Altered perthites from a weathered pegmatite in the Spruce Pine District, North Carolina, were characterized by electron microprobe as a K-rich microcline host with lesser Na-rich plagioclase having a lamellar morphology. Light-optical and transmission electron microscopy (TEM) show microtextural elements such as phase boundaries, holes and microfractures that could serve as potential nucleation sites for alteration to clay minerals.

The host microcline contains albite and pericline twinning textures that vary in character; the amount of each twinning type and/or the size of twin individuals changes on a μm scale. Plagioclase ranges from large lamellar vein and film albite (visible in the light microscope) to cryptoperthite whose size ranges from μm to perhaps 100 Å. The smallest-scale albite appears to be a late-stage phase of exsolution in which lamellae have nucleated heterogeneously on albite-twin composition planes in the microcline.

Alteration is concentrated in vein and film albite, especially along grain boundaries with microcline. Powder X-ray diffraction (XRD) patterns of intensely altered pegmatite show halloysite. Holes, microfractures, vein albite/host microcline boundaries and microcline/halloysite boundaries trend parallel to the traces of (010) and {110}, suggesting that these directions are pathways along which fluids migrate. Cleavage and microfractures occur along, and holes are bounded by, these directions. Holes are associated with dislocations and the latter are observed at feldspar/clay boundaries. Twin domains and cryptoperthitic albite are less susceptible to alteration than coarse lamellar albite and regions containing negative crystals and microfractures. However, microtextures in some areas containing halloysite suggest that once fluids penetrate the crystal, alteration may proceed preferentially in more strongly twinned regions.

The persistence of many seemingly metastable mineral assemblages in sediments and soils is commonly attributed to their sluggish transformation to the stable-phase assemblage. Although undoubtedly kinetics plays a major role, this study shows that thermodynamic factors, particularly surface energy, significantly influence the free energy. Enthalpies of formation of boehmite samples with variable surface area were derived using high-temperature oxide-melt calorimetry. The average surface enthalpy for all faces terminating boehmite particles was calculated at +0.52 ± 0.12 J/m2. This value represents the surface enthalpy for surfaces exposed to vacuum assuming that H2O adsorbed on the surface of boehmite is loosely bound. These results show that the enthalpy of formation of boehmite may vary by ≤8 kJ/mol as a function of particle size. An overview of published values of surface energies of gibbsite, γ-Al2O3, corundum, and the results here indicates that the hydrated phases (boehmite, gibbsite) have lower surface energies than the anhydrous phases (corundum, γ-Al2O3). Lower surface energies allow the hydrated phases to maintain high surface area, i.e., small particle size. Similar surface energies of boehmite and gibbsite suggest kinetic control favoring the crystallization of boehmite or gibbsite from aqueous solution. The enthalpy of formation of bulk boehmite from the elements was calculated at −994.0 ±1.1 kJ/mol. Combining this result with the data in existing thermodynamic databases, we confirm that bulk boehmite is metastable with respect to bulk diaspore at ambient conditions.

The epic, one of the oldest forms of poetic expression, came into being and evolved in time immemorial, long before the appearance of writing - the advent of which, while helping to fix oral traditions since the dawn of history, has at the same time sapped these traditions of their freshness. Not until methods of recording and reproduction were perfected was the oral epic restored to its full compass as a work of enduring dimensions.

A new, well-ordered, thermally robust ethylene glycol intercalate of kaolinite was formed by refluxing the dimethyl sulfoxide intercalate of kaolinite (Kao-DMSO) with dry ethylene glycol (EG). This new phase (Kao-EG 9.4 Å) which is characterized by a d001 of 9.4 Å is distinct from a previously reported ethylene glycol intercalated phase of kaolinite (Kao-EG 10.8 Å) which has a d001 of 10.8 Å. The characterization of these two phases was studied by XRD, NMR, FTIR, and TGA/DSC. It was found that the concentration of water in the ethylene glycol reaction media played a crucial role in governing which of the phases predominated. Water favored Kao-EG 10.8 Å formation, while anhydrous conditions favored the formation of Kao-EG 9.4 Å. It is hypothesized that Kao-EG 9.4 Å is a grafted phase resulting from the product of the condensation reaction between an aluminol group on the interlamenar surface of kaolinite and the alcohol group of ethylene glycol. Ethylene glycol units would be attached to the interlamellar surface of kaolinite via Al-O-C bonds. The Kao-EG 9.4 Å phase was found to be resistant to both thermal decomposition up to 330°C and also, once formed, in the absence of interlamellar water molecules, to decomposition by hydrolysis in refluxing water.

