Kinds Of Deposits Research Articles

Melt–Fluid and Fluid–Fluid Immiscibility in a Na2SO4–SiO2–H2O System and Implications for the Formation of Rare Earth Deposits

AbstractLiquid–liquid immiscibility has crucial influences on geological processes, such as magma degassing and formation of ore deposits. Sulfate, as an important component, associates with many kinds of deposits. Two types of immiscibility, including (i) fluid–melt immiscibility between an aqueous solution and a sulfate melt, and (ii) fluid–fluid immiscibility between two aqueous fluids with different sulfate concentrations, have been identified for sulfate–water systems. In this study, we investigated the immiscibility behaviors of a sulfate‐ and quartz‐saturated Na2SO4–SiO2–H2O system at elevated temperature, to explore the phase relationships involving both types of immiscibility. The fluid–melt immiscibility appeared first when the Na2SO4–SiO2–H2O sample was heated to ∼270°C, and then fluid–fluid immiscibility emerged while the sample was further heated to ∼450°C. At this stage, the coexistence of one water‐saturated sulfate melt and two aqueous fluids with distinct sulfate concentrations was observed. The three immiscible phases remain stable over a wide pressure–temperature range, and the appearance temperature of the fluid–fluid immiscibility increases with the increased pressure. Considering that sulfate components occur extensively in carbonatite‐related deposits, the fluid–fluid immiscibility can result in significant sulfate fractionation and provides implications for understanding the formation of carbonatite‐related rare earth deposits.

Post-diaminobenzidine Treatments for Double Stainings: Extension of Sulfide-Silver-Gold Intensification for Light and Fluorescent Microscopy.

Double staining protocols using the most popular immunoperoxidase techniques may raise difficulties. The two ordinary detection systems may cross-talk, when the primary antibodies are derived from phylogenetically closely related animals. A color shift of the 3,3'-diaminobenzidine (DAB) polymer may occur during the second development, resulting in poor distinction between the two kinds of deposits. A post-DAB technique, sulfide-silver-gold intensification, was fine tuned to eliminate these difficulties, which may be especially suitable for colocalization of cell nuclei and perikarya of the same cells. The revised method was probed in combination with a subsequent other immunoperoxidase step or fluorochrome-tagged reagents. The nuclear antigens (BrdU, c-Fos, and Prox-1) were first visualized with DAB polymer, which were then treated with SSGI, turning the deposit black. Thereafter, cytoplasmic antigens (doublecortin, neuronal nuclei, and calbindin) were detected with either another immunoperoxidase using DAB again or immunofluorescence labeling. In both approaches, the immunopositive nuclei and cytoplasmic sites could be easily distinguished even at low magnifications. Different shielding or eluting posttreatments were compared for consecutive acetylcholinesterase histochemistry terminated with DAB development and immunohistochemistry in the same sections. In conclusion, we recommend post-DAB treatments that abolish interactions between detection systems and allow clear distinction between the two signals under various conditions.

Geomorphologic and Glacial Evolution of the Cachapoal and southern Maipo catchments in the Andean Principal Cordillera, Central Chile (34°-35º S)

