Burial Processes Research Articles

Mine burial in the seabed of high-turbidity area—Findings of a first experiment

The seabed of the North Sea is covered with ammunition dating back from World Wars I and II. With increasing human interference (e.g. fisheries, aggregate extraction, harbor related activities), it forms a threat to the safety at sea. In this study, test mines were deployed on a sandy seabed for 3 months to investigate mine burial processes as a function of hydrodynamic and meteorological conditions. The mine experiment was conducted in a shallow (9m), macrotidal environment characterized by highly turbid waters (yearly and depth-averaged suspended particulate matter concentration of 100mgl−1). Results showed some variability of the overall mine burial, which corresponded with scouring processes induced by a (sub-) tidal forcing mechanism. The main burial events however were linked to storm-related scouring processes, and subsequent mine roll into the resulting pit. Two storms affecting the mines during the 3-month experiment resulted in enduring increases in burial volume to 60% and 80%, respectively. More cyclic and ephemeral burial and exposure events appear to be linked to the local hydrodynamic regime. During slack tides, suspended sediment settles on the seabed, increasing the burial volume. In between slack tides, sediment is resuspended, decreasing the burial volume. The temporal pattern of this never reported burial mechanism, as measured optically, mimics the cyclicity of the suspended sediment concentration as recorded by ultrasonic signals at a nearby benthic observatory. Given the similarity in response signals at the two sites, we hypothesize that the formation of high-concentrated mud suspensions (HCMS) is a mechanism causing short-term burial and exposure of mines. This short-term burial and exposure increase the chance that mines are ‘missed’ during tracking surveys. Test mines contribute to our understanding of the settling and erosion of HCMS, and thus shed a light on generic sedimentary processes.

Resilience of Zostera noltii to burial or erosion disturbances

Dynamic environments like seagrass habitats are characterised by continuous local erosion and burial processes, which may induce seagrass decline if disturbances become too intense or frequent. We aim to quantify for Zostera noltii the resilience of both the edge of a meadow and individual propagules to local-scale burial and erosion events. In a set of mesocosm and in situ manipulation experiments, we varied the frequency (sudden vs. continuous rate) and intensity (different levels; -6 cm erosion to 6 cm burial) of sediment dynamics. Our results showed that the intensity of the disturbance event (-6 up to 6 cm) was negatively correlated with plant survival. Burial frequency also had a significant effect on plant survival, with sudden events having a stronger negative impact than continuous ones. Both experiments, on individual propagules and attached rhizomes at meadow edges, demonstrated a rapid acclimatization of seagrass plants to sediment dynamics within certain levels of disturbance (-6 up to 6 cm). After erosion or burial, all surviving plants in the field and mesocosm experiments were able to relocate their rhizomes to the preferential depth (from 0.3 to 0.8 cm), which was the depth at which the rhizomes of undisturbed plants were most frequently found in the field. In situ manipulation experiments showed that at the edge of the meadow, Z. noltii invaded experimentally created hollows more easily than hills. Overall, our results demonstrate that Z. noltii meadows can rapidly recover by clonal growth after modest sediment disturbance, thereby contributing to the current understanding of seagrass recovery mechanisms following disturbances (e.g. sediment dynamics).

On the impact of impurities on the densification of polar firn

Understanding polar firn densification is crucial for reconstructing the age of greenhouse gas concentrations extracted from ice cores, and for the interpretation of air in ice as a dating tool or as a climate proxy. Firn densification is generally modeled as a steady burial and sintering process of defined layers, where the structure of the layering is maintained along the whole firn and ice column. However, available high-resolution density data, as well as firn air samples, question this picture and point to a lack of understanding of firn densification. Based on analysis of high-resolution density and calcium concentration records from Antarctic and Greenland ice cores, we show for the first time that also impurities may have a significant impact on the densification. Analysis of firn cores shows a correlation between density and the calcium ion (Ca++) concentration, and this correlation increases with depth. The existence of this relationship is independent of the local climatic conditions at the core sites analyzed. The strong positive correlation between the density and the logarithm of Ca++ concentration indicates that impurities induce softening and lead to faster densification over a wide range of concentrations. In one core, the impurity effect manifests itself so strongly that the density develops a seasonal cycle closely following the seasonal cycle of Ca++. Our results clearly show that the structure of the firn layering changes with depth and suggest that the increased variability in density observed in deep firn, recently described as a universal feature of polar firn, may arise from the influence of Ca++ and/or other impurities. The impurity effect is likely to have direct implications on our understanding of glacial firn densification and on glacial gas age estimates.

