Deposition Of Mineral Matter Research Articles

Mineral dust and lead deposition from land use and metallurgy in a 4800-year-old peat record from the Central Alps (Tyrol, Austria)

Humans have occupied the Alps over most of the Holocene. Yet, continuous records on the impact of using montane resources and landscapes are scarce or confined to segregated areas or periods. We present a high-resolution geochemical record of the last 4800 years from the ombrotrophic peatland Piller Moor in the Central Alps (Tyrolean Oberland, western Austria), using inductively coupled mass plasma spectrometry (ICP-MS) and highly efficient inter-calibrated portable X-ray fluorescence analysis (pXRF). Fluctuations of metal enrichment factors (EF) for lead (Pb), copper (Cu), zinc (Zn) and antimony (Sb), accumulation rates of anthropogenic lead (Pbanth AR) and mineral matter (MAR), based on titanium (Ti), are in line with archaeological and pollen evidence for human presence and environmental change. Periods of intensified, erosive land use are indicated by MAR around 4400 cal BP, 3400 cal BP and, very prominently, at 2400 cal BP. After low MAR in the early Middle Ages, soil disturbances reappear around 1200 cal BP (750 AD), after 200 cal BP (1750 AD) and during the 20th century AD. We found evidence that metallurgy was practised in the area as early as 4450 cal BP, again from 3500 to 2900 cal BP and episodically between 2400 and 1400 cal BP. The Central Alps were presumably a source of increased Pb-emissions in the post-Roman period from 1500 to 1400 cal BP (450–550 AD). Generally, our findings suggest that mining predates archaeological and historical evidence. Following a continuous increase since the Middle Ages, atmospheric Pb EF and Pbanth AR peak around 1980 AD. The record of mineral atmospheric input illustrates the notable impact of human activities on soil erosion and dust entrainment in the Central Alps. Furthermore, links between Little Ice Age cold phases and reduced human impact and mining are established. Our high-resolution peat-geochemistry data quantifies atmospheric deposition of mineral matter and Pb, which act as proxies for landscape evolution and metallurgy on a local and regional scale. It provides new insights and a deeper understanding of the interaction of climate, environment and humans in mountainous landscapes like the Central Alps.

Bone Growth and Meat Quality of Quails Submitted to Different Lighting Programs

The present study was executed to evaluate the effect of lighting programs for meat quails on their bone growth and development. A total of 1500 sexed European quails (Coturnix coturnix coturnix) were distributed using a completely randomized design in a 2 × 3 factorial arrangement, with two sexes and three lighting programs (natural, intermittent, and continuous) with five replicates of 50 quails. The lighting programs were applied in the period from 7 to 49 d of age. Weekly slaughterings were performed to remove the tibiotarsus and femur and subsequently determine weight, length, dry and mineral matter content. The growth and deposition curves of dry and mineral matter in the bones were obtained using the Gompertz model. There was no significant interaction between lighting programs and sex for the estimates of the Gompertz curve parameters of all variables studied. There was an effect of the lighting programs only on the time needed to reach the maximum deposition rate of the growth curve and dry and mineral matter deposition. Females showed higher weight and deposition of mineral matter at maturity, and took longer to reach the maximum deposition rate value for these variables. There was influence of the lighting programs on resistance and bone deformity of the tibiotarsus. For quails raised in the tropical region, a natural or intermittent lighting program must be used, as it does not compromise the development of bones and assures bone quality.

