scholarly journals Preliminary coal pétrographie study of the Achlada lignite deposit in the Florida domain

2001 ◽  
Vol 34 (3) ◽  
pp. 1185 ◽  
Author(s):  
Π. A. ΑΝΤΩΝΙΑΔΗΣ ◽  
Α. ΒΛΑΧΟΥ ◽  
Σ. Μ. ΑΜΠΑΤΖΗ ◽  
Ρ. KHANAGA ◽  
W. RIEGEL
Keyword(s):  
Vegetation Index ◽  
Host Environment ◽  
Fine Grained ◽  
Erosion Processes ◽  
Time Period ◽  
Initial Stage ◽  
Host Rocks ◽  
Peat Formation ◽  
Coal Petrography ◽  
Inorganic Components

The present paper is a first stage study of the Achlada lignite deposit (Fiorina Domain) from the coal petrography aspect, aiming at the lignite classification in lithotypes and the extraction of initial conclusions concerning the paleoenvironment of the lignite formation. The Achlada deposit spreads at the NE end of the east borderlands of the Fiorina basin of a SW-NE axis, occupies an area of approximately 7,2 Km2 and is a part of the broader tectonic trench of Monastirion-Florina- Ptolemais-Kozani-Servia, which is ΝW-SE directed and of Miocene age. Due to erosion processes, the lignite deposit with its host rocks is separated into two areas, the Northeastern, where greater thicknesses occur, and the Southwestern (KOTIS TH. et al., 1995). The lignite deposit consists of alternations of mostly thin lignite layers (of approximate thickness up to 23 m) with sediments. The sediments of the lignitiferous suite are mainly sands; mostly fine grained and every now and then clayey, rarely medium grained and including psephit. Besides the lignite layers, layers of humic clays often occur with fragments of xylite and flora residues every now and then. During the present study, which aimed at a forerunning coal pétrographie examination of the deposit, 12 lignite samples have been taken from two representative boreholes. This initial stage of the research shows that the primal macérais of the Achlada deposit basically belong to the huminite group and secondarily to the liptinite group, while the third corresponding category of the inertinite group almost vanishes. From the first category greater percentages are occupied by the macerai densinite (=31%) followed by attrinite (=25%), textoulminite (=22%) and eu-ulminite (=3%), while the second corresponding category gives cutinite (=8%), liptodetrinite (=3%), sporinite (=2,5%) and relatively low percentages of resinite and alginite. The participation of inorganic components is mainly characterized by the relatively low presence of pyrite and clay. According to the results of the coal pétrographie study and their quantative evaluation the following indexes have been calculated; gelification index (GI), vegetation index (VI), groundwater influence index (GWI) and tissue preservation index (TPI). With the correlation between these indexes and the use of diagrams, conclusions are derived concerning the paleoenvironment and the conditions of the lignite formation. From the VI/GWI relationship conclusions are derived concerning the hydrologie status and the nutritient components supply and from the TPI/GI relationship the paleoenvironment in relation to the groundwater level. The evaluation of the data shows that the host environment of the maternal flora was telmatic with mainly mesotrophic and partly rheotrophic conditions (swamp), while for a time period -at least- just before the end of the mire, the environment has changed into a wet area with more intensely telmatic conditions. The conditions of the peat formation were, of course, repeating -frequent alternations with sediments periodically- but always within the scope of a similar environment

scholarly journals Remote sensing assessment of glacial loss and vegetation change from 1989 to 2016: Pond Inlet, Nunavut

2021 ◽  
Author(s):  
Ruby R. Pennell
Keyword(s):  
Vegetation Change ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Relevant Literature ◽  
Arctic Tundra ◽  
The Arctic ◽  
Landscape Changes ◽  
Storm Events ◽  
Time Period ◽  
Induced Changes