The gold decoration technique of electron microscopy was used to observe the microtopography of natural (001) surfaces of 1:1 regularly-interstratified mica/smectite minerals (expandable layer: 40–45%) collected from four different pyrophyllite deposits in Japan. The specimens are characterized by parallel growth steps of malformed, circular or polygonal forms with varying step separations. Many particles exhibit paired steps that seem to show spiral growth. Microtopographic observations suggest that the growth of regular interstratification (at least for the specimens investigated in this study) normally takes place by an interlacing of paired steps. If the height of a single step corresponds to that of a mica or a smectite layer, the particles are estimated to be normally 40–300 Å in thickness. If the particles on which a spiral center is observed are single crystals of interstratified mica and smectite, then some crystals investigated in this study are far thicker than fundamental particles. The results of this study are interpreted to suggest that these regularly-interstratified mica/smectites were formed by hydrothermal metasomatism from their respective host rocks.

First I think I should explain that call. It echoed in my ears for the first time a very long time ago and far, far away: on the Roof of the World, the Afghan Pamir, more than 30 years ago. It was uttered by a Kirghiz shepherd following a herd of sheep. Even if it is not in fact possible to transcribe that call accurately - the combination of the phonetic parameters that determine it would necessitate a representation using a graph or numerical matrices - I will attempt to give it a written shape, HAY, while admitting that this transcription denotes an abstraction that subsumes many possible realizations. But be that as it may. A few years later, when I was living in the Haut-Livradois, in the deepest heart of rural France, I was surprised to hear that call again on the lips of an Auvergnat peasant who was taking his sheep to the meadow. This unlikely coincidence led me to take a closer interest in the problem of communication between humans and animals. It is the essence of that thinking that I would today like to pass on to the readers of Diogenes in an issue devoted to the East/West contrast.

There is no plant that embodies the encounter between humans and plants better than the mandrake, whose myth, as Arlette Bouloumié writes, ‘has the cosmic sense of a profound correlation between nature and humanity and the possibility of their merging’. Zarcone presents a collection of extracts on this theme, under three main headings: (1) ancient documents in which legend and scholarship are mixed in varying degrees; (2) contemporary scholarly studies; and (3) literary texts.

Despite substantial scientific research efforts, accurate determination of the petrophysical effects of clay minerals on reservoir sands remains problematic. Diagenetic clays such as smectite and illite are of particular interest because of the pronounced effects these clays can have on reservoir quality. Here, results are reported from an experimental study based on the hydrothermal growth of smectite in synthetic sands. The sands contained quartz, dolomite and kaolinite, and were reacted at 175–200°C, for 19–45 d. The hydrothermal reaction can be written as follows:

$$dolomite + kaolinite + quartz \to smectite + calcite + CO<Subscript>2</Subscript>$$

Formation of kaolinite-smectite (K-S) mixed layers in a soil toposequence developed from basaltic parent material was examined. The soil formed in a temperate climate with alternating dry and wet seasons in Sardinia (Italy). Chemical composition and charge characteristics of the smectite component in the K-S mixed layers were analyzed to help determine a mechanism for formation. Soils were sampled at the top, intermediate, and base of a steep (35%) slope. As indicated by X-ray diffraction data, the fine clay fraction (>0.1 μm) in the soils is dominated by K-S with a decreasing proportion of kaolinite from the top (70%) to the base (30%). Rapid internal drainage induced by the slope is probably the major factor responsible for the formation of K-S. Chemical composition and charge characteristics of the smectite component in the K-S were analyzed by X-ray diffraction (intercalation with alkylammonium ions), cation exchanged capacity (CEC) and surface area measurements, and infrared spectroscopy. Results indicate that the smectite component is nearly identical over the soil toposequence. The smectite component is the same with respect to charge magnitude and chemical composition, independent of the proportion of kaolinite and smectite components. This suggests the pedogenic formation of K-S by transformation of smectite through dissolution of some smectite layers and subsequent crystallization of kaolinite between the layers of the remaining smectite crystallites.

For a long while the dilemma between ‘not being’ and ‘being other’ has haunted the history of Brazil. The country's mixed-race condition lay at the heart of the dilemma which reached its apogee in the second half of the nineteenth and the beginning of the twentieth centuries. At that point in its history, that is, its emergence as a nation-state, the construction of a national identity became an imperative for the political and intellectual elites of Brazil. In this context, a European, the German naturalist, Carl von Martius, made himself particularly notable for having been one of the first, after Independence, to point out the significance of miscegenation in the composition of Brazilian identity.

The Guise Cooperative, a project out carried in northern Paris by Jean-Baptiste André Godin (1817-88), who was inspired by the utopian ideas of Charles Fourier (1772-1837), put into practice a model that: (a) was politico-democratic in its self-management by the workers in a foundry; (b) was socio-economic in combining for the first time international competition and social benefits; (c) anticipated ecological arguments in developing industrialization processes; (d) embodied religious tolerance; (e) outlived the genuine socialism inspired by Marx. Godin's ‘Palais Social’ in Guise, still lived in today by around 300 descendants of the workers, was proclaimed a Human Heritage monument and handed over to the European Union in 1991.

