Search

Due to a predicted shortage of raw materials, increasing attention is drawn to the utilization of anthropogenic resources through recycling and urban mining. However, in order to assess the availability of anthropogenic resources as potential raw materials, a consistent concept for categorizing anthropogenic materials into reserves, resources and other occurrences is needed. This study presents a framework for the evaluation of anthropogenic resources, derived from the standard procedure for resource and reserve identification, evaluation, and classification of the U.S. Geological Survey for natural stock resources. The framework was applied to a case study on phosphorus (P) stocks in Austria. Results indicate that only 10% of the anthropogenic P stocks in Austria (one million tons in total) are extractable at subeconomic levels with production costs 5–10 times above the market price for P fertilizer. 70% of P stocks are not technically extractable and 20% of such a low grade that recovery is not practically feasible. Based on the assessment, it is found that the extractable amount of P could have been much higher if P-rich materials were not mixed with low-grade materials during landfilling. Although the evaluation of anthropogenic P stocks in Austria was performed on a screening level, the application of the framework highlights that a consistent method for the evaluation of anthropogenic resources can provide a basis for enhanced utilization of anthropogenic resources. In future, further case studies are needed to demonstrate the application of the evaluation framework for various resources and in consideration of environmental, technological, and societal factors. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nematode standing stocks were mainly driven by temporal effects, rather than depth patterns. [•] Topographic/hydrographic differences are important for nematode standing stock patterns. [•] Nematode size distributions seem driven by food pulses in food-rich areas such as the Blanes Canyon. [•] Food pulses may induce the nematode community into a more ‘reproductive’ state. [•] Food pulses may attract or stimulate smaller, more opportunistic nematode species. [Copyright &y& Elsevier]

Peatlands contain a large belowground carbon (C) stock in the biosphere, and their dynamics have important implications for the global carbon cycle. However, there are still large uncertainties in C stock estimates and poor understanding of C dynamics across timescales. Here I review different approaches and associated uncertainties of C stock estimates in the literature, and on the basis of the literature review my best estimate of C stocks and uncertainty is 500±100 (approximate range) gigatons of C (Gt C) in northern peatlands. The greatest source of uncertainty for all the approaches is the lack or insufficient representation of data, including depth, bulk density and carbon accumulation data, especially from the world's large peatlands. Several ways to improve estimates of peat carbon stocks are also discussed in this paper, including the estimates of C stocks by regions and further utilizations of widely available basal peat ages. Changes in peatland carbon stocks over time, estimated using Sphagnum (peat moss) spore data and down-core peat accumulation records, show different patterns during the Holocene, and I argue that spore-based approach underestimates the abundance of peatlands in their early histories. Considering long-term peat decomposition using peat accumulation data allows estimates of net carbon sequestration rates by peatlands, or net (ecosystem) carbon balance (NECB), which indicates more than half of peat carbon (>270 Gt C) was sequestrated before 7000 yr ago during the Holocene. Contemporary carbon flux studies at 5 peatland sites show much larger NECB during the last decade (32±7.8 (S.E.) g Cm-2 yr-1) than during the last 7000 yr (~11 gCm-2 yr-1), as modeled from peat records across northern peatlands. This discrepancy highlights the urgent need for carbon accumulation data and process understanding, especially at decadal and centennial timescales, that would bridge current knowledge gaps and facilitate comparisons of NECB across all timescales. [ABSTRACT FROM AUTHOR]

We examine the influence of climate, soil properties and vegetation characteristics on soil organic carbon ( SOC) along a transect of West African ecosystems sampled across a precipitation gradient on contrasting soil types stretching from Ghana (15° N) to Mali (7° N). Our findings derive from a total of 1108 soil cores sampled over 14 permanent plots. The observed pattern in SOC stocks reflects the very different climatic conditions and contrasting soil properties existing along the latitudinal transect. The combined effects of these factors strongly influence vegetation structure. SOC stocks in the first 2 m of soil ranged from 20 Mg C ha−1 for a Sahelian savanna in Mali to over 120 Mg C ha−1 for a transitional forest in Ghana. The degree of interdependence between soil bulk density ( SBD) and soil properties is highlighted by the strong negative relationships observed between SBD and SOC ( r2 > 0.84). A simple predictive function capable of encompassing the effect of climate, soil properties and vegetation type on SOC stocks showed that available water and sand content taken together could explain 0.84 and 0.86 of the total variability in SOC stocks observed to 0.3 and 1.0 m depth respectively. Used in combination with a suitable climatic parameter, sand content is a good predictor of SOC stored in highly weathered dry tropical ecosystems with arguably less confounding effects than provided by clay content. There was an increased contribution of resistant SOC to the total SOC pool for lower rainfall soils, this likely being the result of more frequent fire events in the grassier savannas of the more arid regions. This work provides new insights into the mechanisms determining the distribution of carbon storage in tropical soils and should contribute significantly to the development of robust predictive models of biogeochemical cycling and vegetation dynamics in tropical regions. [ABSTRACT FROM AUTHOR]

