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The MIS3 paleosol units comprise a prominent element of the loess-paleosol sequences throughout the Eurasian Loess Belt. To the north of the loess regions, the findings of MIS3 paleosols were few: it was supposed that geomorphic processes related to the extensive ice cover of the Last Glacial Maximum destroyed the earlier soil mantle. Recently, much smaller extent of continental ice in the east of Northern Europe and ice-free West Siberian Plain during MIS2 has been hypothesized, supposing preservation of MIS3 and earlier paleopedological records. We discovered in the center-north of European Russia (Upper Volga basin) and Western Siberia (Middle Ob basin), MIS3 paleosols within the Late Pleistocene alluvial and lacustrine sequences and correlated the studied profiles on the basis of macro- and micromorphological characteristics and radiocarbon datings of the paleosol organic materials. Paleosols are represented by hydromorphic profiles with Histic horizons and gleyic color pattern. Conspicuously, they are developed in the well drained geomorphic positions, where modern soils are non-gleyic. We suppose that the presence of permafrost was responsible for water logging and generation of reductomorphic soil environment. We further hypothesize a northern zone of MIS3 soil mantle, comprised of Histic and Reductaquic Cryosols different from synchronous Cambisols and Chernozems formed within loess sequences to the south.

Latest Pleistocene fossil soils and deposits have been described in the geoarchaeological site Divnogorie 9 (the Middle Don drainage basin) under the name of Divnogorie pedolithocomplex. For the first time, a soil-sediment series with 2–3 levels of soil formation has been described in the forest-steppe of the Russian Plain and dated to the Bolling–Allerod interval (BO–AL). That was the last soil formation of Pre-Holocene time. The soils are weakly developed (immature), of meadow and burozem genesis. They formed for a few hundreds of years in periglacial steppe environments, under forest-steppe vegetation. The lower soil (attributed to Bolling) is dated at 13.5–14 ka cal BP and defined as a weakly developed Petrocalcic Skeletic Colluvic Siltic Chernozem. Under coniferous-broadleaf forests the middle soil is described as Umric Calcaric Colluvic Siltic Leptosol and dated at Dryas-2. The uppermost soil dated at Allerod is weakly developed Skeletic Calcaric Colluvic Siltic Cambisol formed under coniferous-broadleaf forest-steppe. The data obtained made possible reconstructions of the Late Glacial climates and landscapes. The underlying sediments are the deposits of Divnogorie paleo-lake. The deposits include seven bone-bearing horizons with Late Upper Palaeolithic lithic tools. They are dated to the interval 17–14 ka Cal BP.

Recent revision of the extent of Late Pleistocene glaciations in Northern Eurasia the justified search for the new paleopedological records in the center-north West Siberian Plain. We encountered paleosols in several exposures of the high alluvial terrace of the river Vakh (Middle Ob' basin), buried in the sequence of alluvial and lacustrine sediments. A paleosol dated to the end of Marine Isotope Stage (MIS) 3, Karga thermochron, was studied in detail in the key section “Zeleniy Ostrov”. The paleosol demonstrates strong morphological evidence of gleysation and accumulation of plant residues, both processes indicating water logging and a reduced environment. The modern soil on top of the exposure is a typical Podzol, formed in under conditions of perfect soil drainage and no water excess, in agreement with current geological and geomorphological conditions. We suppose that permafrost was the main factor hampering percolation and switching redoximorphic processes in the paleosol, which thus was classified as a Reductaquic Cryosol. Presence of permafrost implies colder climate than the present one. Furthermore, neutral reaction, presence of neoformed calcium carbonate and abundance of silt fraction, which points to eolian sedimentation, suggest drier conditions. However, the studied paleosols differ considerably from the synchronous Chernozems found in the loess sequences of Southern Siberia. Paleobiological proxies such as pollen, plant macroremains, phytoliths and fossil insects indicate a tundra or tundra-steppe ecosystem (possibly with some forest stands), in good agreement with the paleopedological and sedimentary records.

Stable isotopes of carbon (δ 13 C) in terrestrial geological materials (paleosol humus and carbonates) as well as fossil bones (collagen and tooth enamel) are established as highly specific records on paleoenvironmental characteristics. It was assumed that comparing the results of different types of materials on regional or local scales provides more accurate and reliable reconstructions and even opens new aspects of interpretation. This was tested by the comparison of the data obtained from the late Pleistocene paleosols and/or remains of Pleistocene megafauna in various locations in Northwestern Mexico: Sonora (paleosols formed in MIS3, MIS2 and MIS1); Central-Northern Mexico: San Luis Potosi (teeth, corresponding to MIS2 and MIS1); and Central-Southern Mexico: Puebla (paleosols corresponding to MIS3 and MIS2, and teeth associated with these paleosols), and State of Mexico (teeth, corresponding to MIS2). The results of isotopic studies are complemented with other paleoenvironmental proxies. The δ 13 C values of paleosols of Sonora is −19.8 to −16.95‰ in organic matter, and shows little difference between paleosols and Holocene soils; δ 13 C values of pedogenic carbonates are −6.4 to −4.52‰. In San Luis Potosi, the δ 13 C values of paleosol are −12.16‰ in organic matter. In Puebla, they vary from −24.6‰ in paleosols to −15.16‰ in the modern surface soil, pointing to contrasting vegetation change. The δ 13 C values in fossils range from −10.7 to 1.2‰ in SLP; of −2.73 and −2.93‰ in Puebla; and −6.5 to −1.3‰ in State of Mexico. The δ 13 C values of paleosols and analysis of megafauna in Northwest and Central-Northern Mexico matched each other, indicating mixed C3–C4 vegetation; while for Central-Southern Mexico, paleosols indicated predominance of C3 plants and megafauna indicated mixed C3–C4 composition. In general, the results indicate that in northern Mexico environmental conditions were slightly wetter than at present, while for the central area there was a large change in the environmental conditions of high humidity in MIS3 and MIS2, with a trend to drier climates in MIS1.

In Cananea, Sonora, the spill of 40 000 m 3 of an acid solution rich in iron and copper reached the main water streams of the Sonora river basin, affecting soils and sediments and giving them an anomalous yellowish brown coloration. In the present study, residual contamination (RC) of soils and sediments in the basin was monitored, evaluating color, pH and electrical conductivity (EC) in 41 samples obtained throughout the basin at various depths in the vertical and horizontal directions in a soil profile (TIIZ1B) affected by RC. These properties were supposed to be indirect indicators of RC because of their modification by the influence of the poured solution. Additionally, total concentrations of potentially toxic elements present in the poured solution were determined in soils and sediments. There is an acceptable lineal correlation (0.75) between EC and the yellow color vector (b*), and between these and the concentrations of As, Cu, Fe and Zn (r = 0.52-0.91). The TIIZ1B soil profile analysis allowed relating color, pH and EC with mineralogical changes and increase in the concentrations of As, Cu and Fe. The increase in color vectors to red (a*) and yellow tones is related to the rise in the Fe concentration and to the increase of brightness (L*), the latter being linked to the precipitation of calcium sulfate. Concentration of As and Fe increases in the portion of the soil with the most acidic pH values, while Cu increases with the increase of pH and a negative point of zero charge. Color, pH and EC are useful parameters in the indirect determination of RC.

espanolEl barrio de Tlajinga es un area ubicada al sur de la ciudad de Teotihuacan, Estado de Mexico, que preserva materiales prehispanicos diseminados en distintas zonas del terreno, asi como estructuras arqueologicas enterradas. Las particulas del suelo, al mezclarse con materiales arqueologicos tales como piedra, estuco, ceramica y fragmentos de murales, enriquecen el suelo principalmente con carbonato de calcio, lo que contribuye al aumento de la reflectancia en distintas zonas del terreno, principalmente en zonas donde habia estructuras arqueologicas. Este fenomeno es registrado desde un nivel sinoptico por los sensores remotos actuales, con mayor resolucion espectral, espacial y radiometrica, correlacionandose a una menor escala con la espectrorradiometria y la micromorfologia de los suelos. De esta forma se identificaron algunos minerales presentes en los pisos y muros, principalmente el estuco arqueologico, ahora transformado en pequenas particulas de carbonato de calcio. La fluorescencia (FRX) y difraccion de rayos X (DRX) complementaron los resultados de la percepccion remota, la espectrorradiometria y la micromorfologia, identificando la composicion elemental de las particulas del suelo y los minerales asociados, de la que sobresale el carbonato de calcio, un compuesto muy importante utilizado para el recubrimiento de pisos y edificios durante la epoca teotihuacana. EnglishThe Tlajinga Barrio is a domestic area situated in the south of Teotihuacan, Estado de Mexico, where preserves original surface materials as well as buried archaeological structures are preserved. Original soil particles mixed with archaeological materials such as stone, stucco, ceramics, and mural fragments enrich the soil mainly with calcium carbonate, contributing to the increase in reflectance in different areas of the terrain, mainly in nearby areas where there were archaeological structures. This is recorded from a synoptic level by the modern remote sensors, with higher spectral, spatial, and radiometric resolution, correlating it to a smaller scale with soil micromorphology analysis. In this way, some minerals present in the floors and walls were identified, mainly the archaeological stucco now transformed into small particles of calcium carbonate. X-ray fluorescence (XFRF) and X-ray diffraction (XRD) complemented the results of remote sensing, spectrometry and micromorphology, identifying the elemental composition of soil particles and associated minerals, mainly calcium carbonate, that were used live in coatings on floors and buildings during the Teoti huacan era.

