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1.
The development of forest-steppe and steppe chernozems on the Dniester-Prut interfluve in the Holocene was studied on the basis of data on the paleosols buried under archaeological monuments of different ages. The parameters of the mathematic models of the development of the soil humus horizons in different subtypes of chernozems were calculated. They were used to determine the rate of this process and the age of the soils formed on the surface of Trajan’s lower rampart. The climate-controlled changes in the character of the soil’s development in the Late Holocene were differently pronounced in the different subtypes of chernozems. The suggested differentiation of the trends in the development of the humus horizon in the studied chernozems corresponds to the differences in the soil-forming potential of particular areas (as judged from the energy consumption for pedogenesis).  相似文献   

2.
The study of soils of different ages in different physiographic regions of the Crimean Peninsula made it possible to reveal the main regularities of pedogenesis in the Late Holocene (in the past 2800 years). With respect to the average rate of the development of soil humus horizons, the main types of soils in the studied region were arranged into the following sequence: southern chernozems and dark chestnut soils > mountainous forest brown soils > gravelly cinnamonic soils. In the newly formed soils, the accumulation of humus developed at a higher rate than the increase in the thickness of humus horizons. A sharp decrease in the rates of development of soil humus profiles and humus accumulation took place in the soils with the age of 1100-1200 years. The possibility for assessing the impact of climate changes on the pedogenetic process on the basis of instrumental meteorological data was shown. The potential centennial fluctuations of the climate in the Holocene determined the possibility of pulsating shifts of soil-geographic subzones within the steppe part of the Crimea with considerable changes in the rates of the development of soil humus horizons in comparison with those in the Late Holocene.  相似文献   

3.
Geoarchaeological methods were used to study chronosequences of surface soils in the steppe zone and to trace soil evolution during the Late Holocene in northwestern Crimea. It was found that the morphological and functional “maturity” of the humus horizons in steppe chernozems of the Late Holocene was reached in about 1600–1800 yrs. After this, their development decelerated irreversibly. The maximum concentration of trace elements accumulated in these horizons in the course of pedogenesis was reached in 1400 yrs. A new method of pedogenetic chronology based on the model chronofunction of the development of irreversible results of pedogenesis over time is suggested. Original pedochronological data and growth functions—the most suitable models for simulating pedogenesis over the past three thousand years—suggest that the development of morphological features of soil as an organomineral natural body follows growth patterns established for biological systems.  相似文献   

4.
Buried Late Holocene paleosols of the Nienshants historical monument at the junction of the Neva and Okhta rivers (St. Petersburg) have been studied. These soils developed from estuary deposits of the Littorina basin with abundant artifacts of the Neolithic and Early Iron ages (7–2 ka BP). The soil cover of the area consists of the mature dark-humus profile-gleyed soils on elevated elements of the mesotopography (3.0–3.5 a.s.l.) and dark-humus gley soils in the local depressions (2.0–2.6 m a.s.l.). The soils are characterized by the low to moderate content of humus of the fulvate-humate type. The beginning of humus formation in the dark-humus gley soil on the slope facing the Neva River is estimated at about 2600 yrs ago; for the darkhumus profile-gleyed soils of the studied paleocatena, at about 2000 and 1780 yrs ago; and for the darkhumus gley soil, at about 1440 years ago. Judging from the spore-pollen spectra, the development of these soils took place in the Subatlantic period under birch and pine-birch forests with the admixture of spruce and alder trees. The gleyed horizons of the buried soil at the depth of 1.6–1.2 m on the Neva-facing slope date back to the Late Subboreal period (2500–2600 yrs ago), when pine-birch-spruce forests were widespread in the area. The new data contribute to our knowledge of the environmental conditions during the Neolithic and Iron ages.  相似文献   

5.
Fragments of buried Late Pleistocene (30000-year-old) and Early Holocene (10000-year-old) paleosols contained viable complexes of microscopic fungi. The mycobiota of these paleosols represents a pool of fungal spores that is lower in number and species diversity as compared to that in the recent humus horizons and higher than that in the inclosing layers. The central part of the paleosol profiles is greatly enriched in microscopic fungi. In the intact humus horizons of the Late Holocene (1000–1200 years) paleosols, actively functioning fungal complexes are present. These horizons are characterized by their higher level of CO2 emission. The buried horizons, as compared to the recent mineral ones, contain a greater fungal biomass (by several times) and have a higher species diversity of microscopic fungi (including fungi that are not isolated from the recent horizons). Nonsporulating forms are also present there as sterile mycelium. The seasonal dynamics of the species composition and biomass of the fungal complexes were more prominent and differed from those inherent to the surface soil horizons. In the buried humus horizons, the dynamics of the fungal biomass were mainly due to the changes in the content of spores. The data on the composition of the fungal complexes in the buried soils confirm (due to the presence of stenotopic species) the results of paleobotanic analyses of the past phytocenoses or do not contradict them.  相似文献   