Contrast comparison of differential diagenetic pathways of Lower Tithonian carbonate materials from the Betic Cordillera (S. Spain): Evidence for physico-chemical paleo-seawater properties

The reconstruction of paleoenvironmental conditions is based on the study of ancient rock materials. For this purpose, skeletal materials are often assumed to have higher preservation potential, sometimes favored over the use of matrix micrite. However, factors such as ecology, depositional setting, mineralogy and diagenetic processes may obscure original geochemical signals, and care must be taken when reading such an intricate record. This work provides a thorough comparison between geochemical signatures of different carbonate materials, interpreted in the light of their paleoenvironmental significance. Burial and diagenetic processes are taken into account, contextualized by ammonite and belemnite ecology.Two sections deposited in epioceanic Tethyan areas and corresponding to the same Lower Tithonian ammonite biozone are under scope: a condensed pelagic and cephalopod-rich limestone (the Alamedilla sector) intercalated in thick mafic rocks piles, and a typical Ammonitico Rosso facies (the Cardador section). In contrast to depositional and taphonomic histories typical for a Tethyan top-swell site (i.e., rather calcareous Ammonitico Rosso), events of carbonate-mud deposition, rapid burial and early lithification, synsedimentary sliding and over imposition of firmground horizons characterize pelagic cephalopod-rich limestones. Differential taphonomy of carbonate skeletals agrees with differential preservation, favoring inner-cast preservation in Ammonitico Rosso and shell preservation (neomorphic calcite) in pelagic cephalopod-rich limestones.Stable carbon and oxygen isotope data, together with trace element data (Sr, Mg, Fe, Mn) are presented for a wide range of carbonate materials: matrix micrite, neomorphic ammonite shells, belemnite rostra and carbonate cements. Optical inspection (including cathodoluminescence imaging) and geochemical data suggest a fair preservation of the above mentioned materials, except for diagenetic marine burial carbonate cements. Carbon isotope values fall within the typical Tethyan Late Jurassic range (ca. 2‰), except data from belemnite rostra which are depleted around −1‰, which is interpreted as resulting from metabolic fractionation. Oxygen isotope values are more variable, but the clustering of different carbonate materials within a narrow range of values between −1 and 1‰ is consistent with conservative diagenesis. Warmer burial fluids explain lower values in later diagenetic carbonate cements. No evidence of pervasive diagenetic imprint is revealed by elemental composition. The increased abundance of Mg, Fe, and especially Mn (up to 1500ppm), is recognized as hydrothermal contamination. Proximity to hydrothermal sources (the Mid-Subbetic Volcanic Ridge) accords with higher Mn concentration at the Alamedilla site. Interestingly, the timing of the mineralogical stabilization of each carbonate material reveals a potential record of a post-sedimentary geochemical event.The obtained information demonstrates the complexity of ancient carbonate records, and encourages future research focused on the preservation potential of geochemical proxies throughout time. The studied case hopes to be a representative example to approach the interpretation of potential past and present rare analogs.

Predatory Behavior ofCanthon virens(Coleoptera: Scarabaeidae): A Predator of Leafcutter Ants

We present a detailed description of the predatory behavior of the beetleCanthon virensMannerheim, 1829, on the leafcutter antAttasp. We observed 51 acts of predation, which were also recorded on film and subjected to behavioral analysis.Canthon virensexhibited 28 behaviors while predating uponAttasp. queens. Adult beetles search for queens while flying in a zigzag pattern, 15 to 20 cm above the ground. After catching a queen, the predator stands on its back and starts cutting the queen cervix. Once the prey is decapitated, the predator rolls it until an insurmountable obstacle is reached. The distance from the site of predation to the obstacle can vary widely and is unpredictable. The beetle rolling the queen also buries it in a very peculiar way: first, it digs a small hole and pulls the queen inside, while another beetle is attached to the prey. The burial process takes many hours (up to 12) and may depend on the hardness of the soil and the presence of obstacles. In general, one or two beetles are found in a chamber with the queen after it is buried. They make the brood balls, which serve as food for the offspring. This study contributes to the knowledge of the predatory behavior ofCanthon virens, a predator poorly studied in Brazil and widespread in the country.