We studied the impact of climate change on the dynamics of soil organic carbon (SOC) stocks in productive grassland systems undergoing two types of management, an intensive type with frequent harvests and fertilizer applications and an extensive system where fertilization is omitted and harvests are fewer. The Oensingen Grassland Model was explicitly developed for this study. It was calibrated using measurements taken in a recently established permanent sward in Central Switzerland, and run to simulate SOC dynamics over 2001-2100 under three climate change scenarios assuming different elements of IPCC A2 emission scenarios. We found that: (1) management intensity dominates SOC until approximately 20 yr after grassland establishment. Differences in SOC between climate scenarios become significant after 20 yr and climate effects dominate SOC dynamics from approximately 50 yr after establishment, (2) carbon supplied through manure contributes about 60% to measured organic C increase in fertilized grassland. (3) Soil C accumulates particularly in the top 10cm soil until 5 yr after establishment. In the long-term, C accumulation takes place in the top 15 cm of the soil profile, while C content decreases below this depth. The transitional depth between gains and losses of C mainly depends on the vertical distribution of root senescence and root biomass. We discuss the importance of previous land use on carbon sequestration potentials that are much lower at the Oensingen site under leyarable rotation and with much higher SOC stocks than most soils under arable crops. We further discuss the importance of biomass senescence rates, because C balance estimations indicate that these may differ considerably between the two management systems. [ABSTRACT FROM AUTHOR]

The article discusses the new type of mineralization which is the gold-bearing explosive breccias of the Vanin stock in Northeastern Russia. It states that Vanin stock was located south of the gold-bearing Natalka deposit and north of the Pavlik deposit which composed of two isolated different-age intrusive complexes. It notes on the gold-bearing explosive breccias of the Vanin stock along with a chart bearing the position of the Vanin stock in the Omchak ore district. It also mentions the characteristics of ore mineralization which are confined to explosive breccias of the Vanin stock which concludes that such provides grounds for taking on development of gold-sulfide ores of the Maiskoe type in the Omchak ore district.

This paper presents results of two-dimensional seismic mapping of the northern East China Sea Shelf Basin. Various igneous features such as sills, volcanic edifices and stocks were identified by the geophysical exploration. The sills are most common, and are observed at more than 90 locations. Most mapped sills in the study area are characterized by high-amplitude continuous reflections with distinct terminations. Saucer- and cup-shaped sills are observed locally. The stocks are discordant (nearly vertical) igneous bodies and they are characterized by seismic transparency, with upturned host rocks and uplifted overburden. The volcanic edifices and/or necks consist of irregular mounds and peaks and are characterized by strong positive top reflections with chaotic internal facies. The oldest igneous activity in the northern East China Sea Shelf Basin is Early Cretaceous (123.3 ± 3.7). This igneous activity coincides with those observed in eastern China which has been related mainly to the subduction of the Pacific Plate beneath Eurasia Plate. The Miocene igneous activity is well constrained based on seismic stratigraphic relationships within the folded stratigraphy, age dating, and the occurrence of igneous sills. The timing of this intrusion is coincident with the intensive igneous activity as previously suggested for the eastern China. Igneous rocks can produce hydrocarbon traps, reservoirs and they can act as a seal, and therefore are of great importance in petroleum study. [ABSTRACT FROM AUTHOR]

Abstract: The major borax producer, Eti Mining Co. of Turkey, planned to construct an export stock site located near the Bandirma Harbor in the northwestern of Turkey. During this construction, some stability problems were encountered. To analyze the stability problems and to assess the engineering properties of soil in the stock site geotechnical investigations were started. As a part of geotechnical investigations one of the most common field tests, the standard penetration tests (SPT), was conducted for soil exploration. In this study, the field is geostatistically simulated to assess the uncertainty associated with the spatial variability of SPT results. Multiple probable realizations of SPT values are generated using sequential Gaussian simulation. Using 122 NSPT data in the borax stockpile site, the characteristics observed in the available data are reproduced in a manner that the heterogeneity of SPT within the field is honored. The estimated NSPT data can also be used for other purposes such as determination of bearing capacity, and estimation of soil strength parameters. [Copyright &y& Elsevier]

