Peat Deposits Research Articles

New multi-proxy record shows potential impacts of precipitation on the rise and ebb of Bronze Age and imperial Persian societies in southeastern Iran

The Achaemenids and Sasanian ‘Persian’ Empires were significant political, economic, and social forces in the Late Iron Age and Late Antiquity Eurasia, respectively, which have left marks on the heritage of the Mediterranean and Middle Eastern world. While attention is often focused on military and political conditions when discussing the prosperity and decline of these imperial powers, their realms, which crossed a variety of environmental settings, were highly dependent on the predictability of rainfall that drove agriculture and effective provisioning. Here, we present a multi-proxy sedimentological, geochemical, and palynological record from a 2.5-m long peat deposit near the excavation site in Konar Sandal near Jiroft in southeastern Iran, covering 4000-850 cal yr BP. Around 3950 cal yr BP a wet period prevailed based on elemental ratios, stable C isotope, pollen, and diagnostic lipids. Between 3900 and 3300 cal yr BP, wet/semi-wet conditions developed with the appearance of Cerealia-type pollen. Dry and windy conditions followed (ca. 3300-2900 cal yr BP), which coincided with the Siberian anticyclones and climatic shifts developing in the Eastern Mediterranean region. Consequently, the Bronze Age settlements around Jiroft, dependent on agriculture, underwent a steady decline. A prolonged wet period followed (ca. 2900-2300 cal yr BP) with the abundance of Sparganium-type pollen and the aquatic lipid proxy (Paq). This change coincided with intensive agricultural practices and the flourishing of the powerful Median and Achaemenid empires. The shift to high Ti/Al ratios coeval with the lowest δ13COM values suggests an increase in aeolian activity and dry conditions ca. 2100-1650 cal yr BP. The Jiroft valley again experienced wet conditions between 1550 and 1300 cal yr BP, which overlapped with the economic prosperity of the middle to late Sasanian empire. The paleoenvironmental reconstruction indicates that wet periods and intensive agriculture coincide with the Persian empires' zenith, political influence, and economic affluence. Therefore, contextualized and detailed paleoenvironmental records are desirable to explore the interplay of political and climatic factors in the development and fragmentation of the ancient settlements and imperial powers in Eurasian history.

Experimental Investigation of Consolidated Undrained Shear Behavior on Peaty Soil in Dian-Chi, China

Peat deposits are extensively distributed worldwide, and the various common engineering-failure problems involving peat have attracted greater attention from researchers in regard to understanding the mechanical behavior of peat. This study investigated extensive index and consolidated undrained triaxial compression tests applied to the peaty soils of Dian-Chi Lake, located in Yunnan, China. A series of consolidated undrained triaxial compression tests on peat specimens were carried out in this study, and the influences of confining pressure, organic matter content and strength parameters were investigated. The test results indicate that, to obtain a B-value greater than 0.98, the average back pressure of the Dian-Chi Lake peaty soil should be at least 150 kPa, with organic matter contents N ranging from 30% to 85%. Compared with the existing oedometer consolidation results of the research team, the values of compressibility and permeability behavior under the oedometer and isotropic consolidation conditions are not significantly different. In addition, the average failure strain, εf, ranged from 9% to 15% for the investigated normally consolidated specimens, and the average effective angle of internal friction was 43.8°, which is greater than the maximum internal friction angle of 35° for typical soft clay and silt soils. A correlation was proposed by curve fitting the experimental data to better capture the nonlinear relationship between φ′ and N. Furthermore, the values of the normalized undrained strength, Su/σc′, varied from 0.56 to 0.84, which is larger than that of the inorganic soft clay and silt deposits.

