of the kurgans and the appearance of these carbonates in the buried soil profiles.

The microbial biomass in paleosols buried under kurgans and in recent soils in the steppe zone of the Lower Volga region

The total microbial biomass (TMB) was assessed in the chestnut and light chestnut soils and in the paleosols under burial mounds (steppe kurgans) in the Lower Volga region on the basis of data on the organic carbon content in the extracted microbial fraction supplemented with the data on the extraction completeness as a conversion coefficient. The completeness of the microbial fraction extraction was determined by direct counting of the microbial cells and colony-forming units (on plates with soil agar). The total microbial biomass varied from 400 to 6600 μg of C/soil. Its values in the buried soils were 3–5 times lower than those in the surface soils. The TMB distribution in the buried chestnut soil profile was close to that in its modern analogue (with the minimum in the B1 horizon). In the buried light chestnut paleosols, the TMB values usually increased down the profile; in the recent light chestnut soils, the maximum TMB values were found in the uppermost horizon.

Chronology of erosion in the center of the eastern European plain over the last 5000 years

All the deposits of linear erosion forms longer than 200 m were dated on the experimental proving ground in the southwestern Moscow region. Relative distribution functions (RDF) were summed up for 65 radiocarbon chronological ages. A summarized RDF diagram for the last 5000 years demonstrates rhythms of millenarian and century ranks. Maximums on the diagram correspond to intense erosion periods (frequency of erosion events), and minimums reflect periods of erosional stability. The most active erosion took place 3900‐2700 years ago and from 1200 years ago to the present. Relatively weak erosion occurred during the period prior to 5000‐3900 and 2700‐1200 years ago. Phases of more active erosion within those periods are noted: 4850‐4550, 3900‐3600, 3150‐2850, 2350‐ 2050, 1800‐1600, and 1050‐750 years ago, and also the last 500 years of human-related erosional activity. For the purpose of better understanding the nature and prognosis of erosional processes, tracing of their intensity in different climatic settings that existed in the modern geological time (Holocene) is useful. A sequence of data on erosion intensity for several thousands years is necessary. Direct dating of erosion products performed in the central part of the Eastern European Plain gives just the age of individual erosional events and the history of certain erosional forms [1, 3, 5, etc.]. Based on the soil stratigraphy of the Central Russian Upland, the complete buried soil profiles in the bottom of ravines show erosion attenuation and the covering detritus correlates to erosion activization [7]. Recently developed methods of processing data on the age of deposits give a new approach to periodization of ancient erosional and other exogenous processes. This approach has been used in a number of recent studies in Europe. Statistical processing of data sets of carbon-14 ages was applied for determination of high fluvial activity phases in Great Britain, Spain, and Poland [13, 15]. Information on the optical-luminescent ages of slope wash products allowed determination of periods of activization and attenuation of erosion in southern Germany [12]. There was insufficient data to carry out such a generalization for Russian territory. This paper presents the first attempt to make a periodization of erosional processes on the Eastern European Plain based on statistical processing of mass carbon-14 dating. The study is based on the notion that the erosional history of any area is a summarized history of all the erosional forms involving all erosional events of this area. On the experimental proving ground in the southwestern Moscow region, all linear erosional forms greater than 200 m and some smaller ones were dated. Statistical analysis of the data set for the last 5000 years allowed us to distinguish millenarian rank periods and the century rank phases of high and low erosion activity within them. The complete coverage of erosional mesoforms within the proving ground makes the obtained results reliable. Part of the century rank erosional phases may be of local importance. The distinguished erosional periods should refer to the center of the Eastern European Plain between the limits of the Valdai and Moscow glaciations. This is based on the similarity in the geological and geomorphological structure, the landscape‐climatic history, and the history of economic development of this area.

Thin-section analysis as a tool to aid identification of palaeoearthquakes on the “slow”, active Geleen Fault, Roer Valley Graben