The sorption of the uranyl oxo-cation (UO22+)at different types of binding sites on layer silicate mineral surfaces was investigated. Well-characterized samples of vermiculite and hydrobiotite were exposed to aqueous uranyl under conditions designed to promote surface sorption either at fixed charge ionexchange sites or at amphoteric surface hydroxyl sites. The local structure of uranium in the sorption samples was directly measured using uranium L3-edge extended X-ray absorption fine structure (EXAFS). Polarized L1- and L3-edge X-ray absorption near-edge structure (XANES) measurements were used to characterize the orientation of uranyl groups in layered samples. X-ray diffraction (XRD) measurements of interlayer spacings were used to assess the effects of ion-exchange and dehydration upon the mineral structure. The most significant findings are: (1) Under conditions which greatly favor ion-exchange sorption mechanisms, uranyl retains a symmetric local structure suggestive of an outer-sphere complex, with a preferred orientation of the uranyl axis parallel to the mineral layers; (2) Upon dehydration, the ionexchange complexes adopt a less symmetric structure, consistent with an inner-sphere complex, with less pronounced orientation of the uranyl axis; and (3) For conditions which favor sorption at surface hydroxyl sites, uranyl has a highly distorted equatorial shell, indicative of stronger equatorial ligation, and the detection of a neighboring U atom suggests the formation of surface precipitates and/or oligomeric complexes.

Nanomorphological structure of well-crystallized Georgia and poorly crystallized North Queensland kaolinite particles have been compared using field emission scanning electron microscopy (SEM) and atomic force microscopy (AFM). In general, there is good agreement in information from the 2 very different imaging techniques. AFM gives more detailed information on step and ledge dimensions, microvalleys and crystallographic orientation of irregularities on basal planes and edges of the crystallites. There are major differences in nanomorphology and surface structure between the 2 kaolin samples with the Georgia kaolin showing 200–500-nm, relatively flat basal planes with some cascade-like step growth 50–100 nm wide. The edges, apparently flat and right-angled in SEM images, appear beveled in AFM images due to artifacts from the aspect ratio of the AFM tip. The North Queensland kaolinite has much more complex surface structure with anhedral crystallites attached to larger particles, high density of steps and nm-scale irregularities (often crystallographically directed). The additional step edge site contribution from the attached crystallites is estimated as a minimum of 6%, giving a total edge contribution above 30% of the kaolinite total surface area. These structures will generate a substantial pH-dependent charge across the surfaces of the North Queensland kaolinite platelets. An idealized, uniform, pH-independent, negatively charged basal plane cannot be assumed from these structures. There is also some evidence, from both SEM and AFM images, of curvature in the thinner, poorly ordered structures of the North Queensland kaolinite particles.

The Lower Pleistocene bentonite deposits of Eastern Milos, Greece have been formed at the expense of volcaniclastic rocks under submarine conditions. Systematic variation of the major chemical elements reveals that the deposits were formed from different precursors which were erupted from different volcanic centers belonging to at least two separate volcanic provinces. The volcanic eruptions were probably subaqueous. The major authigenic phases are smectite, K-feldspar, opal-CT and the zeolites mordenite and clinoptilolite. The deposits have a complex history and have been affected by hydrothermal alteration.

The geological features of bentonites coupled by the presence of abundant authigenic K-feldspar indicate that alteration of the parent volcanoclastic rocks took place under low temperatures and is probably not related to hydrothermal alteration, which is a separate event. Hydrothermal alteration has modified both the mineralogical characteristics and the properties of bentonites. Alteration of the parent rocks to bentonites was favoured by high water: wall rock ratios and fluid flow and is associated with leaching and subsequent removal of Na, K and Ca. The source of Mg was the parent rocks and only small scale Mg-uptake from the sea water has probably taken place. The formation of authigenic K-feldspar has probably been favoured by a high K+/H+ activity ratio and high Si activity of the pore fluid. Such conditions might have been favoured by the pH conditions and the cooling history of the parent rocks.