TAPHONOMIC ANALYSIS OF THE LOWER PLEISTOCENE PIRRO NORD FOSSIL LOCALITY (PIRRO 10 SITE, PUGLIA, SOUTHERN ITALY): A DEPOSITIONAL MODEL FOR VERTEBRATE ASSEMBLAGES IN A KARSTIC ENVIRONMENT

Taphonomic analyses have been conducted on the macromammal remains found in Sedimentary Unit 7 of the lower Pleistocene Pirro 10 site of the Pirro Nord locality in Italy. Recent field research has concentrated on investigating the fossil content of this site and the genesis of the karst network and its related deposits. In the present study, we distinguish between preburial and synsedimentary (during burial) processes in order to group the vertebrate remains into different taphonomic categories according to their various states of preservation, thus introducing the concept of taphorecord—borrowed from invertebrate taphonomy—into macrovertebrate taphonomy for the first time. Element quantification, evaluation of transport effects, and state of preservation of the skeletal elements were studied and all elements separated into four taphorecords according to their relative chronology. The use of taphorecords also improves the accuracy of the data obtained from the various methods of element quantification. The analysis of bone sorting and orientation indicates that the fossiliferous deposits originated by water flows carrying both fossils and sediments, alternating with phases of carcass accumulation and reelaboration of bones from previously deposited layers. The study presented here serves as a proof of concept for the use of taphorecords in analyses of fossiliferous deposits in caves.

Remagnetization and chemical alteration of sedimentary rocks

Abstract Chemical remagnetization is a very common phenomenon in sedimentary rocks and developing a greater understanding of the mechanisms has several benefits. Acquisition of a secondary magnetization is usually tangible evidence of a diagenetic event that can be dated by isolation of the chemical remanent magnetization and comparison of the pole position to the apparent polar wander path. This can be important because diagenetic investigations are frequently limited by the difficulty in constraining the time frames in which most past events have occurred. Remagnetization can commonly obscure a primary magnetization; developing a better understanding of remagnetization could improve our ability to uncover primary magnetizations. Many chemical remagnetization mechanisms have been proposed, including those associated with chemical alteration by a number of different fluids (orogenic, basinal and hydrocarbons), burial diagenetic processes (clay diagenesis and maturation of organic matter) or other processes. This paper summarizes our current knowledge of these chemical remagnetization mechanisms, with a focus on examples where there is a connection with chemical alteration.

About this title ‐ Remagnetization and Chemical Alteration of Sedimentary Rocks

Remagnetization is a common phenomenon in rocks, and developing a greater understanding of its mechanisms has several benefits. Acquisition of a secondary magnetization is usually tangible evidence of a diagenetic or thermal event, which can be dated using palaeomagnetic techniques. This is important because the timing of diagenetic and thermal events is commonly difficult to determine. Remagnetization can also obscure primary magnetizations and a better understanding of remagnetization could improve our ability to uncover primary magnetizations. Many chemical remagnetization mechanisms have been proposed, including those associated with chemical alteration by a number of different fluids (e.g. orogenic, weathering, mineralizing, hydrocarbons) and burial diagenetic processes (e.g. clay diagenesis, maturation of organic matter). This book contains case studies and review articles that focus on remagnetization, chemical remagnetization mechanisms, and magnetic changes associated with chemical alteration by hydrocarbons.