An almost complete cranium of a gomphoterium found in Tepeticpac, Tlaxcala, was analyzed with X-ray diffraction (XRD), Petrography and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) to stablish the transformations of the bone during its burial. The analyses assessed that the bone mineral (bioapatite) had suffered modifications in mineral composition, “crystallinity index”, cell parameters and CO2 content. However, the paleohistological structure of the bone was not significantly affected, although evidence of microbial attack was found in the bone surfaces. The filling minerals of bone macro and micro porosity were also analyzed; its main filling minerals are calcite (micrite and sparite), clays, and minerals of volcanic origin.

"The activities carried out by preindustrial agricultural societies are not usually considered as important factors of soil degradation. Nonetheless, repetitive human daily activities for hundreds of years can substantially transform the natural properties of the soils. At the site of La Playa, Mexico, the activities of early farmers modified the landscape and had an important role in the physical transformations of the natural soil features. This paper depicts the characteristics of La Playa paleosols, which were the living surface of the Early Agriculture Period community (4000 - 1800 cal BP) and we discuss the influence of daily subsistence activities on the soil. The soil features (structuring, differentiation of horizons, texture-in field and laboratory, color, porosity, stoniness, magnetic properties, organic carbon content, carbonation, presence of cutans, nodules and/or concretions, among other pedological features) of three profiles with pedosediments (paleosols interbedded with sediments) formed during late Holocene are discussed. Our study suggests that La Playa Fluvisols are poorly developed and were formed with alluvial deposits (largely composed of reworked soils). The pedogenic properties indicate that overlapping developed during short time periods of stability, under arid conditions of the last 4000 years. The uniformity of the features in all the studied profiles indicate similar pedogenetic conditions across the site. The micromorphological and magnetic properties clearly show that the soil was deeply disturbed by human activities, mainly by roasting features to process food, crematories and grave digging to bury the dead, and removing soil for several agricultural activities."

International audience; The purpose of this article is to explore the operational chain involved in Xajay's ceramic production through a petrographic and statistical analysis, in order to differentiate the ceramic produced locally from the one that was manufactured in other regions. The collection analyzed for this study comes from the excavations conducted in the main ceremonial center of Xajay culture, known as Pahñu, which was occupied between 300 and 950 AD, and located in the municipality of Tecozautla, Hidalgo, Mexico. The study was based in the petrographic analysis of 21 ceramic samples, and the micromorphologic analysis of 6 soil samples. In order to review the different methods of clay preparation, the samples were first grouped by mineralogical composition to be able to infer their origin related to a same source area. In a second moment, groups were defined in subgroups, taking into consideration proportions, morphology, and size of antiplastic particles. Likewise, the purpose of the micro-morphological analysis was the identification and characterization of soils, in order to correlate soils with corresponding ceramic samples. The analysis allows for an understanding of the dynamics involved in raw material exploitation and clay preparation for the elaboration of ceramic objects used at Pahñu. With regards to the different types of soil used in ceramic production-Vertisol, Luvisol and Feozem-the inhabitants of Pahñu opted for the latter two. The information obtained in this study leads to the conclusion that the Xajay culture produced most of their ceramic assemblage locally and acquired, to a lesser degree, ceramic produced in other regions.; El presente artículo tiene por objetivo evidenciar los elementos constitutivos de las primeras dos etapas de producción en la cadena operatoria de la cerámica de la cultura Xajay, es decir, la etapa de obtención de materias primas a partir de la identificación de los yacimientos de barro y, en segundo lugar, la etapa de preparación de las materias primas para inferir las distintas “recetas” de barro utilizadas para la elaboración de las vasijas. Asimismo, diferenciar entre la cerámica producida localmente y aquella procedente de otras regiones. La colección analizada proviene de las excavaciones realizadas en el principal centro ceremonial Xajay conocido como Pahñu, ocupado entre el 300 d. C. y el 950 d. C, localizado en municipio de Tecozautla, Hidalgo. El estudio fue realizado a partir de un análisis petrográfico (21 muestras cerámicas) y micromorfológico (6 muestras de suelo). El primero consistió en agrupar las muestras que compartieran una composición mineralógica para inferir una misma procedencia o yacimiento de materias primas, posteriormente se generaron subgrupos tomando en cuenta proporciones, morfología y tamaño de partículas para estudiar las distintas formas de preparación del barro. El análisis micromorfológico tuvo por objetivo la identificación y caracterización de los suelos para su posterior correlación con las muestras cerámicas. El análisis petrográfico evidenció la existencia de 4 grupos (2 locales y 2 foráneos), y 12 subgrupos de pastas (10 locales y 2 foráneos) correspondientes a distintas recetas de elaboración de barro. El análisis micromorfológico permitió definir tres tipos de suelos: feozem, luvisol y vertisol. A partir de los resultados obtenidos se lograron comprender las dinámicas de explotación y preparación del barro para la elaboración de los objetos cerámicos consumidos en Pahñu. Se propone entonces que el grupo Xajay producía la mayoría de la parafernalia cerámica localizada en sus sitios, y en menor proporción obtenían cerámica producida en otras regiones (al menos dos, no determinadas en esta investigación). Dentro de los distintos tipos de suelos —vertisol, luvisol y feozem—ellos optaron por la utilización de los últimos dos.

Paleosol-sedimentary sequences encountered in the settlements with long occupation history could provide a unique insight into the trends of landscape development and human-environment interaction over long time scales. We studied paleosols exposed by the excavations in the Kremlin of Zaraysk (Central European Russia) which were formed during the late Pleistocene and the Holocene and contain archaeological materials spanning from Upper Palaeolithic till late Medieval. Archaeological findings and numerous radiocarbon dates provide a reliable time frame for paleopedological record which we extracted from paleosols using macro- and micromorphological observations as well as physical and chemical properties and paleobotanical indicators (phytolith assemblages). The basal layer without archaeological materials presents signs of soil formation which resemble Bryansk fossil soil developed in the second half of Marine Isotope Stage (MIS) 3. The overlying archaeological stratum - one of the Gravettian cultural layers is linked to the paleosol level known as Zaraysk soil. Its age is estimated at 16 ka BP. Macro- and micromorphological features point to moderate dark humus accumulation, anthropogenic compaction and cryogenic processes at the final stages of paleopedogenesis. Poorly sorted heterogeneous composition of the mineral material with a large proportion of sand grains indicates colluvial origin of the paleosol parent material. The overlying sorted silty deposit supposes contribution of windblown material to its formation. We associate cryogenic and eolian processes at the end and after Zaraysk soil development with the cold intervals at the end MIS 2, presumably with the Oldest and Younger Dryas. The complete profile of Luvisol/Grey Forest Soil with eluvial and illuvial horizons and relict dark humus morphons is developed within the silty unit. This soil indicates long-term natural pedogenesis under first steppe and then deciduous forest vegetation during major part of the Holocene. The topsoil however is formed by clear plough horizon which points to cultivation started in the Middle Ages. Sharp boundary separates the buried Luvisol from the overlying cultural layer-Technosol developed after building of Zaraysk Kremlin in the 16th century. Technosol presents a mixture of natural soil with construction materials, especially limestone fragments. Soil units, both natural and affected by humans, are not separated one from another by an unaltered C horizon, so soil-forming processes from the upper soils penetrate into the underlying ones forming a multistory pedocomplex.