Hydroclimatic changes since the Last Glacial Maximum recorded in mountain peat deposit on the southwestern margin of the Sichuan Basin, China

Knowledge of the hydroclimatic changes in Southwest China since the Last Glacial Maximum (LGM) is crucial for disentangling the long-term evolution of the Asia Monsoon and predicting the future fate of the mountain peat deposit in the Asia Monsoon region. In this study, we obtained a 530-cm-long peat core from the Ganchi wetland in Southwest China and analyzed its geochemical indices, including total nitrogen (TN), total organic carbon (TOC), stable carbon isotope composition of organics (δ13Corg), and the concentration of several major elements, to investigate the sedimentary and hydroclimate evolution since the LGM. We found that the peat strata in the Ganchi wetland have developed gradually from 13.7 cal kyr BP, which is likely ascribed to the warm climate during the Bølling-Allerød (B/A) period. TOC, δ13Corg, K/Ti, and Fe/Mn records showed notable paleoclimate shifts since the last deglaciation. The first warming period after the LGM was observed starting at 18.2 cal kyr BP, which is consistent with other records from Southwest China. The reconstruction results show that the western margin of the Sichuan Basin during the last deglaciation was most affected by the East Asia summer monsoon (EASM), and less affected by the Indian summer monsoon (ISM). The climate of the early Holocene (11.2–7.5 cal kyr BP) was affected by both the ISM and EASM, resulting in more complex local climatic features. The Holocene Megathermal period observed from 7.5 to 3.5 cal kyr BP, is consistent with the timing detected in other records of Southwest China.

Assessment of Carbon Stock at Oil Palm Plantation in Klias Peninsular West Coast of Sabah

The assessment of carbon stocks in oil palm plantation were carried out in the Klias Peninsular West Coast of Sabah. The geological setting of the oil palm plantation mainly consists of Crocker Formation and Quaternary Alluvium which in mainly composed of peat soil. The peat soil from 10 sites was collected for the carbon percentage values and physico-chemical analysis. The geophysical surveys were performed to measure the thickness of peat deposits and the water table, which influenced the value of carbon stocks. The geochemical analysis of the peat soil at 0.5m depth shows an acidic pH value (3-4) and a high organic matter (30-100) %. The results of the geophysical surveys show the water table in oil palm plantation ranging from 0.3m-1.5m. Moreover, the thickness of peat as carbon storage at oil palm plantation varies from 0-6m. The bulk density obtained at selected depth varies from (0.09-0.59) g/cm3.The carbon stock in oil palm plantation is calculated around 50 tanC/ha - 900 tanC/ha. Site OP7 shows the highest carbon stock (947.73 tanC/ha) compared to site OP1 (91.33 tanC/ha). The high estimated carbon stocks resulted from a high-water table and a thick layer of organic matter.

Provenance changes for mineral matter in the latest Permian coals from western Guizhou, southwestern China, relative to tectonic and volcanic activity in the Emeishan Large Igneous Province and Paleo-Tethys region

Recent studies have found that the provenance for water-transported sediments in some coal seams in the Late Permian and Early Triassic sequences from SW China have changed from mafic rocks of Emeishan Large Igneous Province (ELIP) to intermediate-felsic and alkaline igneous rocks from the ELIP and Paleo-Tethys convergent margins. However, the mechanism of provenance changes for mineral matter in the late Permian coals from SW China remains unclear. This paper uses the detailed mineralogical and geochemical characteristics of the latest Permian coal-bearing strata from the Huopu coal deposit in SW China to identify the potential detrital provenances of mineral matter.The mineralogy of the Huopu coals is dominated by kaolinite, quartz, and calcite. Fracture-filling kaolinite, calcite, quartz, anatase, as well as closely coexisting fracture-filling kaolinite, quartz, and chamosite, were possibly formed by multiple-stage solution injections. The Al2O3/TiO2 values, REY distribution patterns (REY, rare earth elements and Y), as well as Nb/Yb vs. Al2O3/TiO2 and Zr/TiO2 vs. Al2O3/TiO2 diagrams all indicate that the roof and floor sediments of the coal seam were sourced mostly from the ELIP high-Ti basalts. In contrast, the inorganic matter of the coals was derived from the Kangdian tops exposing (1) the Proterozoic meta-granitic complex; (2) the ELIP’s volcanic complex including, in addition to basalts, alkaline and intermediate-felsic lavas and small intrusions; and (3) volcanic ashes from the Paleo-Tethys convergent margins. The latest Permian sedimentation in the Huopu coal deposit is suggested to have been controlled by tectonic activity along the Xiaojiang Fault that separates the inner ELIP from the Western Yangtze Cratonic Basin (WYCB). This activity is characterized by repeated uplifts of the inner ELIP associated with some downward movements in the WYCB and vice versa. The ELIP uplift and WYCB subsidence may have led to intensive erosion of the ELIP basalts and marine transgression producing the clastic sediments, while the ELIP’s downward movement associated with some WYCB uplift may have promoted peat deposition and erosion of the Kangdian tops exposing both the ELIP intermediate-felsic volcanic rocks and the older meta-granitic complexes. Both sedimentation regimes were evidently accompanied by volcanic activity on the Paleo-Tethys convergent margins, but preservation of the volcanic ash layers was possible only during more quiescent peat-accumulation periods. The reduced detrital supply in these periods would result in a higher proportion of the intermediate-felsic pyroclastic debris disseminated in the coals.

