Sökresultat

The deep recycling of surface material into Earth’s mantle is an integral process governing global water and fluid-mobile element cycles. This recycling is largely predicated on subduction operating efficiently, which may not apply for the first two billion years of Earth’s history. Tracing the initiation and evolution of the modern deep fluid-mobile element cycle requires determining when the man

The Sörvik granite forms rounded intrusions in the dominating Revsund granite, north-eastern Jämtland, central Sweden. Laser-ablation single-collector magnetic sector field-inductively coupled plasma-mass spectrometry on zircons was used to date the granite. The zircons are inhomogeneous, some with evident cores. The fractionation curves, 207Pb/235U versus time (depth), are irregular and often inc

Upper-intercept U-Pb ages (TIMS) of two non-foliated I-type granites are 1887 ± 20 Ma (part of a granodiorite-granite sequence) and 1881 ± 2 Ma (leucogranite with transitions into pegmatite). A non-foliated S-granite, which according to field observations, is younger than the two I-granites, occurs within the same composite pluton. Zircons of this granite are heterogeneous and contain abundant cor

The l’Hort de la Boquera site is located in the northeastern part of Iberia and its stone tool assemblage includes up to 25,000 flint artefacts. This is the first approach to the analysis of the raw material through an archaeopetrological study. Results were obtained by use of mineralogical techniques: macroscopic and petrographic analysis, Scanning Electronic Microscopy (SEM), Micro-Raman and X-R

Forward osmosis (FO) and membrane distillation (MD) have emerged as promising processes for seawater desalination. One of the key factors influencing the FO process is the selection of a suitable draw solution (DS), which should exhibit high osmotic pressure and easy regeneration through a secondary process such as MD. Thermo-responsive polymers having ethylene oxide (EO) and propylene oxide (PO)

In 2008, the Geological Survey of Denmark and Greenland began a project in collaboration with the Bureau of Minerals and Petroleum of Greenland with the aim to publish a web-based, seamless digital map of the Precambrian bedrock between 61°30´ and 64°N in southern West Greenland. Such a map will be helpful for the mineral exploration industry and for basic research. Producing an updated digital ma

A migmatitic orthogneiss in the Western Segment in the Sveconorwegian Province of the Baltic Shield was dated using the ion-probe U-Pb method on zircon grains, which were also analysed for rare earth elements. Mesosome zircons have 1.605±0.010Ga magmatic cores, which places the gneiss protolith in the same 1.61-1.59Ga time bracket as continental arc-related gneisses, abundant in this part of the S

Reproducibility of Re-Os molybdenite ages depends on sample size and homogeneity, suggesting that Re and Os are decoupled within individual molybdenite crystals and do not remain spatially linked over time. In order to investigate the Re-Os systematics of molybdenite at the subgrain (micron) scale, we report LA-ICP-MS Re-Os ages for an Archean molybdenite crystal from Aittojärvi, Finland, analyzed

Re and Os concentrations and isotopic composition were analysed in four ultramafic cumulates from the Kedum tectonic lens within the Mylonite Zone, SW Sweden. An 1887±36 Ma isochron is obtained for six samples and interpreted to date the Kedum body. This is significantly older than the -1600-1700 Ma surrounding crust and the first rocks of Svecofennian age west of the Trans Scandinavian Igneous Be

The Re-Os (rhenium-osmium) chronometer applied to molybdenite (MoS2) is now demonstrated to be remarkably robust, surviving intense deformation and high-grade thermal metamorphism. Successful dating of molybdenite is dependent on proper preparation of the mineral separate and analysis of a critical quantity of molybdenite, unique to each sample, such that recognized spatial decoupling of 187Re par

Zircons from anatectic melts of the country rocks of three Proterozoic mafic-ultramafic intrusions from the Sveconorwegian Province in SW Sweden were microanalyzed for U-Th-Pb and rare earth elements. Melting and interaction of the wall rocks with the intrusions gave rise to new magmas that crystallized zircon as new grains and overgrowths on xenocrysts. The ages of the intrusions can be determine

To obtain geologically meaningful and precise results on low-level sulfides that are highly radiogenic, blank corrections that account for the extreme difference in the Os isotope composition of sample and blank are necessary, and the resulting data is best plotted in 187 Re- 187Os space, much like the approach used for molybdenites. We here introduce the acronym LLHR as a means of characterizing

Field relationships and petrology of a mid Proterozoic (1624 ±6 Ma) hornblendite from southwestern Sweden demonstrate that it originated as a mafic-ultramafic hydrous melt. Lobes and veins of hornblendite penetrate the surrounding gneiss and small gneiss xenoliths lie in the main body of the hornblendite, evidence that it intruded with relatively low viscosity. The hornblendite has a composition c

In this research, a straightforward and effective preconcentration technique was developed by integrating three-phase hollow fiber liquid-phase microextraction (HF-LPME) with high-performance liquid chromatography equipped with a photodiode array detector and mass spectrometry (HPLC-DAD/MS) for the simultaneous extraction and quantification of trace levels of tamoxifen (Tam) and clomiphene (Clom)

A single zircon grain dated by ion probe with a minimum age of 3432±30 Ma was found in a microgranite dyke, which cuts norite of 916±11 Ma Hakefjorden Complex at Älgön on the Swedish west coast north of Gothenburg. Zircons are a rare accessory mineral in this dyke. They could be classified by morphology as orthocrysts and xenocrysts. Data from four orthocrysts show that the dyke originated between

Turning sustainable is one of the largest challenges facing the aviation sector. Switching to sustainable aviation fuel (SAF) instead of fossil fuels is a large piece of the sustainability puzzle, but there is no current SAF that is approved as a stand alone fuel. The road to a stand alone SAF is long and requires more diverse biofuels as well as more research on how biofuels combust. This thesis

Polyethylene glycol (PEG) is commonly used in the conservation of wooden artifacts, but its presence adversely affects the accuracy of radiocarbon dating. It is therefore critical to have robust methods for the removal of PEG from heritage materials. This paper presents the results of an experiment designed to test a protocol for the removal of low molecular-weight PEG-400 from conserved wood. We

En essä om tomrummets betydelse i antika textfragment, utifrån boken Sophögen i Oxyrhynchos om papyrusfynden i Egypten.