Abstract: Self-organizing maps (SOMs) are an advanced neural networks application. SOMs were applied for the spatially explicit estimation of forest carbon stocks for a test region in Thuringia (Germany). The approach utilizes in situ national forest inventory data and satellite remote sensing data (Landsat 7 ETM+) and provides maps showing a high-resolution spatial distribution of forest carbon stocks. The generated maps are compared to alternative estimates obtained by the k-nearest neighbour (kNN) method—a remote sensing based carbon assessment. Beside maps the SOM- and kNN-approaches were utilized to calculate statistical estimates of carbon stock and growing stock. The statistical estimates were validated by calculating bias and mean square errors with reference to in situ assessments. SOM- and kNN-approaches have been tested in a forested region in Central Germany. The results show that SOMs are an approach that has the ability to reproduce the spatial pattern of forest carbon stocks. SOMs are—with some restrictions—comparable to spatially explicit estimates generated by the kNN-method. [Copyright &y& Elsevier]

Abstract: This study presents the results of a series of evaluations of a continent-wide soil database (EU/UN-ECE Level I) with the aim to estimate baseline soil carbon concentrations and stocks. The methodology included the biogeographic stratification of soil carbon measurements throughout Europe using climatic zones derived from the Soil Regions Map of Europe. The presented stock estimates range from 1.3 to 70.8tC/ha for the O-layer, and from 11.3 to 126.3tC/ha for the mineral soil 0–20cm (Germany: 0–30cm) (5 and 95 percentiles). Histosols were excluded because of methodological differences and data gaps. When looking at the median values of the strata investigated, relationships were found. For example, carbon stocks in the O-layer of sandy soils are distinctly higher than those of fine-textured soils. However, the variability is so high that some of these relationships disappear. For example in western and central Europe, the level of carbon stocks in the mineral soil between shallow soils (Leptosols) and more deeply developed soils (Podzols and Cambisols) do not differ very much. It was also found that just the investigation of topsoils is not sufficient to understand the regional pattern of organic matter in forest soils – unless the subsoil becomes included as well. It is hypothesized that for Europe, the impact of site factors such as climate, texture and relief are difficult to extract from such a database if the data are only stratified according to macro-climatic areas. It has to be considered that the effect of systematic error in the database is quite large (but cannot be identified on the level of the current data availability). In order to receive a first impression of the landscape-level distribution of carbon, a map of carbon concentrations in the topsoil was generated. The results support the relationships found between carbon stocks and site factors, such as climatic zones and soil type. Compared to the much lower carbon concentrations of agricultural soils, the results demonstrate clearly the importance of forest soils for the terrestrial carbon cycling in Europe. [Copyright &y& Elsevier]

Stanniferrous granite-leucogranite massifs in Vietnam to which the bedrock and placer commercial deposits of cassiterite are associated (Timtuc etc.) are of late Cretaceous age (∼85 Ma by Rb-Sr and Ar-Ar isotope dating). These massifs are presented by stocks and fracture intrusions (to 100 km2 in area) of simple homodromic structure: biotite granites ⇒ two-mica and muscovite leucogranites ⇒ topaz-containing aplites ⇒ rare-metal pegmatites. [ABSTRACT FROM AUTHOR]