We analyzed thin sections from two palaeoseismic trenches across the low-slip-rate Geleen Fault in the Belgian Maas River valley to help identifying the most recent large palaeoearthquake on this fault segment. In the first trench we sampled silty sediment below and above a prehistoric stone pavement that was supposedly at or near the surface at the time of the event, and subsequently thrown down. The samples below show a well-developed in situ argillic Bt soil horizon in parent sediment containing remnants of stratification, whereas the sediment above is a structureless colluvium reworked at least partly from Bt-horizon material. Below the stone pavement, we also found evidence of contorted stratification, which is in agreement with macroscopic observations of both the sediment and the stone pavement itself, and which is attributed to co-seismic soft-sediment deformation. In the second trench, we sampled a sequence of vaguely discernible soil horizons in the hanging-wall, interpreted as a buried soil profile (Bt, E, and possibly A horizons), overlain by a featureless deposit. Thin-section analysis supports the colluvial nature of the latter, and also provides evidence that both the base of this layer and the top of the poorly developed A horizon below have occupied a shallow position in a soil profile. A sample from the same depth in the footwall is composed of very different material. Instead of colluvium, we find patches of Bt soil, most likely representing the same pedogenic level as the in situ Bt horizon at larger depth in the hanging-wall, but displaced and subsequently degraded. Furthermore, thin sections confirm that vertical structures cutting this Bt horizon are sand dykes. These dykes could be traced macroscopically upward to the base of the colluvium. In both trenches, we have thus identified a stratigraphic boundary in the hanging-wall, close to the surface, separating an in situ soil below from colluvium above. We interpret this limit and the overlying colluvium as the event horizon and the colluvial wedge, respectively, of a surface-rupturing palaeoearthquake. In addition, in both cases we found evidence of soft-sediment deformation (related to liquefaction) contemporaneous with the event within the stratigraphic resolution.

Introducing the phytolith analysis: a suitable method in palaeoecology and landscape ecology

The use of silicified plant microremains in palaeoenvironmental reconstructions of landcsape evolution has not been in common use yet. Not only are phytoliths bearers of significant imformation package of soil generation process and landscape evolution, but they can be utilised to reveal important questions related to archaeology and ancient human activities.This paper intends to give a general overview of the discipline and demonstrates the use of phytolith analysis through a case study. The examination of the buried soil profiles and cultural layers of the Lyukas- mound, which is situated near Hajdúnánás on the Great Plains of Hungary, resulted in novel information on the ancient vegetational patterns and environmental conditions of the Holocene. By using the analysis of these plant microfossils, questions regarding the construction and use of kurgans could also be answered.

The Bronze Age landscape of the Bjäre peninsula, southern Sweden, and its relationship to burial mounds

Palaeoecological analyses from a small fen deposit, combined with pollen analysis from buried soil profiles under prehistoric burial mounds, have been used to investigate the timing and vegetation change associated with the Holocene development of a cultural landscape in southern Sweden. Traditional pollen analysis is complemented with plant macrofossil analysis and soil pollen analysis from within and in close proximity to the burial mounds in the coastal Bjäre peninsula, well known for its high density of well-preserved Bronze Age monuments. The vegetation development is linked to the construction of the burial mounds. A marked increase of cultural impact on the landscape is recorded during the Neolithic–Bronze Age transition and estimates of landscape openness suggest that by the onset of the Bronze Age, forest cover was only 20–40%, falling to 10% in the immediate vicinity of the burial mounds themselves. The coastal strip appears to have been affected by human activity to a greater extent and at an earlier date than sites from further inland in southern Sweden and the Bronze Age burial mounds were most likely designed to be visible in a largely deforested landscape.

Soil chronosequence development in dunes on the southeast African coastal plain, Maputaland, South Africa

Dunes have accreted on the southeast African coastal plain in coast-parallel patterns of degraded whaleback ridges, sand megaridges and extended parabolic dunes since the Pliocene. In the Maputaland dune field, relative dating is complicated by soil degradation, erosion and vegetation cover. This project assessed alternative relative and numeric dating techniques that can be used to differentiate dune systems and eolian sand bodies. Soil profile characteristics were used to calculate soil development indices (SDI) for soil horizons sampled from hand augered holes and rare exposures. Infrared stimulated luminescence (IRSL) dating of representative dunes and sand units helped define the pedogenesis achieved since deposition. The quartzose dune sands have weathered to form very deep soil profiles. Enhanced SDI values for horizons or sampled intervals down the profile reflect pH decrease, advanced rubification or distinct mottling, clay increase and harder consistency with depth. The youngest Holocene profiles exhibit decreasing horizon index values with depth below the A horizon whereas late Pleistocene profiles display SDI values increasing with depth within the upper 3 m of the profile. Within some Mid- to Late Pleistocene eolian sands greater profile-horizonation and catena complexity manifests as complex soil profiles or distinctly mottled, clay-enriched horizons, at depths of 2–5 m below the surface. The SDI profiles from specific dune systems or stratigraphic units cluster well and effectively characterize soil development in dune sand units of different ages. Depositional age plotted against sampled horizon index values makes it possible to determine generalized rates of soil profile development, and to compare pedogenic processes on the high-rainfall, coastal barrier dunes to those found in the drier interior. Sampled horizon index values distinguish buried soil profiles and highlight possible localized surficial reworking.

