Calcareous fens constitute a specific habitat which is uncommon in Europe and protected by the EU habitat directive due to its importance to several threatened species. Hagebyhöga in Östergötland is a calcareous fen habitat included in the Natura 2000 Networking Programme. Adjacent to the existing fen, a degraded fen area is situated. The area has been used for agriculture for several years but is now going to be restored to its former state by the county administrative board of Östergötland. When working with restoration of degraded fen areas it is important to aquire knowledge about the chemical soil conditions. Plant growth limited by phosphorus and low fertility are characteristic conditions for calcareous fens, whilst arable land usually is highly fertile and limited by nitrogen. The purpose of this study is to bring forth useful knowledge for restoring the degraded calcareous fen of Hagebyhöga. Phytometric assessments have been conducted on samples from the ground that is going to be restored, to investigate which element limits growth, and whether the fertility is comparable to that in the fen allready present. The results will be used when deciding whether the top soil layer needs to be removed, and if that is the case, how much of the soil needs to be removed to recreate the fen environment. The samples were collected from two areas (A and B) with different moisture content in the arable ground and three depths from each area (0-10 cm, 10-30 cm and 30-40 cm). As reference, a sample from the top soil layer of the existing fen was used. The results from the phytometric assessment reveals all samples from area A and the sample from area B, 30-40 cm to have plant growth limited by phosphorus. The results also reveals the fertility in all samples except for area A, 30-40 cm to be significantly higher than the fertility of the existing fen. Both conditions, low fertility and plant growth limited by phosphorus, are present in the sample from area A, 30-40 cm.

The Mariana convergent plate margin is a non- accretionary subduction system in the western Pacific Ocean. Subduction of the Pacific plate causes dissolution of carbonate minerals releasing inorganic carbon, and causes dehydration of hydrous minerals in the subducted slab, generating hydrous fluids. The hydrous fluids infiltrate the overriding plate and induce serpentinization of mantle peridotite. Serpentinized material is transported by the rising fluids, which are channeled along fractures and faults in the forearc region, consequently erupting at the seafloor forming serpentine seamounts. Manganese (IV) oxides that commonly occur in fractures near convergent plate margins are naturally occurring oxidants for chromite ((Al,Mg,Fe)Cr2O4), which is an accessory mineral in mantle peridotite. Chromite is known to be an efficient catalyst in Fischer- Tropsch type (FTT) reactions where molecular hydrogen produced by serpentinization reacts with dissolved inorganic carbon, producing organic hydrocarbons.   Samples were collected from two serpentine seamounts in the Mariana forearc during Ocean Drilling Program, Leg 125 and Leg 195. The aim of this study is to relate organic content in fluid inclusions to minerals that are known to be efficient catalysts in FTT- reactions. The results show that chromites have been altered, with hematite (Fe2O3) precipitated at the margins of the chromites. This is inferred to be caused by an oxidation reaction where manganese (IV) oxides acted as oxidants, oxidizing Fe (II) in chromites to Fe (III) which precipitated as hematite. No fluid inclusions were found in the samples. However, elemental carbon was detected in fractures of the chromites, suggesting that FTT- reactions has occurred where chromite probably acted as a catalyst / I västra Stilla havet ligger Marianergraven som är en del av en konvergerande plattgräns. Det är ett subduktionssystem där sediment saknas på den överliggande oceanskorpan. Subduktionen av stillhavsplattan leder till att karbonatrika mineral löses upp och frigör oorganiskt kol. Dehydrering av hydrerade mineral i den subducerande plattan genererar vattenhaltiga fluider, när dessa fluider infiltrerar den överliggande plattan orsakar de serpentinisering av mantelperidotit. Det serpentiniserade material som bildats, transporteras av fluiderna längs sprickor och förkastningar i området kring den vulkaniska öbågen. När fluiderna och det serpentiniserade materialet erupterar vid havsbotten bildas vulkanliknande djuphavsberg. Mangan (IV) oxider som förekommer i sprickor är naturliga oxidationsmedel för kromit ((Al,Mg,Fe)Cr2O4), som är ett accessoriskt mineral i mantelperidotit. Kromit är ett mineral som är en effektiv katalysator i Fischer- Tropsch (FTT) reaktioner, en reaktion där molekylärt väte, som är en produkt från serpentinisering, reagerar med frigjort oorganiskt kol och bildar organiska kolväten.   Prover togs på två av Marianergravens djuphavsberg under Ocean Drilling Program, Leg 125 och Leg 195. Syftet med denna studie var att relatera organiskt innehåll i vätskeinneslutningar till mineral som är kända katalysatorer i FTT- reaktioner. Resultaten visade att kromiterna är omvandlade med hematite (Fe2O3) utfällt på kanten av kromiterna. Detta antas därmed vara en redoxreaktion där mangan (IV) oxider agerat som oxidationsmedel. Fe (II) i kromiterna oxiderade till Fe (III) och fälldes ut som hematite. Inga vätskeinneslutningar hittades i proverna, men elementärt kol hittades i sprickor i kromiterna. Förekomsten av kol antyder att Fischer- Tropsch- reaktioner har skett med kromiterna agerandes som katalysatorer.