Porphyry Cu systems host some of the most widely distributed mineralization types at convergent plate boundaries, including porphyry, deposits centered on intrusions; skarn, carbonate-replacement, and sediment-hosted Au deposits in increasingly peripheral locations; and superjacent high- and intermediate-sulfidation epithermal deposits. The systems commonly define linear belts, some many hundreds of kilometers long, as well as occurring less commonly in apparent isolation. The systems are closely related to underlying composite plutons, at paleodepths of 5 to 15 km, which represent the supply chambers for the magmas and fluids that formed the vertically elongate (>3 kin) stocks or dike swarms and associated mineralization. The plutons may erupt volcanic rocks, but generally prior to initiation of the systems. Commonly, several discrete stocks are emplaced in and above the pluton roof zones, resulting in either clusters or structurally controlled alignments of porphyry, Cu systems. The rheology and composition of the host rocks may strongly influence the size, grade, and type of mineralization generated in porphyry Cu systems. Individual systems have life spans of ∼100,000 to several million years, whereas deposit clusters or alignments as well as entire belts may remain active for 10 m.y. or longer. The alteration and mineralization in porphyry Cu systems, occupying many cubic kilometers of rock, are zoned outward from the stocks or dike swarms, which typically comprise several generations of intermediate to felsice porphyry intrusions. Porphyry Cu ± Au ± Me deposits are centered on the intrusions, whereas carbonate wall rocks commonly host proximal Cu-Au skarns, less common distal Zn-Pb and/or Au skarns, and, beyond the skarn front, carbonate-replacement Cu and/or Zn-Pb-Ag ± Au deposits, and/or sediment-hosted (distal-disseminated) Au deposits. Peripheral mineralization is less conspicuous in noncarbonate wall rocks but may include base metal- or Au-bearing veins and mantes. High-sulfidation epithermal deposits may occur in lithocaps above porphyry Cu deposits, where massive sulfide lodes tend to develop in deeper feeder structures and Au ± Ag-rich, disseminated deposits within the uppermost 500 m or so. Less commonly, intermediate-sulfidation epithermal mineralization, chiefly veins, may develop on the peripheries of the lithocaps. The alteration-mineralization in the porphyry, Cu deposits is zoned upward from barren, early sodic-calcic through potentially ore-grade potassic, chlorite-sericite, and sericitic, to advanced argillic, the last of these constituting the lithocaps, which may attain >1 km in thickness if unaffected by significant erosion. Low sulfidation-state chalcopyrite ± bornite assemblages are characteristic of potassic zones, whereas higher sulfidation-state sulfides are generated progressively upward in concert with temperature decline and the concomitant greater degrees of hydrolytic alteration, culminating in pyrite ± enargite ± covellite in the shallow parts of the lithocaps. The porphyry Cu mineralization occurs in a distinctive sequence of quartz-bearing veinlets as well as in disseminated form in the altered rock between them. Magmatic-hydrothermal breccias may form during porphyry intrusion, with some of them containing high-grade mineralization because of their intrinsic permeability. In contrast, most phreatomagmatic breccias, constituting maar-diatreme systems, are poorly mineralized at both the porphyry Cu and lithocap levels, mainly because many of them formed late in the evolution of systems. Porphyry Cu systems are initiated by injection of oxidized magma saturated with S- and metal-rich, aqueous fluids from cupolas on the tops of the subjacent parental plutons.… [ABSTRACT FROM AUTHOR]

The material stocks in the anthroposphere are growing faster than ever due to urbanization and growing per capita use. Owing to the growing potential insecurity of raw material supply the evaluation of resources gains increasing attention. Despite growing utilization of anthropogenic deposits, 'urban mining' has not yet sufficiently been supported by specific exploration methods. An exploration method for anthropogenic deposits is proposed and described by application to the copper stocks of Switzerland. The method combines material flow analysis with a bottom-up analysis of material stocks. The stock composition and temporal characteristics are analysed by surveys and literature analysis. The stock amounts to 269±31 kg capita-1 for the year 2000. The retrospective data are used as parameters to construct a dynamic stock model, which is calibrated by historical trade statistics. The potential for drafting scenarios is discussed. The stock situation in Switzerland is reviewed and compared with that of other regions. [ABSTRACT FROM AUTHOR]

