| 31. |
- Fredricsson, Malin, et al.
(författare)
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Nationell luftövervakning Sakrapport med data från övervakning inom Programområde Luft t.o.m 2019
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Naturvårdsverket ansvarar för den nationella luftövervakningen i bakgrundsmiljö i Sverige. I rapporten redovisas resultat från verksamheten inom Programområde Luft avseende mätningar (genomförda av IVL, SU, SLU och SMHI) till och med 2019 och regionala modellberäkningar (utförda av SMHI) till och med 2018.För flertalet av de luftföroreningskomponenter som övervakas inom den nationella miljöövervakningen har det, sedan mätningarna startade för mellan 20 och 40 år sedan, generellt sett skett en avsevärd förbättring avseende såväl halter i luft som deposition i bakgrundsmiljö. Utvecklingen har dock varierat i något olika utsträckning beroende på komponenter och lokalisering i landet. Föroreningsbelastningen är oftast lägre ju längre norrut i landet man kommer.För de flesta ämnen som det finns miljökvalitetsnormer (MKN) respektive miljömål för ligger halterna i regional bakgrund avsevärt lägre än angivna gräns- och målvärden. Halterna av ozon överskrider dock i dagsläget (2019) MKN för hälsa.
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| 32. |
- Hogmalm, Johan, 1979, et al.
(författare)
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In situ Rb-Sr and K-Ca dating by LA-ICP-MS/MS: an evaluation of N2O and SF6 as reaction gases
- 2017
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Ingår i: Journal of Analytical Atomic Spectrometry. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 32:2, s. 305-313
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Tidskriftsartikel (refereegranskat)abstract
- In situ dating of K-rich minerals, e.g. micas and K-feldspar, by the Rb–Sr isotopic system is a new development made possible by the ICP-MS/MS technique. Online chemical separation of Rb and Sr is possible in an O2-filled reaction cell, wherein a portion of the Sr reacts to SrO+ while simultaneously no RbO+ is formed. O2 reactions provide stable analytical conditions sufficient for precise and accurate determination of Rb/Sr and Sr/Sr isotopic ratios using 80 micron laser ablation spots. However, to date <10% of the Sr reacts with O2 as reaction gas, leaving room for improvement using more potent reaction gases. With a more efficient reactive transfer, it should be possible to obtain similar results with a smaller laser spot size, hence gaining higher spatial resolution. In this study, we have evaluated N2O and SF6 as reaction gases since they have previously been shown to react strongly with Sr+, without affecting Rb+. Analytical conditions, including cell parameters and reaction gas flow rate were optimized while ablating NIST SRM 610. The main reaction product is SrO+ for N2O reaction and SrF+ for SF6 reaction. Both gases show significantly higher reaction product formation compared to O2 with >85% of Sr reacting with N2O and >70% Sr reacting with SF6; Rb does not react with either gas. As a result, the sensitivity for Sr reaction products is ∼10 times higher with N2O and ∼8 times higher with SF6 compared to O2. With these more reactive gases, the error of mica isochron ages, calibrated against a newly developed nano-particulate pressed powder tablet of mica–Mg, is ∼1% using a 50 μm laser spot. Our tests show that both N2O and SF6 form interfering reaction products, e.g., SrOH (N2O), SiF3 and TiF3 (SF6) that are difficult to handle using single mass spectrometer instruments, but which can be overcome using MS/MS. Using SF6 combined with H2, it is possible to measure 40Ca+ as 40Ca19F+, free from interference of 40Ar+ and 40K+. This facilitates the dating of micas by the K–Ca isotopic system; we present the first in situ K–Ca age determination.
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| 33. |
- Konrad-Schmolke, Matthias, 1970, et al.