Desert varnish is a dark microlayer that forms on rocky surfaces that is usually associated with arid and desert environments. It consists mainly of clay minerals (60%), while the rest are Fe and Mn oxides. Growth rates are very slow and vary from

Northern Mexico is predominantly composed of moderately developed red soils that provide evidence of weathering, rubification, neoformation of clay, and pedogenic carbonate accumulation. These soils constitute a pedological unit named San Rafael Paleosol (SRP) which were developed during the late Pleistocene (MIS 2) to the middle Holocene (15,000–4500 cal years BP). These paleosols can use as a chronologic marker at a regional scale. In this paper, we present a pedogenic interpretation of the paleosol-sedimentary processes during the late Quaternary, which contributes to the reconstruction of regional paleoenvironment. The development of SRP takes place over more than 15,000 years, and this pedogenesis is interrupted by stages of strong climatic instability, causing erosion of the SRP and sedimentation, presumably during the Altithermal. The records of La Playa show that SRP is buried by fluvial sediments, which include different facies. These sedimentation events are associated with the end of the Altithermal period and evidence more active geomorphic processes. These conditions are also observed at El Gramal, where dune sediments overly the SRP. This discontinuity evidence an intense erosional/sedimentation phase. In the particular case of El Fin del Mundo site, it is observed more mesic conditions as the water table rose, creating a wetland. Much of the synchronous variation in the morphology of the paleosols (pedofacies) can be explained by differences in local geomorphological conditions. These palaoesols developed under a semi-arid climate, slightly more humid than the present one with winter dominant rains and marked seasonal changes. These assumptions are supported by soil micromorphology, physical characteristics (color, grain size distribution) and composition of total organic and inorganic carbon. Additional paleoenvironmental information is also extracted from microbiomorphic analyses and diatoms assemblages from the one profile at El Fin del Mundo site.

New results on stratigraphy and chronology, obtained on the basis of OSL and 14C-dating of paleosols, sediments, and cryogenic deformations in the Aleksandrov quarry situated at the Central Russian Upland, are discussed. Due to the location of the site in a paleodepression, the section presents various stages of soil formation, cryogenesis and sedimentation starting from the Mikulino interglacial to the middle last glacial time. The studied sequence is well preserved and one of the most detailed soil-sedimentary terrestrial archives within Eastern Europe. It reflects climatic variations comprising the timespan from the marine isotopic stage (MIS) 5e to MIS 3. At the base of the paleodepression the pedogenetic stages are extraordinary detailed. Distinct paleosols are alternating with erosion-accumulative stages, forming the Ryshkovo pedolitocomplex during the Mikulino interglacial. During the Early Valdai time two interstadial paleosols were developed, and the Middle Valdai section comprises two main interstadial paleosols as well. In general, interstadial paleosols of the Late Valdai time are absent in the studied quarry. For the first time, the chronological boundaries of the MIS 5e interglacial are recorded and thus, the duration of soil formation could be determined from 12 to 15 thousand years. Furthermore, stages of periglacial conditions during the Early, Middle and Late Valdai time were dated. The obtained ages form the base for a chronostratigraphic framework, which was correlated with those of the loess-paleosol archives of Eastern, Central, and Western Europe.

In the northeastern margin of the Yucatan Peninsula, which is located in southeastern Mexico, three levels of compact carbonate crusts (calcretes) interlayered with indurated coastal calcareous sediments (calcarenites) are discernible. Since both the calcretes and calcarenites form a continuous carbonate sequence, a combined methodology (macro- and micromorphology, geochemistry and mineralogy) is used to differentiate them. Additionally, the calcrete layers are dated using the Uranium-Thorium method in order to establish a chronological framework. The carbonate differentiation and chronology are then used to establish the paleoenvironmental conditions that prevailed during calcrete formation as well as to reconstruct the coastal landscape evolution and its relation to Pleistocene sea-level changes during Marine Isotope Stages (MIS) 6 and 5. Samples of calcrete layers and calcarenites were taken from two sections in the Cancun-Tulum corridor. The lowest level of calcrete underlies a sequence of calcarenites, and the two younger levels cap the sequence. In calcretes, the micromorphology provides evidence of the presence of a relict soil with subangular blocky microstructure, root traces, and needle-fiber calcite (associated with soil-fungi interactions). In contrast, the micromorphology of the calcarenites shows ooids and bioclasts, typical of a coastal environment. Geochemically, calcretes are depleted in δ13C, compared to calcarenite, with values ranging between −2‰ and −10‰, and they have a lower proportion of rare earth elements. Calcrete mineralogy consists mainly of calcite over aragonite with a low proportion of Mg-calcite. U/Th dating indicates that the oldest calcrete was formed during the Penultimate Glacial Maximum (PGM), in MIS 6, and the two younger calcretes correspond to the Last Interglacial Period, in MIS 5c. The calcarenite formation occurred earlier, also during MIS 5. Soil formation, strong karstification and soil erosion have occurred on younger calcretes. This study suggests that these processes developed between MIS 4 to MIS 1.

The present article describes the basic approach to understanding the nature and the structure of educational results other than traditional subject results of studying. We analyzed the formation stages of the ideas, which of the skills acquired during the period of school studies could facilitate the process of becoming a socially active member of the society and integrating into his or her social environment. We can conclude that a fi ve-dimensional structure of educational results could be applied, according to the types of personal potential: cognitive, axiological, creative, communicative and aesthetical. Lastly, we provide some recommendations on how to apply this model to constructing of training tasks and organizing the process of teaching in accordance with the FSES.

The article describes an approach to structuring educational results based upon the M.S. Kagan�s fi ve-component model of personal potential (cognitive, axiological, creative, communicative and aesthetical potentials). Under the term �students� functional competence� we understand their readiness for socio- economic activity and ability to integrate into their social environment. We consider the principles of constructing the structural model of the school students� functional competence and its didactical possibilities aimed at harmonizing the socialization process of the students.

Volcanic activity affects past and present landscapes. Here we present a case study related to the heat impact of the Xitle lava flow on the former soil cover. The eruption occurred 1670 years B.P., in south Mexico City. The evaluated properties include those related to the “soil memory”, used as tools of paleoenvironmental interpretation in volcanic paleosols: macro and micromorphology, color, grain size distribution, magnetic susceptibility, and carbon and nitrogen contents. Changes of these properties by the heat influence are relevant for an adequate paleoenvironmental reconstruction. Two sites and three soil profiles are selected to show soil modifications by the volcanic activity. The two sites represent the following: 1) slightly transformed paleosol buried by the lava flow, but separated from it by a 10 cm thick volcanic ash layer (site Cuicuilco-ENAH); 2) moderately and strongly transformed paleosols (two profiles inside the Copilco archeological zone). One of the Copilco profiles represents a buried paleosol with a very thin (3 cm) ash layer on top, at the contact with the lava; the second profile is the most affected by the lava flow, as it is directly beneath the lava. All studied paleosols are sandy, have a low amount of organic matter, narrow C/N ratios, and very high values of magnetic susceptibility. The strongest modifications are observed in the upper horizons, which are in contact with the lava. However, the presence of the ash layer minimizes the heat effect. Despite the observed modifications, it is possible to establish three cycles of soil formation in the paleolandscape. The first, and the oldest, related to the development of a Luvisol type soil, indicates a longer time of landscape stability. During the second cycle a pedosediment with a high concentration of artifacts was formed. The last and the youngest cycle includes the Ab and the AEb horizons (present only in Copilco). They form by an Andosol type pedogenesis, which reflects a shorter time of soil development. The presence of the AEb horizon is interpreted as the result of the degradation of the Ab horizon, either due to the heat effect of the lava, or to cultivation and irrigation practiced by the pre-Hispanic communities.

Schwermineralanalysen an alluvialen Sedimenten und Paläoböden des Usumacinta-Flusses sind ein sehr effektives Werkzeug für die Rekonstruktion der relevanten Liefergebiete in den Tieflandgebieten der Mayas. Die mineralogischen Daten können für die pedostratigraphische Korrelation in der Region nützlich sein. Auf der Basis unserer Beobachtungen für Tierra Blanca ist die ultrastabile Schwermineralkomponente (zumeist Zirkon, Turmalin und Rutil) besonders erfolgversprechend für den Nachweis der Liefergebiete der Sedimente. Diese Minerale treten gemeinsam mit einer großen Vielfalt von sehr dichten authigenen Mineralen auf (u.a. Titanit). Unter Berücksichtigung der spezifischen Eigenschaften und der Alter von ausgewählten Horizonten, kann nun versucht werden, eine regionale Chronostratigraphie für Paläoböden und alluviale Sequenzen zu entwickeln. Unsere Daten deuten auf Sedimenttransport in Flussrinnen von den Hochländern Guatemalas gen Westen hin. Die untersuchten Schichten enthalten auch große Anteile an vulkanischen Mineralen mit frischen und eckigen Formen, was auf ein proximales Liefergebiet (wahrscheinlich Tacana Volcano, Mexico/Guatemala) hinweist.

