We present an update of results from the HPQCD collaboration on charm physics using the Highly Improved Staggered Quark action. This includes a precise de termination ofmc using moments of current-current correlators combined with high-order c ontinuum QCD perturbation theory. We also include an update on the determination of αs rom lattice QCD, preliminary results on the determination ofmb and a summary plot of the status of the gold-plated meson spec trum. There is an appendix on tackling systematic errors in fitting using the Bayesian approach.

We present an update of results from the HPQCD collaboration on charm physics using the Highly Improved Staggered Quark action. This includes a precise determination of m_c using moments of current-current correlators combined with high-order continuum QCD perturbation theory. We also include an update on the determination of alpha_s from lattice QCD, preliminary results on the determination of m_b and a summary plot of the status of the gold-plated meson spectrum. There is an appendix on tackling systematic errors in fitting using the Bayesian approach.

We show results for the Upsilon spectrum calculated in lattice QCD including for the first time vacuum polarization effects for light u and d quarks as well as s quarks. We use gluon field configurations generated by the MILC collaboration. The calculations compare the results for a variety of u and d quark masses, as well as making a comparison to quenched results (in which quark vacuum polarization is ignored) and results with only u and d quarks. The b quarks in the Upsilon are treated in lattice Nonrelativistic QCD through NLO in an expansion in the velocity of the b quark. We concentrate on accurate results for orbital and radial splittings where we see clear agreement with experiment once u, d and s quark vacuum polarization effects are included. This now allows a consistent determination of the parameters of QCD. We demonstrate this consistency through the agreement of the Upsilon and B spectrum using the same lattice bare b quark mass. A one-loop matching to continuum QCD gives a value for the b quark mass in full lattice QCD for the first time. We obtain m(b) ((MS) over bar) (m(b)((Ms) over bar))=4.4(3) GeV. We are able to give physical results for the heavy quark potential parameters, r(0)=0.469(7) fm and r(1)=0.321(5) fm. Results for the fine structure in the spectrum and the Upsilon leptonic width are also presented. We predict the Upsilon-eta(b) splitting to be 61(14) MeV, the Upsilon(')-eta(b)(') splitting as 30(19) MeV and the splitting between the h(b) and the spin-average of the chi(b) states to be less than 6 MeV. Improvements to these calculations that will be made in the near future are discussed.

Tourmaline, not hitherto recorded in Lewisian rocks of Sutherland, nor reported as a secondary mineral in Precambrian palaeosols, occurs in a late Proterozoic, sub-Cambrian palaeosol in NW Scotland. From field and petrological criteria, the tourmaline is secondary and peculiarly associated with the alteration profile. Hence, it formed either during weathering or later in the profile’s history. A minor constituent of the palaeoregolith immediately below the unconformity, the tourmaline mostly occurs as sub-millimetre, radiating, acicular aggregates and is schorl in composition. Black, tourmaline+quartz veinlets cross-cut the profile. Stable isotope and fluid inclusion data suggest that the tourmaline formed from surface-derived fluids at c. 110ºC. It is concluded that boron was adsorbed onto precursor illitic clays of the soil profile during the Cambrian marine transgression. Thus the tourmaline formed subsequently after burial under the sedimentary pile, probably during the Caledonian orogeny, when temperatures were high enough to allow its formation at suitable sites of nucleation, e.g. adjacent to biotite. Its peculiarity as a palaeosol phase is due to the combination of a marine transgression over an exposed, permeable illitic soil and underlying regolith, followed by increase in temperature suffcient to allow the tourmaline to form.

Graduates of today may expect to change careers a number of times during their working life and companies are placing more emphasis than previously on acquiring personal transferable skills. Prime among these are the abilities to communicate effectively and to manage time and information. With such a visual subject as structural geology it is not just text that requires storage. Graphs, diagrams, maps, sections, photomicrographs and field photographs are just as important and need to be as easily accessible. Aspects of the structure of the North Sea basin are used to illustrate the power of HyperCard™ to develop and maintain a comprehensive database of linked informa-tion. The HyperCard programming environment for Macintosh com-puters is capable of generating sophisticated applications yet is easy to use by those with no programming experience. The data are held in a ‘stack’ (the analogy is with a stack of file cards) and there may be text, graphics, sounds, or video sequences. Navigation through stacks is by means of ‘buttons’ which make the links between cards. These buttons may be visible and pass one to a specific card, the next in the sequence, for example, or invisible and sit over a feature or a word and bring up a card with more information on it. Two examples show not only how information may be linked but also how the visual appearance of a stack may be increased by the use of special effects and animation.