We present here a reconstruction of the post late Miocene landscape evolution of the western slope of the Andean Cordillera Principal near 34°20’ S. We base our analysis on the available geological information, a morphological characterization of the landform assemblages in the Cachapoal and southern Maipo catchments, and the first 10Be exposure ages for moraines in this area. The Cachapoal drainage basin is characterized by a variety of morphological features, like an elevated low-relief surface, volcanoes and lava flows on valley slopes, U-shaped valley sections, roches moutonnées, and large glaciated areas. Different kinds of deposits have been included in the study, such as moraines, lacustrine and landslide deposits, and a well-developed system of fluvial terraces in the more distal part of the Cachapoal catchment. Landslides are mostly developed on rocks of the late Eocene-early Miocene Abanico Formation. and are less frequent in outcrops of the overlying, early to middle Miocene Farellones Formation. We estimate that the lowest end moraine in the Cachapoal catchment is located next to the locality Bocatoma Chacayes (~950 m altitude), though covered by a major landslide. No evidence exist for glacial deposits further down stream in this region. Lateral moraine ridges of the Cachapoal Glacier at Los Cerrillos yielded 10Be exposure ages of 20.3±2.9 and 21.9±5.3 ka that indicate they are associated with the Last Glacial Maximum (LGM). Holocene moraines exist next to all glacier tongues. Of particular interest in this region is the 12 km-long debris-covered Cachapoal Glacier, the longest valley glacier in the central Chilean Andes, and its distal and proximal moraine deposits. Two lateral moraines adjacent to the present-day Cachapoal Glacier yielded exposure average ages of 13.5±2.4 ka for the external ridge, indicating the Younger Dryas, and 3.8±0.8 ka for the internal ridge, an age that coincides with the 4.2 ka global climatic event that marks the beginning of the Meghalayan Age, at the end of the Holocene. The large size of this moraine on both sides of the ice tongue indicates the great development of the glacier at that time. Some of these ages coincide with ages obtained further north in the Maipo drainage basin, at the latitude of Santiago, and in the eastern flank of the cordillera, however, no pre-LGM deposits were found here, unlike the other mentioned regions. This difference together with the much lower altitude of the LGM moraine deposits in the study region suggests that the Cachapoal catchment is a transition zone to a more humid region further south, and indicates the great need for further reconnaissance and dating of glacial deposits in this Andean region. Our analysis of the geomorphological evolution is consistent with incision start for the Cachapoal Valley in latest Miocene. In this process, glacier incision was apparently not much effective until mid-Pleistocene time, when volcanism was active in the higher regions of the mountain range covering areas not yet incised, whereas in the western Principal Cordillera lavas flowed in deeply incised valleys. Pleistocene glaciers deepened and shaped the already incised valleys, which are presently mostly occupied by rivers.

Mechanical properties of heat-treated duplex electroless nickel coatings

ABSTRACTElectroless nickel coatings present complementary properties: coatings formed using hypophosphite present usually better corrosion resistance while those made with borohydride present better mechanical and wear properties. Duplex coatings, combining both kinds of deposits, are designed to combine features of both nickel–phosphorus (ENP) and nickel–boron (ENB) coatings. In this study, monolayer and bilayer coatings were synthesised on mild steel substrates, in various combinations of ENP and ENB, with a total thickness of 20 µm and heat treated (400°C – 1 h) under non-reactive atmosphere (95% Ar–5% H2) to enhance their mechanical properties. The morphology, roughness, hardness, abrasive wear resistance and scratch behaviour of the coatings were investigated. Samples with ENP as the top layer showed a higher roughness than samples with ENB as the external layer. However, samples with ENB as the top layer provided better wear resistance, even if they presented a lower combined hardness. ENB monolayer showed the best resistance to scratch testing.

Silver-Containing Humic Substance-Based Nanocomposites-Agents for Healing of Potatoes from the Ring Rot.

The influence of silver-containing humic substance (HS)-based nanocomposites (NCs) obtained from mud, shale, and coals of three kinds of deposits in Mongolia on the viability and ability to biofilm formation of a phytopathogenic gram-positive bacterium Clavibacter michiganensis subsp. sepedonicus (Cms), as well as peroxidase activity and potato plant growth in vitro, has been investigated. The maximum reduction of the viability of bacterial cells was found in the case of incubation with HS-mu/Ag NC and HS-coal/Ag NC. It was found that HSs, including HS-mu and HS-sl, and NCs synthesized on the base of these HSs, HS-mud/Ag NC and HS-sl/Ag NC reduce more than twofold the activity of peroxidase in potato tissues. It was also found that HS-co and HS-coal/Ag NC stimulate the potato peroxidase activity, as well as biofilm formation of Cms bacterium. No negative effect of the studied NCs on the growth of potato has been revealed. Moreover, NC HS-mud/Ag based on mud had a stimulating effect on leaf formation in plants.

Reply to comment on “Ichnological analysis of contourites: Past, present and future” by Francisco J. Rodríguez-Tovar and F. Javier Hernández-Molina [Earth-Science Reviews, 182 (2018), 28-41

The comments of G. Shanmugam concerning the paper “Ichnological analysis of contourites: Past, present and future”, by Rodríguez-Tovar and Hernández-Molina (2018), imply that this study has tried to definitively resolve the issues of distinguishing contourites and differentiating them from other kinds of deposits. In reality, however, most of this reviewer's comments refer to issues that lie beyond of the scope of that contribution and therefore are not relevant to the paper. The criticisms of our work appear to be aimed at concepts and ideas from other authors.