In vielen Löss-Paläoboden-Sequenzen der gemäßigten Breiten Europas ist das letzte Interglazial (dt.: Eem, russ.: Mikulino) durch einen Bt-Horizont (Argic horizon nach WRB) repräsentiert, der als pedologisches Resultat entsprechender bioklimatischer Bedingungen dieser Zeit gedeutet wird. Wir untersuchten mikromorphologische, physikalische/chemische (Gesamtelementzusammensetzung, Korngrößenverteilung und dithionitlösliches Eisen) und mineralogische Charakteristika im Profilabschnitt des Eem-Luvisols in Oberösterreich (Oberlaab) und des Mikulino-Albeluvisols in Zentralrussland (Alexandrov Grube nahe Kursk). Aus dem Vergleich der Paläoböden mit entsprechenden rezenten Böden ergeben sich paläoökologische und chronologische Schlussfolgerungen. Beide Profile zeigen eine Reihe von Charakteristika, die auf Verwitterung primärer Minerale und Tonminerale sowie Tonverlagerung und redoximorphe Prozesse hinweisen. Die Paläoböden zeigen jeweils eine weiter fortgeschrittene Entwicklung im Vergleich zu entsprechenden holozänen Böden, jedoch anhand unterschiedlicher pedogenetischer Merkmale. Der Eem-Luvisol in Oberösterreich weist ein höheres Maß an Tonverlagerung auf, was durch einen höheren Tongehalt und zahlreiche Toncutane im Bt-Horizont gezeigt wird. Der Mikulino-Albeluvisol in Zentralrussland ist stärker von Auswaschung und Stauwasser betroffen, was sich in tieferer und stärkerer Ansammlung von gebleichtem schluffigem Material und Tonverarmung zeigt. Wir nehmen an, dass das Ausgangsmaterial diese unterschiedliche Entwicklung hervorruft. Der russische Albeluvisol bildete sich auf Dnjepr-Löss, welcher im Vergleich zu den Riss-Lössen Oberösterreichs ärmer an leicht verwitterbaren Mineralen ist und daher eine geringere Kapazität Säure zu puffern sowie Ton neu zu bilden aufweist. Das fortgeschrittenere Entwicklungsstadium des letztinterglazialen Bodens im Vergleich zu holozänen Böden, die allgemein demselben Bodentyp entsprechen, spricht für eine längere Bodenentwicklungsphase, was mit paläobotanischen Ergebnissen in Einklang steht. Einerseits könnte der letztinterglaziale Paläoboden neben dem MIS 5e auch Teile des MIS 5d umfassen, andererseits könnte eine intensivere Paläobodenentwicklung durch das wärmere und feuchtere Paläoklima während der Interglazialphase des MIS 5e verursacht werden. Mehrere Phasen der Tonverlagerung, unterbrochen durch frostdynamische Strukturierung und Deformation sind im eemzeitlichen Bt-Horizont in Oberösterreich nachweisbar. Die noch weiter reichende Entwicklung könnte bis in noch jüngere Frühwürm-Interstadiale gereicht haben.

La cubierta edafica del estado de Sonora, en el norte de Mexico, esta formada predominantemente por suelos rojos de desarrollo moderado, con procesos de intemperismo, humificacion, rubificacion, neoformacion de arcillas y carbonatacion, clasificados como Cambisoles segun la WRB, que constituyen una unidad edafica denominada Paleosuelo San Rafael (SRP). Sin embargo, en algunos sitios se han registrado suelos grises formados en cuencas semicerradas, con procesos de intemperismo, neoformacion de arcillas, reductomorfia y carbonatacion. Estos suelos se desarrollaron durante el Pleistoceno Superior bajo un clima semiarido y frio, un poco mas humedo que el actual, favorecido por las lluvias invernales y cambios estacionales marcados. Estos paleosuelos se encuentran asociados a restos de fauna pleistocenica rancholabreana de composicion diversa, asociada a climas tanto aridos como humedos, lo que muestra variaciones climaticas locales mucho mas complejas que en la actualidad. Con la intencion de establecer las caracteristicas particulares de los paleosuelos formados en cuencas semicerradas que pudieron permitir la acumulacion de agua y la formacion de estanques, se evaluaron las caracteristicas fisicas, quimicas y micromorfologicas de los paleosuelos localizados en los ranchos San Francisco y El Arenoso, en el norte de Sonora, en los cuales tambien se han hallado restos de megafauna pleistocenica. Los analisis permitieron evaluar las caracteristicas de los paleosuelos, identificar los procesos pedogeneticos principales y establecer las condiciones ambientales predominantes durante su formacion. Estos resultados se contrastaron con los estudios paleopedologicos previos y los antecedentes paleontologicos, lo que permitio enmarcarlos dentro de las tendencias paleoclimaticas regionales.

In this work, we present the results of a soil study in the Teuhtli volcano, located to the south of the Basin of Mexico with the aim to understand the pedogenetic pathways and the evolution of the landscape dynamics. Two different types of soil prof iles were sampled: in “conserved” areas, with less anthropogenic influence and in sites with intense agriculture activities since pre-Hispanic times. The three conserved prof iles are located in different landscape positions: the Cima prof ile in the summit, the Ladera prof ile in the high slope, and the Yotecón in a lower position of the piedemont. The agriculture prof iles are La Cruz, La Era and El Llano, situated in the foothill. Properties in both kind of soils are similar, however, in agriculture sites, structure (evaluated in macro and microscale) is weaker, total organic carbon content is smaller and bulk density is higher. Both soils show two main pedogenetic processes: andosolization and carbonate formation. Despite the age of the parent material (36 000 years), the Andosol phase has not been lost. This is because of the geomorphological dynamics of the zone, in which the processes of erosion and colluviation promote soil loss, restarting the pedogenetic clock. The detection of lithological discontinuities (by the Ti/Zr ratio) documents these processes. By the other hand, the formation of pedogenic carbonates is governed by the seasonal conditions of drought. The age of these carbonates places their formation in the mid-Holocene, an epoch for which drier conditions are detected in other sites of the Basin of Mexico. The agricultural land use has also promoted morphological, chemical and physical changes in the soils. The continuous tillage of the sites has prevented the soils from developing. This could have a negative effect on the fertility of those soils currently used to sustain the peri-urban agroecosystems of Mexico City.

Soils on volcanic ash have specific physical and chemical properties, as well as typical micromorphological characteristics. They are characterised by an extensive accumulation of short-range order Si-Al compounds, such as allophane and imogolite, formed during weathering. This results in a grouping at the highest taxonomic level as Andosols (WRB) or Andisols (USDA) and in the use of ‘andic’ designations at other levels. The microstructure evolves from coarse monic in fresh ashes over chitonic and enaulic to granular in Andosols. A weakly separated intrapedal granular microstructure may persist in Bw horizons with a blocky microstructure or with a lenticular (freeze-thaw) microstructure. In Vertisols on volcanic ash a blocky microstructure is observed. The coarse material generally includes large amounts of volcanic glass. Fresh ash can already be transformed by hydrothermal alteration, resulting in the presence of secondary products. In the first stages of pedogenic weathering, short range order Si-Al compounds are formed. Pedogenic weathering of basaltic glass can produce palagonite-like alteromorphs of allophane. Magnetite and ilmenite can persist even in strongly weathered soils. Phytoliths and fungal hyphae are generally very abundant. The b-fabric is undifferentiated as long as short range order clays and halloysite are predominant, and it becomes stipple- or mosaic-speckled when kaolinite or illite appears. Micromass coatings around coarse fragments, and internal hypocoatings in the case of pumice, develop during a fist stage of soil formation. Other textural pedofeatures, except for rare allophane coatings, are generally not present in Andosols, but appear in intergrades to Luvisols, often still composed of optically isotropic compounds. In certain duripans (Tepetate), clay coatings with opaline zones are observed. Gibbsite coatings and nodules occur in conditions with strong leaching. Opal nodules are common in many soils formed on volcanic ash.