Evolution of Holocene Eolian Landscapes in the Glacial Lake Hind Basin, Manitoba

Stratigraphic investigations into dune fields in Glacial Lake Hind basin reveal three lithologic units: a lake basin unit, a lower eolian unit, and an upper eolian unit. The lake basin unit contains gleyed silty clays representing a low energy lake environment, and coarse sands and black shale gravels representing higher energy depositional environments. The lower eolian unit contains sedimentary and organic laminations and no buried soils. The upper eolian unit does not have laminations, but contains multiple buried soil profiles. Preservation of organic laminations and presence of redoximorphic colouring in the lower eolian unit suggest that it has been preserved by groundwater. The upper eolian unit contains four soil profile types that appear in sequence with an interdunal profile at the bottom and a dune profile at the top. Radiocarbon ages of soils in the upper eolian unit (2350 ± 50 and 1100 ± 40 BP) indicate regional synchronicity with soil forming periods across the northeastern Great Plains. However, the morphology of a buried soil profile depended on the site’s location on the paleolandscape during development.

Textural Pedofeatures and Pre-Hadrian's Wall Ploughed Paleosols at Stanwix, Carlisle, Cumbria, U.K.

During the last 30 years the value of sandy, silty or dusty textural pedofeatures for identifying past agricultural practices has been the subject of debate, particularly with regard to the applicability of modern analogue observations to ancient soils.Macro- and micromorphological analyses were carried out on all the contexts in a series of five trenches containing pre-Roman plough grooves in moderately sandy buried soil profiles at sites near Hadrian's Wall, Cumbria. Micromorphological observations of 31 thin sections showed that the pedofeatures in question were not preferentially distributed in thin sections of sediments from within or below the plough layers, but were more concentrated in contexts which, as shown by field and archaeological evidence, were unlikely to have been affected by cultivation. Conversely, the pedofeatures were absent in other thin sections of sediments from and below the contexts where past agriculture was documented by field and archaeological features. The analysis also showed that the pedofeatures in question tended to be distributed in parts of the sequence with suitable porosity, soil structure and texture rather than in relation to the position of the cultivated layers. All the results in this case study showed that silty, sandy and dusty pedofeatures were not diagnostic for past agricultural practices, and highlighted the need for more research on the micromorphological evidence of ancient soils with a known record of past agriculture.

Episodic Holocene loess deposition in central Nebraska

Abstract The Mirdan Canal section in central Nebraska, USA, provides evidence for multiple episodes of Holocene loess deposition in the central Great Plains. This irrigation canal cut exposes more than 4 m of Holocene sediment that overlies the late Wisconsinan Peoria Loess. The oldest Holocene sediment is local slopewash that fills gullies, but overlying beds are interpreted as Holocene loess (Bignell Loess). Three buried soil profiles occur within the Holocene sediment, and have yielded uncalibrated 14 C ages of 3010 yr BP (uppermost buried soil) and 8790 yr BP (third buried soil from top). A fourth buried soil yielded an age of 9330 yr BP, and is correlated with the Brady Soil. The Bignell Loess has a darker color, slightly more organic matter, more clay, more coarse silt and sand, less smectite, and less volcanic glass than the underlying Peoria Loess. The Bignell Loess is most plausibly interpreted as dust from local flood plains, containing a mixture of reworked Peoria Loess and older silts with contrasting mineralogy. Episodes of loess deposition occurred in the early, middle and late Holocene, probably during periods of dry climate but possibly also as a consequence of large erosive floods that made wind-erodible sediment available on nearby flood plains.