Upland deforestation triggered an ecosystem state‐shift in a kettle peatland

Summary1. European settlement of eastern North America resulted in dramatic changes to ecosystems, although the dynamics and underlying causes of these changes are not always obvious. For example, land clearance likely exposed soils to increased wind erosion, potentially impacting downwind ecosystems indirectly through subsequent enhancement of dust deposition. We hypothesized that otherwise undisturbed wetlands were altered through this indirect disturbance mechanism, increasing nutrient availability and initiating a cascade of ecosystem‐level changes.2. We tested this hypothesis in a floating kettle peatland located in north‐western Pennsylvania, USA, using an interdisciplinary approach. A series of peat cores were collected along a transect oriented parallel to the dominant wind direction. Palaeoecological techniques were used to identify signatures of upland deforestation and mineral matter deposition within the peat profiles. Elemental analyses were used to reconstruct historic availability of major macronutrients, plant community dynamics were reconstructed using plant macrofossils and tree rings (Pinus strobus) and testate amoebae were used as a proxy for microbial community dynamics.3. Strong correlations between the concentration of ragweed (Ambrosia) pollen and fine‐grained mineral matter linked upland deforestation to enhanced dust deposition on the peatland surface. Elemental analyses indicated that nitrogen, phosphorus and potassium concentrations increased coincident with dust deposition. Plant communities shifted from Sphagnum dominance to vascular‐plant dominance coincident with enhanced dust deposition, including increased recruitment of P. strobus onto the peatland. Testate amoeba communities shifted towards those adapted to highly variable microenvironmental conditions and likely reflect broader changes in microbial communities.4. Synthesis. Upland deforestation by European settlers triggered a cascade of ecological changes on a nutrient‐poor peatland by enhancing dust deposition and nutrient delivery on the surface. These results demonstrate that indirect, unintended and often overlooked human disturbances can lead to dramatic structural and functional alterations of carbon‐rich wetland ecosystems, highlighting the potential vulnerability of these systems in human‐dominated landscapes.

Late Holocene multi-proxy records of environmental change on the South Atlantic island Tristan da Cunha

Sediment stratigraphies from three sites, one lake, one overgrown lake, and an exposed section, on the island Tristan da Cunha in the temperate South Atlantic were analysed by means of pollen analysis, total carbon, nitrogen and sulphur content determination, magnetic susceptibility measurements and detailed radiocarbon dating. The aim of these studies was to reconstruct the late Holocene vegetation and climatic variations. The oldest sediment sequence extends back to 2300 cal. years BP. The vegetation was relatively stable up to the arrival of humans in the 17th century. The appearance of the introduced taxon Rumex acetosa/acetosella at c. 300 cal. years BP and a subsequent decline in forest cover on the lowland plain provide evidence of substantial human influence on the vegetation well before the establishment of the first permanent settlement in the 19th century. Before the first anthropogenic influence centennial-scale fluctuations in the proxy records are interpreted as reflections of local hydrological changes, probably caused by variations in precipitation. As inferred mainly from changing proportions of pollen derived from telmatic and terrestrial taxa and corresponding changes in the deposition of mineral matter by fluvial erosion, lake levels were low between c. 1450 and 1050 cal. years BP, and high between c. 1050 and 300 cal. years BP. These variations coincide with known climatic changes in Southern Africa and in the North Atlantic, suggesting that the inferred hydrological changes on Tristan da Cunha were related to large-scale variations in the general oceanic and atmospheric circulation in the Atlantic region.

Rare earth element sources and modification in the Lower Kittanning coal bed, Pennsylvania: implications for the origin of coal mineral matter and rare earth element exposure in underground mines

In this study, we examine the variations in rare earth elements (REE) from the Lower Kittanning coal bed of eastern Ohio and western Pennsylvania, USA, in an attempt to understand the factors that control mineral matter deposition and modification in coal, and to evaluate possible REE mixed exposure hazards facing underground mine workers. The results of this study suggest that the Lower Kittanning coal mineral matter is derived primarily from a clastic source similar to that of the shale overburden. While highly charged cations like silicon, aluminum, and titanium remained relatively immobile within the coal mineral matter, iron (primarily as pyrite) was added from nonclastic sources, either during deposition of the coal mire vegetation or subsequent to burial. Other mobile cations (e.g., alkali and alkaline earth elements) appear to have been added to and/or leached from the originally deposited clastic mineral matter. Most of the sulfur in the Lower Kittanning coal bed is bound as FeS 2 in the mineral matter, but a majority of samples contain a small excess of S that is most likely organically bound. In general, the total rare earth element content (TREE) in coal ash is greater than that in the shale overburden. If the primary source of mineral matter is the same as that for the overlying shale, then REE must have been enriched in the coal mineral matter subsequent to deposition. The total rare earth element content of Lower Kittanning coals correlates strongly with Si concentration ([TREE]≈0.0024 [Si]), which provides a threshold for evaluating possible mixed exposure health effects. Chondrite-normalized REE patterns reveal a shale-like light rare earth element (LREE) enrichment for the coal, similar to that of the shale overburden, again suggesting a primarily clastic REE source. However, when normalized to the shale overburden, most of the coal ash samples display a small but distinct heavy rare earth element (HREE) enrichment. We surmise that the HREE were added and/or preferentially retained during epigenesis, possibly associated with groundwater flow through the coal unit, but not necessarily in close association with the addition of iron. At least some of the “excess” HREE could be organically bound within the Lower Kittanning coal.