Palaeomagnetism of the Mississippian Barnett Shale, Fort Worth Basin, Texas

Abstract A palaeomagnetic study of four oriented cores was conducted to better understand the timing of diagenetic events in the Mississippian Barnett Shale, a primary source rock and the unconventional gas reservoir in the Fort Worth Basin, Texas. Thermal demagnetization removes a present-field modern viscous remanent magnetization (VRM) as well as a chemical remanent magnetization (CRM) that has shallow inclinations and streaked south–SE-directed declinations. The VRM was used to orient the CRM data for one well and it produced a similar streak of directions. The streaking of directions could represent a mixing trend between two or more CRMs. Specimens from bedding-parallel and NE subvertical mineralized fractures contain a CRM that is interpreted to be of Pennsylvanian age and to have formed in response to burial diagenetic processes. NE- and NW-oriented vertical fractures are common to rocks that contain late Permian to Triassic CRMs. Sr and sulphur isotope results from vein minerals around NE fractures suggest the CRM could be related to fluids sourced from the Ouachita front. The SE directions in the streak could be explained if the northern part of the basin experienced a component of anticlockwise rotation of up to 20° in the Pennsylvanian.

Lake trophic status can be determined by the depth distribution of sediment phosphorus

In this meta‐analysis, we examine how sediment phosphorus (P) burial pattern may be related to trophic state. We present sediment P profiles from 94 lakes that demonstrate fundamental differences in P burial between oligotrophic and eutrophic systems. In sediments of eutrophic (≥ 30 µg water column total P (TP) L‐1) lakes, P concentrations are elevated in the surficial sediments in comparison with deeper layers, representing a large P pool that can be recycled. This pattern directly contrasts with sediment P profiles in oligotrophic lakes (< 10 µg water column TP L‐1), which exhibit increasing concentrations of permanently buried P with depth. Sediment processes regulating P burial may be important regulators of internal P recycling and consequently lake trophic status. Thus, mesotrophic lakes (10 to 30 µg water column TP L‐1), which exhibit consistent P concentrations with depth, are more vulnerable to external P inputs than oligotrophic lakes because they are at their maximal sediment P burial flux. Our data suggest that thresholds in sediment P pattern may correlate with thresholds in sediment P burial processes and consequently may indicate whether deposited P will be released to the water column.

Numerical modelling of the hydrocarbon generation of Tertiary source rocks intruded by doleritic sills in the Zhanhua depression, Bohai Bay Basin, China

AbstractAn igneous hydrocarbon reservoir had been found in the Zhanhua depression, Bohai Bay Basin, eastern China. Two doleritic sills successively intruded into the immature source rock of the third member of the Shahejie Formation (Es3). The heat released from the magma changed the mineral composition of wall rocks and accelerated the maturity of organic matter. Thin hornfels and carbargilite zones were found next to the sills. The vitrinite reflectances (%Ro) of these heated wall rocks increased to at least 1.4% near the contacts (<50 m), and accumulation of oil was found in the hornfels zone and dolerite bodies. With the aim of understanding the influence of the sills on the hydrocarbon generation process, a complex heat conduction model was used to simulate the thermal history of the organic‐rich wall rocks, in which both the latent heat of crystallization of intrusions and vapourization heat of pore water in wall rocks were considered. The simulation results suggested that the cooling of each sill continued for about 0.1 Ma after its emplacement and the temperature of wall rocks was considerably raised. The peak temperature (Tpeak) that wall rocks experienced can reach 460–650°C in the region of 10 m away from the contacts. The thermal model was qualitatively verified by comparing the experimental data of vitrinite reflectances and mineral geothermometers of the wall rocks with the simulation results. Furthermore, we modelled the hydrocarbon generation of the source rocks based on the simulated thermal history. In the region of about 100 m from the contacts, the organic matter was heated and partially transformed into hydrocarbon within only a few 1000 years, which was significantly faster than the normal burial generation process.