The climate change phenomenon occurring across the globe is having an increasingly alarming effect on Canada’s Arctic. Warming temperatures can have wide spanning impacts ranging from more rain and storm events, to increasing runoff, thawing permafrost, sea ice decline, melting glaciers, ecosystem disruption, and more. The purpose of this MRP was to assess the climate-induced landscape changes, including glacial loss and vegetation change, in Pond Inlet, Nunavut. A time series analysis was performed using the intervals 1989-1997, 1997-2005, and 2005-2016. The two methods for monitoring change were 1) the Normalized Difference Snow Index (NDSI) to detect glacial change, and 2) the Normalized Difference Vegetation Index (NDVI) to detect vegetation change, both utilizing threshold and masking techniques to increase accuracy. It was found that the percent of glacial loss and vegetation change in Pond Inlet had consistently increased throughout each time period. The area of glacial loss grew through each period to a maximum of 376 km2 of glacial loss in the last decade. Similarly, the area of the Arctic tundra that experienced vegetation change increased in each time period to a maximum of 660 km2 in the last decade. This vegetation change was characterized by overall increasing values of NDVI, revealing that many sections of the Arctic tundra in Pond Inlet were increasing in biomass. However, case study analysis revealed pixel clustering around the lower vegetation class thresholds used to classify change, indicating that shifts between these vegetation classes were likely exaggerated. Shifts between the higher vegetation classes were significant, and were what contributed to the most change in the last decade. The observations of higher glacial melt and increases in biomass are occurring in parallel with the increasing temperatures in Pond Inlet. Relevant literature in the Arctic agrees with the findings of this MRP that there are significant trends of glacial loss and vegetation greening and many studies attribute this directly to climate warming. The results of this study provide the necessary background with regards to landscape changes which could be used in future field studies investigating the climate induced changes in Pond Inlet. This study also demonstrates that significant landscape modifications have occurred in the recent decades and there is a strong need for continued research and monitoring of climate induced changes.

Mineralogical and Isotopic Characteristics of Sodic-Calcic Alteration in the Highland Valley Copper District, British Columbia, Canada: Implications for Fluid Sources in Porphyry Cu Systems

2020 ◽  
Vol 115 (4) ◽  
pp. 841-870 ◽  
Author(s):  
Kevin Byrne ◽  
Robert B. Trumbull ◽  
Guillaume Lesage ◽  
Sarah A. Gleeson ◽  
John Ryan ◽  
...  
Keyword(s):  
Water Source ◽  
White Mica ◽  
Late Triassic ◽  
Supporting Evidence ◽  
Fine Grained ◽  
Porphyry Cu ◽  
Mineral Assemblages ◽  
Alteration Minerals ◽  
External Water ◽  
Host Rocks

Abstract The Highland Valley Copper porphyry Cu (±Mo) district is hosted in the Late Triassic Guichon Creek batholith in the Canadian Cordillera. Fracture-controlled sodic-calcic alteration is important because it forms a large footprint (34 km2) outside of the porphyry Cu centers. This alteration consists of epidote ± actinolite ± tourmaline veins with halos of K-feldspar–destructive albite (1–20 XAn) ± fine-grained white mica ± epidote. The distribution of sodic-calcic alteration is strongly influenced by near-orthogonal NE- and SE-trending fracture sets and by proximity to granodiorite stocks and porphyry dikes. Multiple stages of sodic-calcic alteration occurred in the district, which both pre- and postdate Cu mineralization at the porphyry centers. The mineral assemblages and chemical composition of alteration minerals suggest that the fluid that caused sodic-calcic alteration in the Guichon Creek batholith was Cl bearing, at near-neutral pH, and oxidized, and had high activities of Na, Ca, and Mg relative to propylitic and fresh-rock assemblages. The metasomatic exchange of K for Na, localized removal of Fe and Cu, and a paucity of secondary quartz suggest that the fluid was thermally prograding in response to magmatic heating. Calculated δ18Ofluid and δDfluid values of mineral pairs in isotopic equilibrium from the sodic-calcic veins and alteration range from 4 to 8‰ and −20 to −9‰, respectively, which contrasts with the whole-rock values for least altered magmatic host rocks (δ18O = 6.4–9.4‰ and δD = −99 to −75‰). The whole-rock values are suggested to reflect residual magma values after D loss by magma degassing, while the range of hydrothermal minerals requires a mixed-fluid origin with a contribution of magmatic water and an external water source. The O-H isotope results favor seawater as the source but could also reflect the ingress of Late Triassic meteoric water. The 87Sr/86Srinital values of strongly Na-Ca–altered rocks range from 0.703416 to 0.703508, which is only slightly higher than the values of fresh and potassic-altered rocks. Modeling of those data suggests the Sr is derived predominantly from a magmatic source, but the system may contain up to 3% seawater Sr. Supporting evidence for a seawater-derived fluid entrained in the porphyry Cu systems comes from boron isotope data. The calculated tourmaline δ11Bfluid values from the sodic-calcic domains reach 18.3‰, which is consistent with a seawater-derived fluid source. Lower tourmaline δ11Bfluid values from the other alteration facies (4–10‰) suggest mixing between magmatic and seawater-derived fluids in and around the porphyry centers. These results imply that seawater-derived fluids can infiltrate batholiths and porphyry systems at deep levels (4–5 km) in the crust. Sodic ± calcic alteration may be more common in rocks peripheral to porphyry Cu systems hosted in island-arc terranes and submarine rocks than currently recognized.