(författare)
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Discrimination of thermodynamic and kinetic contributions to the heavy rare earth element patterns in metamorphic garnet
- 2022
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Ingår i: Journal of Metamorphic Geology. - : Wiley. - 0263-4929 .- 1525-1314. ; 41:4, s. 465-90
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Tidskriftsartikel (refereegranskat)abstract
- Variations of rare earth element (REE) concentrations in metamorphic garnet are an important source of information of geodynamic and geochemical processes in the deeper Earth. In order to extract this information, the thermodynamic equilibrium and kinetic contributions of the REE uptake in garnet must be distinguished and quantified. Utilizing high-resolution trace element and μ-Raman mapping together with combined thermodynamic–geochemical–diffusion models, we demonstrate that the equilibrium and kinetic aspects of the REE uptake in metamorphic garnet can be discriminated by interpreting 2D trace element mapping in a single sample. The heavy (H) REE (Tb to Lu) zoning in the investigated garnet from a high-pressure blueschist comprises an inner part with an overall decrease from core to inner rim, followed by a concentric zone of HREE enrichment and a drastic HREE decrease towards the outermost rim. The central peak in the garnet core decreases in intensity with decreasing atomic number of the REE. The broad overall shape of this pattern resembles those often observed in metamorphic garnet from different rock types and tectonic settings. Superimposed on this trend is a concentric pattern of minor recurring fluctuations in the HREE concentrations with at least six regularly spaced sets of peaks and troughs along the entire garnet radius. Comparison of the observed inclusion suite, the trace element maps and thermodynamic–geochemical models show that the inner part with decreasing HREE concentrations results from fractional garnet growth in an unchanged mineral assemblage, whereas the REE enrichment zone is caused by the breakdown of titanite. We suggest that the width of the central peak is controlled by the bulk permeability of the interconnected transport matrix and the fraction of matrix minerals that the garnet equilibrates with. The superimposed REE fluctuations result from changing element transport properties of the host rock and mark recurring changes from equilibrium REE uptake to transport-limited REE uptake in garnet. Such fluctuating element transport properties can be best explained by pulse-like fluid fluxes that rhythmically change the interconnectivity of the intercrystalline transport matrix. Increasing numbers of published spatially highly resolved REE analyses show that such trace element fluctuations are common in metamorphic garnet indicating that recurring changes in rock permeabilities due to pulsed fluid fluxes are a common phenomenon during metamorphism.
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| 34. |
- Lorenz, Henning, Dr. 1972-, et al.
(författare)
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COSC-2 – drilling the basal décollement and underlying margin of palaeocontinent Baltica in the Paleozoic Caledonide Orogen of Scandinavia
- 2022
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Ingår i: Scientific Drilling. - Göttingen : Copernicus Publications. - 1816-8957 .- 1816-3459. ; 30, s. 43-57
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract.The Collisional Orogeny in the Scandinavian Caledonides (COSC) scientific drilling project aims to characterise the structure and orogenic processes involved in a major collisional mountain belt by multidisciplinary geoscientific research. Located in western central Sweden, the project has drilled two fully cored deep boreholes into the bedrock of the deeply eroded Early Paleozoic Caledonide Orogen. COSC-1 (2014) drilled a subduction-related allochthon and the associated thrust zone. COSC-2 (2020, this paper) extends this section deeper through the underlying nappes (Lower Allochthon), the main Caledonian décollement, and the upper kilometre of basement rocks. COSC-2 targets include the characterisation of orogen-scale detachments, the impact of orogenesis on the basement below the detachment, and the Early Paleozoic palaeoenvironment on the outer margin of palaeocontinent Baltica. This is complemented by research on heat flow, groundwater flow, and the characterisation of the microbial community in the present hard rock environment of the relict mountain belt. COSC-2 successfully, and within budget, recovered a continuous drill core to 2276 m depth. The retrieved geological section is partially different from the expected geological section with respect to the depth to the main décollement and the expected rock types. Although the intensity of synsedimentary deformation in the rocks in the upper part of the drill core might impede the analysis of the Early Paleozoic palaeoenvironment, the superb quality of the drill core and the borehole will facilitate research on the remaining targets and beyond. Protocols for sampling in the hard rock environment and subsequent sample preservation were established for geomicrobiological research and rock mechanical testing. For the former, a sparse sample series along the entire drill core was taken, while the target of the latter was the décollement. COSC-2 was surveyed by a comprehensive post-drilling downhole logging campaign and a combined borehole/land seismic survey in autumn 2021. This paper provides an overview of the COSC-2 (International Continental Scientific Drilling Project – ICDP 5054_2_A and 5054_2_B boreholes) operations and preliminary results. It will be complemented by a detailed operational report and data publication.