A sensitivity analysis of the parameters controlling water–sediment interactions in the coastal zone: Consequences to man and environment

A sensitivity analysis has been carried out on the basis of the local and global sensitivity indexes for selected radionuclides ( 3H, 137Cs, 238Pu, 241Am and 244Cm) and main parameters describing the water–sediment interaction (sediment reworking rate, pore–water turnover rate, sediment distribution coefficient, suspended sediment load in water column, sedimentation rate, molecular diffusion coefficient, surface sediment thickness, porosity of bottom sediment and density of sediment material). Sensitivity analysis has been carried out using a compartment model for dose assessment to man and biota, which includes the processes of advection of radioactivity between compartments, sedimentation, diffusion of radioactivity through pore water in sediments, particle mixing, pore water mixing and a burial process of radioactivity in deep sediment layers. The sensitivity analysis indicates that for the conditions in the Norwegian Current (the Norwegian Sea) particle mixing dominates the transfer of radioactivity between the bottom water and surface sediment compartments. For the conditions in the Ob Bay (the Kara Sea), the sedimentation process has also been found to be significant. The calculated dynamics of the sensitivity indexes demonstrate clearly the complexities encountered when modeling water–sediment interactions. It is also shown that the results can be strongly dependent on the time of analysis. For example, given a specific change of parameters the radionuclide concentration will be either increased or decreased, depending on the temporal interval. Information provided by the sensitivity analysis can contribute to a better understanding of experimental data and might further improve the parameterization process. The obtained results show that water–sediment interactions can play a key role in the marine coastal environment, thus demonstrating the need to further deepen our understanding of them, as well as improve the models describing them.

Medium and coarsely crystalline dolomites in the Middle Devonian Ratner Formation, southern Saskatchewan, Canada: origin and pore evolution

Carbonate rocks of the Middle Devonian Ratner Formation in southern Saskatchewan vary from undolomitized, to partly dolomitized, to completely dolomitized. Two major types of medium and coarsely crystalline dolomite are differentiated in the formation: medium crystalline, planar-e to planar-s (ME) dolomite, and medium to coarsely crystalline, nonplanar-a (CA) dolomite. ME dolomite, which commonly occurs in the lower and middle parts of the Ratner Formation, has more radiogenic Sr (87Sr/86Sr ratios averaging 0.7085) and significantly higher Fe and Mn concentrations (averaging 2,260 and 160 ppm, respectively) than do associated limestone. ME dolomite is interpreted as resulting from dolomitization by ascending basin fluids in a burial environment during late Devonian and Carboniferous time. ME dolomite has relatively high porosity (up to 19.3% based on point counting); intercrystalline pores are dominant, and vugs are locally abundant. The improved petrophysical quality of ME dolomite is due to burial dolomitization processes and the ability of dolomite to resist compaction and retain porosity. In contrast, CA dolomite, present mainly in the top parts (locally below the top parts) of the formation, has 87Sr/86Sr ratios (averaging 0.7081) and Fe and Mn concentrations (averaging 250 and 104 ppm, respectively) similar to adjacent micro-finely crystalline dolomite. CA dolomite is considered to have formed by recrystallization of early-formed microcrystalline dolomite. Recrystallizing fluids probably consist of gypsum dehydration water mixed with formation waters. CA dolomite has less than 2% vuggy porosity and rare visible intercrystalline pores.

Characteristics of Fluid Inclusions and its Significance to the Coaliferous Gas Reservoirs of the Xujiahe Formation in the Central Sichuan Basin, China

In the central Sichuan Basin, the maturity of source rocks in the Xujiahe Formation of the Upper Triassic is not high, with Ro values ranging from 0.8% to 1.2%. However, the gas reservoirs nowadays show characteristics of high gas-oil ratios and low condensate oil content (3.8–91.9 g/m3 on average). There are abundant gas hydrocarbon inclusions developed in the reservoir, with few liquid hydrocarbon inclusions, which indicates that the coal measures gave priority to gas rather than oil. In the fluid inclusion group, the CH4 and C2H6 contents are 79.62–96.42% and about 10% respectively, while the content of C3H8 ranges from 3% to 5%. The carbon isotope values are δ13C1= −44.59 ∼ −39.31‰, δ13C2= −24.82 ∼ −28.05‰, δ13C3= −21.39‰, δ13C4= −22.05 ∼ −20.2‰, δ13Cco2= −9.14 ∼ −13.86‰. The component and isotope compositions of gas in fluid inclusions coincide with those in the reservoirs, indicating that the gas hydrocarbon in the fluid inclusions can represent the residual gas in the reservoirs. The coal-measure source rocks can generate gas all the time during its burial process. The formation of salt-water inclusions associated with the gas inclusions can be divided into three stages. Firstly, the subsidence stage was at 170∼100 Ma, with the temperature of 70∼120°C. Secondly, the deep burial stage was during 100∼60 Ma, with the temperature of 120∼150°C. Thirdly, the uplift stage was at 60∼0 Ma, with the temperature of 90∼120°C. The time range reflected from gas inclusion is very wide, showing that the coal measures gave priority to gas hydrocarbon and can generate and expel gas continuously in a long period.