Estimating the potential for submergence for two wetlands in the Mississippi River Delta

We used a combined field and modeling approach to estimate the potential for submergence for one rapidly deteriorating (Bayou Chitigue Marsh) and one apparently stable (Old Oyster Bayou Marsh) saltmarsh wetland in coastal Louisiana, given two eustatic sea level rise scenarios: the current rate (0.15 cm year−1); and the central value predicted by the Intergovernmental Panel on Climate Change (48 cm by the year 2100). We also used the model to determine what processes were most critical for maintaining and influencing salt marsh elevation including, mineral matter deposition, organic matter production, shallow subsidence (organic matter decomposition + primary sediment compaction), deep subsidence, and sediment pulsing events (e.g., hurricanes). Eight years of field measurements from feldspar marker horizons and surface elevation tables revealed that the rates of vertical accretion at the Bayou Chitigue Marsh were high (2.26 (0.09) cm yr−1 (mean ± SE)) because the marsh exists at the lower end of the tidal range. The rate of shallow subsidence was also high (2.04 (0.1) cm yr−1), resulting in little net elevation gain (0.22 (0.06) cm yr−1). In contrast, vertical accretion at the Old Oyster Bayou Marsh, which is 10 cm higher in elevation, was 0.48 (0.09) cm yr−1. However, there was a net elevation gain of 0.36 (0.08) cm yr−1 because there was no significant shallow subsidence. When these rates of elevation gain were compared to rates of relative sea level rise (deep subsidence plus eustatic sea level rise), both sites showed a net elevation deficit although the Bayou Chitigue site was subsiding at approximately twice the rate of the Old Oyster Bayou site (1.1 cm yr−1 versus 0.49 cm yr−1 respectively). These field data were used to modify, initialize, and calibrate a previously published wetland soil development model that simulates primary production and mineral matter deposition as, feedback functions of elevation. Sensitivity analyses revealed that wetland elevation was most sensitive to changes in the rates of deep subsidence, a model forcing function that is difficult to measure in the field and for which estimates in the literature vary widely. The model also revealed that, given both the current rate of sea level rise and the central value estimate, surface elevation at both sites would fall below mean sea level over the next 100 years. Although these results were in agreement with the field study, they contradicted long term observations that the Old Oyster Bayou site has been in equilibrium with sea level for at least the past 50 years. Further simulations showed that the elevation at the Old Oyster Bayou site could keep pace with current rates of sea level rise if either a lower rate for deep subsidence was used as a forcing function, or if a periodic sediment pulsing function (e.g., from hurricanes) was programmed into the model.

Study on the Predicting Technique of Ash Deposition Tendency in the Entrained-Flow Coal Gasifier. 2nd Report. The Analytical Results of Ash Deposition Tendency in a 2T/D Coal Gasifier Using Numerical Simulation Code with Ash Adhension Model.

The phenomenon of coal ash deposition on the walls is observed in an entrained-flow coal gasifier. The deposits interfere with heat transfer, and if they are heavy, they not only interfere with operation but also cause unplanned shutdowns of a gasifier. In order to commercialize IGCC power plant, ash adhesion behavior in a coal gasifier should be predicted when operational conditions of a gasifier or coal types might be changed. CRIEPI has been conducting study on the predicting technique of mineral matter deposition behavior in a coal gasifier. In this study, ash sticking/rebounding discrimination model based on ash liquid phase ratio was evolved. This model was introduced into numerical simulation code which had been developed by CRIEPI. Numerical simulation of ash behavior has been conducted for a 2/day coal gasifier and the ash deposition tendencies in a gasifier were evaluated. Numerical analysis results were in good agreement with experimental results of ash deposition tendency in a 2/day coal gasifier.