6.
Paleosol studies were conducted on the Moskva-Oka interfluve in the center of the East European Plain. Three paleosol complexes were distinguished in the sequence of soil-loess deposits: the Mezin complex of the Late Pleistocene age and the Kamensk and Inzhavin complexes of the Middle Pleistocene. Each of them consisted of the paleosols of two phases: the earlier interglacial phase and the later interstadial phase. In some cases, the paleosols of these two phases were separated by a thin layer of sediments with distinct features of cryoturbation. Paleosols of the interstadial phases are represented by the dark-colored humus-rich meadowchernozemic and chernozem-like prairie soils. During the interglacial periods in the Middle and Late Pleistocene, the soils with pronounced eluvial-illuvial differentiation of their profiles were developed under forest cenoses. Data on the morphology of paleosols; their physical, chemical, and physicochemical properties (particle-size distribution, pH, humus, carbonates, amorphous and crystallized iron oxides, etc.); and their micro-morphological features studied in thin sections prepared from undisturbed soil monoliths make it possible to judge the character of the pedogenesis during different epochs.  相似文献   

7.
The construction of the Volga–Kama cascade of water reservoirs and hydroelectric power stations in the middle of the 20th century resulted in the inundation of vast areas and the development of abrasion along the shores that threatens many monuments of the archaeological and cultural heritage. The soils buried under northernmost kurgans of the Lugovskaya culture dating back to the 15th–14th centuries BC (kurgan Komintern I) were studied on the surface of the second terrace of the Kama River near its confluence with the Volga River. Burial sites of kurgan Komintern III were subjected to destruction in 1981, and archaeological excavations of kurgan Komintern II were performed in 2008. The danger of complete disappearance of these archaeological sites necessitated their thorough study with the use of multiple methods, including special paleosol studies. The soils buried under the kurgans ceased to be active components of the soil cover about 3500 years ago. They preserve information on the paleoenvironmental conditions before their burying. The analysis of morphological features and physical, physicochemical, and chemical properties of the buried soils attests to their chernozemic nature. Background surface soils that have passed through the entire cycle of the Holocene pedogenesis have evolved since that time into gray forest soils (Luvic Greyzemic Phaeozems) under forest vegetation. These soils are characterized by the increased acidity of the surface horizons (pHКСl 4.3) and the development of lessivage. Data on the coefficients of mineral weathering in the buried paleosols and background surface soils attest to the identical precipitation both for the surface and buried soils in the Middle and Late Holocene.  相似文献   

8.
The morphology and chemical and physicochemical properties of paleosols buried at the Upper Paleolithic multilayered site Kostenki-1 in Kostenki–Borshchevo district of Voronezh oblast were studied. Four in situ paleosols formed 20–40(45) ka ago were separated in the archaeological excavation. Together with the surface soils, they characterized two different epochs of pedogenesis—the interstadial and interglacial (Holocene) epochs—and three shorter cycles of pedogenesis. The traces of human occupation in the studied hollow in the Late Paleolithic were found in the layers corresponding to the interstadial epoch. The buried paleosols had a simple horizonation: A(W)–C. A shallow thickness of the soil profiles could be due to relatively short periods of pedogenesis and to the shallow embedding by the carbonate geochemical barrier. The degree of the organic matter humification in the paleosols varied from 0.6 to 1.5, which corresponded to the mean duration of the period of biological activity of 60 to 150 days per year characterizing the climatic conditions of the tundra, taiga, forest-steppe, and steppe natural zones. In the excavation Kostenki-1 (2004–2005), soil–sediment sequences composed of five series of lithological layers with soil layers on top of them were found. Their deposition proceeded in two phases—the water phase and the aerial phase—that predetermined the morphology and composition of the soil–sediment sequences. The history of sediment accumulation in the studied hollow consisted of five stages. Similar morphologies and compositions of the soil–sediment sequences corresponding to these stages attest to the cyclic pattern of their development. The stages of sedimentation and soil formation corresponded to cyclic climate fluctuations with changes in the temperature and moisture conditions. A comparative analysis of the morphology and properties of the paleosols and soil–sediment sequences made it possible to characterize the environmental conditions of ancient humans and the dynamics of the climate during the past 50 ka.  相似文献   