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| 35. |
- Marks, Michael A. W., et al.
(författare)
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The F, Cl, Br and I Contents of Reference Glasses BHVO-2G, BIR-1G, BCR-2G, GSD-1G, GSE-1G, NIST SRM 610 and NIST SRM 612
- 2017
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Ingår i: Geostandards and Geoanalytical Research. - : Wiley. - 1639-4488 .- 1751-908X. ; 41:1, s. 107-122
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Tidskriftsartikel (refereegranskat)abstract
- Halogen contents for the widely distributed reference glasses BHVO-2G, BIR-1G, BCR-2G, GSD-1G, GSE-1G, NIST SRM 610 and NIST SRM 612 were investigated by pyrohydrolysis combined with ion chromatography, total reflection X-ray fluorescence analysis, instrumental neutron activation analysis, the noble gas method, electron probe microanalysis and laser ablation-inductively coupled plasma-mass spectrometry. Glasses BHVO-2G, GSD-1G and GSE-1G have halogen contents that can be reproduced at the 15% level by all bulk techniques and cover a significant range in halogen mass fractions for F (~ 20–300 μg g−1), Cl (~ 70–1220 μg g−1) and Br (~ 0.2–285 μg g−1) and I (~ 9–3560 ng g−1). The BIR-1G glass has low F (< 15 μg g−1), Cl (~ 20 μg g−1), Br (15 ng g−1) and I (3 ng g−1). The halogen contents for the silica-rich NIST SRM 610 and 612 glasses were poorly reproduced by the different techniques. The relatively high Cl, Br and I abundances in glasses GSD-1G and GSE-1G mean that these glasses are well suited for calibrating spatially resolved micro-analytical studies on silicate glasses, melt and fluid inclusions. Combined EPMA and laser ablation-inductively coupled plasma-mass spectrometry data for glass GSE-1G demonstrate homogeneity at the 10% level for Cl and Br.
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| 36. |
- Rösel, D, et al.
(författare)
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LA-ICP-MS U–Pb dating of detrital rutile and zircon from the Reynolds Range: A window into the Palaeoproterozoic tectonosedimentary evolution of the North Australian Craton
- 2014
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Ingår i: Precambrian Research. - : Elsevier BV. - 0301-9268 .- 1872-7433. ; 255:1, s. 381-400
-
Tidskriftsartikel (refereegranskat)abstract
- The Palaeoproterozoic Reynolds Range of the Arunta Region, central Australia, comprises a series of shallow marine clastic sediments (Reynolds Range Group) which overlies deeper water sequences of turbidites (Lander Rock Formation) and minor sandstones (“unnamed sandstone”). U–Pb age data collected from detrital rutile and zircon in these rocks indicates these sequences contain very similar age spectra, although with a notable and important shift to younger ages within the stratigraphically younger Reynolds Range Group. Detrital zircons from the “unnamed sandstone” directly underlying the unconformity with the Reynolds Range Group contain a major age component at ca. 1860 Ma, together with a wide spread of ages between ca. 3.2 and 2.0 Ga and a minor age component of 1830–1805 Ma. Detrital rutile from the same rock yield a unimodal age spectrum with a mean age of ca. 1840 Ma. The detrital zircon age spectrum from the Reynolds Range Group is similar, although the youngest cluster of ages is younger and dates to between 1800 Ma and 1780 Ma. Detrital rutile from these rocks yield a unimodal age spectrum with a mean age of ca. 1790 Ma. Although the observed differences in ages are subtle, we suggest these nevertheless mark a significant change in provenance. We attribute the predominance of 1860–1820 Ma detrital zircon and 1840 Ma detrital rutile within the “unnamed sandstone” and the characteristic ca. 1860 Ma detrital zircon age cluster in previously published provenance studies from the Lander Rock Formation to uplift and erosion of the Halls Creek–Pine Creek Orogen. This orogenic belt marks collision between the North Australian and Kimberley cratons, an event dated to between 1835 Ma and 1810 Ma and which incorporates marginally older rocks dating to 1860 Ma from the foreland of the Kimberley Craton. By contrast we attribute the influx of younger rutile and zircon, together with a distinct facies change observed with the onset of the deposition of the Reynolds Range Group, to a shift in provenance region to