SACRIFICE VS. SUSTENANCE: FOOD AS A BURIAL GOOD IN LATE PRE-IMPERIAL AND EARLY IMPERIAL CHINESE TOMBS AND ITS RELATION FUNERARY RITES

AbstractOne of the medical manuscripts recovered from Tomb No. 3 at Mawangdui (dated 186 b.c.e.) states that, “When a person is born there are two things that need not to be learned: the first is to breathe and the second is to eat.” Of course it is true that all healthy newborn human beings possess the reflexes to breathe and eat. Yet, the implications of death should have been just as obvious to the ancient Chinese. Once the human brain ceases to function, there is no longer a biological need for oxygen and nourishment. Nevertheless, a large number of people in late pre-imperial and early imperial China insisted on burying food and drink with the dead. Most modern commentators take the deposition of food and drink as burial goods to be a rather trite phenomenon that warrants little reflection. To their minds both kinds of deposits were either intended to sustain the spirit of the deceased in the hereafter or simply a sacrifice to the spirit of the deceased. Yet, a closer look at the archaeological evidence suggests otherwise. By tracking the exact location of food and drink containers in late pre-imperial and early imperial tombs and by comprehensively analyzing inscriptions on such vessels in addition to finds of actual food, the article demonstrates that reality was more complicated than this simple either/or dichotomy. Some tombs indicate that the idea of continued sustenance coincided with occasional sacrifices. Moreover, this article will introduce evidence of a third kind of sacrifice that, so far, has gone unnoticed by scholarship. Such data confirms that sacrifices to spirits other than the one of the deceased sometimes were also part of funerary rituals. By paying close attention to food and drink as burial goods the article will put forth a more nuanced understanding of early Chinese burial practices and associated notions of the afterlife.

Water driven processes and landforms evolution rates in mountain geomorphosites: examples from Swiss Alps

Geomorphic processes driven by water are particularly active in mountain environments, especially under the current climate conditions. Erosion and dissolution processes shape meaningful landforms, in different kinds of deposits and rocks, and in some cases they are classified as geomorphosites. Such landforms, especially earth pyramids and rock pillars, are usually characterized by a high scientific value (e.g., representativeness, ecologic support role) and by additional values (e.g., cultural and aesthetic value) contributing to the local geoheritage. Mountain geomorphosites are growing in importance within scientific community and their morphological evolution can affect the global value of the site itself (e.g., integrity). In this paper, after a first review on the terminology used for classifying landforms modelled by water runoff and on their meaning within the mountain environment, the results of a detailed research performed at two sample sites, included in the Swiss National Inventory of Geosites, are presented. The two study sites are representative respectively of: i) water runoff on glacial deposits shaping earth pyramids (Pyramides d'Euseigne); ii) water dissolution on gypsum rocks, modelling articulate karst landscapes (Pyramides de gypse du Col de la Croix). For each site, landforms evolution was investigated and denudation rates were estimated by means of different methods: iconographic material analysis, quantitative geomorphology and dendrogeomorphology on exposed roots. Despite the long-term, average rates obtained by means of roots exposure for both water runoff on glacial deposits (e.g., 5.8mm/y) and dissolution on gypsum rocks (5.6mm/y) are comparable. Moreover, a strict relation between the activity degree of processes, the integrity of the site and the assignment of geomorphosites to a specific category (i.e., active, passive or evolving passive) emerged from the results.

The highly active Anhur–Bes regions in the 67P/Churyumov–Gerasimenko comet: results from OSIRIS/ROSETTA observations

The Southern hemisphere of the 67P/Churyumov-Gerasimenko comet has become visible from Rosetta only since March 2015. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rate, thus exposing the subsurface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spectrophotometry and some transient events of two Southern hemisphere regions: Anhur and part of Bes. Bes is dominated by outcropping consolidated terrain covered with fine particle deposits, while Anhur appears strongly eroded with elongated canyon-like structures, scarp retreats, different kinds of deposits, and degraded sequences of strata indicating a pervasive layering. We discovered a new 140 m long and 10 m high scarp formed in the Anhur/Bes boundary during/after the perihelion passage, close to the area where exposed CO$_2$ and H$_2$O ices were previously detected. Several jets have been observed originating from these regions, including the strong perihelion outburst, an active pit, and a faint optically thick dust plume. We identify several areas with a relatively bluer slope (i.e. a lower spectral slope value) than their surroundings, indicating a surface composition enriched with some water ice. These spectrally bluer areas are observed especially in talus and gravitational accumulation deposits where freshly exposed material had fallen from nearby scarps and cliffs. The investigated regions become spectrally redder beyond 2 au outbound when the dust mantle became thicker, masking the underlying ice-rich layers.