The cation exchange capacities (CEC) and extractable cations in smectite, corrensite and palagonitized glass from hydrothermally-altered pillow lavas and hyaloclastite breccias were measured by both bulk wet chemical and in situ microanalytical techniques. Smectite has CEC's between 60 and 120 meq/100 g, palagonitized glass between 30 and 60 meq/100 g, and corrensite approximately 35 meq/100 g as determined by the in situ CsCl-exchange method. These experiments generally verify that Cs exchanges for those cations that are presumed (from the stoichiometry implied by microprobe analyses) to occupy interlayer sites in sheet silicates. Results of conventional CEC determinations are consistent with those determined by the in situ experiments: the individual microanalytical values for smectite and palagonitized glass bracket the bulk CEC values. The in situ experiments imply that Mg is the major extractable cation in smectite, Ca in corrensite, and both Mg and Ca in the palagonitized glass. We speculate that discrepancies between the equivalents of extractable cations predicted from elemental analysis and the equivalents of Cs sorbed may be due to the presence of charge-balancing protons that are not detected by the microprobe analyses. The sum of equivalents of cations extracted by NH4-acetate is about the same as the CEC determined by both the in situ and the bulk methods. Cation proportions indicated by NH4-acetate extractions from bulk samples are also generally consistent with the in situ results for all elements except Mg, which is a minor leachate of the NH4-acetate extractions in all the samples. To explain this discrepancy, we propose that 1) Mg may occupy structural sites within palagonitized glass, which inhibit its extraction by NH4 or Cs, and/or 2) there is a significant quantity of smectite, unsampled by the electron microprobe analyses, which contains insignificant interlayer Mg.

The Middle Proterozoic (1.1 Ga) Nonesuch Formation, host of the stratiform copper deposit at White Pine, Michigan, consists of 200 m of principally dark grey clastic sediments which contain detritus obtained dominantly from underlying mafic to intermediate volcanic rocks. Clay minerals from samples collected from the mine area and drill holes up to 100 km away have been studied using SEM, EMPA, TEM and AEM. Two morphologies of phyllosilicates, both including white mica and chlorite, occur in the ‘lower’ Nonesuch Formation: (1) detrital-shaped and (2) matrix. Detrital-shaped phyllosilicate grains are up to 450 microns long with long axes parallel to bedding. Matrix phyllosilicates occur as packets typically <200 Å thick and as pore-filling cement.

TEM images of detrital-shaped chlorite generally display 14-Å periodicity, although 24-Å corrensite- like units occur locally. Most detrital-shaped chlorite from the mine area samples have a relatively restricted range of Fe/(Mg+Fe) ratios from 0.52 to 0.58, but the Fe/(Fe+Mg) ratios of detrital-shaped chlorite outside the mine area range from 0.27 to 0.64. TiO2 crystals occur within and surrounding the detrital-shaped chlorite. Matrix chlorite has Fe/(Fe+Mg) ratios of 0.47 to 0.63, indicating that it is relatively homogeneous and enriched in Fe compared to detrital-shaped chlorite.

Detrital-shaped white mica occurs as a 2Mi polytype and generally has a phengitic composition. Matrix illite-rich I/S occurs as a 1Md polytype, is K and Al deficient relative to end-member muscovite and contains significant Fe and Mg.

The data are consistent with homogenization of detrital-shaped chlorite in the White Pine mine area by hydrothermal fluids during copper mineralization. The TiO2 crystals and corrensite-like units in detrital- shaped chlorite imply that it is at least in part derived from alteration of biotite. The presence of immature 1Md illite-rich I/S and a one layer chlorite polytype with stacking disorder suggests that the matrix clays are in their original, post-smectite state of formation as consistent with an authigenic origin during early burial diagenesis; i.e., they have not undergone subsequent transformation even though sedimentation and ore deposition occurred prior to 1 Ga.

Contrary to accepted ideas, questions of gender started to be raised around the end of the 19th century. The characters of problematic sex and sexuality who abounded in literature at that time had the function of emblems of the fears aroused by the erasure and divorce between the sexes in a civilization in disarray. The figure of the androgyne was used to name and depict those condemned to indecision. But its closeness to the invert led to the decline of the myth, which in the meantime was taken over by turn-of-the-century clinical medicine. Just like homosexuality, hermaphroditism became an anomaly, and those affected by it were depicted as deviant, incomplete beings. However, it was from the explosive superimposition of those two denigrated figures - the homosexual and the androgyne - that the concept of gender emerged in its true nature, that is, as a mental construction as much as an anatomical destiny.

Literary translation, especially poetic translation, is one of the rare domains where aesthetic, literary, and technical fields meet. This characteristic makes it the sort of work where a number of theoretical and practical problems converge. It is necessary to approach the issue on three essential planes. The first is theoretical: translation is an operation defined by rules; the second, functional: translation is a practical procedure, which is to say an a posteriori task; the third, specific: poetic translation is itself a poetic activity.

Let us begin with the last. From the point of view of literary creation, there is actually no specific difference between the original text and that of the translation. For poet and translator alike take part in a creative act, each laboring according to his means and tastes. For each of them linguistic competence and poetic competence are essential. Indeed, the act of translating is based on a “task of purification of words and ideas” which requires the application of mental effort on the one hand to the problems and the constraints of the poetic art as such, and on the other hand, to the descriptive and analytic nature of language, which is also music. Which is to say that one should not see translation as a simple operation of a lexical order. Nor should one forget that each language requires a specific lexical classification.