Peat Deposits Research Articles

Using marine deposits to understand terrestrial human environments: 6000-year old hyperpycnal flash-flood events and their implications

Offshore sedimentary deposits preserved in submarine canyons in southern Calabria, Italy, provide evidence for mid-Holocene (ca. 6000 BP) erosion and the transport of organic-rich floodplain sediments by flash-flood (hyperpycnal) flows from the San Pasquale River. Marine geophysical surveys (bathymetry, side-scan sonar) and diver reconnaissance revealed an unusual offshore peat deposit containing plant macrofossils representing local habitats, potentially reflecting human modified landscapes. The 20–30 cm thick organic deposit included a large tree trunk, well-preserved seeds, leaves, sticks and other delicate organics. Textural and microfossil (foraminifera) analysis of associated sediments (sands and muds) indicate that these deposits resulted from hyperpycnal flood events that were deposited as sediment gravity flows within gullies on the canyon margins. Whilst the value of studying in situ submerged prehistoric landscapes is well documented, we demonstrate that reworked floodplain deposits preserved in offshore environments can provide useful palaeoenvironmental information that may not be preserved in terrestrial settings. The botanic archive preserved in submarine flood deposits at San Pasquale affords a unique insight into the local environment in which people lived during the Final Neolithic.

Perubahan Iklim Danau Bandung Purba Berdasarkan Analisis Palinologi, Daerah Cihideung, Lembang, Jawa Barat

IClimate is the prevailing weather condition of an area throughout the year. Climate affects the vegetation in a region. The research aimed to study the climate and humidity change during the Holocene in Bandung Paleo-Lake based on palynomorph analysis. The twenty-four samples were taken using hand drill in 172.5 - 52.5 cm depth, continued with preparation and determination. In this study, descriptive analysis and comparison between pollen, spores and their sediments to show the climate and humidity change in Bandung Paleo-Lake. The results show that the samples which were taken on peat deposits showing four times climate changes in five zones, which characterized by montane forest pollens, i.e. Podocarpaceae and Pinaceae, lowland forest pollen i.e. Commelinaceae, Moraceae, spores from the Family Polypodiaceae, Pteridaceae and Dennstaedtiaceae, and Gramineae at the study area.Keywords: Climate, palaeo, analysis, palinology, Bandung Lake.

Constraints on microbial communities, decomposition and methane production in deep peat deposits.

Peatlands play outsized roles in the global carbon cycle. Despite occupying a rather small fraction of the terrestrial biosphere (~3%), these ecosystems account for roughly one third of the global soil carbon pool. This carbon is largely comprised of undecomposed deposits of plant material (peat) that may be meters thick. The fate of this deep carbon stockpile with ongoing and future climate change is thus of great interest and has large potential to induce positive feedback to climate warming. Recent in situ warming of an ombrotrophic peatland indicated that the deep peat microbial communities and decomposition rates were resistant to elevated temperatures. In this experiment, we sought to understand how nutrient and pH limitations may interact with temperature to limit microbial activity and community composition. Anaerobic microcosms of peat collected from 1.5 to 2 meters in depth were incubated at 6°C and 15°C with elevated pH, nitrogen (NH4Cl), and/or phosphorus (KH2PO4) in a full factorial design. The production of CO2 and CH4 was significantly greater in microcosms incubated at 15°C, although the structure of the microbial community did not differ between the two temperatures. Increasing the pH from ~3.5 to ~5.5 altered microbial community structure, however increases in CH4 production were non-significant. Contrary to expectations, N and P additions did not increase CO2 and CH4 production, indicating that nutrient availability was not a primary constraint in microbial decomposition of deep peat. Our findings indicate that temperature is a key factor limiting the decomposition of deep peat, however other factors such as the availability of O2 or alternative electron donors and high concentrations of phenolic compounds, may also exert constraints. Continued experimental peat warming studies will be necessary to assess if the deep peat carbon bank is susceptible to increased temperatures over the longer time scales.