Experimental study on under-deposit corrosion and its inhibition using electrochemical methods and electronic coupon technique

PurposeIn this study the aim was to investigate under-deposit corrosion (UDC) behavior and the action effects of amino trimethylene phosphonic acid (ATMP) in the oxygen-contained solution.Design/methodology/approachElectrochemical methods and wire beam electrode techniques were used for the study of ATMP action effect for X65 steel under silica sand and CaCO3 particle deposit. Electronic coupon technique was used for the study of galvanic effect caused by the deposits and the action effect of ATMP.FindingsATMP would cause localized corrosion for the silica sand-covered steel. However, it could inhibit the localized corrosion of the steel beneath CaCO3 particle deposit. Galvanic effect test showed that the galvanic effect caused by the deposits was an important factor for the acceleration of UDC. ATMP had an obvious promotion effect for the galvanic current between bare coupon and silica sand covered coupon and different degrees of localized corrosion were observed beneath both deposits.Originality/valueThe authors believe that the paper may be of particular interest to the readers of the journal as the measurement methods for the UDC of X65 pipeline steel. The experiment they did in the laboratory found that the inhibitor ATMP has a good inhibition effect for bare steel, but it would accelerate the UDC. Different kinds of deposits would have different influences for the UDC behavior with inhibitor added.

The Study of Banking System Functionality Based on Data Envelopment Analysis (DEA) Method: A Case Study in Keshavarzi Banks in Kurdistan Province

This project has concentrated on technical evaluation and scales of Keshavarzi Bank in Kurdistan Province. To access this objective, descriptive and survey research has been used. In this order , different check lists of research input such as operational , non- operational and investment costs, industrial criterion , agricultural criterion , cite condition, branch ranking and the rate of literacy and also the research output including different kinds of deposits, delivered facilities, income and function have been collected. The studied society of this project is the whole 42 branches of Keshavarzi Banks in Kurdistan Province. Using the Data Envelopment Analysis and CCR and BCC models , the scale and technical productivity of the branches have been studied . Also the hierarchical analysis has been used to determine the importance coefficient of the research outputs. The results of this research shows that 25 out of 42 branches of Keshavarzi Banks have technical productivity based on CCR model and 16 branches based on BCC model have both the scale and technical productivity. The branches of Quorveh , Bijar , divandareh and Sanandaj are higher 5 branches regarding the scale and technical productivity, and the branches of Meidan-E-Bar Sanandaj, Bazar Bijar Jomhuri Street of Marivan are of non-productive branches of Keshavarzi banks in Kurdistan Province. Also, based on these results of hierarchical analysis of the data (AHP), the efficiency of deposits was 0.633 , delivered facilities was 0.287 and income was 0.08 DOI: 10.5901/mjss.2015.v6n6s2p547

Organic-matter quality of deep permafrost carbon – a study from Arctic Siberia

Abstract. The organic-carbon (OC) pool accumulated in Arctic permafrost (perennially frozen ground) equals the carbon stored in the modern atmosphere. To give an idea of how Yedoma region permafrost could respond under future climatic warming, we conducted a study to quantify the organic-matter quality (here defined as the intrinsic potential to be further transformed, decomposed, and mineralized) of late Pleistocene (Yedoma) and Holocene (thermokarst) deposits on the Buor-Khaya Peninsula, northeast Siberia. The objective of this study was to develop a stratigraphic classified organic-matter quality characterization. For this purpose the degree of organic-matter decomposition was estimated by using a multiproxy approach. We applied sedimentological (grain-size analyses, bulk density, ice content) and geochemical parameters (total OC, stable carbon isotopes (δ13C), total organic carbon : nitrogen (C / N) ratios) as well as lipid biomarkers (n-alkanes, n-fatty acids, hopanes, triterpenoids, and biomarker indices, i.e., average chain length, carbon preference index (CPI), and higher-plant fatty-acid index (HPFA)). Our results show that the Yedoma and thermokarst organic-matter qualities for further decomposition exhibit no obvious degradation–depth trend. Relatively, the C / N and δ13C values and the HPFA index show a significantly better preservation of the organic matter stored in thermokarst deposits compared to Yedoma deposits. The CPI data suggest less degradation of the organic matter from both deposits, with a higher value for Yedoma organic matter. As the interquartile ranges of the proxies mostly overlap, we interpret this as indicating comparable quality for further decomposition for both kinds of deposits with likely better thermokarst organic-matter quality. Supported by principal component analyses, the sediment parameters and quality proxies of Yedoma and thermokarst deposits could not be unambiguously separated from each other. This revealed that the organic-matter vulnerability is heterogeneous and depends on different decomposition trajectories and the previous decomposition and preservation history. Elucidating this was one of the major new contributions of our multiproxy study. With the addition of biomarker data, it was possible to show that permafrost organic-matter degradation likely occurs via a combination of (uncompleted) degradation cycles or a cascade of degradation steps rather than as a linear function of age or sediment facies. We conclude that the amount of organic matter in the studied sediments is high for mineral soils and of good quality and therefore susceptible to future decomposition. The lack of depth trends shows that permafrost acts like a giant freezer, preserving the constant quality of ancient organic matter. When undecomposed Yedoma organic matter is mobilized via thermokarst processes, the fate of this carbon depends largely on the environmental conditions; the carbon could be preserved in an undecomposed state till refreezing occurs. If modern input has occurred, thermokarst organic matter could be of a better quality for future microbial decomposition than that found in Yedoma deposits.

