Industrial minerals and rocks, aggregates and natural stones in the Nordic countries     

Kurt Johansson Rune B. Larsen Markku J. Lehtinen Lars Persson Mika Raeisaenen Stig A. Schack Pedersen Paer Weihed Nils-Gunnar Wik 《《幕》》2008,31(1):133-139

The Nordic countries, including Greenland, have a long tradition in mining. The industrial minerals sector is expanding in most Nordic countries and extensive development has taken place during the last few years. The main commodities mined are carbonate rocks, quartz, feldspar, apatite, olivine and talc.
A number of diferent types of dimension stones are quarried in all countries. Rock aggregates are increasingly important, replacing sand and gravel aggregate as construction materials in some countries due to the need to protect ground water supplies.  相似文献   

Suspended‐sediment sources in an urban watershed,Northeast Branch Anacostia River,Maryland     

Olivia H. Devereux  Karen L. Prestegaard  Brian A. Needelman  Allen C. Gellis 《水文研究》2010,24(11):1391-1403

Fine sediment sources were characterized by chemical composition in an urban watershed, the Northeast Branch Anacostia River, which drains to the Chesapeake Bay. Concentrations of 63 elements and two radionuclides were measured in possible land‐based sediment sources and suspended sediment collected from the water column at the watershed outlet during storm events. These tracer concentrations were used to determine the relative quantity of suspended sediment contributed by each source. Although this is an urbanized watershed, there was not a distinct urban signature that can be evaluated except for the contributions from road surfaces. We identified the sources of fine sediment by both physiographic province (Piedmont and Coastal Plain) and source locale (streambanks, upland and street residue) by using different sets of elemental tracers. The Piedmont contributed the majority of the fine sediment for seven of the eight measured storms. The streambanks contributed the greatest quantity of fine sediment when evaluated by source locale. Street residue contributed 13% of the total suspended sediment on average and was the source most concentrated in anthropogenically enriched elements. Combining results from the source locale and physiographic province analyses, most fine sediment in the Northeast Branch watershed is derived from streambanks that contain sediment eroded from the Piedmont physiographic province of the watershed. Sediment fingerprinting analyses are most useful when longer term evaluations of sediment erosion and storage are also available from streambank‐erosion measurements, sediment budget and other methods. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Microstructural evidence of low‐strain,time‐transgressive subglacial deformation     

N. K. Larsen  J. A. Piotrowski  J. Menzies 《第四纪科学杂志》2007,22(6):593-608

Microstructural analyses were used to investigate the formation of a macroscale‐massive till at Knud Strand in Denmark. More than 100 thin sections were examined and microstructures mapped and counted for quantitative comparison and interpretation. Microstructures indicative of both brittle (grain lineations, edge‐to‐edge crushed grains) and ductile (turbate structures) deformation are evenly distributed in vertical profiles through the till, suggesting that strain contributed to its formation. Discrete shears (grain lineations and plasmic fabric) probably accommodated most deformation, whereas rotational deformation was less prominent. The microshear geometry fits the predicted Coulomb–Mohr failure criterion, indicating that till behaves as a plastic material. Strain estimate of ca. 10¹ from micromorphological proxies is two–three orders of magnitude lower than expected if the till was subjected to pervasive deformation. A hybrid of lodgement and time‐transgressive deformation is envisaged as the till‐forming processes. Our data suggest that even abundant evidence of microscale deformation at continuing high levels of strain may only record the latest process of deposition and deformation and therefore not fully reflect the complexity of till genesis. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Glacial stratigraphy of East and Central Jutland     

Christian  Kronborg  Henry  Bender  Regnar  Bjerre  Rud  Friborg  Hans O.  Jacobsen  Lars  Kristiansen  Poul  Rasmussen  Poul R.  Sørensen Gunnar  Larsen 《Boreas: An International Journal of Quaternary Research》1990,19(3):273-287

Glaciostratigraphic investigations at one key locality (Haldum), 9 major and about 160 minor localities in East and Central Jutland, Denmark, together with laboratory work, have led to the establishment of a stratigraphy consisting of 10 till units, usually separated by meltwater deposits. The stratigraphy is in some degree supported by thermoluminescence datings. The complete sequence includes one till unit with associated meltwater deposits of Menapian age, three till units with intercalated meltwater deposits of Elsterian age, marine sediments deposited during the Holsteininan, and three till units with intercalated of Elsterian age, marine sediments deposited during the Holsteinian, and three till units with intercalated glaciofluvial sedimants of Saalian age. Eemian deposits are present above this level, and the whole sequence is capped by till and meltwater deposits related to three glacial advances during the Weichselian.  相似文献   