Soil‐Stratigraphic Correlation of a Doline in the Valley and Ridge Province

AbstractDolines of the Valley and Ridge Province of eastern Tennessee act as sediment traps and can provide detailed information on the recent geomorphic history of the surrounding landscape. The objective of this study was to determine the soil stratigraphy, age, morphology, and late Quaternary history in an upland doline on the Mascot Formation in eastern Tennessee. Soils were sampled on the doline rim (DR), upper sideslope (US), lower sideslope (LS), and near the doline center (DC). Pedogenesis of this large upland doline is related to parent material and geomorphic processes. Stratigraphy, age, and morphology varies among the soils. Pedon DC has two buried soil profiles. The upper buried A horizon (2Ab) was radiocarbon dated to 320 ± 70 years before present (YBP). This horizon separates a weakly developed, yellowish brown soil above, with 10 to 20% chert that formed in post‐European agricultural‐related sediments (late 18th and 19th centuries) with laminae, from silty pre‐European sediments (middle to late Holocene) that are low in chert but contain an argillic horizon. The second buried horizon (3Ab) was dated at 6100 ± 100 YBP and provides evidence of landscape stability during the middle Holocene, probably during the Hypsithermal Interval. Below this horizon, the soil has less clay and chert content varies. In contrast, Pedon DR has only a veneer of cherty silt loam late Holocene colluvium and cherty clay Mascot residuum. Geomorphic processes of mass wasting and slope wash on the doline sideslopes have provided a variety of sediments that have been trapped within this doline and subsequently subjected to pedogenesis.

Quaternary stratigraphy and geoarchaeology of the colorado and concho rivers, west texas

AbstractGeoarchaeological investigations in an area surrounding the confluence of the upper Colorado and Concho Rivers, Edwards Plateau of West Texas, have produced a detailed landscape evolution model which provides a framework for discussion of the influences of geomorphic processes on the development, preservation, and visibility of the archaeological record. Field mapping within the study area has differentiated six allostrati‐graphic units of fluvial origin in both valleys, as well as extensive eolian sand sheets along the Colorado River. Early to middle Pleistocene terrace remnants cap many upland areas, whereas two distinct late Pleistocene terrace surfaces are widespread within the study area at somewhat lower elevations. Fluvial activity during the time period of human occupation is represented by an extensive Holocene terrace and underlying valley fill, which is up to 11 m in thickness. Valley fill sediments can be subdivided into allostratigraphic units of early to middle Holocene (ca. 10,000–5000 yr B.P.) and late Holocene age (ca. 4600–1000 yr B.P.), which are separated by a buried soil profile. The modern incised channels and very narrow floodplains represent the last millennium. Eolian sand sheets of early to middle Holocene age overlie limestone‐ and shale‐dominated uplands, Pleistocene terraces, and in some cases the Holocene valley fill along the Colorado River.Pleistocene terraces have been stable features in the landscape and available for settlement through the time period of human occupation. Archaeological materials of all ages occur at the surface, and the record preserved in individual sites range from that associated with discrete periods of activity to longer‐term palimpsests that represent repeated use over millennia. Sites within early to middle Holocene and late Holocene fills represent short‐term utilization of constructional floodplains during the Paleoindian through early Archaic and middle to late Archaic time periods respectively. By contrast, those that occur along the buried soil profile developed in the early to middle Holocene fill record middle to late Archaic cultural activity on stable terrace surfaces, and represent relatively discrete periods of activity to longer‐term palimpsests that represent repeated use over the 3000–4000 years of subaerial exposure. Late Prehistoric sites occur as palimpsests on soils developed in late Holocene alluvium or stratified within modern floodplain facies. Paleoindian through Late Prehistoric sites occur stratified within eolian sand sheets or along the unconformity with subjacent fluvial deposits.The landscape evolution model from the upper Colorado and Concho Rivers is similar to that developed for other major valley axes of the Edwards Plateau. This model may be regionally applicable, and can be used to interpret the geomorphic setting and natural formation processes for already known sites, as well as provide an organizational framework for systematic surface and subsurface survey for new archaeological records. 0 1992 John Wiley & Sons, Inc.

Aspects of climatic influence on the clay mineralogy and geochemistry of soils, palaeosols and clastic sedimentary rocks

