| 1. |
- Andersson, Magnus, et al.
(författare)
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Magma transport in sheet intrusions of the Alnö carbonatite complex, central Sweden
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Magma transport through the Earth's crust occurs dominantly via sheet intrusions, such as dykes and cone-sheets, and is fundamental to crustal evolution, volcanic eruptions and geochemical element cycling. However, reliable methods to reconstruct flow direction in solidified sheet intrusions have proved elusive. Anisotropy of magnetic susceptibility (AMS) in magmatic sheets is often interpreted as primary magma flow, but magnetic fabrics can be modified by post-emplacement processes, making interpretation of AMS data ambiguous. Here we present AMS data from cone-sheets in the Alno carbonatite complex, central Sweden. We discuss six scenarios of syn- and post-emplacement processes that can modify AMS fabrics and offer a conceptual framework for systematic interpretation of magma movements in sheet intrusions. The AMS fabrics in the Alno cone-sheets are dominantly oblate with magnetic foliations parallel to sheet orientations. These fabrics may result from primary lateral flow or from sheet closure at the terminal stage of magma transport. As the cone-sheets are discontinuous along their strike direction, sheet closure is the most probable process to explain the observed AMS fabrics. We argue that these fabrics may be common to cone-sheets and an integrated geology, petrology and AMS approach can be used to distinguish them from primary flow fabrics.
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| 2. |
- Andrén, Thomas, 1954-, et al.
(författare)
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IODP expedition 347 : Baltic Sea basin paleoenvironment and biosphere
- 2015
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Ingår i: Scientific Drilling. - : Copernicus GmbH. - 1816-8957 .- 1816-3459. ; 20, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The Integrated Ocean Drilling Program (IODP) expedition 347 cored sediments from different settings of the Baltic Sea covering the last glacial–interglacial cycle. The main aim was to study the geological development of the Baltic Sea in relation to the extreme climate variability of the region with changing ice cover and major shifts in temperature, salinity, and biological communities. Using the Greatship Manisha as a European Consortium for Ocean Research Drilling (ECORD) mission-specific platform, we recovered 1.6 km of core from nine sites of which four were additionally cored for microbiology. The sites covered the gateway to the North Sea and Atlantic Ocean, several sub-basins in the southern Baltic Sea, a deep basin in the central Baltic Sea, and a river estuary in the north.The waxing and waning of the Scandinavian ice sheet has profoundly affected the Baltic Sea sediments. During theWeichselian, progressing glaciers reshaped the submarine landscape and displaced sedimentary deposits from earlier Quaternary time. As the glaciers retreated they left a complex pattern of till, sand, and lacustrine clay, which in the basins has since been covered by a thick deposit of Holocene, organic-rich clay. Due to the stratified water column of the brackish Baltic Sea and the recurrent and widespread anoxia, the deeper basins harbor laminated sediments that provide a unique opportunity for high-resolution chronological studies.The Baltic Sea is a eutrophic intra-continental sea that is strongly impacted by terrestrial runoff and nutrient fluxes. The Holocene deposits are recorded today to be up to 50m deep and geochemically affected by diagenetic alterations driven by organic matter degradation. Many of the cored sequences were highly supersaturated with respect to methane, which caused strong degassing upon core recovery. The depth distributions of conservative sea water ions still reflected the transition at the end of the last glaciation from fresh-water clays to Holocene brackish mud. High-resolution sampling and analyses of interstitial water chemistry revealed the intensive mineralization and zonation of the predominant biogeochemical processes. Quantification of microbial cells in the sediments yielded some of the highest cell densities yet recorded by scientific drilling.
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| 3. |
- Apler, Anna, 1980-
(författare)
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Contaminated organic sediments of anthropogenic origin: impact on coastal environments
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The Baltic Sea is negatively affected by legacy pollutants such as metals and persistent organic pollutants (POPs) that are known to have adverse effects on living organisms, including, humans and were banned decades ago. This thesis addresses the dispersal of these pollutants from heavily contaminated, cellulose-rich sediments of industrial origin in the Ångermanälven river estuary in northern Sweden. Relatively thick deposits, known as fiberbanks, in the studied area derive from historical wastewater emissions from the pulp and paper industry (P&PI) that began in the 19th century. These fiberbanks formed on shallow seabeds, where they currently remain. In addition, extensive areas of the deeper seabed are covered by fiber-rich sediments. The fiberbanks contain higher levels of pollutants than the fiber-rich sediments and the sediments less affected by P&PI emissions, and the fiberbank concentrations may be of ecotoxicological concern. Metals and POPs were found to be strongly partitioned to organic material and partitioning coefficients were higher in fiberbanks that contain elevated levels of organic matter. Metals and POPs were detectable in sampled pore water, even if low sediment-water fluxes of metals were expected. Metal contaminant concentrations in sampled bottom water were measured before and after resuspension of underlying sediments, which showed that concentrations of particle bound metals dominated over dissolved forms. One out of three studied fiberbank sites was covered with a natural capping layer that probably shields the water column from metals in the deposit underneath. Studies of geological archives in the form of sediment cores show the rise and fall of an anthropogenic industrial era and the recovery of an aquatic system, but the established chemostratigraphy fails to reveal the current hotspots (fiberbanks) that will stay for decades to come. The potential impacts of climate change and isostatic land uplift are factors that complicate the long-term risk assessment of fiberbanks. These knowledge gaps combined with the lack of a common risk assessment strategy for contaminated sediments hinder the achievement of national quality objectives (NQOs) and fulfillment of Agenda 2030 goals. Fiberbanks resulted from an accelerating global demand for paper products and hence, the issue of these artificial seabed forms is an example of how the geological epoch of humankind, the Anthropocene, can be viewed in a cross-scalar perspective and be important in the management of a sustainable future in the Baltic Sea region.