the Yapungku Orogen, which marks the collision between the West Australian and North Australian cratons and is dated to ca. 1800–1765 Ma. A change in provenance is additionally consistent with significant differences in rutile trace element composition. The Lander Rock Formation and the Reynolds Range Group are stratigraphically correlated with sedimentary rocks that overly large parts of the North Australian Craton. We suggest this indicates spatially continuous basinal conditions within the North Australian Craton between ca. 1840 Ma and 1780 Ma, although the erosion and drainage systems feeding this basin were strongly influenced by the collision and orogenesis along the northwest and southwest margins of the North Australian Craton.
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| 37. |
- Salter, Matthew E., et al.
(författare)
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Calcium enrichment in sea spray aerosol particles
- 2016
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Ingår i: Geophysical Research Letters. - : Blackwell Publishing. - 0094-8276 .- 1944-8007. ; 43:15, s. 8277-8285
-
Tidskriftsartikel (refereegranskat)abstract
- Sea spray aerosol particles are an integral part of the Earth's radiation budget. To date, the inorganic composition of nascent sea spray aerosol particles has widely been assumed to be equivalent to the inorganic composition of seawater. Here we challenge this assumption using a laboratory sea spray chamber containing both natural and artificial seawater, as well as with ambient aerosol samples collected over the central Arctic Ocean during summer. We observe significant enrichment of calcium in submicrometer (<1 μm in diameter) sea spray aerosol particles when particles are generated from both seawater sources in the laboratory as well as in the ambient aerosols samples. We also observe a tendency for increasing calcium enrichment with decreasing particle size. Our results suggest that calcium enrichment in sea spray aerosol particles may be environmentally significant with implications for our understanding of sea spray aerosol, its impact on Earth's climate, as well as the chemistry of the marine atmosphere.
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| 38. |
- Sengun, Firat, et al.
(författare)
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Trace element composition of rutile and Zr-in-rutile thermometry in meta-ophiolitic rocks from the Kazdag Massif, NW Turkey
- 2016
-
Ingår i: Mineralogy and Petrology. - 0930-0708. ; 110, s. 547-560
-
Tidskriftsartikel (refereegranskat)abstract
- In northwest Turkey, ophiolitic meta-gabbros are exposed on the Kazdağ Massif located in the southern part of the Biga Peninsula. Trace element composition of rutile and Zr-in-rutile temperatures were determined for meta-gabbros from the Kazdağ Massif. The Zr content of all rutiles range from 176 to 428 ppm and rutile grains usually have a homogeneous Zr distribution. The rutile grains from studied samples in the Kazdağ Massif are dominated by subchondritic Nb/Ta (11–19) and Zr/Hf ratios (20–33). Nb/Ta and Zr/Hf show positive correlation, which is probably produced by silicate fractionation. The Nb/Ta and Zr/Hf ratios increase with a decrease in Ta and Hf contents. The core of rutile grains are generally characterized by low Nb/Ta ratios of 17–18 whereas the rims exhibit relatively high Nb/Ta ratios of 19–23. Trace element analyses in rutile suggest that these rutile grains were grown from metamorphic fluids. The P-T conditions of meta-gabbros were estimated by both Fe–Mg exchange and Zr-in-rutile thermometers, as well as by the Grt-Hb-Plg-Q geothermobarometer. The temperature range of 639 to 662 °C calculated at 9 kbar using the Zr-in-rutile thermometer is comparable with temperature estimates of the Fe-Mg exchange thermometer, which records amphibolite-facies metamorphism of intermediate P-T conditions. The P-T conditions of meta-ophiolitic rocks suggest that they occur as a different separate higher-pressure tectonic slice in the Kazdağ metamorphic sequence. Amphibolite-facies metamorphism resulted from northward subduction of the İzmir-Ankara branch of the Neo-Tethyan Ocean under the Sakarya Zone. Metamorphism was followed by internal imbrication of the Kazdağ metamorphic sequence resulting from southerly directed compression during the collision.