The Plio-Pleistocene glaciation of the Barents Sea–Svalbard region: a new model based on revised chronostratigraphy     

Jochen Knies  Jens Matthiessen  Christoph Vogt  Jan Sverre Laberg  Berit O. Hjelstuen  Morten Smelror  Eiliv Larsen  Karin Andreassen  Tor Eidvin  Tore O. Vorren 《Quaternary Science Reviews》2009,28(9-10):812-829

Based on a revised chronostratigraphy, and compilation of borehole data from the Barents Sea continental margin, a coherent glaciation model is proposed for the Barents Sea ice sheet over the past 3.5 million years (Ma). Three phases of ice growth are suggested: (1) The initial build-up phase, covering mountainous regions and reaching the coastline/shelf edge in the northern Barents Sea during short-term glacial intensification, is concomitant with the onset of the Northern Hemisphere Glaciation (3.6–2.4 Ma). (2) A transitional growth phase (2.4–1.0 Ma), during which the ice sheet expanded towards the southern Barents Sea and reached the northwestern Kara Sea. This is inferred from step-wise decrease of Siberian river-supplied smectite-rich sediments, likely caused by ice sheet blockade and possibly reduced sea ice formation in the Kara Sea as well as glacigenic wedge growth along the northwestern Barents Sea margin hampering entrainment and transport of sea ice sediments to the Arctic–Atlantic gateway. (3) Finally, large-scale glaciation in the Barents Sea occurred after 1 Ma with repeated advances to the shelf edge. The timing is inferred from ice grounding on the Yermak Plateau at about 0.95 Ma, and higher frequencies of gravity-driven mass movements along the western Barents Sea margin associated with expansive glacial growth.  相似文献   

Management of a marine protected area for sustainability and conflict resolution: Lessons from Loreto Bay National Park (Baja California Sur,Mexico)     

Karen Stamieszkin  Jeffrey Wielgus  Leah R. Gerber 《Ocean & Coastal Management》2009,52(9):449-458

The Loreto Bay National Park was established to protect the area's ecosystems from habitat destruction and overexploitation. However, the park has not met two of its primary goals: recovery of commercially valuable fish populations and their sustainable use by stakeholders. Based on evidence from the literature, dialogue with stakeholders, a literature review on using recreational fees for marine protected area (MPA) management, and an economic valuation survey, we provide practical guidelines for addressing factors hindering the park's success. These include: 1) the implementation of management based upon ecosystem science, and rigorous monitoring of park ecosystems, 2) increased communication among stake-holder groups, outreach and education, and 3) a re-organization of the park's administrative structure that would allow for more efficient use of funds. Our results also suggest that the park entrance fee could be raised to support these proposed improvements.  相似文献   

Introduction to “tectonics and sedimentation of Southeast Asian continental margin and marginal seas”     

Zhen Sun  Chun-Feng Li  Guo-Liang Zhang  Hans Christian Larsen 《Marine Geophysical Researches》2015,36(2-3):99-100

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Mobilization of arsenic and iron from Red River floodplain sediments, Vietnam   总被引：3，自引：0，他引：3  

Dieke Postma  Søren Jessen  Mai Thanh Duc  Pham Hung Viet  Flemming Larsen 《Geochimica et cosmochimica acta》2010,74(12):3367-508