Idag finns det tusentals verksamheter i Sverige som kräver tillstånd enligt miljöbalkens 9 kap 6 § då de klassas som miljöfarlig verksamhet. Vissa av verksamheterna omfattas också av Sevesolagstiftningen vilket innebär att åtgärder ska vidtas för att förebygga och begränsa följderna av allvarliga kemikalieolyckor. Vid sidan av de legala kraven väljer många företag att certifiera verksamheten enligt ledningssystemen ISO 14001 och OHSAS 18001, vilka ställer krav på verksamheten att arbeta med miljö och arbetsmiljö på ett strukturerat sätt. De legala kraven ovan samt ledningssystemen innebär att berörda företag ska arbeta med riskinventering samt kommunikation till externa intressenter. Nynas raffinaderi Nynäshamn är en verksamhet som omfattas av tillståndsplikt enligt miljöbalken och Sevesolagen, samt innehar certifikat enligt ISO 14001 och OHSAS 18001. Syftet med det här examensarbetet var att genom en enkätundersökning studera riskperceptionen, dvs. upplevelsen av risker, hos närboende till Nynas raffinaderi Nynäshamn. Även riskkommunikationen som sker mellan Nynas raffinaderi Nynäshamn och närboende till raffinaderiet undersöktes genom enkäten samt en intervju med Nynas, där de närboendes uppfattning om kommunikationens betydelse för den upplevda risken beaktades såväl som Nynas syn på kommunikationen. Enkäten skickade ut till 406 personer i Nynäshamn och gav svarsfrekvens på 37,4 %. Adresser togs fram slumpmässigt via hitta.se. Resultatet visade på signifikanta skillnader mellan samtliga jämförda grupper i enkätundersökning, utom mellan personer med olika avstånd till Nynas. Flest signifikanta skillnader fanns det i svaren mellan män och kvinnor. Slutsatserna var att män tillsammans med personer som är 50 år eller äldre och personer som skickade in sina svar innan den 1/3 då Nynas polisanmäldes för miljöbrott, i större utsträckning upplever riskkommunikationen som god jämfört med kvinnor, personer under 50 år samt personer som skickade in sina svar efter den 1/3. De största upplevda riskerna var utsläpp av farliga ämnen till luft, mark och vatten samt brand; det fanns också skillnader mellan män och kvinnors riskperception. Kvinnor tenderade att värdera risker högre än män. Vidare tillhandahåller Nynas en rad olika tjänster och aktiviteter för att sprida information till närboende.

The purpose with this essay is to highlight the environmental risk that black-carbon aerosols represent to the ice melting in the Arctic. When the ice melting in the Arctic and other climate-related issues are highlighted, the focus is primarily on carbon dioxide and the risks related thereto. Black-carbon aerosols and their environmental effects are much more unknown to most people. The effect that black carbon exerts on the Arctic ice melting is mainly that it causes a decrease in albedo. The term albedo is a measure of the proportion of the sunlight that hits the surface and then is reflected. A reduction in albedo means that a greater proportion of the incoming solar radiation is absorbed by the surface area. This is exactly what happens when black-carbon aerosols end up in the Arctic. Because of the black colour of the aerosols, the surface where the aerosols are deposited becomes darker, which means an increased light absorption, which in turn heats the surface and accelerates the ice melting process. The essay deals with the subject based on the environmental risk paradigm. That means that the focus is placed on the following three steps: the -risk assessment, the -risk communication and the -risk management. The risk assessment is used to assess the threat posed by black-carbon aerosols. Where and how black carbon occurs, and its ability to disperse to the Arctic constitute an important part of the risk assessment. Other environmental risks and especially the health risks associated with black carbon have also to some extent been treated in this essay. This is primarily because of the fact that those other environmental hazards that are not related to the Arctic may be relevant when it comes to increasing the incentives to reduce the emissions of black carbon. The facts that emerge in the risk assessment clearly indicate that Southeast Asia is of great importance when it comes to black carbon that ends up in the Arctic. The risk management is used to analyse the methods which are most appropriate and profitable in terms of reducing the emissions. The available technologies to reduce the emissions of black carbon are also treated. It turns out that the profitability to make emission reductions is greatest in Southeast Asia. The fact that the profitability to make emission reductions is greatest in the part of the world where the emissions are greatest indicates that there is a great potential to overcome the problem. The countries in Southeast Asia may need support from the Western countries when it comes to implementing measures in order to reduce the emissions. The risk communication is a part of the environment risk paradigm that is constantly needed in order to communicate the risks at various levels. An important conclusion of this essay is that the environmental risk communication between researchers and policy makers is insufficient. An improvement of this could lead to more vigorous measures to be taken in order to overcome this problem.