Burial Consolidation Processes of Deep-Sea Sediments: An Example of Core Sediments Collected from the Labrador Sea in the Northwest Atlantic

ABSTRACT Progressive change of microfabrics of deep-sea sediments during early diagenesis was analyzed using two drill cores collected from the Sites U1305 and U1306 of the Integrated Ocean Drilling Program Expedition 303 in the Labrador Sea in the northwest Atlantic Ocean. Microfabrics were analyzed by scanning electron microscope and deduced from anisotropy of magnetic susceptibility. Different microfabrics in three layers were distinguished in both cores: Surface layer with general void ratio >2.5, subjacent layer with void ratio 2.5-1.5, and deep layer with void ratio 2.5 and 2) change of clay microfabrics in the layer with the void ratio

Flow characteristic of the horizontal cylinder placed on the plane boundary

In this study, the flow characteristic of the circular cylinder laid on the free surface is studied quantitatively using the particle image velocimetry technique. The flow phenomena in the upstream and downstream regions of the horizontal cylinder and free surface junctions increase the instability of the vortical flow structure significantly. Since the scour and burial process of the pipelines laid on the seabed depends mostly on the hydrodynamic behavior of the flow, the present investigation concentrates on the characterization of the flow structures using the time-averaged and instantaneous flow data. Distributions of velocity vectors, patterns of streamlines, vorticity contours and corresponding Reynolds stress correlations characterize the flow structure in detail.

Illitization of Early Paleozoic K-Bentonites in the Baltic Basin: Decoupling of Burial- and Fluid-Driven Processes

AbstractThe mineralogical characteristics of Ordovician and Silurian K-bentonites in the Baltic Basin were investigated in order to understand better the diagenetic development of these sediments and to link illitization with the tectonothermal evolution of the Basin. The driving mechanisms of illitization in the Baltic Basin are still not fully understood. The organic material thermal alteration indices are in conflict with the illite content in mixed-layer minerals. The clay fraction of the bentonites is mainly characterized by mixed-layered illite-smectite and kaolinite except in the Upper Ordovician Katian K-bentonites where mixed-layer chlorite-smectite (corrensite) occurs. The variation in expandability plus other geological data suggest that the illitization of Ordovician and Silurian K-bentonites in the Baltic Basin was controlled by a combination of burial and fluid driven processes. The illitization in the south and southwest sectors of the basin was effected mainly by burial processes. The influence of the burial process decreases with decreasing maximum burial towards the central part of the basin. The advanced illitization of the shallowburied succession in the north and northwest sectors of the basin was enhanced by the prolonged flushing of K-rich fluids in relation to the latest phase of development of the Scandinavian Caledonides ≈420–400 Ma.

Relevance of large litter bag burial for the study of leaf breakdown in the hyporheic zone