Estimation of Physicochemical Parameters and Vertical Migration of Atmospheric Radionuclides in a Raised Peat Bog in the Arctic Zone of Russia

The article presents the results of a study of activity levels and features of the vertical distribution of 210Pb, 137Cs, 234U, 238U and their relationship with the physicochemical parameters of peat deposits. Analysis of the data showed that the vertical distribution of 137Cs and 210Pb was related to the content of water-soluble salts, the water saturation of the deposit, and the values of Eh (oxidation–reduction potential) and rH (relative humidity), which indicates a complex geochemical barrier at a depth of 20 cm in the peat core. The 210Pb dating of the peat core, carried out according to the CF model using the Monte Carlo method (to improve the dating accuracy), showed that the above horizon corresponded to 1963, which is consistent with the data of the 137Cs reference horizon and in terms of several physicochemical parameters (in particular, ash content) also corresponds to the age of 1963, which confirms the correctness and adequacy of the chosen peat core dating model. The peak of anthropogenic radionuclides in peat deposits correlates with a particular major event in the history of radioactive fallout, the Partial Nuclear Test Ban Treaty of 1963, providing a benchmark for geochronological research. The obtained results of the linear accumulation rate, the mass accumulation rate of the peat deposit, and the value of the atmospheric flux of 210Pb are congruent with the data on the peatlands of Northern Europe and the data obtained by earlier analysts of the Subarctic region of European Russia.

Evolution of organic matter quantity and quality in a warm, hypersaline, alkaline lake: The example of the Miocene Nördlinger Ries impact crater, Germany

The Nördlinger Ries (NR) impact crater in southern Germany contains Miocene lacustrine fine-grained post-impact sediments, which were deposited under saline, alkaline, and hydrologically closed aquatic conditions. To obtain information on the organic matter quantity, quality and environmental evolution, samples from one central (NR 1973) and one more marginal (Enkingen SUBO-18) well were analyzed by pyrolytic, organic geochemical and micro-petrographic techniques. Deposits of the marginal drilling can be linked to the thicker stratigraphic units of the well from the lake center based on total organic carbon (TOC), hydrogen index (HI) and lithology. Central deposits contain mainly hydrogen-rich type I kerogen with a mean HI of 447 mg HC/g TOC, whereas the marginal sequence contains type II-III kerogen with an average HI of 206 mg HC/g TOC. In the center, high total sulfur (TS) over TOC ratios of 1.5 on average, and δ13C values of biomarkers in combination with low α-/total MTTC (α-/total methyl-trimethyltridecyl chromans ∼ <0.6) and Pr/Ph ratios <0.2 suggest the prevalence of hypersaline water. Salinity only decreased during deposition of the uppermost Miocene units, when the then shallow alkaline lake turned, at least temporarily, into acidic-neutral conditions during the time of peat deposition. A similar trend, but at overall lower salinities is recorded for the marginal site. Water stratification in the center is stronger than in the marginal domain based on salinity variation. Anoxic bottom water prevailed in the whole lake, as recorded by exceptionally low Pr/Ph ratios (∼<0.2), the occurrence of des-A-lupane and small pyrite framboids (<5 µm) except for the youngest layers of the Miocene lake. Autochthonous, halophilic red algae/plankton prevailed as reflected by abundant C27steranes, while terrestrial material and aerobic bacteria significantly contributed to the OM only in the latest stages of lake as evident from abundant vitrinite/inertinite particles, high values of diterpenes/C27sterane (up to 255) as well as low values of C27-29regular steranes/C29-32hopanes (<0.5). The same trend, but less well resolved, can be seen at the margin of the paleo-lake.