scholarly journals Characterizing mineralogy and redox reactivity in potential host rocks for a UK geological disposal facility

2015 ◽  
Vol 79 (6) ◽  
pp. 1353-1367 ◽  
Author(s):  
J. Quirke ◽  
C. M. B. Henderson ◽  
R. A. D. Pattrick ◽  
K. M. Rosso ◽  
A. Dent ◽  
...  
Keyword(s):  
Iron Content ◽  
Host Rock ◽  
Azo Dye ◽  
Total Iron ◽  
Geological Disposal ◽  
Potential Host ◽  
Fine Grained ◽  
Reducing Conditions ◽  
Redox Reactivity ◽  
Host Rocks

AbstractGeological disposal facilities (GDF) are intended to isolate and contain radioactive waste within multiple protective barriers, deep underground, to ensure that no harmful quantities of radioactivity reach the surface environment. The last line of defense in a multi-barrier GDF is the geosphere, where iron is present in the host rock mineralogy as either Fe(II) or Fe(III), and in groundwater as Fe(II) under reducing conditions. The mobility of risk-driving radionuclides, including uranium and technetium, in the environment is affected significantly by their valence state. Due to its low redox potential, Fe(II) can mediate reduction of these radionuclides from their oxidized, highly mobile, soluble state to their reduced, insoluble state, preventing them from reaching the biosphere. Here a study of five types of potential host rocks, two granitoids, an andesite, a mudstone and a clay-rich carbonate, is reported. The bulk rocks and their minerals were analysed for iron content, Fe(II/III) ratio, and for the speciation and fine-grained nature of alteration product minerals that might have important controls on groundwater interaction. Total iron content varies between 0.9% in clays to 5.6% in the andesite. X-ray absorption spectroscopy reveals that Fe in the granitoids and andesite is predominantly Fe(II), and in mudstones, argillaceous limestone and terrestrial sandstone is predominantly Fe(III). The redox reactivity of the potential host rocks both in the presence and absence of Fe(II)-containing 'model' groundwater was investigated using an azo dye as a probe molecule. Reduction rates as determined by reactivity with the azo dye were correlated with the ability of the rocks to uptake Fe(II) from groundwater rather than with initial Fe(II) content. Potential GDF host rocks must be characterized in terms of mineralogy, texture, grain size and bulk geochemistry to assess how they might interact with groundwater. This study highlights the importance of redox reactivity, not just total iron and Fe(II)/(III) ratio, when considering the host rock performance as a barrier material to limit transport of radionuclides from the GDF.

APPLICATION OF NOVEL CLONAL ALGORITHM IN MULTIOBJECTIVE OPTIMIZATION

2010 ◽  
Vol 09 (02) ◽  
pp. 239-266 ◽  
Author(s):  
JIANYONG CHEN ◽  
QIUZHEN LIN ◽  
QINGBIN HU
Keyword(s):  
Multiobjective Optimization ◽  
Coarse Grained ◽  
Pareto Optimal ◽  
Pareto Optimal Front ◽  
Fine Grained ◽  
Initial Stage ◽  
Speed Up ◽  
Main Notion ◽  
Hybrid Mutation Operator ◽  
Cooling Schedule

In this paper, a novel clonal algorithm applied in multiobjecitve optimization (NCMO) is presented, which is designed from the improvement of search operators, i.e. dynamic mutation probability, dynamic simulated binary crossover (D-SBX) operator and hybrid mutation operator combining with Gaussian and polynomial mutations (GP-HM) operator. The main notion of these approaches is to perform more coarse-grained search at initial stage in order to speed up the convergence toward the Pareto-optimal front. Once the solutions are getting close to the Pareto-optimal front, more fine-grained search is performed in order to reduce the gaps between the solutions and the Pareto-optimal front. Based on this purpose, a cooling schedule is adopted in these approaches, reducing the parameters gradually to a minimal threshold, the aim of which is to keep a desirable balance between fine-grained search and coarse-grained search. By this means, the exploratory capabilities of NCMO are enhanced. When compared with various state-of-the-art multiobjective optimization algorithms developed recently, simulation results show that NCMO has remarkable performance.