Climate strongly influences soil clay mineralogy and bulk chemical composition. In humid climates chemical weathering is at its most intense and virtually all ‘primary’ bedrock minerals suffer complete breakdown. They are replaced by authigenic hydrated oxides of Fe and Al together with halloysite and kaolinite in deep profiles. These minerals develop where the residence time of water in the soil is slight. Longer residence times lead to higher solute concentrations and the stabilization of smectite. Authigenic palygorskite and sepiolite may form in highly saline, alkaline soils. The stability of these precipitated minerals is problematic: they may be metastable or even unstable. All other clays found in soils are unstable, being incomplete, solid-state hydrolysis products of substrate minerals. The balance between stable, metastable and unstable minerals and the rate of profile development are both much influenced by temperature, rainfall and activities of soil biota; themselves reflecting climate. Bedrock influence is greatest under conditions of low to moderate precipitation where unstable minerals persist. Local topography, however, also strongly influences both the rate and products of chemical weathering, quite independently of climate. On the grand scale, tectonic factors may constrain the time available for profiles to develop, hence the extent to which bedrock minerals survive or are altered. Mountain soils reflect local climate and bedrock composition much more than latitude. The sediments delivered to major basins today do not reflect global soil distribution patterns. The bulk composition of suspended sediment entering the Indian Ocean, for example, is rather similar to that entering the Arctic Ocean. Sediment dispersal patterns can also confuse climatic signals: a problem not encountered with palaeosols. Authigenic clays formed within sedimentary basins and post-depositional (burial) alteration of both sediments and buried soil profiles must lead to interpretational ambiguities. Climatic signals are likely to survive best in bulk compositional data (although diagenetic reactions at depths in excess of about 2 km do not appear to be isochemical) and in the distribution of more stable yet climatically sensitive minerals (kaolinite as opposed to illite, chlorite).

3.7 A Buried Soil Profile

3.7 A Buried Soil Profile

Time as a Factor in the Genesis of Four Soils Developed in Recent Alluvium in Pennsylvania

AbstractFour soils developed in recent alluvium in the Ridge and Valley physiographic region of central Pennsylvania were studied in an attempt to relate chronologic age to pedologic age. Wood or charcoal found at the boundary between a recent and a buried soil profile at each site was radiocarbon dated. These dates were as follows: (i) < 205, (ii) 320 ± 80, (iii) 470 ± 80 and (iv) 1955 ± 80 years B. P., and indicate the maximum age of the alluvium in which the recent soil profiles developed. The relative distinctness of horizons evaluated by a field morphology rating scale, the volume (in cross section) of oriented illuvial clay films and the in situ weathering of clay minerals in these soil profiles indicate that morphological properties are effective in distinguishing chronologic age differences in alluvial soils which differ by approximately 1,500 years in age, but are not effective when the age differences are only a few hundred years. The data also indicate that cambic horizons can develop in <200 years and are still present after 2,000 years of soil formation.

A Study of Paleosols in the Saskatoon Area of Saskatchewan

Postglacial paleosols developed in lacustrine and aeolian sediments occur on terraces and in banks of the South Saskatchewan River near Saskatoon. At each of three sites a sequence of two paleosols was studied: a lower soil of immediate postglacial age as indicated by radiocarbon dates, that is buried by aeolian sands, and an upper one, located within the dune sands, that marks a period of stability of the dunes. Climatic fluctuations are inferred to be the cause of aeolian activity.One paleosol met the classification criteria for an Orthic Black Chernozemic soil. The other soils, particularly those developed in the dune sands, were weakly developed, Regosolic types of soils.Pedogenic interpretations were based on macro- and micromorphological observations as well as chemical characteristics. Micromorphology and the determination of calcite and dolomite distribution were particularly useful in differentiating sedimentary, pedogenic, and postburial alteration processes in the buried soil profiles. Studies of the organic matter suggest that it had changed markedly after burial.