Специфика распространения и тушения торфяных пожаров в зимний период

The article touches upon the analysis the number of peat fires in the Sverdlovsk region for the period from 2016 to 2021. It was found that the number of such fires in 2021 was 11,3 times higher than their average annual number over the past 5 years. It is noted that reason for the sharp increase in peat fires in 2021 is the accumulation of moisture deficiency in the soil and a decrease in the level of ground water. Steady ground fires led to the formation of many local peat fires in the autumn period, which continued to spread even after the snowfalls. In December 2021 28 active peat fires were recorded on the territory of the Sverdlovsk region. All peat fires can be conditionally divided into 2 types. The first type of peat fires is formed for lack of forest stand on the slope of the main drainage channel or on elevated relief elements. Smouldering in the hearth of this type spreads slowly forming cavities up to 2…9 m. The second type of the hearths is formed in the area of the peat deposit with the available forest stand. At the same time the smouldering foci expand under the roots of tree. The snow covering is not the reason for smouldering cessation. But rather maintains it by preserving the temperature to dry the adjacent layers of the peat. Peat fires should be extinguished by uprooting trees and mixing smouldering peat with snow and cold soil, followed by compaction to reduce temperature. Experimental extinguishing of peat fires in march 2022 showed that when using a bulldozer, it is possible to extinguish 0,5 of active foci in one shift.

Soil- and biodiversity of the former peat mines in Shaturskaya Meshchera in the context of their anthropogenic transformation

The problem of pedo- and biodiversity of mire ecosystems under the long-term multiple anthropogenic impact was studied in one of the most intensively technogenically transformed areas of Shaturskaya Meshchera, adjacent to power station Shaturskaya in the north and stretching along the route Kerva – Dolgusha – Severnaya Griva. For more than a hundred years, mires in the Shatura area have been under the influence of drainage, peat extraction, fires, attempts to create agricultural land, secondary watering and pollution, resulting from the power station, transport, and settlements wastewaters. Currently, the bio- and soil diversity of secondary ecosystems has increased significantly compared to undisturbed mires. Instead of bog, in some cases there appeared secondary meadow, grass-shrub communities, small-leaved forests, and dry sparse areas. The remaining bogs experience stable eutrophication, which leads to the formation of mesotrophic and eutrophic phytocenoses and, accordingly, peat mesotrophic and oligotrophic secondary eutrophic soils. In addition, the proportion of eutrophic mires is slightly increased by the peat formation in shallow lakes, which at the initial stage of peat extraction were used for storing wood waste. The phenomenon of secondary oligotrophization of the disturbed bogs of Meshchera, noted in the literature, is not observed in the area under consideration due to a significant anthropogenic load. To preserve the local flora of oligotrophic bogs, marginal areas of flooded quarries and cofferdams with undeveloped peat deposits are of great importance. The increase in pedodiversity was facilitated by the agricultural development of drained peatlands for the cultivation of perennial grasses, which resulted in the formation of torfozems and agrotorfyano-gleyzems.

Vegetation and climate changes since the Last Glacial Maximum inferred from high-resolution pollen records from the Sichuan Basin, southwest China