The BABEL project (Baltic And Bothnian Echoes from the Lithosphere) was a collaboration among British, Danish, Finnish, German and Swedish geoscientists to acquire deep-crustal reflection and wide-angle refraction data in the Baltic Shield and Gulf of Bothnia. In 1989, the collection of 2,268 km of deep marine reflection seismic data was carried out. BABEL line 7, one of several BABEL profiles, is the focus of this study and runs north of the Åland islands, in an E-W direction in the Bothnian Sea, east of the city of Gävle. The previous seismic image of the BABEL line 7 displays a considerable change in the reflectivity pattern from a weak reflective lower crust in thewest to a more highly reflective lower crust in the east, interpreted to be due to a transition from a stiff crust to a plastic crust from the west to the east. The seismic results were presented by the BABEL Working Group (1993) which focused on imaging and interpreting deep crustal structures as well as assessing the seismic velocities within the crust, the depth and nature of the Moho discontinuity and the seismic reflectivity texture in the crustal geological structures. Early Proterozoic plate tectonics in the Baltic Shield was also suggested from the reflection seismic data.The BABEL line 7 reflection data were collected with a profile length of 174 km, a group of 48 air guns towed at 7.5 m depth, and 3000 m long streamer, 60 hydrophones spaced at 50 m intervals towed at 15 m depth. Seismic data were acquired for a 25 s record length using a 4 ms sampling interval and a 75 m shot interval. Seismic data are characterized by strong source-generated noise at shallow travel times and strong but randomly distributed spurious spikes at later arrival times. In this thesis, the seismic data along BABEL line 7 were recovered and re-processed. Modern processing techniques that were not available previously, were used. A special emphasis on the shallow parts of the seismic data was given and resulted in revealingreflections as shallow as 300 ms. Some of these reflections seem to be a continuation of the deeper ones and now appear to come to the surface which can now improve thecorrelation with the surface geology. Two major apparently moderately dipping shear zones are now interpreted to reach to the surface in the re-processed data in comparison with the previous work.The deep reflections are also enhanced together with the improvement in the shallow parts which provide further insights about the nature of the Moho and its geometry along BABEL line 7. The re-processed seismic image demonstrates the potential in improving shallow and deep crustal structures along the BABEL offshore seismic data.

Seismic reflection surveying is a powerful method to explore the structures of the Earth’s crust and describe it is layers. It is also used extensively in the oil industry. Offshore seismic profiles were acquired in southern Sweden (Skane area) for petroleum exploration purposes, but no productive fields were discovered in that area. The seismic reflection data were collected and processed in the 1970s. The purpose of this thesis is to reprocess some of the seismic profiles from the 1970s with new processing programs to improve the results and compare it with the previous results. Offshore lines 208, 206, 212 have been selected in this project because they cross each other and are close to a borehole with sonic data. The borehole lies close to lines 208 and 212 as seen from the Skane area map. Also this report can be used to introduce the reader to fundamentals of seismic data processing. The processing was done using Claritas software by applying standard processing steps to produce migrated stacked sections for every line as a final product.

The Hammerfest Basin was formed through downfaulting in Late Jurassic-Early Cretaceous times, allowing the deposition and preservation of Jurassic sediments which later were covered by thick Cretaceous sequences filling in the basin. This study has been conducted along the southern margin of the Loppa High to develop a complete sequence stratigraphic framework and to map Early Cretaceous Knurr Formation turbidite lobes along the slope of the High. Six seismic profiles have been selected for interpretation along the southern margin of the Loppa High on the basis of the availability of good quality data. A complete sequence stratigraphic framework has been developed to mark the major surfaces (Sequence Boundary, MFS) by geologic characterization of high-resolution seismic reflection geometries (truncation patterns, sigmoidal reflections) and seismic facies using the coarsening-up, fining up and blocky GR log motifs from both the offset wells and the wells located on the seismic section. Two Wheeler Diagrams (Chronostratigraphic Charts) have been constructed for type sections to obtain better insight into the time relationships of the depositional system, and define surfaces of non-deposition, condensation and erosion. WinPICS interpretation software has been used for seismic interpretation. Sequence stratigraphic analysis has been carried out on two scales (3rd order and 2nd order cycles). The whole sedimentary package is divided into various sequences and system tracts. In addition to a detailed sequence stratigraphic analysis to investigate the hydrocarbon prospectivity, an Early Cretaceous turbidite sand lobe has been mapped (LHSG-84-428) using seismic stratigraphy and compared with a drilled analogue (well 7122/2-1). Two paleogeograhic maps have also been constructed to show the Early to Late Cretaceous progradation and accommodation space filling in the Hammerfest Basin.