Pengaruh Deforestasi Dan Tingkat Kebakaran Hutan Terhadap Tingkat Emisi Gas Rumah Kaca

This study aims to determine the effect of the area of Forest Fire and Deforestation Figures on Green House Gas Emission Level. This study uses descriptive quantitative research, with statistical analytical methods. The data source is processed with the Importance-Performance Analysis, so that the area can be used as a reference in reducing the level of greenhouse gas emissions. The provinces of South Kalimantan, South Sumatra and Papua are areas prone to fires which are suspected not to be affected by the high level of Indonesia's deforestation within and outside the Forest Zone, but there may be other factors that play a role in the emergence of the forest fires. It is suspected that among the factors that can be a trigger factor for high levels of forest fires that are directly related to the increase in the number of greenhouse gas emissions, namely the distribution of the peat deposits.

Study of Bottom Sediments of the Chiryurt Reservoir, Dagestan, Russia with a View to their Utilisation in Land Reclamation following Anthropogenic Interference

Aim. To study the physicomechanical and physicochemical properties of bottom sediments of the Chiryurt Reservoir, Kizilyurtovskiy District, Republic of Dagestan, Russia with a view to their possible utilisation as building materials for the production of certain grades of concrete and road asphalt-concrete, as well as for the preparation of soil substrate and as additives to potassium and phosphate mineral fertilizers. Material and Methods . The bottom sediments of the Chiryurt Reservoir, taken from different depths and different reservoir locations, were studied by spectrophoto-metric and granulometric methods. Results. The study identified: particle size distribution of samples of bottom sediments; humus content; soil fertility elements: potassium, nitrogen, phosphorus as well as heavy metal content. Conclusions: 1. Analysis of the bottom sediment samples indicates that the soil fertility elements potassium, nitrogen, phosphorus are not sufficient for them to be used as an independent fertilizer, although they might perhaps be used as an auxiliary additive to a principal fertilizer. The levels of toxicity of heavy metals were found to be very low - much lower than the Maximum Allowable Concentrations. 2. The sediments could be used as soils for the reclamation of land after anthropogenic interference (e.g. after a quarry has been excavated for brick production, after excavations during road construction of roads), for the modification of vertical terrain in settled areas, for landscaping, etc. 3. According to the granulometric analysis of the material composition of the samples, the bottom sediments are 85-90% composed of clay particles (thus there is no need to undertake procedures to separate out the sand fraction). 4. Since peat deposits are present in the bottom sediments of the reservoir, it makes sense to separately assess their volumes for independent development for use as fertilizer for the re-cultivation of floodplain lands.

Geochemical barriers in oligotrophic peat bog (Western Siberia)

Peat bogs play an important role in the functioning of the biogeochemical cycles of the chemical elements that are connected to climatological and environmental changes, at least at the regional level. For several decades, this has made the issue of wetland evolution of particular interest among the scientific community worldwide. A number of authors have studied different aspects of wetland geochemistry and evolution: the chemical composition of bog water and peat, including nutrient dynamics, bog vegetation, hydrological characteristics, and the mineralogical composition of peat. However, some issues remained insufficiently studied, including the distribution of chemical elements in peat deposits and, particularly, the causes of the formation of some minerals in the peat deposits. To research these issues, we estimated the geochemical conditions of the formation of some minerals in the oligotrophic pine-shrub-sphagnum bog and adjacent area (part of the Vasyugan Swamp, Western Siberia) in the winter period of 2017 and 2018. It was revealed that there were no less than two complex geochemical barriers in the peat deposit. These barriers correspond to changes in advective and diffusion flows and result in the accumulation of Fe and some other chemical elements in the peat deposit. The upper complex geochemical barrier of redox, sulfide, and sorption type is located approximately at a depth of 0.40–1.25 m. The bottom barrier, which is the combination of complex geochemical barrier of alkaline and sorption type with mechanical barrier, are located at the bottom layer of the peat deposit, at a depth of 2.25–2.50 m. Accumulation of substances in the upper geochemical barrier is always less significant than in the bottom barrier. Therefore, the probability of detecting high concentrations of various substances is very high in the bottom part of the peat deposit, the organomineral sediments, and the upper part of the underlying mineral ground.