Reconstructing the vegetation history of southwest China since the Last Glacial Maximum is crucial for understanding the evolution of the Indian summer monsoon. In this study, we present a high-resolution palynological investigation from a 5 m core from the Ganchi peatland (southwest margin of the Sichuan Basin, southwest China) in order to reconstruct regional vegetation and climate over the last 25 kyrs. The succession, from bottom to top, comprises lake, wetland, and peat deposits, and wetland/aquatic pollen types are found to be a sensitive indicator of palaeoenvironmental change. Deciduous broad leaf forests dominated by Betula were present between 25-18 cal kyrs BP, suggesting a cold and dry climate during the Last Glacial Maximum. After 18 cal kyrs BP, temperature and summer insolation increased gradually, marking the Lateglacial transition. Thermophilous and hygrophilous species expanded between 11-8 cal kyrs BP, indicating a progressively warmer and wetter climate. From 8-4 cal kyrs BP, evergreen forests developed, while Tsuga reached its maxim abundance, implying a warm and humid climate coincided with the mid-Holocene climatic optimum. Results indicate that residual ice sheets may have impeded the northward shift of the Intertropical Convergence Zone, resulting in peak Holocene warmth lagging behind peak summer insolation forcing. Vegetation change was primarily controlled by climate, with no obvious evidence of anthropogenic disturbance until the last 1 cal kyrs BP. Our study shows that vegetation and climate in the southwest margin of the Sichuan Basin were controlled by summer insolation and ice sheet dynamics, and also influenced by sea surface temperature in the Indian Ocean.

TOWARDS THE UNDERSTANDING OF THE PRESENT-DAY HUMAN IMPACT ON PEATLAND DEPOSITS FORMED SINCE THE LATE GLACIAL: A “RETROSPECTIVE” AGE–DEPTH MODEL OF THE GREL RAISED BOG (POLISH INNER CARPATHIANS)

ABSTRACTDuring the last 60 years, the thickness of the Grel peatland deposits (Polish Inner Carpathians), was decreased twice: from about 7.4 m in 1962, to 3.9 m in 2019. Pollen analyses of peat deposits performed in 1962 (Koperowa 1962) and 2019 (this study) showed that the peatland deposits have accumulated since the Oldest Dryas Stadial up to the present day. Comparative analysis of both palynological profiles was carried out, which exhibits a high consistency of the percentage of pollen of several taxa for the 10 horizons occurring in both profiles. Based on the age–depth curve made for the new profile, the modeled age for the above-mentioned compliance levels was obtained and based on this age, a “retrospective” age–depth model was elaborated for the Koperowa’s profile. The analysis of both profiles showed that the compaction of sediments did not occur proportionally in the entire sequence. The conducted research indicates that contemporary human activity may significantly affect the whole length of peatland profiles, not only their upper parts, as previously was considered. The reconstruction of the palaeoenvironment (palaeoclimate) based on multiproxy analysis of the peatland deposits is capable to precisely document this phenomenon.

Nature conservation significance of Plav-ІІ, Yamny peat ecosystems of Zhytomyr region

The materials of the Report on environmental impact assessment of peat extraction of the Plav-II deposit in the administrative boundaries of Olevskyi district of Zhytomyr region were analyzed. Nature conservation studies of peat ecosystems of Plav-II, Yamny have been carried out. We do not recommend the development of peat deposits. The territory of the planned activity (the southern section of the Yamny peat deposit) is partially located on the territory of the Emerald Slovechanskyi Kriazh (UA 0000173) facility. Among the animal species included in the Red Book of Ukraine, Lanius excubitor Linnaeus, 1758, Lyrurus tetrix Linnaeus, 1758 were recorded. In the last case, a hen with chicks was noted. This fact testifies to the importance of this locality for the reproduction of the species, since the hatching and hatching of the offspring in grouse takes place in the foci of their moulting in the spring. In addition to the mentioned species, the noted Crex crex Linnaeus, 1758 is a species included in Appendix II of the Berne Convention, ratified by Ukraine. For the first time, new habitats of six plant species listed in the Red Data Book of Ukraine were discovered: Carex chordorhiza Ehrh., Carex heleonastes Ehrh. Dactylorhiza incarnata (L.) Soó (Orchis incarnata L.), Utricularia intermedia Hayne, Salix lapponum L., Salix myrtilloides L. Noted regionally rare species of flora: Parnassia palustris L., Nymphaea candida C. Presl., Carexlimosa L. Monitoring such rare species of higher vascular plants as Andromeda polifolia L., Drosera rotundifolia L., Rhynchospora alba (L.) Vahl, etc. need research. Habitat types from resolutions of the Convention on the Conservation of Wild Flora and Fauna and Natural Habitats in Europe (Bern Convention): C1.222 Floating Hydrocharis morsusranae rafts — Hydrocharis morsus-ranae, D2.3 Transition mires and quaking bogs. One of the features of the flora and vegetation of the Plav-II tract is the absence of adventive, invasive plant species (with the exception of Aronia melanocarpa (Michx.) Elliott). On the other hand, on the drained Yamny peatland, phytoinvasions appear massively, but in comparison there is a much greater and sozologically important diversity of avifauna. It is recommended to create a reserve of local importance Plav-II, as well as justify rehabilitation and renaturalization measures in the Yamny peatland.

