Rare earth element investigation of the Cliefden Outcrop,N.S.W., Australia

The effect of low grade hydrous burial metamorphism (prehnite-pumpellyite facies) upon the rare earth elements (REE) has been studied by using samples from the Cliefden Outcrop, New South Wales. The REE, together with other reputedly immobile elements, have been mobilised during the metamorphism. Although mobile, the REE have behaved remarkably coherently with little light rare earth (LREE) fractionation. This is reflected in the chondrite normalised patterns which are sub-parallel to parallel in shape. High correlations of REE with other elements can be used to predict the maximum likely variation of these elements in the studied outcrop. The high correlations do not necessarily mean that, for similarly metamorphosed terrains, crystallisation-differentiation processes have operated but may rather have resulted from strong geochemical coherence during post-crystallisation elemental redistribution. The REE do not appear to be strongly domain controlled within the Cliefden Outcrop.     

Underground Storage Tank Monitoring: Observation Well Based Systems

A growing number of state and local governments and petroleum-related companies require the use of release detection systems for underground petroleum storage tanks. This has resulted in a confusing array of commercially available petroleum product detection devices, many of which have not been extensively field-tested. These systems, which are installed in ground water observation wells, vapor wells or U-tubes, include hydrocarbon-detecting paste, bailers, interface probes, electrical resistivity sensors, thermal-conductivity sensors, hydrocarbon-soluble devices, hydrocarbon-permeable materials and vapor detectors. This paper describes the available state-of-the-art technology for leak detection and the application for which each system is best suited.     

Agpaicity revisited: pattern recognition in the chemistry of nepheline syenite rocks

An attempt is made to describe global variations in the geochemistry of major and minor elements within a population of nepheline syenite samples defined by mineralogical criteria.Using correspondence analysis, a new pattern recognition procedure, it is possible to define a few trends of common behaviour which reflect most of the initial dispersion.As Al and Na participate in the scattering along the two main trends, agpaicity is recorded by them. However, the traditional form of the coefficient which measures it is proved to be unsatisfactory as variations of K are not significant.     

Relationships between granite-gneiss terrains,greenstone belts and granulite belts in the archean crust of Lapland (Fennoscandia)

The Archean crust of Lapland (Fennoscandia) consists of four units (from north to south): (1) the Inarijärvi nucleus, old basement complex of gneisses and greenstones, (2) the granulite belt, thick terrigenous metasedimentary sequence intruded by small amounts of calc-alkaline plutonic rocks, (3) the Tana River belt composed of tholeiitic metavolcanics, and (4) a set of gneiss domes fringed with younger greenstone belts.The main feature of their metamorphic and tectonic evolution are described. Geodynamic models applied to the Archean are discussed and a crustal evolutionary model suitable for this region is proposed.We assume that the Tana River and granulite belts represent a suture between an older domain in the north (craton of Kola Peninsula) and the northern part of the Archean basement of Central Finland.

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Zusammenfassung Die archaische Kruste von Lapland (Fennoscandia) besteht von Nord nach Süd aus vier Einheiten: (1) der Inarijärvi-Kern, ein alter Grundgebirgskomplex mit Gneisen und Grünschiefem; (2) der Granulit-Gürtel mit mächtigen terrigenen Metasedimenten, in die kleine Kalkalkaliplutone intrudierten; (3) der Tana-Gürtel, der aus tholeiitischen Metavulkaniten besteht; (4) eine Gruppe von Gneisdomen, die von jüngeren Grünschieferzonen umgeben werden.Wir nehmen an, daß der Tana-Gürtel und der Granulit-Gürtel eine Sutur zwischen einem älteren Kern im Norden (Kola-Kraton) und dem nördlichen Teil des archaischen Grundgebirges von Zentralfinnland bildet.

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Résumé La croûte archéenne de Laponie (Fennoscandie) comprend quatre unités principales. Ce sont du Nord au Sud: (1) le nucleus de l'Inarijärvi, formé par un vieux socle complexe avec des gneiss et des roches vertes, (2) la ceinture granulitique, à l'origine formée par une épaisse séquence sédimentaire térrigène et par des intrusions calcoalcalines, (3) la ceinture de la Tana River composée de métavolcanites tholéitiques et, (4) un ensemble de dÔmes de gneiss flanqués de jeunes ceintures de roches vertes.Les grands traits de l'évolution tectonométamorphique de cet ensemble sont décrits. Les modèles géodynamiques archéens classiques sont discutés et un modèle d'évolution crustale pour cette région est proposé.Nous pensons que la ceinture de la Tana River et celle des granulites représentent une suture entre un domaine ancien au Nord (craton de la Péninsule de Kola) et la partie septentrionale du socle archéen de Finlande centrale.

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Cluster analysis of seismic moment tensor orientations

This paper demonstrates that well-known methods of cluster analysis and multivariate data analysis are useful for geodynamic interpretation of seismic moment tensors. To use these methods, moment tensors are expressed as vectors in a 6-D space. These are vectors in a rigorous sense, rather than an arbitrary set of ordered numbers, because a dot product can be defined that is independent of the coordinate system. In this vector space, non-isotropic moment tensors are a 5-D linear subspace and normalized moment tensors are unit vectors, or points on a unit sphere. Distance along a great circle of the unit sphere satisfies reasonable requirements for any measure of the difference between normalized moment tensors. In regions with a few isolated sets of orientations, cluster analysis based on the great circle distance identifies the same groups of earthquakes that a seismologist would. Figures based on principal component analysis and discriminant analysis illustrate orientation clustering better than equal area projections of moment tensor principal axes. In one case where clusters have been claimed to exist, orientations appear to be continuously distributed and no evidence is found for separate populations of moment tensors.     

The distribution of rare phenolic type compounds in wild and cultivated wheats

In 14 species of Aegilops, four species of Triticum and two species of Hordeum, a complex of rare phenolic compounds was found and showed quantitative differences between the wild and domestic species. There was a dramatic reduction in the cultivars to about 5% of the amount of these phenolic constituents. In the wild species these phenolic compounds may act as important germination regulators, such as water-dissolving germination inhibitors which may act as 'rain gauges'. This is especially important for the germination at the appropriate time in species inhabiting arid regions or deserts.     

Limnological and sedimentary processes at Sawtooth Lake,Canadian High Arctic,and their influence on varve formation

This paper synthesizes data collected to document the modern limnological and sedimentary processes in South Sawtooth Lake located on northern Ellesmere Island, Nunavut, Canada. Field observations show that the finely laminated sediments deposited in the distal basin are formed by the settling of overflows and interflows, and in rare occasions, by non-erosive hyperconcentrated density flows. Thin-sections of these sediments allowed for the classification of the sedimentary fabrics into six facies, each representing different limnological processes. The sediments in this distal basin are considered to be continuous and annually laminated (varved) based on radioisotope analyses, and both limnological and sedimentological evidence.