A relative elevation model for a subsiding coastal forested wetland receiving wastewater effluent

This paper describes a wetland elevation/sediment accretion model for a subsiding forested wetland located within the coastal zone of Louisiana, USA. We designed the model to determine if the addition of secondarily treated municipal wastewater to the wetland could stimulate organic matter production and deposition to the point that sediment accretion would balance relative sea level rise (deep subsidence plus eustatic sea level rise (ESLR)). We also used the model to simulate the effect of predicted increases in ESLR on wetland stability and to determine the amount of additional mineral sediment that would be required to compensate for relative sea level rise. The model utilizes a cohort approach to simulate sediment dynamics (organic and mineral matter accretion, decomposition, compaction, and below-ground productivity) and yields total sediment height as an output. Sediment height is balanced with ESLR and deep subsidence, both forcing functions, to calculate wetland elevation relative to mean water levels. The model also simulates primary production (roots, leaves, wood, and floating aquatic vegetation) and mineral matter deposition, both of which are feedback functions of elevation. Simulated wetland elevation was more sensitive to the uncertainty surrounding estimates of deep subsidence and future ESLR rates than in other processes that affect wetland elevation and could be influenced by wastewater (i.e. rates of decomposition and primary productivity). The model projected that, although the addition of wastewater effluent would increase long term accretion rates from 0.35 to 0.46 cm year −1, it would not be enough to offset the current rate of relative sea level rise. A series of mineral input simulations revealed that, given no increase in ESLR rates, an additional 3000 g m −2 year −1 of mineral sediments would be required to maintain a stable elevation.

Catalytic Activity of NiMo Sulfide Supported on a Particular Carbon Black of Hollow Microsphere in the Liquefaction of a Subbituminous Coal

The liquefaction of Wyoming coal (subbituminous coal) was investigated with an autoclave of 50 mL capacity, using Ketjen Black (KB)-supported NiMo catalyst, which has higher hydrogenation activity of 1-methylnaphtalene than a commercial NiMo/Al 2 O 3 . KB-supported NiMo catalyst gave the oil and oil plus asphaltene yield of 54 and 69% under reaction conditions of 440 °C, 60 min, and 13 MPa. These yields were much higher than those of a commercial NiMo/Al 2 O 3 and synthesized FeS 2 catalysts. The KB-supported NiMo catalyst was found to be recovered from the solid products using polar solvents such as THF because it is highly dispersed in liquid products due to its low specific gravity and the hydrophobic property of its surface. It was also found that KB-supported NiMo catalyst suffered the least deactivation by coke formation and mineral matter deposition because the recovered catalyst as THFI residue appeared to regenerate the activity to a level similar to the fresh catalyst.

Long range transport and deposition of mineral matter as a source for base cations

Mineral dust in the atmosphere is generally alkaline, and is a source of base cations in precipitation. Annual emissions of particles from large combustion plants and industrial processes in Europe is of the order of 24 million tonnes, and the calcium content may be as high as 1.4 million tonnes. Emissions from diffuse sources such as agricultural activities, construction and quarrying are much less well known. Emissions of dust from the Sahara have been estimated to more than 200 tonnes, with a calcium content of 3–5%.

Effect of process conditions on ash levels and trace elements in a coal liquefaction extract

The activity of hydrocracking catalysts used for the upgrading of coal extracts is reduced by mineral matter deposition. The influence of digestion and filtration conditions in a coal liquefaction process have been investigated to determine their effect on ash levels and trace elements in the extract solution. It has been shown that the digestion pressure has a significant effect on ash levels, while other conditions have little effect. Trace element proportions vary considerably from feed coal ash to extract solution ash with known deactivating species showing the largest increase.

Catalyst contamination in the process of coal extract hydrogenation

The coke and mineral-matter deposition on NiMo/Al2O3 and NiCoMo/Al2O3 catalysts used in the process of coal extract hydrogenation is described.

Short‐term temporal variability of eolian particles in surface waters of the northwestern North Pacific

The concentrations of particulate Al and total suspended particulate matter (TSP) were measured in surface waters at 42 stations on a cruise from Tokyo to Alaska and return during the summer of 1978. The mean particulate Al concentration in early July (5.5 μg kg−1) was almost 8 times higher than in mid‐August (0.72 μg kg−1). However, the mean TSP concentration was only twice as high. The high particulate Al concentration in the surface waters during early July was correlated with high atmospheric dust concentrations over this area. This dust was likely transported from the desert regions of central and eastern Asia. The data suggest that atmospheric mineral matter deposited on the ocean surface was removed to deeper waters within 1 month. The temporal variability of atmospheric concentrations and deposition of mineral matter may significantly affect the distributions and fluxes of this material in the North Pacific.