Assessment of Influence of Technological Parameters on Peat Extraction

The article evaluates the weather and hydrological impact on geotechnology when fragmented peat is milled and dried at a peat deposit. The amount of moisture feeding the fragmented peat of a deposit was studied and was determined to depend on the ground water level. The influence of drainage on the water regime of a high-more peat deposit and that of weather conditions on ground water level fluctuations over time have been evaluated at production sites with an open drainage network. When a peat deposit is drained, under the action of gravitation (the pressure differential in the ground and a drain), ground water seeps into the drains and is transported along them, down-grade, to the collection network and diverted from the drained area. The processes of moisture movement at a peat deposit help evaluate and justify measures to improve its water-air regime which is used in the development of intensive draining methods for a peat deposit and the maintenance of the necessary water regime in peat deposits.

Assessment of Peat Deposits in Rwanda

The peat deposits in Rwanda are distributed over an area of 50,000 ha and were formed about the end of last glaciations period. However Akanyaru peat is 20,000 years old and contains peat of glacial and postglacial period. The studies show that Rwanda has 155 million tons of dry peat which can generate electrical energy and this deposit is sufficient to meet country’s vast energy requirements for 30 years. Hence, it was felt necessary to map prospective locations of peat and their energy potential. The result of the study and assessment of peat to power in Rwanda show that the average in-situ ash content, in-situ moisture content and in-situ bulk density of the collected peat samples are 36 wt%, 70.8 wt% and 1112 kg/m3 respectively. Their average thickness ranges from 0.9 to 7.8 m. In Finland, peat was used as fuel in 1996 and produced 10% of total installed capacity. Rwanda has the same operational peat power plant in Gishoma: Rusizi District generating 15 MW connected to the national electrical grid. A peat-fuelled power plant is under construction and is expected to generate 80 MW. This plant, once completed, is expected to connect 50% more households into national grid. Thus, this effort along with other projects will increase electrical power from 208 MW to 563 MW in 2024. Peat deposit is expected to generate 500 Megawatt electrical powers for 30 years. Although an effort was done to use peat as fuel, the power plant is still vulnerable to the lack of good quality of dry peat to operate and thus efforts are on to develop suitable technology for exploitation.

Application of image analysis technique for measurement of sand grains in sediments

This paper provides a methodological protocol for measuring diameter and other properties of mineral sand grains using an image analysis technique. The aeolian sand influx (ASI) from coastal bogs has been used to reconstruct changes in the past storminess. However, concentrations of sand grains in peat deposits, from which the ASI is calculated, tend to be low, and sieving and laser diffractometry cannot be applied. Manual counting of sands under microscope is time-consuming and less efficient because of possible human errors. This paper describes a protocol for an image analysis method used in our recent paper (Vandel et al. 2019) that overcomes those issues in sand grain measurements. After preliminary sample preparations, including loss-on-ignition and chemical pretreatments, this study uses ImageJ - a semi-automated image processing program – to analyze images captured under microscope. With proper sample size selection, pre-treatment, image capturing and image analysis settings in ImageJ described in this paper, the approach proved to be:•objective and efficient for analysing grain-size distribution even with low concentrations of sands in samples,•increasing reliability of the measurement and providing reproducible results by avoiding manual measuring processes, and•non-destructive and enabling further analyses on mineral composition and other properties of sand grains.