Rethinking deposit insurance on brokered deposits

In a bid to understand how the Federal Deposit Insurance Corporation (FDIC) can aid in promoting financial stability, economists have recently called the definition of core deposits into question. Deposit insurance is extended to core deposits because they represent the stable funding base that the banking system relies on for liquidity. The criteria used by the FDIC to determine whether a funding source is insurable are not consistent with any objective criteria available to define core deposits. Herein I assess current FDIC criteria and whether the kinds of deposits currently insured are good candidates for coverage. I find brokered deposits to be particularly ill-suited to insurance. The FDIC could further promote banking-system stability while simultaneously reducing potential costs by ending its extension of insurance to brokered deposits.

Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region’s past and offers a new context within which the late Holocene “Earthmovers” of the Llanos de Moxos could have emerged.

English

  The goal of the present research is to study the activity-based costing system and the traditional system based on the volume comparatively in order to calculate the cost of the deposits in Refah Bank in Iran. Thus, first the deposit costs were calculated by using the volume based costing and then activity-based costing system was used to calculate the cost of deposits. In this research, the data from the whole branches of Refah Bank of Iran was used instead of focusing on the data gained from a limited number of branches. Also, regarding the existence of four different kinds of deposits, four different hypotheses were devised. Additionally, in an independent hypothesis, hypothesis 5, we studied the meaningfulness of the relationship between the ratio of staff's activities and the ratio of indirect costs of the deposits. The results show that there is not a meaningful difference between the cost calculated by activity-based costing and traditional method for current and saving deposits. But regarding the accounting calculations and the figure of cost ranking, there is a significant difference and activity-based costing system is absolutely more efficient than the traditional one. Also, the results of the research show that there is a meaningful difference between the cost calculated by activity-based costing and traditional system for long-term and other deposits. Also, the results of the research show that there is a meaningful relationship between the ratios of staff activities with overhead cost ratio for each of the deposits.   Key words: Activity-based costing (ABC), volume based costing, direct and indirect cost, over head appropriation bases.

A new conceptual model for the deposition process of homogenite: Application to a cretaceous megaturbidite of the western Pyrenees (Basque region, SW France)

The north Pyrenean megaturbidite is a 19–63 m exceptional thick bed deposited during the Late Turonian and extending over more than 90 km in the Basque region Country (SW France). Its thickness varies from more than 63 m to about 19 m from east (Mauléon area) to west (Basque coast). It represents a total compacted volume of about 90 km 3 of carbonates. On the field, rare sedimentary structures are visible in the turbidite bed. They consist of laminar planar lamination and rare cross laminations in the eastern region and antidune-like structures in the western region. Five sites have been sampled with a vertical step of 50 cm to 1 m. Thin sections have been quantitatively analyzed for counting the terrigeneous fraction, the quartz grain size and the mineral orientation. The deposits fine westward, which suggests a source located in the east of the Mauléon Basin. This is consistent with the quartz grain orientation in the lower part of the megaturbidite. The deposits fine upward from medium sand to clayey-silt. This is consistent with the classical definition of homogenites and suggests that these kinds of deposits are turbidites. These observations also suggest that the term “megaturbidite” is appropriated for these deposits. The sedimentary analysis indicates that the deposit results from a single event. The volume of sediment involved in the process, as well as the quartz grain orientation indicating flow motion in the opposite direction of the initial flow and the antidune-like structure suggest the formation of reflected flows and the formation of standing waves over the complete water column in the Basque flysch sub-basins corresponding to a “Seiche effect”. The origin of the megaturbidite is probably an earthquake-generated collapse on the carbonate platform. This example allows providing a new conceptual model for the process of homogenite deposition. This model explains the deposition of thick, fine-grained, crudely-graded megaturbidites.