Sediments from the Red River and from an adjacent floodplain aquifer were investigated with respect to the speciation of Fe and As in the solid phase, to trace the diagenetic changes in the river sediment upon burial into young aquifers, and the related mechanisms of arsenic release to the groundwater. Goethite with subordinate amounts of hematite were, using Mössbauer spectroscopy, identified as the iron oxide minerals present in both types of sediment. The release kinetics of Fe, As, Mn and PO₄ from the sediment were investigated in leaching experiments with HCl and 10 mM ascorbic acid, both at pH 3. From the river sediments, most of the Fe and As was mobilized by reductive dissolution with ascorbic acid while HCl released very little Fe and As. This suggests As to be associated with an Fe-oxide phase. For oxidized aquifer sediment most Fe was mobilized by ascorbic acid but here not much As was released. However, the reduced aquifer sediments contained a large pool of Fe(II) and As that is readily leached by HCl, probably derived from an unidentified authigenic Fe(II)-containing mineral which incorporates As as well. Extraction with ascorbic acid indicates that the river sediments contain both As(V) and As(III), while the reduced aquifer sediment almost exclusively releases As(III). The difference in the amount of Fe(II) leached from river and oxidized aquifer sediments by ascorbic acid and HCl, was attributed to reductive dissolution of Fe(III). The reactivity of this pool of Fe(III) was quantified by a rate law and compared to that of synthetic iron oxides. In the river mud, Fe(III) had a reactivity close to that of ferrihydrite, while the river sand and oxidized aquifer sediment exhibited a reactivity ranging from lepidocrocite or poorly crystalline goethite to hematite. Mineralogy by itself appears to be a poor predictor of the iron oxide reactivity in natural samples using the reactivity of synthetic Fe-oxides as a reference. Sediments were incubated, both unamended and with acetate added, and monitored for up to 2 months. The river mud showed the fastest release of both Fe and As, while the effect of acetate addition was minor. This suggests that the presence of reactive organic carbon is not rate limiting. In the case of the river and aquifer sediments, the release of Fe and As was always stimulated by acetate addition and here reactive organic carbon was clearly the rate limiting factor. The reduced aquifer sediment apparently can sustain slower but prolonged microbially-driven release of As. The highly reactive pools of Fe(III) and As in the river mud could be due to reoxidation of As and Fe contained in the reducing groundwater from the floodplain aquifers that are discharging into the river. Deposition of the suspended mud on the floodplain during high river stages is proposed to be a major flux of As onto the floodplain and into the underlying aquifers.  相似文献   

Nitrogen Uptake by Native and Invasive Temperate Coastal Macrophytes: Importance of Dissolved Organic Nitrogen     

Thomas J. Mozdzer  Joseph C. Zieman  Karen J. McGlathery 《Estuaries and Coasts》2010,33(3):784-797

We investigated if the success of the invasive common reed Phragmites australis could be attributed to a competitive ability to use dissolved organic nitrogen (DON) when compared to the dominant macrophyte Spartina alterniflora in tidal wetlands. Short-term nutrient uptake experiments were performed in the laboratory on two genetic lineages of Phragmites (native and introduced to North America) and S. alterniflora. Our results provide the first evidence for direct assimilation of DON by temperate marsh plants and indicate that amino acids are assimilated intact by all plant types at similar rates. Both Phragmites lineages had significantly greater urea–N assimilation rates than S. alterniflora, and the affinity for dissolved inorganic nitrogen (DIN) species was the greatest in native Phragmites > introduced Phragmites > S. alterniflora. Field studies demonstrated uptake of both DON and DIN in similar proportion as those determined in the laboratory experiments. Based on these uptake rates, we estimate that DON has the potential to account for up to 47% of N demand for Phragmites plants, and up to 24% for S. alterniflora plants. Additionally, we suggest that differences in N uptake between native and introduced Phragmites lineages explain one mechanism for the success of the introduced type under increasingly eutrophic conditions.  相似文献   

The water impacts of climate change mitigation measures     

Philip J. Wallis  Michael B. Ward  Jamie Pittock  Karen Hussey  Howard Bamsey  Amandine Denis  Steven J. Kenway  Carey W. King  Shahbaz Mushtaq  Monique L. Retamal  Brian R. Spies 《Climatic change》2014,125(2):209-220

A variety of proposed activities to mitigate greenhouse gas emissions will impact on scarce water resources, which are coming under increasing pressure in many countries due to population growth and shifting weather patterns. However, the integrated analysis of water and carbon impacts has been given limited attention in greenhouse mitigation planning. In this Australian case study, we analyse a suite of 74 mitigation measures ranked as highest priority by one influential analysis, and we find that they have highly variable consequences for water quantity. We find: (1) The largest impacts result from land-based sequestration, which has the potential to intercept large quantities of water and reduce catchment yields, estimated to exceed 100 Mm³/MtCO₂-e of carbon mitigated (100,000 l per tonne CO₂-e). (2) Moderate impacts result from some renewable power options, including solar thermal power with a water cost estimated at nearly 4 Mm³/MtCO₂-e. However, the water impacts of solar thermal power facilities could be reduced by designing them to use existing power-related water supplies or to use air or salt-water cooling. (3) Wind power, biogas, solar photovoltaics, energy efficiency and operational improvements to existing power sources can reduce water demand through offsetting the water used to cool thermal power generation, with minor savings estimated at 2 Mm³/MtCO₂-e and amounting to nearly 100 Mm³ of water saved in Australia per annum in 2020. This integrated analysis significantly changes the attractiveness of some mitigation options, compared to the case where water impacts are not considered.  相似文献