Coupled modeling of peatlands carbon cycle and carbon dioxide emission from their peat deposits

COmplex Model of BOg LAndscapes (COMBOLA) is a set of dynamic models of carbon and nitrogen turnover, net ecosystem exchange, water balance, heat and water transport, generation and transfer of CO2 and CH4 in a peat deposit on a number of time scales. Combined modeling of carbon turnover and carbon dioxide emission from peat deposits on an annual time scale is carried out as part of COMBOLA for several bog landscapes in Western-Siberian south taiga. One-dimensional vertical reaction-diffusion model for carbon dioxide emission from peat deposit is combined with compartment carbon cycle model allowing estimate both bog type vegetation changes and greenhouse gases balance under probable climate change or perturbations initiated by human activities. Water table level (WTL) separating aerobic peat layer from the anaerobic one is calculated by means of the whole peat layer depth and its water balance relations. Minimal statistical information is used for calibrating temperature dependencies together with coefficients of heat and water transfer equations. The stationary states of carbon cycle are accompanied by steady average profiles of carbon dioxide concentration and can loose stability under human or climatic perturbations. The model dynamics is simulated with several climatic projections of the IPSL atmospheric circulation model for 21st century with anthropogenic scenarios RCP-2.6 and RCP-8.5.

ВЫНОС МИНЕРАЛЬНЫХ КОМПОНЕНТОВ И ОРГАНИЧЕСКОГО ВЕЩЕСТВА ВОДАМИ БОЛОТНОГО МАССИВА КОЛЬСКОГО ПОЛУОСТРОВА

Removal of mineral components and organic matter by the wetland water is evaluated using the observations on the Pulozero oligotrophic bog (the Kola Peninsula). Precipitation is a source of mineral components for bogs, its mean annual mineralization is 26.8 mg/dm3. The average annual inflow of mineral components per bog unit area is 13.0 t/km2. Their mean annual channel flow modulus (14.8 t/km2) is 38% greater than the modulus of their total loss (10.7 t/km2) from the wetland (by infiltration, discharge, and accumulation). It is explained by the partial discharge of groundwater into the stream channel. The accumulation of mineral components within a peat deposit is equal to 2.3 t/km2 per year, or 17.7 % of fallen ones. The concentration of organic matter in the water of a hummock-ridge complex is on average equal to 140.3 mg/dm3, varying from 68.2 to 200.8 mg/dm3. The modulus of organic substance loss within the complex is on average equal to 38.2 t/(km2 year). Its annual channel flow is 12.5 t/(km2 year). The accumulation of organic matter within the peat deposit reaches 25.7 t/(km2 year), or 67.3% of the organic substance mass formed within the bog microlandscape during a year.

Carbon accumulation dynamics of the Klukva peatland at the southern boundary of broad-leaved forest zone in European Russia

The study is focused on reconstructing the carbon accumulation rate of the peatland Klukva (1 ha) situated at the southern boundary of broad-leaved forest zone within the Oka river basin in European Russia. The age of the peatland is about 9400 cal years BP and it is one of the oldest peatlands within the Central Russian Upland. The results of our experimental study showed that the rate of peat accumulation is ranged from 0.15 to 0.9 mm/year and it was strongly influenced by climatic factors. Two main stages were distinguished in the peatland genesis. The longest was the mesotrophic stage, which began in the Early Holocene at about 9400 cal years BP and ended in the Late Holocene at about 1500 cal years BP. Since 1500 cal years BP there has been a gradual transition of the peatland from mesotrophic to oligotrophic type. The mean carbon accumulation rate during the peatland Klukva development was about 20 gC/(m2yr). This process was most actively going between 2500 and 6300 cal yrs BP, when the rates of peat accumulation increased to 26-29 gC/(m2yr). Nowadays, the carbon stock in the peat deposit of the peatland Klukva is amounted to 175 kgC/m2 and it is comparable with the carbon stocks of boreal peatlands in Northern Eurasia. This means that the oligotrophic peatlands situated at the southern boundary of broad-leaved forest zone, despite the small areas, continue to be a large stock of atmospheric carbon.