In this paper, we present an overview of the Mexican volcanic palaeosol sequences, as a valuable tool to establish the duration of soil formation at different chronological scales. We have selected four study cases which cover time intervals from decennial, centennial, to millennial pedogenesis. The first case corresponds to the soils in El Chichon volcano, where the short interval between the eruptions gives the opportunity to study the soil formation in periods less than 500 years. In this interval, the transformation from Regosol to Andosol is observable. In El Nevado de Toluca, pedogenesis of longer duration (4000 to 6000 y), characterizes a vitric Andosol stage. In this area, the transformation of Andosol to Luvisol is also shown, in periods longer than 10,000 years. The third study case corresponds to the Tlaxcala palaeosol sequence, where pedogenesis in intervals from 10,000 to 100,000 years is observable. In this case, no Andosols are present, and a complete set of Luvisols showing different properties is found. This differentiation is not only related to the duration of the pedogenesis, but also to the climatic conditions, which lead to changes in specific properties (clay content, weathering of the primary minerals, Fed content). In this way, these soils are valuable for palaeoenvironmental reconstruction. The fourth case is related to faster pedogenesis in the volcanic regions of Mexico, where highly developed Luvisols are found, formed in intervals less than 15,000 y. In this case, the influence of a pre-weathered volcanic material as a source of clay allows the rapid transformation.

In Sonora, northwest Mexico, we have recognized the existence of paleosol units of Late Pleistocene/Early and Middle Holocene age (13,000 to 4,250 Cal years BP) at several archaeological sites with Paleo-indian occupations (e.g. La Playa, Fin del Mundo, El Bajio, El Aigame and El Arenoso). The few paleoenviromental reconstructions from the region indicate that the end of the Pleistocene was dominated by temperate climate that promoted the establishment of the first people in coexistence and interaction with the Pleistocene megafauna. The study of the spatial distribution of various soil units developed during late Pleistocene in the region provides information about local environmental settings of the initial peopling of Sonora. Several pedosedimentary sequences were analyzed in the different parts of Sonora, the age control in which was provided by archaeological and paleontological findings and/or by the radiocarbon dating of carbonates and paleosol humus. Two trends of the Late Pleistocene pedogenesis have been identified. The profiles located in the south, center and north of the state are dominated by red soils (earlier referred as Big Red in the archaeological literature) whose characteristics are represented by the Red San Rafael Paleosol (SRP). The properties of SRP in the lower part of the profile (rubification, clay accumulation, hig magnetic susceptibility, illuvial carbonates, and redoximorphic features) are indicative of a more humid environment. Above them is a late Holocene polycyclic sequence of soils with morphological characteristics displaying a more incipient development. In contrast with the sequence described above, El Arenoso, north of Caborca, show a sequence of gray soils. Two paleosols were formed in alluvial sediments. At the Cantera profile (CTP) and El Arenoso profile (ARP) paleosols are represented by Bgk horizons and evidence of weathering and clay neoformation, redoximorphic processes and illuvial accumulation of carbonates. We explain the differences of north-western profiles by specific geomorphic conditions which imply limited soil drainage and the possibility of over-wetting. These processes indicate alternating a humid environment (weathering, rubification, clay formation and redoximorphic processes); and dry periods (carbonates accumulation). Despite regional differences of the late Pleistocene paleosols, the comparison with the Holocene soils demonstrates clear trends towards desertification in the region. The first people that inhabited Sonora during the late Pleistocene found a more temperate and wetter climate than they encountered further to the north, but subsequent generations witnessed a rapid desiccation of the region with the formation of the Sonoran Desert in the early Holocene.

The reconstruction of the Maya Lowlands vegetational history and its paleoecological implications during the Middle-Late Holocene was carried out using phytolith analysis and organic matter stable isotopic ratios. Three sections located in a terrace of the Usumacinta River were studied: Tierra Blanca I, Tierra Blanca II, and El Pochote. They consisted of a series of alluvial sediments alternating with paleosols that contained artifacts belonging to the Formative, Classic, and Postclassic periods according to the Mesoamerican chronology. Our results showed that the Middle Holocene paleosols had well developed vertic features with −16‰ δ13C values, which evidence seasonal-semiarid conditions. However, phytolith content recorded a predominance of C3 plants, and paleosol micromorphology showed a set of features related to an alternation of humid and drier conditions. Therefore, stable isotope composition reflects the integral signal of the last period of soil formation. Phytoliths and soil micromorphology correspond to a more extensive record that represents the successive stages of pedogenetic and environmental changes.

A variety of studies of the re-examined (new exposure) Late Pleistocene key section Cheremoshnik (East European plain, middle of the Volga Basin of Yaroslavl) was conducted on a new methodological level using modern methods. For the first time, a series of paleosols (MIS5–MIS1) from the section offering significant information in regard to chronostratigraphy and landscape evolution have been studied in detail and dated. An excavation ∼7 m deep reveals a soil-sediment stratum which formed over the course of ∼115 ka in an accumulative beam-like terrace and consists of five lithological layers and six pedostratigraphical units. The base of the section was determined to be an Early Mikulino peat-dark humus paleosol which marked incipient subaerial pedogenesis on the Moscow (Riss II) moraine and was covered with a thickness of gyttja with a peat horizon (Histosol) which had formed 114–115 ka and was reliably dated using uranium–thorium dating. The following paleosols were successfully identified within the series of weak stone gullied-channel sediments within the Valdai (Wűrm) thickness (from bottom to top): (1) Bryansk paleosol (MIS3) – Gleysol – with three pedogenesis rhythms; (2) Trubchevskaya paleоsol – Gleyic Turbic Cryosol (MIS2) and (3) pedosediment formed at the end of the Bӧlling interstadial (MIS2). Terminal Pleistocene formations are marked with a gravelly stratum on the section's surface formed during the Preboreal period. Recent Regosol formed on loess-like loam deposits was identified at the top of the whole soil-sediment stratum. The 14C age of the paleosol humus varied between 27,500 and 11,400 cal. BP. The paleosols represent the northernmost occurrence of MIS5–MIS2 fossil soil in Europe, dominated by features of gleyzation, cryogenic aggregation, cracking, and humus and peat formation. Pollen analysis results allowed estimation of changes in vegetation cover, climatic conditions and the age of deposit sedimentation for the period from the Moskow Late Glacial to the Valdai Late Glacial and early Holocene times. Successive stages in the development of vegetation, high contents of alder and hazel pollen and the climax and distinct appearance of broadleaf trees relate the formation of biogenic sediments (LPAZ 2–6) in the Cheremoshnik section to the Mikulino Interglacial. Valdai (MIS4–MIS2) glacial sediment is absent within the investigated area.

Dada la importancia que revisten los suelos en los procesos que ocurren en la zona critica (zona de interaccion entre agua, suelo, aire, organismos), en este trabajo presentamos la distribucion temporal y espacial de una secuencia de paleosuelos arcillosos con carbonatos secundarios (capas de caliches y carbonatos diseminados) en el sector nororiental de la Cuenca de Mexico, particularmente en el valle de Teotihuacan. El proposito de este trabajo consiste en reconstruir la distribucion temporal y espacial de la cubierta de suelos del pasado para entender su relacion con la estructura actual de suelos y sedimentos en este sector semiarido de la cuenca de Mexico. Con esta informacion, determinar la participacion de estos materiales en la Zona Critica (ZC). Para ello, se ha llevado a cabo un transecto de direccion norte-sur, que inicia en las elevaciones del Cerro Gordo, cruza el valle de Teotihuacan y termina en la Sierra Patlachique, describiendo perfiles de suelo en diferentes posiciones geomorfologicas. El marco cronologico se ha establecido con base en fechamientos de radiocarbono realizados en las capas de caliches. De acuerdo a la cronologia, al tipo y grado de pedogenesis, y a los procesos de sedimentacion, se han reconocido cuatro unidades. La primera unidad, denominada Paleosuelos del Pleistoceno, fase I (50000 – 20000 anos AP), esta compuesta de paleosuelos arcillosos, los cuales son Luvisoles cromicos y estagnicos, dependiendo de su posicion en el paisaje. Estos paleosuelos muestran tanto carbonatos secundarios diseminados y en fracturas, como capas de caliches. En la segunda unidad, Paleosuelos del Pleistoceno, fase II (20000 –10000 anos AP), dominan los sedimentos sobre los suelos; unicamente en el fondo del Valle, se han encontrado Gleysoles cortados por canales aluviales. La unidad, Paleosuelos del Holoceno, fase I (10000 a 1000 anos AP) se caracteriza por presentar suelo

Based on a W–E transect through the northern loess regions of Austria, palaeoenvironmental studies were carried out in three loess–palaeosol sequences (Gunderding, Krems-Wachtberg and Stillfried B locus typicus) to complement available results in the context of a multi-methodological approach. On the base of previously published datings, our study concentrates on the MIS 3/2 transition. The results of detailed micromorphological investigations prove that palaeopedogenesis, frost processes, and sedimentation rates differ in their spatial occurrence in the loess belt of Austria. All three sequences are in line with the general trend of a reduced intensity of pedogenic and cryogenic features from western to (south-)eastern Europe, which can be explained by lower Atlantic moisture influence towards the east. Interstadial cambic horizons are well developed in the MIS 3 sequence of western Austria, whereas the eastern loess profiles only show weak pedogenesis. In all studied sequences frost processes were active during the upper MIS 3 and MIS 2. The studied MIS 2 records are characterised by tundra soils with reductaquic horizons, which is a clear sign for prolonged phases of permafrost. On the spatial scale, the sedimentation rate increases in the eastern loess regions and particularly the Krems-Wachtberg sequence in the centre of the transect experienced an exceptionally high sedimentation rate and can thus be seen as one of the most important high resolution records for the MIS 3/2 transition in European loess regions.