9.
The Late Holocene stage of forest pedogenesis has been studied on the interfluves along river valleys in the forest-steppe zone of the Central Russian Upland. The development of gray forest soils from the former chernozems as a result of the Late Holocene advance of forest vegetation over steppes is discussed. It is argued that the climatic conditions of the Subatlantic period were unstable, so that multiple alternation of forest and steppe vegetation communities took place. This specified a complex character of soil evolution upon contrasting substitution of forest pedogenesis for steppe pedogenesis. On the interfluves near the natural drainage network (balkas, ravines, and steep slopes of river valleys), the climate-driven dynamics of forest and steppe vegetation with corresponding changes in the character of pedogenesis could take place during the entire Holocene, which is reflected in a lower thickness of humus profiles and deeper leaching of carbonates from chernozems of the Early Iron Age in comparison with their analogues formed under steppe cenoses in central parts of the interfluves. Two variants of the evolution of gray forest soils can be suggested: the pulsating evolution typical of balkas and interfluves near river valleys and the continuous progressive evolution typical of automorphic (plakor) positions in central parts of the interfluves.  相似文献   

10.
The humus characteristics in buried Holocene and Late Pleistocene paleosols of the tundra zone have been studied. It is shown that the paleosol sequences encompassing the time span from 55 to 2.5 ka BP contain paleosols with analogous types of humus, attesting to the cyclic repeatability of the corresponding stages of soil formation. A tendency for an increase in the degree of humification in the course of soil development has been revealed. Within the ultracontinental areas of East Siberia, the accumulation of salts accompanied soil formation in the Late Pleistocene and Holocene.  相似文献   

11.
《CATENA》2008,72(3):456-466
Morpho-analytical features of the paleocatena (a complexly organized heterochronous sequence), which contains 2 pedostratigraphical units: formed on the Holocene mantle loams Umbric Albeluvisol and the underlain Middle Valday (Wűrmian) paleopedocomplex developed on Moscowian (Riss II) moraine deposits, are described. The buried pedocomplex consisted of: 1) the paleohumus and paleogley (2Atgb–2Gtb–3Atgb) and 2) paleohumus (3Atgb–3AtGb) horizons. Thus, these pedostratigraphic units reflect two studies of pedogenesis marked by two paleohumus horizons. The horizons of the paleopedocomplex are separate parts of the profile classified as the Umbric Gley soil formed during OIS3. The 14C age of the three paleosol horizons varied between 24,350–30,900 yr BP. The studied paleopedocomplex is the only one known containing the Middle-Valday paleosol formed on moraine deposits, which is a clear sign of the northernmost occurrence of the Bryansk fossil soil in Europe. A detailed hierarchical morphological study of the paleopedocomplex, including meso- and submicromorphological and magnetic susceptibility analyses, allowed us to identify the Late Quaternary pedogenic processes under severe extra-continental climate, including gleyzation, aggregation, cracking and humus formation. Good preservation of these individual pedogenic processes is shown to be a soil memory under the overlapping press of Holocene pedogenesis. It was shown that the clay coating in the Middle Valday of the pedocomplex is a part of the Holocene soil formation. Based on the palynological data, it is possible to subdivide the development of paleovegetation of the area into four stages during which the paleosol horizons had being formed. At the beginning and the final stage of the Middle Valday, the forest–tundra landscapes with inclusions of tundra–steppe associations predominated. During the optimum of Bryansk Interstade, the periglacial pine-birch formations were widespread.  相似文献   

12.
Chemical and optical characteristics of soil humus have been analyzed as “memory” components of the Pleistocene volcanic paleosols in Mexico. We have studied the A1 horizons of buried Andosols of the Nevado de Toluca series and of the modern Andosols formed under different bioclimatic conditions. Data on the organic matter of buried paleosols suggest that Andosols of the Nevado de Toluca series were formed in humid forest ecosystems. Optical characteristics of the humic acids and data on the molecular-mass distribution of the humus make it possible to assume that these soils were formed under pine forests rather than under fir forests.  相似文献   