Preliminary data on formation and depositional environments of lake Chaika in the central part of the Curonian Spit (Kaliningrad region, Russia, South-Eastern Baltic)

Lake Chaika is the only major water body present in the sand barriers of the entire territory of South-Eastern Baltic shoreline. The article provides new insights into the formation of Lake Chaika, based on data acquired through a lithological investigation of the lake sediment core combined with an organic matter content analysis, a macrofossil analysis, a radiocarbon AMS-dating and a bathymetric survey. The study revealed that Lake Chaika was formed around 500 years ago. The kettle of the lake appears to have not been submerged during the Littorina transgressions. During the mid-late Holocene, the kettle of the lake was occupied by the peat-forming ecosystems of alder carrs and sedge fens with scattered alder. The accumulation of ligneous and sedge peat occurred. The sand horizon, separating the gyttja layer from peat deposits, is considered to be a time marker for the so-called “sand disaster”, which began in the study site 200-250 years earlier than in the main territory of the Curonian Spit. There are three main formation phases of the lake’s ecosystem: the period of carrs (5390–510 cal. yr BP), the “sand disaster” period (≈550–500 cal. yr BP) and the proper lake period (500 cal. yr BP – present time).

Paleoenvironmental reconstruction for mineral groundwater area Marcial Waters (Lake Onega catchment)

Assessment of the conditions for the formation of Marcial waters was carried out on the basis of complex isotope-geochemical studies of water, peat deposits in the area of mineral water discharge and regional climate paleoreconstruction. The dependence of the chemical composition of water and flow rate of wells on weather and climatic conditions was discovered. Variations in the chemical composition of water do not coincide in time with a change in the flow rate of wells due to the mixing of modern waters of infiltration origin and, possibly, meltwater of permafrost. The evolution of the hydrogeological system of ferrous waters after the retreat of the glacial edge from the northwestern coast of Lake Onega is shown. It is shown that a permanent aquifer was formed at the end of the Preboreal time. The distribution of iron and uranium isotopes in the peat core reflects a change in the redox conditions due to climate change and the participation of meltwater in the groundwater flow.

A Case Study of Combined Drainage Consolidation‐Preloading Methods for a Highway Subgrade on Peat Soils

A highway project of up to 100 km/h is currently being constructed between Colombo and Katunayake International Airport across a Sri Lankan muskeg area. At this site, peat deposit was initially 0.8∼15.3 m thick and was underlain by sand, clay, or gneiss. The ground improvement methods adopted in the project were combined drainage consolidation‐preloading methods, pipe pile foundation, and geogrids. This paper provides a detailed insight into the implementation of combined drainage consolidation‐preloading methods used in the project, including sand pile, gravel pile, and plastic drainage plate as the prefabricated vertical drains. Periodical field‐level observations were taken during the ten years, including the construction and postconstruction periods. The results show that peat soils’ consolidation coefficient has been increased several times to tens of times due to ground improvement. After removing the temporary surcharge, the highway embankments did not heave and was followed by long‐term settlements totaling 1.3∼7.4 cm over the following seven years of observations. Analysis of the settlement records shows that combined drainage consolidation‐preloading methods have helped accelerate drainage consolidation and reduce postconstruction settlement.

Holocene vegetation and climate changes in the North-Eastern Caucasus (pollen data from mountains and plain peatlands)

Dagestan (North-Eastern part of the Caucasus) is characterized by a unique historical and environment development, however, there is little, if no, data on nature changes throughout the Holocene history of the region. In contrast to the much-studied neighboring Caucasus regions, Dagestan remains mostly unexplored from the standpoint of paleoecology. In 2017, we investigated a detailed radiocarbon-dated 185 cm peat sequence from the Shotota swamp located in the mountainous zone of Dagestan. Peat and soil deposits span most of the Holocene (about 9000 years), and they let us study vegetation history of the Eastern Caucasus for the first time. The results of the study show significant discrepancies in the timing and sequence of the expansion of tree species in the Holocene in comparison with Transcaucasia and the Western Caucasus. The second key study, an examination of a 270 cm peat sequence from Arkida swamp, formed in the second half of the Holocene, also provided new paleoenvironmental data on the south of the Caspian lowland. The vegetation of the flat parts of Dagestan, adjacent to the mountainous zone, has been dry and treeless for the last four thousand years, however, humidification fluctuations and vegetation changes were distinguished.