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| 4. |
- Apler, Anna, 1980-
(författare)
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Dispersal and environmental impact of contaminants in organic rich, fibrous sediments of industrial origin in the Baltic Sea
- 2018
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The health of the Baltic Sea is negatively affected by hazardous substances such as metals and persistent organic pollutants (POPs), which include legacy pollutants that were banned decades ago, but still circulate in the ecosystem. Elevated levels of legacy pollutants, identified by HELCOM as key hazardous substances, have been found in accumulations of fibrous sediments, so-called fiberbanks and fiber-rich sediments, which derive from old pulp mills along the Swedish north coast. The fiberbanks are deposited in shallow water and bathymetrical models show evidence of their erosion, potentially caused by propeller wash, submarine landslides and gas ebullition. This thesis addresses the potential dispersal of key substances from three fiberbank sites located in a non-tidal Swedish estuary, in which metals and POPs are present in concentrations that may pose a risk for benthic organisms. Metals and POPs are partitioned to organic material and, as expected, show the highest partitioning coefficients (KD) in fiberbanks that have higher TOC levels compared to adjacent areas with fiber-rich sediments (natural clay sediments mixed up with fibers) or relatively unaffected postglacial clays. However, many analytes were found to be present in quantifiable concentrations in pore water, which indicates diffusion of substances from the solid phase to the aqueous phase. To assess the dispersive influence of an abrupt erosional event on dispersion, metals were measured in undisturbed bottom water and in bottom water disturbed by artificial re-suspension of fibrous sediments. The bioavailable, dissolved fraction of metals decreased in bottom water after re-suspension, probably due to the particle concentration effect. In contrast, the total concentrations of metals and number of quantifiable metals increased with particle concentration caused by re-suspension. At one station, the total concentration of chromium (Cr) was elevated to a level where it may lower the ecological status of the water body during periods of substantial erosion (e.g. spring floods or submarine landslides). Analyses of disturbed bottom water revealed, however, that minerogenic particles were preferentially re-suspended compared to organic. This suggests that physical erosion and re-suspension of fiberbank sediments might have a larger effect on dispersal of metals than on POPs.
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| 5. |
- Apler, Anna, 1980-, et al.
(författare)
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Dispersal of cellulose fibers and metals from contaminated sediments of industrial origin in an estuary
- 2020
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 266:3
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Tidskriftsartikel (refereegranskat)abstract
- The boreal forest’s pulp and paper industry plays a major role in economic prosperity but, historically, caused an environmental burden. Remnants of discharges of contaminated suspended solids (fiberbanks) are continuously being discovered on the beds of shallow seas, rivers and lakes in the northern hemisphere. We investigated the dispersion of Cd, Cr, Cu, Hg, Ni, Pb and Zn from deeper to surficial layers in fiberbanks in a Swedish estuary and the larger-scale transport of the same metals to distal areas of sediment accumulation. We also tested the C:N ratio as a common denominator for these anthropogenic, cellulose-rich deposits. Sampling and analyses of three fiberbanks located in the inner part of the estuary and from sediment accumulation sites outside and along the estuary reveals that metal concentrations are regressing to background levels towards the surface at the accumulation sites. The fiberbanks show a higher degree of contamination and C:N ratios demonstrate inclusion of cellulose fibers. C:N ratios also indicate that there is currently no significant transport of fiberbank material into the distal areas. A ∼10 cm natural cap of recently settled fine-grained sediment covering one of the fiberbanks seems to prevent metals dispersing into overlying water whereas the other two fiberbanks show signs of metal enrichment and potential mercury methylation in surficial layers. Although the estuarine system seems to recover from the impact of industrial waste, there is no evidence that the fiberbanks will be remediated naturally but instead will continue to threaten the aquatic environment.
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| 6. |
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| 7. |
- Apler, Anna, 1980-, et al.