Microscopic changes in the coal-based catalysts used in the hydrocracking of Athabasca bitumens

Conventional catalysts are rapidly fouled with coke and metal deposits when used to hydrocrack residual oils. This work is part of a study in which a slurry of coal particles coated with catalyst was used in the hydrocracking of Athabasca bitumen in a continuous-flow pilot plant operated on the scale of one barrel (159 litres) per day. The fusinite and semi-fusinite macerals were unreacted after passing through the reactor and served as sites for coke and mineral-matter deposition. Unoxidized vitrinite macerals were converted to gas and oil and gradually disappeared, but oxidized vitrinite remained visible. This oxidized vitrinite, which had an oxidation rim around the periphery of the maceral, was coked in the interior. It is presumed that the gases and liquids evolved passed through fractures in the oxidation rim. The semi-coke-like structure resulting from partially oxidized vitrinite then behaved like the other coal inerts and served as a site for deposition of coke and mineral matter from the bitumen.

Pressure solution and the force of crystallization: a phenomenological theory

The phenomena of pressure solution and the force of crystallization result from removal or deposition of mineral matter in the region of contact between the mineral grains. We assume that this transport takes place by diffusion in a solution film between the grains. The rate of transport depends on the grain size, the effective normal stress between the grains, the diffusion constant in the solution film, the film thickness, and the stress coefficient of solubility. Values of these parameters required to obtain the amount of pressure solution observed in the St. Peter sandstone are reasonable. The theory predicts an increase in pressure solution with decreasing grain size. The effect of clay films between the grains is also to increase the rate of pressure solution owing to the more rapid rate of diffusion in the clay layer relative to a single solution film between clean mineral grains. This explains how pre-existing clay films in the sediment may, because of the greater rate of pressure solution, develop into stylolites. If the interstitial water is supersaturated with respect to the minerals present, precipitation in the area of contact will take place as long as the supersaturation divided by the stress coefficient of solubility is greater than the average effective normal stress between the grains. If the stress is increased above this limit, pressure solution will take place.

Radiographic studies on the formation of the hen's egg shell.

ABSTRACT Radiographic methods have been used to study the rate of deposition of the hen’s egg shell and the changes in volume and orientation undergone by the egg in the shell gland. Shell deposition commences about 5 hr. after the yolk is ovulated and several series of radiographs were obtained tracing the process from these earliest stages through to the fully calcified shell. From radiographs of calcium carbonate-gelatin mixtures it was found that, for a series of comparable objects differing only in calcium carbonate content, the densitometer readings on their radiographs were directly proportional to the density of calcium carbonate traversed by the X-rays in each object. Hence, densitometer measurements on the periphery of the shell in each of a series of radiographs taken during the development of a single egg shell give values which are proportional to the density (or thickness) of calcium carbonate traversed by the tangential rays. It is shown that the radial thickness is closely proportional to the square of these values. Plotting these squared densitometer readings against time indicates that the rate of deposition of mineral matter in the shell follows an S-shaped curve, with a marked acceleration in shell deposition 5–6 hr. after its onset. During its first few hours in the shell gland, the egg undergoes a 25 % osmotic increase in volume. This swelling is brought to a fairly abrupt halt by the increase in the rate of shell deposition and the consequent increase in the impermeability and rigidity of the shell. Throughout all but the last hour or two of its 20 hr. stay in the shell gland, the egg lies with its pointed end caudal. Shortly before it is laid, however, it usually undergoes a 180° rotation in a horizontal plane. Thus the blunt end finally becomes caudal and emerges first when the egg is laid. During the rotation, the egg sinks to a more ventral position. This is necessary because, in most hens, the length of the egg plus the thickness of the walls of the shell gland is greater than the width of the pelvis. The possible significance of the S-shaped curve of shell deposition is discussed. The volume, shape and orientation of the egg are considered in relation to the needs of the chick embryo and to the characteristic structure of the bird’s oviduct and pelvis.