Source-bordering aeolian dune formation along the Scheldt River (southern Netherlands – northern Belgium) was caused by Younger Dryas cooling, high river gradient and southwesterly summer winds

Abstract The Younger Dryas cold period caused major changes in vegetation and depositional environments. This study focuses on the aeolian river-connected dunes along the former, Weichselian Late Glacial, course of the Scheldt River in the southern Netherlands. Aeolian dunes along the Scheldt have received little attention, as they are partly covered by Holocene peat and marine deposits. The spatial distribution of the dunes is reconstructed by digital elevation model analysis and coring transects. Dunes are present on the high eastern bank of the Scheldt and in the subsurface of the polder area west of the Brabantse Wal escarpment. A reach-specific higher channel gradient probably caused a channel pattern change from meandering to braiding during the Younger Dryas. This enabled deflation from the braid plain and accumulation in source-bordering river dunes east of the incised and terraced, subsurface Late Pleistocene Scheldt valley. The age of the dune formation is established by pollen analysis and radiocarbon dating of underlying and overlying peat beds. The peat layer below the dune at Zomerbaan is attributed to the Allerød and early Younger Dryas periods. Dune formation occurred predominantly during the second part of the Younger Dryas stadial, both on and in front (west) of the Brabantse Wal escarpment. Wind direction was reconstructed by geomorphic analysis and sedimentary structures on lacquer peels. A southwesterly wind direction is demonstrated by the parabolic dune morphology. For the first time, Younger Dryas wind direction is reconstructed based on adhesion ripple cross-laminated sets on lacquer peels. Sand-transporting south-southwesterly winds were dominant during the Younger Dryas, most likely during summer.

The Early Holocene vegetation changes in the vicinity of the Gorbunovo peat bog in the Middle Urals (Russia)

The paper presents the results of a comprehensive palaeobotanical research of lacustrine and peat deposits of archaeological Mesolithic sites discovered at the Gorbunovo peat bog (Middle Urals). Pollen and plant macrofossil data, as well as a biome model were used to describe the vegetation changes in the study area in the Early Holocene. It was found out that in the second half of the Pre-Boreal and the first half of the Boreal periods of the Early Holocene (approximately to 9,800–9,600 cal BP), the vicinity of the Gorbunovo peat bog was dominated by cold deciduous forests. Larch, spruce-larch and birch forests and meadow communities with periglacial elements were widespread. Various aquatic plants could be found in the pond, though it started to turn into swamp. In the second half of the Boreal period (approximately at 9,600–9,500 cal BP), the taiga biome, including pine and birch-pine forests with occurrence of spruce started to prevail. Periglacial communities became degraded. Aggressive water logging led to the formation of a peat bog.

Monitoring of agrophysical properties of the active layer of drained long-frozen peat deposits in Western Siberia

In this study, the authors considered the dynamics of the main agrophysical properties of hydromorphic geosystems in Western Siberia. In the process of evolution, as well as in the conditions of technogenic impact, the soils of natural-territorial complexes, their properties are subject to significant changes. New hydromorphic geosystems are formed, the soils of which are characterized by changed agrophysical properties. Modern technologies for developing investment projects for soil reclamation of hydromorphic geosystems should be based on agrophysical characteristics of reclaimed soils, on the basis of which it is possible to create the necessary parameters of drainage systems and, as a result, provide optimal soil regimes for agricultural crops for a long period. The difficulty is that these soil characteristics are variable over time. Until recently, agrophysical characteristics of soils obtained in other regions of the country were used in the development of reclamation projects for hydromorphic soils in Western Siberia. The attempt to borrow them has led to the fact that large areas of drained soil have become completely unsuitable and to restore their project productivity, a number of agro-reclamation activities and the attraction of large financial resources are currently required. In this regard, there is a need for a comprehensive, long-term study of the main properties of hydromorphic soils used for agricultural purposes, and especially their changes over time under the influence of anthropogenic load.