In August 2008 and June 2009 two sets of airborne measurements were made in Falun and Borlänge, respectively, by the Geological Survey of Sweden (SGU). The purpose of these campaigns was to test the new Multi Frequency Receiver (MFR) instrument called ADU07 for the collection of airborne data in the VLF and LF bands. This system was designed by Metronix and adapted by Uppsala University together with the SGU in the frame of a joint research project. The SGU in its bedrock mapping program routinely records VLF signals from only two transmitters in the frequency band of 14‐30 kHz. The RMT technique also makes use of electromagnetic signals in both the VLF and LF bands in the frequency range of 10‐250 kHz. By measuring all the three magnetic field components in this broader band, the data acquired by the new MFR system can provide high lateral and vertical resolution compared to the VLF data. This can be done by applying the concepts used for the EnviroMT. The joint research therefore aims at extending the VLF technique currently used by the SGU for geophysical investigations and whereby generating improved and more detailed anomaly maps. The airborne measurements with the ADU07 system were performed by continuously recording the three magnetic field components with a sampling frequency of 512 kHz in three channels. The prior evaluation of the data gave good results in the beginning. However, later tests showed that there were some near field sources onboard the aeroplane that contaminated the data and highly affected the estimation of transfer functions from the radio transmitters’ signals. The noise was basically generated by other measuring instrumentation and the common power supply used to feed both the ADU07 and the PC controller. The main aim of the present project is to develop a processing method that identifies frequencies from these near field sources and filters them out from the spectral ADU07 data. This work has been carried out by writing MATLAB routines. After the filtering, more reliable transfer functions that provide relevant information about the Earth’s resistivity structure can be estimated. Different methods were applied in order to detect the noise in the data. The mean value of the real part of the vertical magnetic field component (Hz) and the scalar tippers were firstly calculated along the profiles. These values should normally be close to zero. These methods did not give any valuable information since no patterns could be seen in the results. Afterwards, the vertical signal‐to‐noise ratio (VSNR) was calculated for every frequency at each station. This criterion showed that, for the first campaign, there were practically two sets of noise frequencies in the spectra: the first group corresponds to the even and odd harmonics of frequency 8 kHz, and the second group to frequency 23.47 kHz and its harmonics. For the last campaign, frequency 10.28 kHz and its harmonics were identified. The band averaging technique that splits the main frequency band into 9 overlapping sub‐bands with 1 octave of width was used. Finally, Prediction Errors (PE’s) were estimated to detect the remaining noise. A threshold was then chosen in order to remove from the spectra those frequencies with a PE above 3 and up to 20% of the number of transmitters in the sub‐bands. These processing steps improved considerably the tipper behaviour for the VLF band along the profiles, although some noise was also added. For the LF band, the filtering steps seem to have worsened the data quality and therefore the tipper estimation. The removal of important frequencies that were hidden in the high noise levels and the useof some other instruments during the data collection could be the causes of these responses.

In this thesis I have investigated the upper bounds on the possible presence of radiogenic heat sources in the inner core of the Earth, using both steady state and transient models, built during this work. Necessary theory for this and model descriptions are collected into appendices at the end of this work. In addition, the published literature is reviewed for various formation scenarios, modelling of the inner core, theoretical and experimental values of relevant thermodynamic parameters. A general expression for the upper thermodynamical bounds on the initial heat source abundance at onset of inner core soldification is derived, which in the range of the published values of the thermodynamical parameter space yields upper bounds of 0.20 ± 0.15 wt% initial abundance of 40K, the most favoured radiogenic candidate in the inner core. Alternatively the expression can be used to set an upper limit to the age of the inner core given that we know the present abundance of heatsources and thermal parameters. E.g. assuming a heat transfer coefficient of k = 80 W m−1 K−1, a melting temperature of iron of 5500 K at the inner core boundary, and a value of the thermodynamical Grüneisen parameter of  γth,ICB = 1.5, it is found that if the core is older than 0.9 Gyr the inner core 40K abundance has to be lower than 0.142 wt% (the constraint set by cosmochemical arguments) and if the inner core is older than 2.52 Gyr the upper bound is less than 0.058 wt% (upper limit as set by high pressure experiments). Several geotherms for the inner core in subspaces of the parameter space are also presented. A comparison between the steady state and transient models is also performed, with the result that steady state models generally underestimates the temperatures and are not suitable for the inner core geotherm, mainly due to the transient nature of inner core formation and evolution. Finally the nickel-silicide/georeactor inner core model, as proposed by Herndon is investigated. It is found that this would generate a large molten region at the centre of the inner core, which has not been observed today. Hence it is concluded that a georeactor can not be operational at the centre of the Earth today.

No description available.