Weathering, during late Precambrian times, of pink granitic gneisses and pegmatites of the Middle Proterozoic Lewisian Complex in northwest Scotland has produced a characteristic pea-green palaeosaprolite called agalmatolite, which occurs from centimetres to metres beneath the planar unconformity with the overlying quartz sandstones of the Lower Cambrian marine transgression. Agalmatolite consists predominantly of massive, felted, very fine-grained muscovite of the form called pinite together with variable amounts of relict quartz. Pyrophyllite may also occur in the most altered parts, close to the unconformity, and the proportions of precursor minerals, mainly quartz and feldspar, increase as the parent gneisses are approached. Trends in whole-rock elemental variations are consistent with a weathering hypothesis, and the present mineralogy reflects the burial of the saprolite subjected to conditions of anchimetamorphism. Palaeosols developed on both granitic and basaltic basement rocks, with ages ranging up to about 3.0 Ga, have been described from a number of areas throughout the world. In all these palaeosols, muscovite, usually referred to as sericite, is the dominant mineral. In northwest Ontario weathering of the granitic basement beneath the Steep Rock Lake Group has produced a rock almost identical to the Scottish agalmatolite and consisting of muscovite, of the form pinite, relict quartz, and rutile. From published descriptions of other palaeosols, we conclude that the term agalmatolite may be applied to most Precambrian palaeosols, as it conveys more information than terms such as argillite and saprolith that have previously been in use. Compared with the less well-exposed alteration profiles of older palaeosols, the clear field relationships of agalmatolite in northwest Scotland allow more confidence to be placed on interpretations that such alteration profiles have been caused by surficial weathering, with subsequent changes due to burial and even low-grade metamorphism.

Learning juggling skills during brief interludes in long classes has been used to refresh students and increase concentration on difficult intellectual tasks. The coursework required students to visualize angular relationships of planes and lines in three dimensions from a two dimensional representation known as a spherical projection. Students commonly find it a difficult, and often frustrating, concept to grasp. By practicing juggling during a ten-minute break after two hours of a three-hour laboratory class, the students were able to clear their minds and improve their circulation, concentration, resistance to distraction, and motivation. The primary aim was not to learn to juggle, but rather to reflect on how one acquires a new skill, how one copes with setbacks, and how small successes enhance motivation.

Synopsis Agalmatolite is a term used to describe a soft waxy rock amenable to carving composed of massive, felted muscovite with very minor quartz and feldspar. The term is derived from αγαλμα meaning sculpture or statue. The occurrence of agalmatolite was recognised, during the initial geological survey of the NW Highlands, as resulting from a “peculiar Precambrian weathering of the Lewisian” which occurs beneath the Cambrian unconformity. We have examined the effects of this weathering on the Lewisian gneisses in a zone of alteration extending two to three metres below the Cambrian unconformity on the west side of Loch Eriboll on the north coast of Scotland. The mafic minerals, a large proportion of feldspar and even some quartz have been altered to a green muscovite in what we take to be a palaeosaprolite resulting from alkaline weathering. We imagine a loose Precambrian quartz-rich soil being river-borne a short distance to the Dalradian basin or reworked to form the Eriboll Sandstones, a supposition strongly supported by the intermittent development of discontinuous layers of green micaceous shale in the Eriboll Sandstone reminiscent in colour and composition of the agalmatolite. The alumina dissolved from the Lewisian is transported as a colloid or in solution in groundwater to the sea where it reacts with dissolved silica and K + , Na + or Ba ++ to form huge bodies of authigenic or hydrothermal-sedimentary feldspar now preserved in the Fucoid Beds and in the Middle Dalradian.

An appreciation of how structures form in deformed rock is greatly aided by appropriate model analogues. We describe the method of construction and use of a device to simulate structures produced in fault zones of dominantly strike-slip motion. Simple modifications to the apparatus allow simulation of transtension and transpression as well as pure strike-slip fault motion. The structures which develop in the models include both synthetic and antithetic Riedel shears, en echelon folds and extension cracks. Numerous natural examples are illustrated in the literature from strike-slip zones around the world. We illustrate the formation of these structures using the apparatus and compare them with natural examples.