13.
14.
The evolution of alluvial soils in the Bikin River basin in the Middle and the Late Holocene is discussed. On the basis of biostratigraphic data, four pollen zones have been identified in the soils: Pinus koraiensis-Picea, Pinus koraiensis-Quercus-Sphagnum, Betula-Alnus-Alnaster, and Quercus. A set of soil characteristics (texture, acid-base properties, and the organic matter content and group composition) have also been determined. These data allow us to distinguish between four stages of alluvial soil formation in the Bikin River basin. They characterize humus-forming conditions in the Middle and the Late Holocene. Reconstruction of ancient vegetation conditions makes it possible to conclude that climatic fluctuations were synchronous with changes in the soil characteristics. During the Holocene climatic optimum, humus was formed in a slightly acid medium, and humic acids predominated. In cold periods with increased precipitation, fulvic acids predominated in the composition of humus, and the portion of insoluble residue was high because of the more acid medium. The stages of alluvial pedogenesis in the Bikin River valley follow the sedimentation model of soil evolution. Alluvial gray humus soils evolved from typical gray humus soils under meadow communities during warm periods to gleyic and gleyed soils under birch shrubs and alder groves in colder and wetter periods.  相似文献   

15.
High rates of pedogenesis on unconsolidated volcanic materials imply the accelerated generation of the soil memory. The purpose of this research was to extract the high resolution (centennial scale) paleopedological records from the Late Holocene paleosols of the El Chichón volcano formed during the last 2000 years. We studied buried monogenetic Andosols on the dated tephras and a pedocomplex formed from a set of thin ash layers deposited on older Acrisol derived from shales. Particle size distribution, DCB-extractable Fe, oxalate-extractable Fe, Al and Si, sand and clay mineralogy, organic carbon content and stable C isotope composition in humus were evaluated and interpreted as the elements of the soil memory. However, some differences were found in properties of two buried soils, especially in the kind of A horizons. We attribute such differences of individual Andosols to be caused by ancient human impact because it has been demonstrated that humid conditions persisted during the last 1300 years. Thus the drought that was supposed to provoke the collapse of the Maya civilization at the end of I millennium A.D., should have been a short-term event, below the resolution of this paleopedological record. The Andic Acrisol pedocomplex demonstrated the domination of the humid tropical climate over longer time intervals (probably major part of the Holocene) with possible minor dry episodes.  相似文献   

16.
《CATENA》2008,72(3):444-455
High rates of pedogenesis on unconsolidated volcanic materials imply the accelerated generation of the soil memory. The purpose of this research was to extract the high resolution (centennial scale) paleopedological records from the Late Holocene paleosols of the El Chichón volcano formed during the last 2000 years. We studied buried monogenetic Andosols on the dated tephras and a pedocomplex formed from a set of thin ash layers deposited on older Acrisol derived from shales. Particle size distribution, DCB-extractable Fe, oxalate-extractable Fe, Al and Si, sand and clay mineralogy, organic carbon content and stable C isotope composition in humus were evaluated and interpreted as the elements of the soil memory. However, some differences were found in properties of two buried soils, especially in the kind of A horizons. We attribute such differences of individual Andosols to be caused by ancient human impact because it has been demonstrated that humid conditions persisted during the last 1300 years. Thus the drought that was supposed to provoke the collapse of the Maya civilization at the end of I millennium A.D., should have been a short-term event, below the resolution of this paleopedological record. The Andic Acrisol pedocomplex demonstrated the domination of the humid tropical climate over longer time intervals (probably major part of the Holocene) with possible minor dry episodes.  相似文献   