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| 39. |
- Smit, Matthijs, et al.
(författare)
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Early evolution of the Pamir deep crust from Lu-Hf and U-Pb geochronology and garnet thermometry
- 2014
-
Ingår i: Geology. - 0091-7613 .- 1943-2682. ; 42:12, s. 1047-1050
-
Tidskriftsartikel (refereegranskat)abstract
- Determining early orogenic processes within the Pamir-Tibet orogen represents a critical step toward constructing a comprehensive model on the tectonic evolution of the region. Here we investigate the timing and cause of prograde metamorphism of Cenozoic metamorphic rocks from the Pamir plateau through Lu-Hf geochronology, U-Pb rutile thermochronology, and garnet thermometry. Regional prograde metamorphism and heating to 750–830 °C, as constrained by thermometry, occurred between 37 and 27 Ma. Prograde growth of garnet first occurred in the South Pamir and spread to the Central Pamir during the following 10 m.y. The early metamorphism is attributed to high mantle heat flow following the ca. 45 Ma break-off of the Indian slab south of the Pamir. Our investigation confirms a long-lived thermal history of the Pamir deep crust before the Miocene, and provides a causal link between break-off, enhanced mantle heat flow, and prograde heating of the subduction hanging wall.
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| 40. |
- Kankainen, Max, et al.
(författare)
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In situ ecological quality status in the Kosterhavet National Park (Skagerrak, North Sea): a 100 year-perspective
- 2023
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X. ; 147
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Tidskriftsartikel (refereegranskat)abstract
- The Koster Trench is the deepest part of the Kosterfjord located in the Skagerrak at the north-west coast of Sweden. In 2009 the Kosterfjord was included into the Marine Protected area Kosterhavet National Park characterized by high biodiversity and a presence of cold-water coral reefs dominated by Lophelia pertusa. The cold-water coral reefs show signs of deterioration and are known to have a much wider distribution during the past. In this study we investigate the temporal variability of the Ecological Quality Status (EcoQS) using benthic foraminifera and sediment geochemistry from a sediment core collected in the Koster Trench together with available hydrographic timeseries and meteorological data. We found that the EcoQS for TOC, metals, and foraminiferal indices suggest high to good ecological status close to natural background levels (reference conditions). However, arsenic (As) content in the sediment has been rising steadily over the period ∼ 1880–2009. Given this pollutant will continue to rise further, it may pass a threshold after which it becomes toxic to the benthic organisms, reaching intermediate EcoQS as it was shown by previous studies. Multivariate statistics performed on foraminiferal data identified three assemblages characterising the record: 1) Stainforthia fusiformis group at ∼ 1880–1940; 2) Bulimina marginata, Cassidulina laevigata and Hyalinea baltica group between ∼ 1940–1985, and, finally, 3) Stainforthia fusiformis and Textularia earlandi group at ∼ 1985–2009. The benthic foraminifera and sediment geochemistry suggests that a decrease in coastal upwelling due to positive NAO together with an increase in freshwater inflow from 1979/1980s; changes in phytoplankton community composition in late 2000s, and trawling activity shifted to the deepest fjord basin from 2009, all together likely have caused a shift towards more opportunistic foraminiferal species with an omnivorous feeding strategies and tolerance of physical disturbance.
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