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| 2. |
- Bazarnik, Jakub, et al.
(author)
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U-Pb zircon dating of metaigneous rocks from the Nordbreen Nappe of Svalbard's Ny-Friesland suggests their affinity to Northeast Greenland
- 2019
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In: Terra Nova. - : WILEY. - 0954-4879 .- 1365-3121. ; 31:6, s. 518-526
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Journal article (peer-reviewed)abstract
- SIMS U-Pb zircon dating of metaigneous rocks of the Nordbreen Nappe from the West Ny-Friesland terrane (Eastern Basement Province of Svalbard) yields crystallization ages of 1,761 +/- 4 Ma for a felsic metatuff and 1,373 +/- 4 Ma for a metagabbro dyke. The Palaeoproterozoic age of the metatuff is similar to previously obtained ages for various felsic rocks from the study area, whereas the Mesoproterozoic age of the metagabbro has not been thus far documented on Svalbard. However, a similar age pattern has been reported from Northeast Greenland. Therefore, we conclude that the West Ny-Friesland terrane can be correlated with age equivalent units of Northeast Greenland. We also explore similarities and dissimilarities between the study area and other terranes of Svalbard and speculate on regional-scale correlations. Together, the presented new ages provide critical piercing points in palaeogeographic reconstructions of the relatively poorly understood circum-Arctic region.
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| 3. |
- Brengman, L., et al.
(author)
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Micro-scale silicon isotope heterogeneity observed in hydrothermal quartz precipitates from the >3.7 Ga Isua Greenstone Belt, SW Greenland.
- 2016
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In: Terra Nova. - : Wiley. - 0954-4879 .- 1365-3121. ; 28, s. 70-75
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Journal article (peer-reviewed)abstract
- Pillow basalt and chert form integral lithologies comprising many Archean greenstone belt packages. To investigate details of these lithologies in the >3.7 Ga Isua Greenstone Belt, SW Greenland, we measured silicon isotope compositions of quartz crystals, by secondary ion mass spectrometry, from a quartz-cemented, quartz-amygdaloidal basaltic pillow breccia, recrystallized chert and chert clasts thought to represent silica precipitation under hydrothermal conditions. The recrystallized chert, chert clasts and quartz cement have overlapping δ30Si values, while the δ30Si values of the quartz amygdules span nearly the entire range of previously published values for quartz precipitates of any age, despite amphibolite facies metamorphism. We suggest that the heterogeneity is derived from kinetic isotope fractionation during quartz precipitation under disequilibrium conditions in a hydrothermal setting, consistent with the pillow breccia origin. On the basis of the present data, we conclude that the geological context of each sample must be carefully evaluated when interpreting δ30Si values of quartz.
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| 4. |
- Goodfellow, Bradley W., et al.
(author)
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Palaeocene faulting in SE Sweden from U-Pb dating of slickenfibre calcite
- 2017
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In: Terra Nova. - : Wiley. - 0954-4879 .- 1365-3121. ; 29:5, s. 321-328
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Journal article (peer-reviewed)abstract
- Estimating the timing of faulting is crucial to modelling tectonics, palaeoseismicity, landscape evolution and fault mechanics. Four slickenfibre calcite samples from a conjugate strike-slip fault set in a platformal limestone, SE Sweden, were dated using U-Pb. Three of the samples yielded an average age of 64.8 +/- 6.5Ma, while the fourth yielded a marginally younger age of 54.7 +/- 5.5Ma. Precipitation of the fibres is interpreted as syn-deformational. Age uncertainty and dispersion reflect incorporation of common Pb and tiny host-rock components into the dated calcite and/or possible fault reactivation through ca. 55Ma. We infer from crystal characteristics, stable isotopes (O-18 and C-13) and rare-earth elements that fibres formed in an environment rich in deep-seated fluids, at temperatures of 40-200 degrees C, with shear stresses exceeding 10 MPa and at a maximum burial depth of c. 4km. This Palaeocene faulting may reflect far-field stresses from shortening in the Alps.
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| 5. |
- Bergemann, Christian A., et al.
(author)
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Constraining long-term fault activity in the brittle domain through in situ dating of hydrothermal monazite
- 2018
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In: Terra Nova. - : Wiley. - 0954-4879. ; 30:6, s. 440-446
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Journal article (peer-reviewed)abstract
- Abstract SIMS Th–Pb dating of hydrothermal fissure-vein monazite-(Ce) has the unique potential to date multiple tectonic events under low-grade metamorphic brittle/ductile conditions over large time frames. Monazites-(Ce) from brittle fault systems in the Eastern Alps allow us to constrain their Cretaceous activity over 20 Ma within single crystals, recording all major tectonic events. Eo-Alpine formation of the fluid-filled fissure-veins occurred 90 Ma ago at 352 ± 19°C and 342 ± 42 MPa. This corresponds to peak conditions during regional metamorphism of the Cretaceous collisional nappe stacking. Several stages of dissolution–reprecipitation/recrystallization record fault activity between 84 and 70 Ma. Corresponding fluid inclusions indicate conditions of 229 ± 10°C and 143 ± 20 MPa. This correlates with the formation of sedimentary basins during post-orogenic extension associated with strike-slip movements. The results strengthen the hypothesis that many large fault systems in the Eastern Alps developed during the Cretaceous orogeny and became reactivated during Neogene Alpine tectonics.
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| 6. |
- Forsberg, Angelica, et al.
(author)
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Patients' perceptions of their postoperative recovery for one month
- 2015
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In: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 24:13-14, s. 1825-1836
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Journal article (peer-reviewed)abstract
- Aims and objectivesTo explore orthopaedic and general surgery patients' perceptions of their postoperative recovery for one month.BackgroundIn general, nursing research in the postoperative context has been directed towards a single symptom or area, which is valuable. However, there is a lack of studies of orthopaedic and general surgery patients' perceptions of postoperative recovery from a short-term perspective.DesignA quantitative approach with a longitudinal design was used.MethodsA total of 180 patients participated in the study. Data were collected using a standardised questionnaire, the Postoperative Recovery Profile, for self-assessment of recovery. Descriptive statistics reported as proportions were used for the categorical variables. Analytic statistics were used to identify statistically significant differences. Mean values and t-tests were used for quantity variables, and Mann–Whitney U-tests and Chi-squared tests were used for nonparametric variables.ResultsOverall, the orthopaedic patients were substantially less recovered than the general surgery patients. Two-thirds of the orthopaedic patients and half of the general surgery patients perceived severe or moderate pain in the acute recovery phase. Within the general surgery group, there were significant differences in the recovery between the Gastric Bypass patients and colon/ileum surgery patients. The gastric bypass patients were overall more recovered than the other groups of patients. The Gastric Bypass patients reported that they had improved after one month compared to their own status prior to surgery.Conclusions and relevance to clinical practiceNursing support for orthopaedic patients must be improved, especially after they are discharged from the hospital. To structure and monitor individual recovery, a top-five priority profile of the most important problems should be used during follow-up calls after the patient is discharged from the hospital. Postoperative pain continues to represent a clinical problem that requires attention. Heterogeneity in the perceptions of recovery within the general surgery group was indicated, which may depend on the surgical procedure as well as the patients' expectations and comparisons with their lives before surgery. Rather than return to their preoperative levels, certain patients tend to continue towards a new or different life postoperatively.
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