We present first results about an Archaic (9000–4000 BP) site, El Tebernal, in the eastern part of Mexico. At El Tebernal, a set of lithic artifacts was found associated with a paleosol (lower paleosol) and buried by an upper paleosol and a modern soil. The artifacts are made from local limestone and chert. Selected paleosol properties were evaluated (total organic carbon, grain size distribution, carbon stable isotope composition, magnetic susceptibility, and micromorphology) that provide information about paleoenvironmental conditions. The lower paleosol is composed of the following horizons: 3E, 3EB, 3BE, 3Btg1, 3Btg2, 3C while the upper paleosol only has a 2A horizon. The lower paleosol is very well developed, with in situ clay coatings, moderate weathering of primary minerals, and a matrix free of carbonates, although the alluvium in the lowermost part of the profile contains a mixture of limestone and volcanic materials. The entire sequence is covered by the modern soil mantle which is formed by an A horizon. Radiocarbon ages determined on soil organic matter from the 3Btg1 and 2A horizons were 5580 to 5320 Cal BP and 2350 to 2320 Cal BP, respectively. We interpret the age of 3Btg1 as close to the final stage of soil formation, because the organic matter content in this horizon is illuviated. Pedogenesis likely began sometime prior to the reported age in the Early Holocene. The paleosol properties indicate a long period of landscape stability ( n × 10 3 –10 4 years) under humid and temperate conditions. It is probable that volcanic events from Pico de Orizaba, located several kilometers from El Tebernal, affected this stability. One of the last eruptions produced a block-and-ash flow of dacitic composition dated at 4100 BP that contributed to the end of pedogenesis. The upper paleosol (2A horizon) as well as the modern soil contain ceramics from the Post-classic period (AD 900–1521). The profile is cut by a channel and infilled by a dark material that dates to 1140 to 970 Cal BP (AD 810–980). In consequence, the area has been strongly affected by human occupations during the Holocene. We suggest these ceramic societies caused erosion and activation of geomorphic processes.

Summary 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 >18000 and 4300calibrated 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 4200years 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.

Alluvial paleosol–sedimentary sequences containing animal fossils, and paleobotanical and paleopedological archives have a potential for reconstructing Quaternary paleoenvironments in Southern Mexico and for understanding the paleoecology of Pleistocene megafauna. In the section of Axamilpa river four pedostratigraphic units were recognized. The lower Gleyic and Vertic pedological Units are at the end of marine isotopic stage (MIS) 3 while the upper Humic and (most probably) Calcic Units correspond to MIS 2 according to the radiocarbon dates of humus. The micromorphological analysis indicates an incipient development and syn-sedimentary character of paleopedogenesis in the periodically water-saturated environment (indicated by redoximorphic features, hydrogenic carbonates and low values of magnetic susceptibility in most strata). The δ 13 C values of the paleosol humus range from − 22.6 to − 24.7, indicating a C3 vegetation, whereas in the modern soil it is higher (− 15.2) pointing to an abundance of the C4 and CAM plants. The δ 13 C signature of the vegetation inferred from the teeth enamel of the fossil fauna appeared to be less negative than that of humus from corresponding paleosols. The alimentary preferences of the paleofauna which fed on grasses with high proportion of C4 plants explain this difference. The phytolith analysis shows dominance in conifer forms, followed by C4 and C3 grasses. The content of conifer phytoliths is progressively reduced towards the top of the sequence. We interpret the Late Pleistocene landscape of this area as a heterogeneous forest–grassland landscape with the forest shrinking through time and the grass areas increasing. Swampy floodplain meadows (inferred from paleopedological results) could provide a habitat for grassy vegetation. Both isotope and phytolith records demonstrate a contrasting difference between Pleistocene and recent vegetation dominated by xerophytic shrubs and succulents. This vegetation change could play important role in the extinction of Pleistocene megafauna.

In the past four thousand years, Luvisols with a clearly differentiated profile have developed on kurgans of the Bronze Age under beech and oak stands in humid climatic conditions of the foothills of the North Caucasus. The great height of the kurgans (up to 10 m) and their homogeneous composition (the kurgans were constructed of Chernozemic soil and are underlain by Chernozem) make it possible to study the direction and rate of pedogenetic and diagenetic processes acting at a considerable depth. In these kurgans, the profiles of Luvisols are underlain by the carbonate-illuvial horizon that has been shaped by illuviation processes acting for about 4000 years. The major part of this horizon lies at the depths of 110–350 cm, though carbonates penetrate as deep as 9 m along the deep earthworm burrows. At this depth, they occur within the noncalcareous mass of the lower part of the kurgans' bodies and in the upper part of the underlying Chernozem. At the depth of 5–9 m, in the kurgans and in the buried Chernozem, gypsum and iron pedofeatures (nodules and red-brown films on ped faces) have appeared. Humus-clayey infillings are present in some of the earthworm burrows at this depth. The formation of such a deep profile with the carbonate-illuvial, gypsiferous, and ferruginated horizons is related to the local bioclimatic conditions characterized by high precipitation and the growth of forest vegetation. Deep washing of the soil with atmospheric precipitation is combined with the manifestation of illuviation processes and alteration of the soil mass at a considerable depth. The mineralization of humic substances and some alkalization of the soil mass also take place in the deep horizons. However, these processes may occur at different depths independently from the illuviation processes and can be attributed to the group of diagenetic processes.

[EN] Researchers have related the manufacturing technique of plasters and stucco in the Maya area with their period of production but not with their architectural function. In this paper, we establish a relationship between those three features (manufacturing technique, age, and architectural function) in the plasters of the Maya site of Dzibanche in southern Quintana Roo. Dzibanche has abundant remains of stuccos and plasters found mainly in three buildings (Plaza Pom, Pequena Acropolis, and Structure 2). We used thin sections, SEM and XRD, and archaeomagnetic dating processes. The pictorial layer of Structure 2 was the earliest (AD 274-316 and the stuccoes and plasters of the other two buildings were dated to the Middle Classic (AD 422-531), but we obtained different archaeomagnetic dates for the red pigment layers found in the buildings of the Pequena Acropolis and thus we were able to determine their chronological order of construction. The raw materials and proportions were carefully chosen to fulfil the mechanical necessities of the architectonic function: different proportions were found in plasters of floors, in the external walls, and inside the buildings; differences between earlier and later plasters were also detected., We acknowledge the archeological project of Dzibanche and Centro INAH Quintana Roo who generously allowed the extraction of the samples for this study; also we acknowledge the Universidad Nacional Autonoma de Mexico that gave a grant that allowed a three month research in the laboratories of the Universitat Politecnica de Valencia. Financial support for the analysis of organic materials is kindly acknowledged; it was provided by the Spanish MINECO R+D project CTQ2014-53736-C3-1-P and also supported with ERDEF funds. The authors thank Jaime Diaz for his assistance in preparing thin sections.

A fragipan is a diagnostic subsurface soil, not a cemented horizon, which is characterised by high density, and so restricts root penetration and water percolation. Although fragic horizons are considered to be pedogenic, the exact genesis of this phenomenon is not well understood. Quantitative study of pore space characteristics in a profile with a fragipan could help in understanding its origin and its pedogenic links to the other diagnostic horizons. Micromorphological and morphometric study of the porous network in soil thin sections and computed tomography in an Albic Fragic Retisol (Cutanic), formed in glacial till of Valday (Wurm) Glaciation in the South Karelia region in the north of Russia, showed a differentiation of pores by shape and distribution for each soil horizon controlled by the type of soil-forming processes. In particular we detected a difference in pore space organisation in the fragic EBx compared with other horizons. The pore space in the EBx was mainly represented by closed micropores, spread homogenously in the soil horizon body, independent of fissure and packing pores. Thus we propose that the pore system in this horizon was heterochronous, with micropores formed at the time of structural collapse and the fissures and other pores formed later.