Carbon, nitrogen and their stable isotope (δ13C and δ15N) records in two peat deposits of Central Siberia: raised bog of middle taiga and palsa of forest-tundra ecotone

The peatlands in the northern hemisphere accumulated substantially more atmospheric carbon (C) during the Holocene than other terrestrial ecosystems. In this study we applied a multi-proxy record to distinguish variations in dynamics of two peatlands in the boreal belt (raised bog) and the forest-tundra ecotone (palsa mire) in Central Siberia. Carbon and nitrogen content in peatland soils and their stable isotope composition δ13C and δ15Μ) were used to trace likely changes of hydrothermal regimes, vegetation shifts and diagenetic alteration of accumulated peat. Several inter-related allogenic and autogenic forcings have influenced the changes in macroelement content and stable isotope composition of peat with depth. In particular, there were climate-induced and succession-driven vegetation community shifts in domination of plants characterized by specific nutrient requirements, nutrient stoichiometry and fractionation of stable isotope values. The climate and permafrost-mediated processes like hummock uplift affected 13C uptake by Sphagnum mosses in wet and dry periods and changing hydrothermal conditions in peat profiles resulted in perturbations of the nitrogen cycle inducing N loss and enrichment 15N abundance, as well as enhanced decomposition was responsible for enrichment of organic matter in the heavier isotopes. These findings confirm the hypothesis that combined use of elemental and stable isotope composition provide meaningful insights in tracing the hydrothermal conditions and the functional state of peatbogs for paleoecological and paleoclimate reconstructions.

ASSESSMENT OF THE CURRENT STATE OF PEAT DEPOSITS OF BREST, GOMEL AND MOGILEV REGIONS OF BELARUS BASED ON THE ANALYSIS OF SATELLITE IMAGES

Based on the analysis of satellite images of high and ultra-high resolution of the territories of peat deposits of Brest, Gomel and Mogilev regions of the Republic of Belarus, a database of areas of peat deposits that are in an undisturbed state (natural peat wire); disturbed state (areas with the presence of reclamation systems covered with shrub vegetation); drained areas with forest vegetation; drained areas that are effectively used in agriculture; developed areas. The database created in the GIS format made it possible to estimate the remaining peat reserves for each of the deposits, to obtain statistical data on the state and directions of use of the areas of peat deposits. The estimation of the remaining reserves took into account the loss of peat from the depleted areas and the mineralization of organic matter at sites used in agriculture.
 In total, explored peat deposits with an area of more than 10 hectares in Brest region – 469, in Gomel region – 1290
 and in Mogilev region – 1385, the total area of which is 498.9, 530.8 and 221.0 thousand hectares respectively. According
 to the methodology used in the calculations, the remaining geological reserves of peat are: in Brest region - 772.3 million tons, in Gomel region – 798.5 million tons and in Mogilev region – 267.4 million tons.
 Analysis of satellite images of the territories of peat deposits of the studied areas showed that from 30 to 37 % of
 the areas of peat deposits are in an undisturbed state (natural peat swamps). The main part (more than 50 %) in Brest and Gomel regions is a drained land with peat soils of agricultural use, in Mogilev – about 30 %. In all three regions there are
 141 deposits with depleted peat reserves and 1457 deposits (46 % of the total) with geological reserves of less than 40 thousand tons (reserves that are not of interest for integrated peat processing).