Tephrochronogical Study in South Kanto

It is well known that the pyroclastic-fall (tephra) layers are the best key beds for regional geologic chronology. South Kanto is a good field for Quaternary tephrochronology in Japan, since there exists a vast amount of tephra mainly supplied from the two volcanoes, Mt. Hakone and Mt. Fuji to the east, covering upon and interbedding wihtin Quaternary sediments.There exists a considerable number of literature on the tephrochronology around Tokyo and Yokohama about 100 kilometers away from the source volcanoes. However, so many tephra beds there consisting of weathered and yet thinner fine ashes with similar brown loamy appearance make it extremely difficult to discriminate some definite time-markers of tephra.As one goes nearer to the source volcanoes, coarser and thicker tephras are expected. In this connection, the best type field is placed in the Ooiso hills, adjacent to the Hakone volcano, where a great number of time-markers is easily distinguished even to the naked eyes and several Quaternary sediments are developed.In this study, each sheet of time-markers which fell after the marine Shimosueyoshi or Kissawa formation was constructed, is precisely discriminated at the type field, Kissawa, eastern part of the Ooiso hills. And then each is traced and correlated eastward along the main axis of distribution to the environs of Tokyo which have been a standard Quaternary succession in Japan (Fig. 1, 2, 4, Table 1, 2, 3).As the first part of this study, the stratigraphy of tephra and absolute ages of several time-markers are discussed in this paper together with the history of the source volcanoes. Former interpretations as to the development of the volcanoes and the marine terraces in this area would be improved considerably.1) The tephra layers of South Kanto were formerly divided into four groups; Tama, Shimosueyoshi (Kissawa), Musashino, Tachikawa tephras. Time gaps during the accumulation of each group were estimated by soil profiles and unconformable relations to about 10, 000 years or more in length. But few data concerning large breaks of tephra falls are found at every boundary in the Ooiso hills and its neighbourhood. A buried soil profile and unconformity are inferred not to indicate a great stratigraphic hiatus but possibly to show a slow accumulation and to be apparent features revealed in the air-laid tephra deposits upon slopes and at the scarps of terraces. In addition, some absolute ages measured by Carbon-14 and Fission track datings indicate that the tephra was supplied rather successively through the late Quaternary (Fig. 10). The longest break of tephra accumulation might be less than several thousand years.2) The Younger tephra groups consisting of the Musashino and the Tachikawa tephra are roughly estimated to have successively accumulated from about 60, 000 years to about 10, 000 years B. P. This estimation is based upon the Fission track age of the Tokyo pumice (TP) and the C-14 ages of the several horizons of the Tachikawa loam (Fig. 10). And the underlying Shimosueyoshi or Kissawa tephra layers are estimated to have successively fallen from about 130, 000 or 120, 000 years B. P. to about 60, 000 years B. P. based upon the Fission track datings of obsidian and zircon included in the several pumice beds (Fig. 10). This result seems to coincide the stratigraphic facts that the total volume of the Shimosueyoshi tephra is about the same as that of the Younger one (Fig. 2) and that some short stratigraphic hiatuses are found at several horizons such as the boundaries of the three subgroups (K1; the lower Kissawa tephras, Km; the middle Kissawa tephras, Ku; the upper Kissawa tephras, Fig. 6A, B). The above age of the lower limit of the Shimosueyoshi tephra layers must suggest that the Shimosueyoshi transgression was dated back to the past a little older than the former concept.

Plaggen soils in the Netherlands

In the Pleistocene sandy areas of The Netherlands, Germany and Belgium there are soils which, for centuries, have been fertilized with a mixture of manure and sods, litter or sand. In this way the original soil has been buried under a humose sand cover of varying thickness. In The Netherlands there are more than 221,000 ha of land with a humose sand cover thicker than 50 cm, and more than 196,000 ha with a cover from 30 to 50 cm thick. Many of these so-called plaggen soils are very old; exactly how old, it is impossible to say, as the methods of investigation applied (calculation of the age from the thickness of the cover, and determining the age by the 14C- method) do not permit precise conclusions. However, with the aid of archeological, historical and toponymical data, it can be assumed that the building-up of many soils began more than a thousand years ago. The oldest plaggen soils are found on moderpodzol soils. These are soils in the sandy areas with a relatively high content of easily weatherable minerals. Plaggen soils are particularly found in those places where the ground water is within the reach of man, but where the chance of a too-high ground water level is slight. When the choice became more restricted, due to the increasing acreage of cultivated land, the reclamation of humuspodzol soils and hydromorphic sandy soils was undertaken in the same way. The specific demands made on the place of reclamation result in a fairly close relation between the places where plaggen soils occur and the geomorphology of the area. Plaggen soils have, of old, been mainly used as arable land. The degree to which they are suitable for this purpose depends on their chemical and physical properties. Prior to the introduction of commercial fertilizers, their chemical properties often left a lot to be desired. Particularly because of their favourable physical properties, they belong among the good arable soils of the West European sandy areas. According to the System of Soil Classification for The Netherlands, they are classified as “enk” earth soils if the humose topsoil is thicker than 50 cm. The “enk” earth soils are classified further into brown and black. Soils with a plaggen cover of 30–50 cm thick are classified according to the buried soil profile (e.g., a podzol). In the 7th Approximation, plaggen soils with a humose topsoil of at least 50 cm are classed as plaggepts, in the order of the inceptisols. The soils with a humose topsoil of less than 50 cm could under this system be classified as plaggic intergrades.