Tepetates are indurated subsoil horizons developed in tephra-derived materials in various parts of the Trans-Mexican Volcanic Belt. The term ‘tepetate’ includes fragipans, duripans, pedosediments and saprolites, derived from vitric rhyolitic tuff, Pleistocene volcanic ashes or pyroclastic flows. All soils with tepetates are at high risk of erosion and so they have been intensively studied for decades. The tepetates are common in Tlaxcala State of central Mexico, being formed under Ustic Isomesic soil climate. The aim of this investigation was to characterise the pore space of fragipan-type tepetates and the role of clay components in their formation. We studied porosity of tepetate from a tephra-palaeosol sequence in the north of Tlaxcala State, in undisturbed soil samples. Observations of pore space were made in 2D and 3D by analysing microscope images of thin sections and cross-sectional images from a computed tomography scanner. In the thin sections we also identified and described clay illuvial pedofeatures. Micromorphological observations showed two main pore types. Small rounded pores had a homogeneous distribution and were probably formed before the clay illuviation process that took place in a palaeosol formed on the tepetate material. The distribution pattern of the small pores in the studied tepetate was similar to that in the fragic horizon, which was probably formed by a hydro-consolidation process. Large crack-pores were formed during the palaeosol formation. Later these large pores were filled by illuvial clay coatings and so we conclude that each tepetate was part of the set of Bt horizons in the palaeosols of Luvisol type.

Carbonate materials – limestone and lime stuccos – were widely used in ancient Maya construction. Deterioration of these materials presents a major problem for the conservation of Maya architectural heritage. However, the mechanisms of deterioration and their interaction with the diverse inner structures of these materials are still insufficiently understood. We performed micromorphological and mineralogical research of the limestone alteration in the buildings of Rio Bec and stuccos in Dzibanche, two Late Classic Maya sites in the southern Yucatan peninsula. Dissolution and recrystallization of calcite were found to be universal and the most important weathering process in both materials. Dissolution is selective, affecting mostly micrite. Larger crystals, especially rhombohedral calcitic pseudomorphs developed after dolomite, are more stable. Selective dissolution of micritic cement of limestones and stuccoes enhances physical breakdown by producing numerous pores and loosening bounds between coarser inclusions. This process clearly controls the deterioration grade of different limestones: those with more intensive fragmentation and powdering have higher contents of micrite. Secondary carbonates are represented mostly by acicular calcite filling fissures and forming coatings on the outer surface. Clear spatial relation to fungi and roots and their similarity to well-known soil neoformations indicate biogenic origin of these neoformations. In most cases, they contribute to macroscopic powdering being loose. However, in the cracks of some limestones they form dense infillings, which could plug the fractures and prevent further advance of weathering to the core of the stone. Neoformed sulfates and iron oxides are fewer, but also participate in the deterioration.

The methodological properties related to planning of modern lesson meeting the requirements of the Federal State Educational Standards (FSES) are considered in this paper. On the example of a mathematics lesson in the secondary school the expected educational results of pupils are described, and requirements to lesson structure are formulated. Some particular variants of fi lling the lesson’s stages with educational activities which parameters meet the FSES requirements are proposed. The author puts forward approaches and methodical solutions, which allow focus a lesson to achievement of subject, metasubject, and personal educational results. At the same time, according to FSES’ objective on forming of pupils’ individual educational paths, the pedagogical situations requiring educational activity correction are simulated and analyzed. In such a case for the category of less successful pupils it is proposed an extension of educational activity related to external motivation for learning, and therefore more oriented towards the achievement of a meta-subject and personal results. For more successful in this subject’s area pupils the focus is made on intrasubject motivation, and more intensive advancement in the subject area.

Grain size analyses, bulk and clay mineralogical data were used to characterize weathering within the loess-paleosol-sequence of Oberlaab in Upper Austria. Soil horizons can be clearly identified by the calculation of weathering index Kd from granulometric parameters. The mineralogical composition of the bulk samples shows increasing weathering intensity from the top to the bottom. The weakest weathering stage 1 is not present in Oberlaab, because all samples are free of carbonate minerals. Weathering stage 2 can be found in the upper part of the profile, whereas stage 3 is mainly present in the lowermost horizons. The highest weathering stages 4 and 5 are not present in Oberlaab. The clay mineral distribution in the profile is dominated by the disappearance of primary chlorite in the upper part of the profile and the neoformation of vermiculites from illite by pedogenesis in the lower part. Two different types of mixed layer minerals were found in the pedocomplexes. An illite/chlorite mixed layer mineral occurs following the disappearance of chlorite and is present in the Eemian luvisol. The second mixed layer mineral consists of illite/vermiculite and is present in the whole profile. The weathering stages obtained from the clay mineral composition are slightly lower than that of bulk mineralogy, but reach as well stage 3 in the lower part of the profile., research

Paleosol sequences along the lowest terraces of the Usumacinta River in southern Mexico were used to reconstruct Holocene environmental changes and examine human–environmental interactions. Study sections were correlated through paleosol morphology, radiocarbon dating, and artifact seriation of Formative, Classic, and Postclassic ceramics. The oldest paleosols have gleyic features. Although they contain hard carbonate concretions dating to 5450–5380 cal. yr B.P., these Gleysols formed in the Late Pleistocene to Early Holocene. Carbonates were deposited later. The uppermost paleosols lack gleyic features, the oldest of which contains vertic features, dating to 2000– 2700 cal. yr B.P., and contains abundant Formative period ceramics. The upper two paleosols are morphologically less developed and are strongly affected by human activities; radiocarbon ages and ceramic assemblages indicate that they belong to the Maya Classic and Postclassic periods. Stable carbon isotope values from the decalcified organic matter vary among paleosols of different ages and sites. δ 13 C values are highest (−16 to −20‰) in the Formative period paleosol. Although it is possible that maize cultivation could contribute to the isotopic signatures, we believe that the δ 13 C values indicate the dominance of drought-resistant C4 and CAM vegetation due to their association with vertic soils. The Classic period paleosol has a slightly lower isotopic value (−20 to −22‰), while the Postclassic paleosol shows the lowest values (−22 to −23‰), suggesting reforestation of the floodplain. These results indicate that the Early Holocene paleosols formed in a humid climate similar to that of today, which transitions toward dryer conditions around 5500 cal. yr B.P. In the Late Holocene (approximately 3000 B.P.) an increase in seasonality occurs. This condition favored the formation of Vertisols, suitable for agriculture. C � 2013 Wiley Periodicals, Inc.

Although archaeologists have generally assumed that the ancient landscape in the Teotihuacan Valley was somewhat similar to the present day, recent research has documented large-scale modification of the soil by accelerated human-induced erosion–sedimentation processes from the pre-Hispanic and Colonial periods up until the present. Consequently, the Formative and Classic period soil (approximately 400 B.C.–A.D. 650) is buried in most of the Teotihuacan Valley. Recent soil survey and archaeological excavation have shown that the modern soil horizon differs remarkably from the Teotihuacan soil horizon. In this paper, we present a pedogenic interpretation of the Teotihuacan paleosol referred to as the Black San Pablo Paleosol (BSPP), which contributes to the reconstruction of regional paleoenvironment and human-induced processes. The BSPP has been identified in both natural landscapes and under Classic period Teotihuacan buildings, as well as inside the fill of the Moon Pyramid. Maize pollen and phytoliths testify to the soils use for agriculture, whereas diatoms and phytoliths indicate irrigation practices. These results are supported by soil micromorphology. The evaluation of agronomic properties of the BSPP indicates qualities suitable for agriculture; however, water infiltration is low, indicating possible problems with seasonal water saturation.

Cenotes (natural wells or sinkholes) comprise the most common landscape features in the northern Maya Lowlands of the Yucatan Peninsula, Mexico. Detailed study of dated soil-sedimentary sequences, recovered from a cenote at the archaeological site T’isil and nearby wetlands, allows a partial reconstruction of environmental variability at the site for the last 2000 years. Biogenic calcite sedimentation and Calcisol development occur during three intervals of increased inundation in cenote and wetland environments, ca. A.D. 300, A.D. 1000, and A.D. 1300. Periods of increased inundation in the cenote and wetlands correlate with wetter climatic intervals, and periods of Maya occupation at sites in the Yalahau region. Evidence for Maya modification of the cenote environment may relate to regional wetland agricultural practices.

