1,054 research outputs found
Geochemistry of post-tectonic mafic intrusions in the Central Gneiss Terrane of southwestern Newfoundland
South of Grand Lake, mafic igneous complexes of proven or probable Silurian age intruded quartzofeldspathic gneisses that had been deformed and raised to granulite fades in mid-Ordovician time. The mafic igneous complexes consist of gabbroic units, which locally exhibit igneous layering and contain ultramafic cumulate pods, that grade to and are cut by finer-grained hornblende gabbro. Compositions more felsic than diorite exhibit intrusive to co-mingling relationships with more mafic rocks. Chemical data for possible liquid-derived rocks exhibit characteristics suggesting derivation from diverse mantle sources, followed by varying combinations of fractionation, contamination, mixing and metasomatism by hydrous fluids during ascent and emplacement. The post-tectonic emplacement of the plutons suggests stabilisation of die Central Gneiss Terrane by late Ordovician or Silurian time, when the adjacent terrane to the southeast (Meelpaeg Terrane) was still undergoing deformation and granitic plutonism.
RÉSUMÉ
Au sud de Grand Lake, des complexes ignés mafiques, dont l’âge est assurément ou probablement silurien, firent intrusion dans desgneiss quartzofeldspathiques qui avaient été déforrnés avaient atteint le faciès des granulites au milieude l’Ordovicien. Les complexes ignés mafiques sont constitues d'unités gabbroiques (montrant localement un aspect rubanné et contenant des lentilles de cumulate ultramaflques) passant graduellement à un gabbro à hornblende moins grenu qui les recoupe aussi. Les compositions plus felsiques que la diorite sont en relation d'intrusion ou de mélange avec les roches plus mafiques. Les données chimiques concernant des roches possiblement derives du liquide montrent des caractéres suggèrant une dérivation à partir de diverses sources mantelliques, suivie d'une combinaison variée de fractionnement, contamination, mélange et métasomatisme par des fluides aqueux durant l'ascension et l’emplacement. L'emplacement post-tectonique des plutons suggère une stabilisation de la lanière Central Gneiss Terrane avant l'Ordovicien tardif ou le Silurien, au moment ou la lanière adjacente au sud-est (la Lanière de Meelpaeg) subissait encore une déformation et un plutonisme granitique.
[Traduit par le journal
Age of high-grade gneisses south of Grand Lake, Newfoundland
Crystalline rocks of the Steel Mountain Subzone of the Humber Zone in southwest Newfoundland give an age for granulite-grade metamorphism of 1498+9/-8 Ma, similar to ages from the Long Range inlier and northwestern Cape Breton Island. Peralkaline leucogranite was emplaced at 608 ± 4 Ma. The emplacement of anorthosite-gabbro complexes and amphibolite-grade metamorphism took place between these dates. The southern part of the Dunnage Zone (Central Gneiss Subzone), in contact with the Steel Mountain Subzone at the Long Range Fault, lacks Precambrian crystalline rocks, but was intruded by charnockitic plutons and metamorphosed to granulite facies at 460 ±10 Ma. This subzone was exhumed before 435 Ma. In the Meelpaeg Subzone of the Gander Zone, which is in contact with the Central Gneiss Subzone along the Victoria River Fault, the oldest intrusive component of a granoblastic migmatitic gneiss was emplaced at 418 ± 4 Ma.
These data demonstrate that both the Long Range and Victoria River faults form major tectonic boundaries. Subzones appear to have been thrust westward in Silurian or later time.
RÉSUMÉ
Les roches cristallines de la sous-zone du mont Steel, dans la zone de Humber du sud-ouest de Terre-Neuve, ont donné des âges de 1498+9/-8 Ma pour le métamorphisme de haul grade, similaires à ceux de la boutonnière de Long Range et du nord de l'ile-du-Cap-Breton. Un leucogranite peralcalin s'est mis en place à 608 ± 4 Ma. L'intrusion des complexes à anorthosite-gabbro et le métamorphisme au faciès amphibolite se sont produits entre ces deux évènements. La partie sud de la zone de Dunnage (sous-zone de gneiss centrale), en contact avec la sous-zone du mont Steel a la faille de Long Range, ne contient pas de roches cristallines précambriennes mais à 616 recouped par des plutons charnockitiques et à 616 métamorphisée au faciès granulite à 460 ± 10 Ma. Cette sous-zone a été exhumge avant 435 Ma. Dans la sous-zone Mulpaeg de la zone de Gander, qui est mise en contact avec la sous-zone de gneiss centrale par la faille de la rivière Victoria, la phase intrusive la plus ancienne d'un gneiss migmatitique et granoblastique s'est mise en place à 418 ± 4 Ma.
Ces données démontrent que les failles de Long Range et de la rivière Victoria sont des frontières tectoniques majeures. Les sous-zones semblent avoir subi un chevauchement vers l'ouest au plus tard au Silurien.
[Traduit par le journal
Physical and psychosocial health in pediatric uveitis patients
Background: To investigate the possible associations between childhood noninfectious uveitis and cardio-respiratory fitness, physical activity, health related quality of life and fatigue. Methods: Cross-sectional analysis of 23 patients with noninfectious uveitis, aged 8-18 years. BMI, exercise capacity, muscle strength and physical activity were measured. Health-related quality of life and fatigue were assessed. The results were compared to standardized values for age matched healthy children. Results: Twenty-three patients were included. Children with uveitis had a higher bodyweight and body mass index. Children with uveitis had lower cardio-respiratory fitness and they were less physically active, but they experienced a normal quality of life and normal fatigue. Parents of children with uveitis reported a lower quality of life and more fatigue for their children than parents of healthy children. Conclusion: Our study indicates that children with noninfectious uveitis are at risk of developing lower physical and psychosocial health
Correcting for non-periodic behaviour in perturbative experiments: application to heat pulse propagation and modulated gas-puff experiments
This paper introduces a recent innovation in dealing with non-periodic behavior often referred to as transients. These transients can be the result from unforced response due to the initial condition and other drifts which are a source of error when performing and interpreting Fourier analysis on measurement data. Fourier analysis is particularly relevant in system identification used to build feedback controllers and the analysis of various pulsed experiments such as heat pulse propagation studies. The basic idea behind the methodology is that transients are continuous complex-valued smooth functions in the Fourier domain which can be estimated from the Fourier data. Then, these smooth functions can be approximately subtracted from the data such that only periodic components are retained. The merit of the approach is shown in two experimental examples, i.e., heat pulse propagation (core transport analysis) and radiation front movement due to gas puffing. The examples show that the quality of the data is significantly improved such that it allows new interpretation of the results even for non-ideal measurements.</p
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Global Challenges (FSW
Genome Sequence of Stenotrophomonas maltophilia PML168, Which Displays Baeyer-Villiger Monooxygenase Activity
Stenotrophomonas maltophilia PML168 was isolated from Wembury Beach on the English Coast from a rock pool following growth and selection on agar plates. Here we present the permanent draft genome sequence, which has allowed prediction of function for several genes encoding enzymes relevant to industrial biotechnology, including a novel flavoprotein monooxygenase
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