(författare)
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Distribution and dispersal of metals in contaminated fibrous sediments of industrial origin
- 2019
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 215, s. 470-481
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Tidskriftsartikel (refereegranskat)abstract
- Industrial emissions can impact aquatic environments and unregulated discharges from pulp and paper factories have resulted in deposits of cellulose fiber along the Swedish coast. These deposits are contaminated by metals, but due to their unique fibrous character the extent of sorption and dispersal of the metals is unclear. Fibrous sediments were sampled at two sites in the Ångermanälven river estuary, Sweden. The partitioning of metals between the sediment, pore water and bottom water was investigated and the degree of bioavailability was evaluated. The levels of metals in the sediment were high in fibrous or offshore samples, depending on the metal, whereas the levels of dissolved metals in pore water were low or below the limit of quantification. Partition coefficients (KD) showed that sorption to the sediment was stronger at one of the fibrous sites, possibly related to the type and size of organic matter. Undisturbed bottom water samples contained low levels of both dissolved and particle bound metals, but when comparing measured metal concentrations to threshold values of ecological status and ecotoxicological assessment criteria, both sediments and bottom water may be detrimental to living organisms. In-situ re-suspension experiments showed that the concentrations of particle bound metals increased whereas the dissolved concentrations decreased. The analyzed metals are probably retained by the solid phases of the fibrous sediment or adsorbed to particles in the water, reducing their bioavailability.
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| 8. |
- Apler, Anna, 1980-, et al.
(författare)
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The Anthropocene in the northern Baltic Sea – the case of contaminated fiberbanks and implications for sustainable development
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The epoch of humankind, the Anthropocene, is usually characterized by the global gaze, which places its focus on global environmental phenomena i.e. global warming and ocean acidification. In this article we argue that the Anthropocene could be better understood with a cross-scalar perspective and present the case of anthropogenic contaminated “fiberbanks” as an example. We present a geological example of the Anthropocene in a Swedish river estuary in the northern Baltic Sea, which hosted nine P&P mills along its’ shores and received large amounts of metal containing wastewater during the 20th century. As a result of the great acceleration and an increased national and global demand for pulp and paper products these fiberbanks formed in shallow waters. As artificial seabed features these thick deposits of contaminated organic-rich material negatively affect the adjacent aquatic environment. By constructing a chemostratigraphy based on sediment cores from accumulation areas and a metal pollution index we show how the aquatic system has recovered from metal pollution. We note, however, that the established stratigraphy fails to identify the fiberbanks, which remain in the shallow zones and are contaminant hotspots. In Sweden, there is an insufficient knowledge of contaminated sediments for a sustainable water and marine management. This knowledge gap in combination with human induced climate changes that may chemically and physically affect sediments and thus, alter dispersion of imbedded pollutants, results in poor understanding and long-term perception of the risks of contaminant dispersion from fiberbanks. We claim that these gaps of knowledge must be filled in order to reach an effective conservation at the same time as a sustainable blue growth in the northern Baltic Sea.
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| 9. |
- Björck, Svante, et al.
(författare)
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A Holocene lacustrine record in the central North Atlantic: proxies for volcanic activity, short-term NAO mode variability, and long-term precipitation changes
- 2006
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 25:1-2, s. 9-32
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Tidskriftsartikel (refereegranskat)abstract
- Lake and peat corings on three Azores islands in the central North Atlantic, resulted in the discovery of a 6000 year long lacustrine sequence in a small crater lake, Lake Caveiro, on the island of Pico. This island is dominated by Pico mountain (2351 m), Portugal's highest mountain, and the lake site is situated at 903 in asl. Two sediment profiles, one central and one littoral, were sampled. Due to large facial shifts and disconformities in the littoral cores the analyses were concentrated on the central core; only the earliest 1000 years of the littoral core were studied to complement the central profile. We used sedimentology, geochemistry, diatom analyses, magnetic properties, and multivariate statistics, together with C-14 and Pb-210 dating techniques, to analyse the environmental history of the lake. Volcanic activity seems to have had a dominating impact on sediment changes and partly also on the diatom assemblages; a large number of tephras are found and seem to be connected with large (diatom) inferred pH variations. However, by a combination of methods, including multivariate techniques, we infer that precipitation changes can be detected through the volcanic noise. In the youngest part of the record (AD 1600-2000), with its decadal resolution, these humidity variations seem partly related to shifts in dominating NAO mode. The more long-term precipitation changes further back in time (350-5100 cal yr BP) roughly correspond to the well-known North Atlantic drift-ice variations as well as other North Atlantic records; low precipitation during drift-ice periods. We think these alterations were driven by changes in the thermolialine circulation as large-scale equivalences to the Great Salt Anomaly; low sea surface A temperatures and changes in circulation patterns of the central North Atlantic decreased the regional precipitation. Cooler/drier periods occurred 400-800, 1300-1800, 2600-3000, 3300-3400 and possibly also 4400-4600 cal yr BP,. while 300-400, 900-1000, 2000-2400, 3100-3200, 3800-4000 and 4700-5000 cal yr BP seem to have been more humid phases on the Azores. (c) 2005 Elsevier Ltd. All rights reserved.
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| 10. |
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