Two paleosol-sedimentary sequences Koskovo and Puzbol developed within the nearest periglacial zone of Valday glaciation of the East European Plain (56.7°–58.5° N, the Upper Volga River basin) were studied to reconstruct soil mantle and landscape evolution since Marine Isotope Stage (MIS) 3. The sequences are formed on terraces at 130–141 and 172 m a.s.l., constituted by ancient (Early Valday (Wurm) or Late Moscow (RissII)) lake clayey sediments. The buried paleosols are represented by system of horizons Hb–G3b (Histosol), Agb–G3b and AGb horizon (Umbric Gleysol). The 14 C age of the paleosol humus and peat varied between 50,300–39,700 cal. BP. These paleosols were developed under forest-tundra and pine-spruce forests with the meadow plant communities and the areas of swampy vegetation according to palynological data from Puzbol. They represent the northernmost occurrence of the MIS3 fossil soil in Europe dominated by the features of gleyzation, cryogenic aggregation, cracking, and humus and peat formation. Clay coatings in the Middle Valday paleosols and pedosediments are products of Holocene pedogenesis. The upper lithological layers covering the MIS3 paleosols are loess-like (mantle) loams underlain by clayey Late Pleistocene lake deposits. They mark the presence of wide extraglacial lakes with existed within the Upper Volga basin during the maximum advance of the Valday glaciation (MIS2). Based on the stratigraphy of the studied sections, the highstands of these Late Quaternary lakes might exceed ≈170 m a.s.l. For the first time it was possible to date the age of humus-clay coatings developed in the Bthk3 horizon (c.1.6–2.0 m) of Puzbol where in the upper part of the section the Cutanic Albeluvisol formed. The Early Middle Holocene age of humic acid of humus-clay coatings (≈10,900 cal. BP) and carbonate nodules 7500–8180 cal. BP refer to the first stage of pedogenesis of this polygenetic soil, which occurred from pre-Boreal to the Atlantic period, and was characterized by dark humus accumulation and carbonate precipitation in a poorly drained landscape. The 14 C age of the fulvic acids of these coatings (≈6130 cal. BP) is indicative of the beginning of the second stage, dominated by clay illuviation under a better drained, leaching environment.

The Alexandrovsky quarry exposure (near Kursk, central European Russia) represents one of the most complete and detailed records of paleosols, colluvial sediments and loess for the last glacial-interglacial cycle in Eastern Europe. The buried toposequence of Mikulino (Eemian) paleosols, developed on a gully slope cut in the Dnepr (Riss) loess and overlain by Early Valdai (Wurmian) colluvium, was subjected to detailed morphological study. The paleosol on the upper slope is an Albeluvisol that contrasts from the Holocene Chernozem. Analysis of thin sections of the Albeluvisol demonstrated that elluvial features – concentrations of bleached silt in the pores and in the groundmass – dominate not only in E and EB but also in the Bt 1 horizon. They also penetrate into lower Bt 2 and Bt 3 horizons where they combine with illuvial clay pedofeatures. The paleosol profile at the bottom of the gully shows synsedimentary development with several A, AE and E horizons reflecting several phases of geomorphic activity as a response to a complex environmental history during the last interglacial. The shift from dark humus accumulation under grasslands towards forest pedogenesis dominated by clay illuviation and stagnic processes comprised the major trend of the Mikulino (Eemian) soil evolution.

Resumen Numerosos trabajos han demostrado la relacion existente entre la mineralogia magnetica de suelos y paleosuelos y las variaciones climaticas y ambientales, o el efecto de la contaminacion en los mismos. Con el proposito de analizar esta relacion en una toposecuencia del valle de Teotihuacan, se llevo a cabo un estudio de las propiedades magneticas en cinco suelos y un paleosuelo desarrollados en depositos volcanoclasticos distribuidos en diferentes posiciones del relieve entre 2250 y 3060 msnm, que incluyen: dos Cambisoles, un Calcisol, dos Fluvisoles y un Vertisol. La mineralogia magnetica fue caracterizada a traves de tecnicas de magnetismo de rocas que determinan la composicion, concentracion y distribucion de tamanos de dominio de los minerales magneticos, y esta caracterizacion fue comparada y validada con parametros no magneticos. Los resultados de la investigacion muestran que existe una marcada diferenciacion de las propiedades magneticas en funcion de las condiciones ambientales de cada suelo y su grado de pedogenesis. Las caracteristicas magneticas varian entre dos extremos: 1) los Cambisoles contienen mayor concentracion de minerales magneticos de mayor tamano; y 2) los Fluvisoles presentan bajas concentraciones de minerales magneticos dominados por particulas finas. El Calcisol presenta variaciones entre estos dos extremos, tanto en la concentracion de minerales magneticos como en su tamano, mientras que el Vertisol presenta baja concentracion y tamanos gruesos. A diferencia de lo que sucede en las secuencias de loess-paleosuelos que registran un aumento en susceptibilidad magnetica ( χ ) en la parte superficial, originado por un incremento de minerales ferrimagneticos y antiferrimagneticos de tamano fino DS y SP, los realces observados en un Cambisol y un Fluvisol de Teotihuacan se deben a la incorporacion de nuevos materiales de origen volcanico y fluvial en la superficie. Por el contrario, las mayores concentraciones de particulas SP y DS ocurren en general en los horizontes inferiores. En ellos es debil aun la formacion de minerales magneticos pedogenicos, tanto ferrimagneticos como antiferrimagneticos. La baja magnetizacion intrinseca de estos ultimos y la proporcion relativamente baja en la que se presentan ocasionan que sea dificil su deteccion, ya que quedan enmascarados por las fases ferrimagneticas. Nuestros analisis muestran las parti-cularidades de suelos desarrollados en materiales volcanicos y el potencial de los estudios de propiedades magneticas en combinacion con otros indicadores pedogeneticos en las reconstrucciones de las condiciones ambientales en el pasado.Palabras clave: mineralogia magnetica, suelos volcanicos, toposecuencia, valle de Teotihuacan.

Factors controlling spatial soil organization have recently attracted the attention of soil scientists because they can contribute to regional management of soil resources. We present here a case study in the Glacis de Buenavista (Mexico), an extended volcanic piedmont, in order to develop an integral understanding of its soil cover as a product and, at the same time, as a record of the main stages of landscape evolution. Three phenomena were considered: Luvisol and Vertisol type soils, and pedosediments, all of them analyzed in terms of their development degree (clay content, macro and micromorphology, selective extractions of Fe (Fed, Feo), silicon (Sio) and aluminum (Alo), weathering index and clay mineralogy). Luvisols, represented in the Ahuatenco, Mexicapa and Buenavista sections, are located in the northern and central part of the area. They are red-clayey, polygenetic soils that show strong weathering (with high kaolinitic clay content and high weathering index values), clay illuviation, and reductomorphic processes, combined with vertic features in some parts of the profiles. Vertisols dominate the central and southern portion of the Glacis. They exhibit cracking, angular blocks with wedge-like shapes, slickensides and stress-cutans. The pedogenesis of the Vertisol type is clearly associated with the presence of smectitic minerals in the clay fraction as a product of neoformation. Factors controlling this pedodiversity are: relief, which affects bioclimatic differentiation within the studied landsurface and defines the lateral redistribution of moisture and dissolved substances; and time. Luvisols represent a longer pedogenetic phase that started in the Late Pleistocene, according to the age of buried paleosols, while Vertisols mainly originated in the Late Holocene (according to the age of buried organic horizons). Pedosediments are located in the central area of the Glacis. Here, past and present geomorphic processes interact to produce the greatest soil diversity. The recent human-induced erosion partly destroyed polycyclic Luvisols and exposed ancient subsurface pedosedimentary strata. At the same time it produced patches of unconsolidated pedosediments consisting mostly of redeposited Luvisol materials.

article i nfo At the Tongoy palaeobay in north-central Chile, a series of beach ridges developed during seaward progradation that took place after the MIS 11 sea-level highstand (412 ka). The microrelief left by this succession of beach ridges has been well preserved from erosion due to the development of a calcrete (petrocalcic horizons), which was resistant to the chemical and physical weathering that characterized the area during humid phases of the late Pleistocene and middle Holocene. Macro- and micro-morphological analysis shows that the calcrete is of pedogenic origin and formed during two stages: in the first stage a massive (beta) calcrete developed, followed during the second stage by a laminar (alpha) calcrete. Each event in the development of the calcrete was intimately related to the foregoing process, mainly due to changes in the permeability of the profile horizons. During the first stages of development, organisms played an important role in the precipitation of calcite, which made the calcrete less permeable and favored the accumulation of ponded water during the wet season. As a result of this increased humidity, calcium carbonate with a laminar structure was precipitated. The development of the calcrete was also intimately associated with the evolution of the drainage network, which is characterized by a trellis pattern of tributaries parallel to the beach ridges. This study demonstrates the importance of soil genesis in the geomorphological evolution of landscapes.