Understanding carbonaceous deposit formation resulting from engine oil degradation

The formation processes of carbonaceous deposits in the first piston ring grooves of direct injection diesel engines have been studied. Deposits generated during engine tests were analysed by SEM/EDX, thermogravimetric analysis, pyrolysis/gas chromatography/mass spectrometry, and FT-IR spectroscopy. These analyses showed that the deposits, with a structure of cracked varnishes, mainly resulted from the degradation of lubricants. Their state strongly depends on the severity of the tests, which resulted in the formation of two kinds of deposits, termed as ‘oily’ and ‘dry’, according to their content of volatile organic matters. Then, to better understand the deposit formation process, a thermo-oxidative degradation of the lubricating oil was carried out in a tubular furnace, while varying temperature, duration of the test, and adding metallic elements to simulate the engine wear. The consumption of antioxidant additives and the lubricant carbonization were highlighted. Temperature level was identified as the most influential parameter during the lubricant degradation process. The presence of metallic elements appeared to act as a catalyst by speeding up the degradation when the tests duration was increased.

The effect of heat treatment on the structure and hardness of pulse electrodeposited NiP–WC composite coatings

In the present work pure nickel–phosphorous and nickel–phosphorous composite coatings with WC particles (mean diameter 200 nm) have been produced under both direct and pulse current conditions, from a modified, organic-free, Watts bath. The produced coatings were thermally treated at various temperatures and the structure, morphology and the microhardness of the deposits were examined after each cycle of heat treatment. Imposition of pulse current conditions led to composite deposits with high-incorporation percentage of WC particles in the matrix. Also, the presence of WC particles resulted in coatings with enhanced microhardness values and retarded diffusion phenomena in the deposits during thermal treatment. Annealing of all coatings at 400 °C revealed complete crystallization of the matrix to the phases of Ni, Ni 2P and Ni 3P accompanied by a significant increase of microhardness for all deposits. Further heating at higher temperatures demonstrated a decrease in microhardness of both kinds of deposits. The experimental data proved that it is possible to produce NiP–WC composite coatings under specific pulse current conditions followed by proper thermal treatment that exhibited considerable enhanced microhardness.

Metallic mineral deposits in the Nordic countries

The Nordic countries, including Greenland, have a long tradition in mining. Documented mining dates back to the 8th century AD. Today this region is the most important metallic mining district of the European Union. Metals are produced from active mines in all countries except Iceland and related industries are thriving in all countries. Important ore deposit types include: volcanogenic massive sulphide deposits (Cu, Zn, Pb, Au, Ag), orogenic gold deposits (Au), layered intrusions (Ni, PGE, Ti±V), intrusive hosted Cu-Au, apatite-Fe deposits, Cr- and anorthosite hosted Ti deposits. Besides these welldocumented deposits, new kinds of deposits are being explored, e.g., iron oxide-copper-gold (IOCG), shale-hosted Ni-Zn-Cu and different types of uranium deposits.

Depressurization-Induced Gas Production From Class 1 Hydrate Deposits

Summary Class 1 hydrate deposits are characterized by a hydrate-bearing layer underlain by a two-phase zone involving mobile gas. Two kinds of deposits are investigated. The first involves water and hydrate in the hydrate zone (Class 1W), while the second involves gas and hydrate (Class 1G). We introduce new models to describe the effect of the presence of hydrates on the wettability properties of porous media. We determine that large volumes of gas can be readily produced at high rates for long times from Class 1 gas-hydrate accumulations by means of depressurization-induced dissociation using conventional technology. Dissociation in Class 1W deposits proceeds in distinct stages, while it is continuous in Class 1G deposits. To avoid blockage caused by hydrate formation in the vicinity of the well, wellbore heating is a necessity in production from Class 1 hydrates. Class 1W hydrates are shown to contribute up to 65% of the production rate and up to 45% of the cumulative volume of produced gas; the corresponding numbers for Class 1G hydrates are 75% and 54%. Production from both Class 1W and Class 1G deposits leads to the emergence of a second dissociation front (in addition to the original ascending hydrate interface) that forms at the top of the hydrate interval and advances downward. In both kinds of deposits, capillary pressure effects lead to hydrate lensing (i.e., the emergence of distinct banded structures of alternating high/low hydrate saturation, which form channels and shells and have a significant effect on production).