Particulate organic matter is the major source of energy for most low-order streams, but a large part of this litter is buried within bed sediment during floods and thus become poorly available for benthic food webs. The fate of this buried litter is little studied. In most cases, measures of breakdown rates consist of burying a known mass of litter within the stream sediment and following its breakdown over time. We tested this method using large litter bags (15 × 15 cm) and two field experiments. First, we used litter large bags filled with Alnus glutinosa leaves (buried at 20 cm depth with a shovel) in six stations within different land-use contexts and with different sediment grain sizes. Breakdown rates were surprisingly high (0.0011–0.0188 day−1) and neither correlate with most of the physico-chemical characteristics measured in the interstitial habitats nor with the land-use around the stream. In contrast, the rates were negatively correlated with a decrease in oxygen concentrations between surface and buried bags and positively correlated with both the percentage of coarse particles (20–40 mm) in the sediment and benthic macro-invertebrate richness. These results suggest that the vertical exchanges with surface water in the hyporheic zone play a crucial role in litter breakdown. Second, an experimental modification of local sediment (removing fine particles with a shovel to increase vertical exchanges) highlighted the influence of grain size on water and oxygen exchanges, but had no effect on hyporheic breakdown rates. Burying large litter bags within sediments may thus not be a relevant method, especially in clogged conditions, due to changes induced through the burial process in the vertical connectivity between surface and interstitial habitats that modify organic matter processing.

Family networking in the Czech countryside: the funeral ceremony as a factor in preserving family relationships in the Czech countryside

This paper presents the funeral ceremony as one of the factors helping to preserve networks and relationships among families in the countryside. The development of family relationships in the countryside is discussed on the basis of an analysis of attendance at funeral ceremonies in model areas of the Czech countryside. The precise forms assumed by funeral ceremonies (church funeral vs. civil funeral, funeral without ceremony, attendance, associated traditions) differ in relation to culture on the state, regional and local levels as well. The differentiation to forms of funeral ceremony and burial processes depends on a number of factors, of which the main ones are religiosity rate and community size at regional level and tradition at local level. In the Czech regions, mainly in the countryside, the extraordinary attendance at funeral ceremonies is typical. Attendance at a funeral ceremony via a representative of the family is considered a social duty. This tradition of family get-togethers for funeral ceremonies has been maintained from generation to generation. Through it families that may now be scattered are able to keep together the network of relationships of inhabitants in countryside.

Sedimentation and particle dynamics in the seasonal ice zone of the Barents Sea

The Barents Sea seasonal ice zone (SIZ) is one of the most dynamic areas in the world ocean. This biologically productive area undergoes extreme intra- and inter-annual variabilities in sea ice and water mass transport properties. Here, we investigate seafloor burial processes in three regions of the SIZ with different ice-cover frequencies: predominantly open water (POW), marginally ice-covered (MIC), and predominantly ice-covered (PIC) with approximately 0, 10 and 50% sea ice cover, respectively, in 2002–2003. Down-core sediment profiles of the radionuclides 234Th, 210Pb, and 137Cs, along with sediment carbon, nitrogen and phosphorus concentrations are examined in two to three cores from each region. Sedimentation rates and velocities using 210Pb ex (excess 210Pb) profiles and assuming negligible mixing below a surface mixed layer are relatively uniform throughout the study area, averaging 558 ± 154 g m − 2 y − 1 and 1.1 ± 0.4 mm y − 1 ( n = 7). These sedimentation velocities are confirmed using 137Cs (1.0 ± 0.4 mm y − 1 , n = 7). 234Th ex (excess 234Th) derived bioturbation rates are positively correlated with number of benthic individuals per 0.5 m 2 ( R 2 = 0.83) and exhibit a pattern of higher rates in the MIC (14.5 ± 2.1 cm − 2 y − 1) relative to both the POW (6.3 ± 2.2 cm − 2 y − 1) and PIC (5.3 ± 1.2 cm − 2 y − 1) ( p < 0.01). 234Th ex inventories are also significantly higher ( p = 0.026) within the MIC, while both 210Pb ex and 137Cs sediment inventories are more regionally uniform. Furthermore, organic carbon (C org) and total nitrogen (N tot) concentrations are relatively high in both the MIC and PIC compared to POW. For this limited data set, higher bioturbation rate coefficients and higher 234Th ex sediment inventories in the MIC relative to the other sampled regions, suggest that the MIC exhibits a greater predominance of marine versus terrestrial sediment sources that support enhanced scavenging and benthic biological activity. These results suggest that a climate-driven northward shift in sea ice will result in a corresponding shift in benthic communities that currently depend upon surface derived fluxes of organic matter associated with the present-day location of the ice edge in the Barents Sea.