17.
Morpho-analytical features of the paleocatena (a complexly organized heterochronous sequence), which contains 2 pedostratigraphical units: formed on the Holocene mantle loams Umbric Albeluvisol and the underlain Middle Valday (Wűrmian) paleopedocomplex developed on Moscowian (Riss II) moraine deposits, are described. The buried pedocomplex consisted of: 1) the paleohumus and paleogley (2Atgb–2Gtb–3Atgb) and 2) paleohumus (3Atgb–3AtGb) horizons. Thus, these pedostratigraphic units reflect two studies of pedogenesis marked by two paleohumus horizons. The horizons of the paleopedocomplex are separate parts of the profile classified as the Umbric Gley soil formed during OIS3. The 14C age of the three paleosol horizons varied between 24,350–30,900 yr BP. The studied paleopedocomplex is the only one known containing the Middle-Valday paleosol formed on moraine deposits, which is a clear sign of the northernmost occurrence of the Bryansk fossil soil in Europe. A detailed hierarchical morphological study of the paleopedocomplex, including meso- and submicromorphological and magnetic susceptibility analyses, allowed us to identify the Late Quaternary pedogenic processes under severe extra-continental climate, including gleyzation, aggregation, cracking and humus formation. Good preservation of these individual pedogenic processes is shown to be a soil memory under the overlapping press of Holocene pedogenesis. It was shown that the clay coating in the Middle Valday of the pedocomplex is a part of the Holocene soil formation. Based on the palynological data, it is possible to subdivide the development of paleovegetation of the area into four stages during which the paleosol horizons had being formed. At the beginning and the final stage of the Middle Valday, the forest–tundra landscapes with inclusions of tundra–steppe associations predominated. During the optimum of Bryansk Interstade, the periglacial pine-birch formations were widespread.  相似文献   

18.
Pedostratigraphic levels (PLs) are typical assemblages of soil‐genetic horizons, formed by materials having the same degree of weathering. The pedostratigraphic approach can be very useful to comprehend the formation of the Quaternary soil cover, the environmental evolution of a territory, and to estimate the age of paleosols. A pedostratigraphic study of a Terra Rossa was carried out to understand the soil–parent material origin and to estimate the time of the beginning of pedogenesis. Besides soil and geomorphological survey, the Terra Rossa was analyzed for Fe forms, geochemistry, clay mineralogy, micromorphology, and with scanning electron microscope. Optical dating was applied to obtain age estimates for the deposition of the parent material of soil formation. The insoluble residue of limestone was obtained and analyzed for geochemistry and clay mineralogy. The bedrock is constituted by Quaternary lacustrine limestone, showing pronounced karst landforms. The soil profile is situated in a little dissolution doline and was divided into three PLs: PL1 (0–110 cm) is constituted by cambic and ochric horizons, formed during Holocene in a mixture of colluvial soil sediments and fresh limestone, with aeolian components; PL2 (110–290 cm) includes two argic horizons, which began to form during Late‐Middle Pleistocene in colluvial soil sediments, with few aeolian additions; PL3 (290–330 cm) is constituted by a red argic horizon, with nitic properties, which developed from the insoluble residue of the limestone. The age of PL3 was calculated through a mass balance and an estimation of the limestone‐dissolution rate during the Quaternary, which led to an approximate age of Middle Pleistocene, between 250 and 500 ky BP. The time of the beginning of pedogenesis on limestone can be used as a reference for the tectonic uplifting of the area and emersion of the plateau.  相似文献   

19.
Traditional chemical methods and 13C-NMR spectroscopy were used to study the humus in chestnut paleosols buried under kurgans of different ages (the 16th–15th centuries BC; the 1st, 2nd–3rd, and 13th–14th centuries AD) and under the Anna Ioanovna Rampart (1718–1720) and in their recent analogues on virgin plots. It was found that the decrease in the humus content of the paleosols as a result of the diagenetic processes is exponentially related to the age of the soil burial. The loss of humus from the upper 30 cm of the paleosol buried 3500 yrs ago amounted to 76 ± 14%, and this system did not reach a stationary state. The constants of the humus mineralization in the paleosols were determined. A tendency for an increase in the degree of the organic matter humification in the chestnut soils during the past 3500 yrs was found. With an increase in the age of the burial, the portion of aromatic structures in the structure of the humic acids increased and the portion of aliphatic fragments decreased. The cyclic changes in the composition of the humus related to the secular variations in the climatic humidity were identified.  相似文献   

20.
陇东和陇中黑垆土的发生与演变   总被引:3,自引:0,他引:3  
胡双熙 《土壤学报》1994,31(3):295-304
前人认为,我国黑垆土是现代草原环境条件下形成的。我们通过对陇东和陇中黑垆土理化性质分析,14C年代和孢粉组成的测定。认为这里的黑垆土是由深色埋藏古土壤层和浅色表土覆盖层叠加构成。剖面呈两段性构造。古土壤层由晚更新世晚期开始发育,主要成壤于全新世中期,具有与现代成土环境不相符合的深厚腐殖质蓄积层,理化性质,孢粉成分等残遗埋藏特性。浅色表土层是全新世晚期气候传向旱型化条件下发育的土壤,其性质和现代成土  相似文献   

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