Fisheries managers frequently try to protect juveniles in order to preserve stocks. Juveniles can be protected by either implementing changes designed to avoid catching immature animals (e.g. increasing mesh size or altering fishing techniques) or protecting nursery grounds. To prevent the capture of immature animals, an estimate of size at maturity is required as well as a knowledge of both fishing methods and the exact location of the nursery grounds. Strong demand for juvenile mud crabs to stock aquaculture ponds has resulted in development of fisheries targeting crabs of all sizes from instar 1 to mature individuals. Using five different fishing methods, different stages in the life cycle of Scylla paramamosain were followed for a period of 16 months in an estuarine population in the Mekong Delta, Vietnam. Mangrove habitat utilisation begins when crabs settle out from the plankton at instar 1 [modal internal carapace width (ICW), 0.5 cm] amongst the pneumatophores at the mangrove fringe. Increasingly larger crabs were found deeper into the mangrove but they were still living on the surface (modal ICW size class, 1.5 cm). As their size increases, the crabs either dig burrows (modal ICW size class, 4.5 cm) or they live in the sub-tidal zone, migrating into the mangrove with each tide to feed (modal ICW size class, 4.5 cm). Larger crabs were caught offshore (modal ICW size class, 12.5 cm) where females accounted for 60% of the catch although of these, only 63% were mature. Recruitment of early instars was continuous but peaked in December to February. Subsequent peaks in the catch rates of larger size classes indicated the development of a single cohort with an estimated growth rate of 2.0 cm ICW per month. On the basis of abdominal width, females were estimated to mature at 10.2 cm ICW although at 9.7 cm ICW, 50% of females had disengaged abdomens. Abdominal disengagement occurred in males at the slightly smaller size of 9.1 cm ICW. Allometric relationships between chela height and carapace width suggested 50% of males acquire mature chelae at 10.2 cm ICW. These results demonstrate the close linkage between early life stages of S. paramamosain and certain specific niches within mangrove habitats, with the main adult population found to be living sub-tidally at some distance from the mouth of the estuary. The study also highlights the special importance of the mangrove fringe, the border between the mangrove forest and the sea, an area which is particularly vulnerable to physical and anthropogenic impacts. [ABSTRACT FROM AUTHOR]

The analysis of mitochondrial DNA in loggerhead sea turtles ( Caretta caretta) from eight foraging grounds in the Mediterranean and the adjoining Atlantic revealed deep genetic structuring within the western Mediterranean. As a consequence, the foraging grounds off the North-African coast and the Gimnesies Islands are shown to be inhabited mainly by turtles of the Atlantic stocks, whereas the foraging grounds off the European shore of the western Mediterranean are shown to be inhabited mainly by turtles from the eastern Mediterranean rookeries. This structuring is explained by the pattern of sea surface currents and water masses and suggests that immature loggerhead sea turtles entering the western Mediterranean from the Atlantic and the eastern Mediterranean remain linked to particular water masses, with a limited exchange of turtles between water masses. As the north of the western Mediterranean comprises mostly individuals from the highly endangered eastern Mediterranean rookeries, conservation plans should make it a priority to reduce the mortality caused by incidental by-catch in these areas. [ABSTRACT FROM AUTHOR]

Presents a study which analyzed the Alta stock and aureole rocks in Utah to determine the source, composition and physical-chemical conditions of infiltrating fluids. Boron distribution in rocks and minerals from alpha-track mapping; Discussion.

New field investigations in the Wet Mountains of Colorado reveal informative structuralplutonic relationships surrounding Mesoproterozoic intrusions. Gneisses and schists of the Wet Mountains host syntectonic ∼ 1.7-Ga and ∼ 1.4-Ga plutons plus two to three generations of sills and stocks. Comparison of two study areas reveals a variation in metamorphic grade, crustal position, and structural rigidity of gneisses hosting the 1.4-Ga intrusions, with implications for the interpretation of dynamic versus anorogenic intrusive settings. An episode of post-1.4-Ga mineral growth was recorded in the Wet Mountains by overprinting mineral textures and [sup40]Ar/ [sup39]Ar hornblende ages of 1369 ± 4 to 1342 ± 6 Ma. Mineral textures and rock fabrics provide evidence of three significant Proterozoic deformational events in the Wet Mountains. Predominant northwest- to west-striking foliation is a second-phase fabric, S[sub2], developed during regional plutonism at 1.66-1.7 Ga. S[sub0], relict sedimentary layering, and S[subv] an earlier penetrative foliation, are preserved within cordierite. Fabric development and metamorphism during 1.4-Ga magmatism varied across the range. Middle amphibolite-grade gneisses of the Arkansas River Canyon in the north give way to stromatic migmatites in the central Wet Mountains. S[sub2] was completely transposed in two discrete shear zones. The Five Points Gulch shear zone strikes approximately north, south and records sinistral-oblique displacement along a sillimanite mineral lineation. The Newlin Creek shear zone strikes northwest, with top-southwest transport. Fabric within 1.4-Ga intrusions varies from locally developed foliation on discordant margins (northern Wet Mountains) to strong concordant foliation in extensive sills (central Wet Mountains). Later sills are less well-foliated and slightly discordant, indicating syntectonic granitic emplacement. Blocks of host gneiss were assimilated along some sill margins... [ABSTRACT FROM AUTHOR]