At Miéville, in the Aiguilles-Rouges Massif, granitic rocks of the basement are deformed into mylonites within a major subvertical shear zone. The ambient temperature during translation is estimated at 250° C±30° C from fluid inclusion filling temperatures in syntectonic microveins, from Δ18O quartzilmenite of+15%, and from mineralogical criteria. Porphyroclasts of both oligoclase and orthoclase feldspar decrease from initial diameters of 20 mm and assume elliptical shapes during progressive deformation, due to recrystallisation of the margins to ultra-fine polygonal grains which extend out from the porphyroclasts in thin trails: the final stable grain size is <5 μ. The recrystallised feldspar has a composition of the parent porphyroclast,+albite, requiring relative gains of Na and losses of K+Ca compared to the precursor, and implying short range redistribution of the components during deformation. Decrease of free energy associated with the deformation catalysed change in feldspar composition, coupled with stored strain energy in the porphyroclasts may account for recrystallisation to a stable aggregate of ultrafine grain size. The long trails imply exceptionally high ductility, which, coupled with microstructural criteria, and admixture of quartz from neighbouring pure quartz aggregates by grain boundary sliding, is interpreted in terms of superplastic flow. Estimated temperatures of T/Tm≈0.2 for the inferred superplastic deformation is lower by a factor of 2 than previously recorded for this flow michanism in silicates. The feldspar and quartz probably accomodated grain boundary sliding by intercrystalline diffusion.

Comparison of observed microstructures and deduced physical parameters of natural deformations with those encountered in superplastic metals permits identification of superplastic behaviour in rocks. From microstructural evidence, superplastic flow of feldspar is inferred to have occurred in the deformation of a granite from Miéville, Aiguilles-Rouges massif, Switzerland. The original igneous orthoclase and oligoclase phenocrysts have both recrystallised to fine-grained albite which has deformed by superplastic flow. This change in crystal chemistry was associated with a large negative change in free energy, enabling recrystallised grains of a very small size to be stable under the prevailing conditions, thereby producing the pre-requisite conditions for superplastic behaviour.

Synopsis Using deformed Skolithos pipes as strain markers, a folded sequence of Pipe Rock quartzites in the Heilam Nappe at Loch Eriboll is shown to have deformed dominantly by flexural flow. However, elliptical pipe sections on bedding evince a pre-folding strain. Microstructures observed in the hinge zone imply deformation dominated by the intercrystalline diffusion mechanism, pressure solution. On the limbs microstructural evidence for dislocation creep has almost obliterated features associated with pressure solution. It is concluded that the quartzite sequence deformed by pressure solution during an initial phase of layer parallel shortening and subsequently, when buckling was initiated and fold amplification occurred, the mechanism switched to dislocation creep. It is argued that this change in mechanism is related to changes in strain rate.

Deformation of the crust is believed to occur dominantly by cataclasis at low temperatures and/or effective confining pressure, by pressure solution at intermediate temperatures, and by dislocation creep at high temperatures. Each flow mechanism gives rise to distinctive microscopic and small scale structures. Brittle deformation with grain fracture leading to a reduction of particle diameter is characteristic of cataclastic flow. Pressure solution produces grain shape fabrics by intercrystalline diffusion assisted by the presence of water. Grains may change shape at constant mass, or decrease in mass (and therefore in size) by long range diffusion: mass is then not locally conserved. Reduction of grain diameter leads to increased rates of deformation (strain softening). Distinctive spaced cleavage zones form by pressure solution in which mineral species are redistributed due to different rates of deformation: the displacement field is discontinuous and deformation non-isochemical. Tectonic veins associated with pressure solution structures probably form by local mass transport; thus brittle and ductile mechanical behaviour coexist. Dislocation creep produces grain shape fabrics by intracrystalline deformation. and may cause grain size reduction by subgrain formation and recrystallization. Preferred crystallogra-phic orientations can arise from dislocation glide. Mass is conserved and deformation is believed to be essentially isochemical. Small scale structures formed by dislocation creep are ductile, with a continuous displacement field.