An Experimental Analysis of a New Interval-Based Mutation Operator

2015 ◽  
Vol 14 (03) ◽  
pp. 1550018 ◽  
Author(s):  
K. Liagkouras ◽  
K. Metaxiotis
Keyword(s):  
Experimental Analysis ◽  
Pareto Front ◽  
Computational Experiments ◽  
Coarse Grained ◽  
Mutation Operator ◽  
Fine Grained ◽  
Initial Stage ◽  
Speed Up ◽  
Better Than

In this paper, we present a novel Interval-Based Mutation (IBMU) operator. The proposed mutation operator is performing coarse-grained search at initial stage in order to speed up convergence toward more promising regions of the search landscape. Then, more fine-grained search is performed in order to guide the solutions towards the Pareto front. Computational experiments indicate that the proposed mutation operator performs better than conventional approaches for solving several well-known benchmarking problems.

scholarly journals Succession and features distribution plant associations in row of railways

2016 ◽  
Vol 5 (4) ◽  
pp. 31-35
Author(s):  
Nikolay Alexandrovich Nikitin ◽  
Vera Valentinovna Solovieva
Keyword(s):  
Water Erosion ◽  
Processes Of Change ◽  
Ruderal Vegetation ◽  
Soil Lead ◽  
Erosion Processes ◽  
Plant Associations ◽  
Initial Stage ◽  
Motley Grass ◽  
Exchange Structure

ROW is a specific man-made landscape, in which the processes of change occur in its direction and intensity. Erosion processes, in particular the processes of water erosion of soil, lead not only to changes in the soil, but the plant through changes in soil fertility, nutrient richness, and by changing moisture exchange, structure and texture of soils. The main characteristics of flora undergo structural, quantitative and other changes. Vegetation characteristics, composition of plant associations, the speed and direction of succession, from the initial stage of overgrown weeds and ruderal vegetation to sustainable tree and shrub communities also modify. An ecological and geomorphological zoning shows the prevalence of the most eroded soils in the vicinity of the web. The regularity according to which in most habitats anthropogenic disturbed grow motley-grass-wheatgrass association with a reduction of anthropogenic load becomes dominant forb meadow-grass association. The role of indication of Eletrygia repens L. was also identified as an indicator of habitat disturbance.

scholarly journals Application of Benford’s Law on Cryptocurrencies

2021 ◽  
Author(s):  
Jernej Vičič ◽  
Aleksandar Tošić
Keyword(s):  
Machine Learning ◽  
Anomalous Behavior ◽  
Use Cases ◽  
Disruptive Technology ◽  
Graph Analysis ◽  
Established Method ◽  
Fine Grained ◽  
The Past ◽  
Time Period ◽  
The Law

Blockchain-based currencies or cryptocurrencies have become a global phenomenon known to most people as a disruptive technology, and a new investment vehicle. However, due to their decentralized nature, regulating these markets has presented regulators with difficulties in finding a balance between nurturing innovation, and protecting consumers. The growing concerns about illicit activity have forced regulators to seek new ways of detecting, analyzing, and ultimately policing public blockchain transactions. Extensive research on machine learning, and transaction graph analysis algorithms has been done to track suspicious behaviour. However, having a macro view of a public ledger is equally important before pursuing a more fine-grained analysis. Benford’s law, the law of first digit, has been extensively used as a tool to discover accountant frauds (many other use cases exist). The basic motivation that drove our research presented in this paper was to test he applicability of the well established method to a new domain, in this case the identification of anomalous behavior using Benford’s law conformity test to the cryptocurrency domain. The research focused on transaction values in all major cryptocurrencies. A suitable time-period was identified that was long enough to sport sufficiently large number of observations for Benford’s law conformity tests and was also situated long enough in the past so that the anomalies were identified and well documented. The results show that most of the cryptocurrencies that did not conform to Benford’s law had well documented anomalous incidents, the first digits of aggregated transaction values of all well known cryptocurrency projects were conforming to Benford’s law. Thus the proposed method is applicable to the new domain.

scholarly journals Soil erosion risk assessment: a case study of the Jos Plateau, Nigeria

2021 ◽  
pp. 109-117
Author(s):  
Ayodele Owonubi
Keyword(s):  
Soil Erosion ◽  
Vegetation Index ◽  
Vegetation Coverage ◽  
Anthropogenic Factors ◽  
Rainfall Erosivity ◽  
Entire Area ◽  
Jos Plateau ◽  
Erosion Rates ◽  
Erosion Processes ◽  
Soil Erosion Rates