Применение метода моделирования по типу Монте-Карло для оценки погрешностей 210Pb-датирования торфяных отложений Европейской субарктики России (на примере Архангельской области)

Применение метода моделирования по типу Монте-Карло для оценки погрешностей 210Pb-датирования торфяных отложений Европейской субарктики России (на примере Архангельской области)

Post-fire ecological consequences within the drained site of the Great Vasyugan Mire: retrospective water-thermal regime and pyrogenic disturbance estimation

The aim of this research is to carry out an assessment of pyrogenic load after the fire event in 2016 within the drained site of Great Vasyugan mire (Bakchar bog, North-East part of The Great Vasyugan mire). Specifically, the objectives of this study were to: 1) perform a retrospective analysis of the water-thermal regime of the area under study according to monitoring data on the nearby site for estimation of development emergence of a fire-dangerous situation conditions; 2) determine the quantitative characteristics of vegetation and microtopography fire transformation based on field data; 3) estimate zone of contamination by combustion products and 4) estimate the hydrocarbons composition of mire and river water, peat and typical plants of the pyrogenic disturbed bog. The water-thermal retrospective analysis confirmed that in August 2016, the most favourable conditions for the emergence of a fire-dangerous situation were developed. The area of fire spread was 5.54 km2, including within the mire of 4.44 km2. The area of Zn and Pb pollution covers an area of 8 km, which is consistent with the prevailing wind direction and atmospheric deposition data for 2016. The zone of extreme pollution of heavy metal peat deposits is limited mainly by the zone of intensive burning of the surface, however, and beyond it, there was also a significant (2 times) Zn, Cd and Pb concentration (except Cu) increase, mainly due to the migration of elements with water flow. Carbon losses for the burned area of 1 square metre to a depth of 30 cm were about 3,800 gC/m2. Against the background of a decrease in the content of n-alkanes, their share in the composition of peat lipids of the burnt area increases slightly, and among them the content of homologues C23–C25 increases, C29–C33 decreases and the CPI value decreases.

Evaluation of KTT-2 Pneumatic Peat Harvesting Machine’s Nozzle Suction Capacity

Milled peat harvesting with pneumatic harvesting machines has a number of doubtless advantages over mechanical harvesting: operating time decreases down to 1 day, additional milling of wet peat deposit during the harvesting is not needed, list of necessary machinery decreases. However, in the late 1980s, due to the imperfection of the design of pneumatic machines, this method began to be used less and less frequently. Market appearance of KTT-2 and MPTU-30 pneumatic harvesting machines promoted their introduction into operating processes of peat extractive companies. According to feedback from operators, these machines work well with high-moor peat but work much worse with low- moor peat which is of higher density. One of basic parameters of pneumatic harvesting is suction velocity, that’s why field experiment for evaluation of KTT-2 machine suction nozzle performance was held. Experiment results enabled us to plot velocity diagram of suction flow and find maximum suction velocity: 26.74 m/s. Velocity diagram analysis showed distance from the nozzle – air flow speed relation. We calculated size of suction flow’s active area and offered methods of active area sizing.

ИССЛЕДОВАНИЕ РАБОТЫ ВСАСЫВАЮЩЕГО СОПЛА ТОРФЯНОЙ ПНЕВМОУБОРОЧНОЙ МАШИНЫ

The extraction of milled peat by the pneumatic harvesting complex of machines has a number of advantages in contrast to the mechanical method. These advantages are as follows: the milling of wet peat deposits during harvesting is excluded, the range of required equi-pment is reduced, and the cycle time is shortened from two to one day. The latter is especially important, since two-day periods with good sunny weather in the production season are much less than one-day ones. Therefore, in general, the reliability of the method with pneumatic peat harvesting is higher. To evaluate the efficiency of the modern KTT-2 pneumatic harvesting machine, a field experiment was conducted to evaluate the suction speed of the nozzle of the machine. The results of the study made it possible to build the velocity field of the suction torch and determine the maximum suction speed – 26.74 m/s. The minimum air flow velocity in the studied zone is 0.3 m/s and is observed at a distance of 0.5 m from the nozzle. An analysis of the velocity field of the suction torch revealed the dependence of the air flow velocity on the distance from the nozzle. The size of the active zone of the suction plume has been identified and ways to optimize its size have been proposed.