RATIONALE FOR CHOOSING OF ORGANIC SAPROPEL DEPOSITS FOR THE DEVELOPMENT IN ORDER TO OBTAIN MARKETABLE PRODUCTS

Based on fund and archival materials of peat and sapropel resources of the Ministry of Natural Resources and Environmental Protection of the Republic of Belarus, design institutes for water management (DIWM) and the fuel industry ("Belgiprotorf"), field studies of the SSI "Institute of Nature Management of the NAS of Belarus", an analysis and assessment of the resources of organic sapropel occurring in peatlands exit of exploitation was carried out. In total, geological surveys of various categories revealed 224 peatlands exit of exploitation, where, along with other types of sapropel, there is organic sapropel, the total volume of which is 162.6 million m3.
 Depending on the ratio of areas occupied by sapropel and peat deposits, thickness and quality composition, sapropels are divided into three groups according to the conditions of extraction: very promising, promising and conditionall promising.
 It has been established that sapropel of an exclusively organic type lies under the layer of the remaining peat at 26 deposits.
 Based on the information received, a database of organic sapropel was developed in the Microsoft Excel program
 and a scheme for placing its deposits on peatlands exit of exploitation of the Republic of Belarus.
 The raw material bases of organic sapropel buried under peat were identified and characterized, which are the most
 promising for development in the near future, from the entire list of deposits, as a result of the analysis.

USE OF PEAT AND SAPROPEL FOR OBTAINING HUMIC PLANT GROWTH REGULATOR

The selection of peat and sapropel raw materials for obtaining a humic plant growth regulator with increased biological activity is experimentally substantiated. The use of peat and sapropel as raw materials for hydrolysis and the production of biologically active preparations makes it possible to transfer a significant amount of microelements into solution. In Lelchitsky district of Gomel region, the raw material bases of peat and sapropel, suitable for obtaining biologically active preparations, have been identified and characterized. The choice of the priority site Pribylovichi with deposits of low-lying sedge and sedge-reed peat and siliceous sapropel is substantiated. Carbonate sapropel is not suitable for obtaining humic preparations due to the low yield of humic acids; its scope is the use as a part of feed additives or as a soil deoxidizer.
 An experimental batch of a humic preparation with established optimal parameters has been produced, which has
 been tested with a positive effect in the field on plot experiments with winter barley and triticale. The preferred option for using a liquid humic preparation isolated from a mixture of peat and sapropel is the pre-clotting of seeds with the optimal concentration of the preparation for this purpose – 0.07–0.10 %. For irrigation under the root the concentration of the drug is 0.004–0.006 %. The humic preparation "Tosagum" was developed, which passed the necessary two-year tests on various crops in specialized centers of the National Academy of Sciences of Belarus.

Evaluation of the wider applications of the alkanol index BNA15 as temperature proxy in a broad distribution of peat deposits

The BNA15 biomarker proxy, which reflects the relative abundance of the branched over the normal C15 alkan-1-ols, was recently proposed as a novel terrestrial paleothermometer and applied to ancient peat deposits to reconstruct past temperature variations across the Holocene. However, to date, a peat-specific calibration for this novel temperature proxy does not exist. Here we analyzed a set of surface and downcore peat samples from Chinese peatlands with a broad range in mean annual air temperature (MAAT) (–3.2 °C to 18.5 °C) and pH (4.7 to 8) to understand the relationship between the BNA15 proxy and temperature in peat deposits. Downcore samples from three peatlands outside China were also obtained to test its wider applicability. Our results show that the variations in BNA15 across multiple surface samples from a single peatland are relatively large, suggesting that we must be careful with the application of BNA15 to reconstruct small amplitude temperature variations. In addition, the BNA15 changes significantly with depth, with higher values in the anoxic catotelm in mid/low latitude peatlands and slightly higher values in the oxic acrotelm in high latitude/altitude peatlands. Combined with concentrations of alkan-1-ols in a subtropical peat core retrieved from central China, we propose that branched alkan-1-ols are predominantly produced at the acrotelm-catotelm boundary. BNA15 has a moderate correlation with the growth temperature (including the months that the daily temperature is over 0 °C) in surface peat samples. In contrast, a strong positive correlation exists between BNA15 and MAAT using catotelm samples from Chinese peatlands (MAAT = 2.03 × BNA15 – 2.33; R2 = 0.95, p < 0.01, RMSE = 2.3 °C). We find no clear correlation between BNA15 and pH in the surface peat samples. The application of the BNA15 index to two forest/woody wetlands from outside of China highlights that care should be taken when applying this index in these environments.