Soil erosion is a treat to global food security. The objective of this study was to evaluate factors influencing erosion on the arable lands of the Jos Plateau; and to estimate the extent of soil erosion in the area. Universal Soil Loss Equation (USLE) model was used to evaluate soil erosion processes in the study area. This was facilitated with the aid of Geographic Information System Both for Interpolation and Geospatial analysis. Soil data from field survey was the primary source of data for analysis of soil erodibility. Topographic factor was determined from 90-meter elevation data. Rainfall erosivity was determined from rainfall data at 1 kilometer resolution. Whereas vegetation cover factor was determined from Normalized Difference Vegetation Index. Results of the study indicate that rainfall erosivity values were remarkably high and have mean values of 5117MJ.mm/ ha.h.y. Analysis of percent areal coverage indicate that the entire area had 52, 34, 7, and 7% low, moderate, high and very high topographic factors respectively. Further analysis indicate that anthropogenic factors had severely affected vegetation coverage of the Jos plateau, especially on the arable lands. Furthermore, during this research, the mean annual actual and potential soil erosion rates were estimated spatially over the Jos Plateau area. Soil erosion rates were far more than tolerable rates thereby affecting soil fertility and productivity.

scholarly journals INVESTIGATION OF THE CHANGES OF LAKE SURFACE TEMPERATURES AND AREAS: CASE STUDY OF BURDUR AND EGIRDIR LAKES, TURKEY

2021 ◽  
Vol XLIII-B3-2021 ◽  
pp. 299-304
Author(s):  
N. Aslan ◽  
D. Koc-San
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Aquatic Systems ◽  
Lake Area ◽  
Lake Surface ◽  
Water Index ◽  
Time Period ◽  
Eğirdir Lake ◽  
Egirdir Lake ◽  
Landsat Satellite

Abstract. The world's average surface temperature has been increasing in recent decades. This situation is expected to affect aquatic systems and lakes are one of the most important aquatic systems. The main aims of this study are to examine Lake Surface Water Temperature (LSWT) and area changes of Burdur and Egirdir lakes located in the West Mediterranean Region (TR61) of Turkey for the years 1998, 2008 and 2018 using Landsat satellite images. For this purpose, initially, Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) images were generated and the lake shorelines were extracted by thresholding these images. Then, the LSWT values were obtained by using Landsat thermal images. Finally, the area and LSWT changes of Burdur and Egirdir lakes between the years 1998-2008-2018 and the relationships of these parameters with each other were analysed. The obtained results showed that the lake boundaries could be semi-automatically extracted with overall accuracy values higher than 95%. In 20-year time period it was also observed that the Burdur Lake area decreased significantly, while the Egirdir Lake area decreased slightly. When the LSWT values were analysed, it can be stated that the LSWT values increased in both lakes during this time period. The amount of increase in LSWT values was about 2.2 °C for Burdur Lake, while about 1.3 °C for Egirdir Lake.

scholarly journals A field investigation on rill development and flow hydrodynamics under different upslope inflow and slope gradient conditions

2020 ◽  
Vol 51 (5) ◽  
pp. 1201-1220
Author(s):  
Pei Tian ◽  
Chengzhong Pan ◽  
Xinyi Xu ◽  
Tieniu Wu ◽  
Tiantian Yang ◽  
...  
Keyword(s):  
Soil Loss ◽  
Field Investigation ◽  
Rill Erosion ◽  
Slope Gradient ◽  
Power Functions ◽  
Stream Power ◽  
Erosion Processes ◽  
Initial Stage ◽  
Quantitative Impact ◽  
Inflow Discharge

Abstract Few studies focus on the quantitative impact of upslope inflow rate and slope gradient on rill development and erosion processes. Field plot experiments under varying inflow rates (6–36 L min−1m−1) and slope gradients (26, 42 and 57%) were conducted to address this issue. The results showed soil loss rates significantly demonstrated temporal variability in relevance to the rill developing process. Rill erosion and its contribution to soil loss increased with increasing inflow rates and slope gradients by power functions. There was a threshold inflow discharge (12–24 L min−1m−1), under which, rill erosion became the dominant erosion pattern. At the initial stage, downcutting of rill bottom and headward erosion were obvious, whereas rill broadening was significant at the actively rill developing period. Rill density increased with slope gradient increasing from 26% to 42%, and then decreased. For the 57% slope under high inflow rates (24–36 L min−1m−1), gravity caused an increase in the collapse of rills. Mean rill width increased with increasing inflow rates but decreased as slope gradients increased, while mean rill depth increased with increasing inflow rates and slope gradients. Stream power and rill flow velocity were the best hydrodynamic parameter to simulate rill erosion and rill morphology, respectively.

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