(Table 1) Geochemistry of upper Paleocene and upper Eocene glass particles at DSDP Hole 80-549

Two ash horizons have been identified in Hole 549, one in the upper Paleocene (basal NP9), the other in the upper Eocene (NP18); both are mixed lithic crystal tuffs of rhyolitic composition. These tuffs are absent in Hole 550 owing to unconformities, but the basal Eocene (NP10) of Hole 550 includes a series of over 50 thin bentonite layers. Intermediate plagioclase associated with these bentonites indicates that the original ash was of basaltic to andesitic composition. The bentonites are absent in Hole 549, probably because of an unconformity, but they have been identified in Hole 401 (Leg 48, Bay of Biscay). Two of the pyroclastic phases can be matched with phases previously reported for the North Sea Basin. The bentonites of Site 550 are probably equivalent to the widespread "ash series" of northwestern Europe, which may therefore be regarded as being lower Eocene in terms of Martini's calcareous nannoplankton zonation.

Clay and silica minerals of ODP Site 123-765

Sediments recovered from Site 765 can be divided into seven mineral associations, based on differences in clay mineralogy. These clay mineral associations correlate with the lithologic units and reflect the rift-to-drift history of the passive Australian margin. In general, the Lower to mid-Cretaceous sediments represent altered volcanic material and detrital aluminosilicates that were deposited during the early formation of the Argo Basin. The predominant clay mineral is randomly interstratified illite/smectite (I/S) that contains less than 10% illite layers. The transformation of smectite to illite is suggested by an increase in the percentage of illite layers in the basal sediments (from <10% to 40%) that corresponds to the silica transformation of opal-CT to quartz. This mixed-layered illite/smectite has an average composition of (K0.14 Na0.29 C0.07)(Al0.88 Mg0.43 Fe0.61 Ti0.06)(Si3.88 Al0.12)(O)10(OH)2. The highly smectitic composition of the I/S and its association with bentonite layers and zeolite minerals suggest that much of the I/S was derived from the alteration of volcanic material. The condensed middle to Upper Cretaceous sediments consist of palygorskite and detrital I/S that contains 30% to 60% illite layers. The condensed Paleogene sediments contain no palygorskite and are dominated by detrital clay minerals or by highly smectitic I/S associated with bentonite layers and zeolite minerals. The overlying, rapidly deposited Neogene clayey calcareous turbidites consist of three distinct clay mineral associations. Middle Miocene sediments contain palygorskite, kaolinite, and a tentatively identified mixed-layered illite/smectite/chlorite (I/S/C) or saponite. Upper Miocene sediments contain abundant sepiolite and kaolinite and lesser amounts of detrital I/S. Detrital I/S and kaolinite dominate the clay mineralogy of Pliocene and Pleistocene sediments. The fibrous, magnesium-rich clay minerals sepiolite and palygorskite appear to be authigenic and occur intimately associated with authigenic dolomite. The magnesium required to form these Mg-rich minerals was supplied by diffusion from the overlying seawater, and silica was supplied by the dissolution of associated biogenic silica.

Counts and abundance of macrozoobenthic organisms settled in artificial soft sediment at Brandal, Kongsfjorden, Spitsbergen

In the Arctic the currently observed rising air temperature results in more frequent calving of icebergs. The latter are derived from tidewater glaciers. Arctic macrozoobenthic soft-sediment communities are considerably disturbed by direct hits and sediment reallocation caused by iceberg scouring. With the aim to describe the primary succession of macrozoobenthic communities following these events, scientific divers installed 28 terracotta containers in the soft-sediment off Brandal (Kongsfjorden, Svalbard, Norway) at 20 m water depth in 2002. The containers were filled with a bentonite-sand-mixture resembling the natural sediment. Samples were taken annually between 2003 and 2007. A shift from pioneering species (e.g. Cumacea: Lamprops fuscatus) towards more specialized taxa, as well as from surface-detritivores towards subsurface-detritivores was observed. This is typical for an ecological succession following the facilitation and inhibition succession model. Similarity between experimental and non-manipulated communities from 2003 was significantly highest after three years of succession. In the following years similarity decreased, probably due to elevated temperatures, which prevented the fjord-system from freezing. Some organisms numerically important in the non-manipulated community (e.g., the polychaete Dipolydora quadrilobata) did not colonies the substrate during the experiment. This suggests that the community had not fully matured within the first three years. Later, the settlement was probably impeded by consequences of warming temperatures. This demonstrates the long-lasting effects of severe disturbances on Arctic macrozoobenthic communities. Furthermore, environmental changes, such as rising temperatures coupled with enhanced food availability due to an increasing frequency of ice-free days per year, may have a stronger effect on succession than exposure time.

Mordenite from Spain and its application as pozzolana

In Spain, natural zeolites have been only found in the volcanic areas of Canary Islands (San Gil, M.M., 1959). However, several years ago the study of the South Eastern region of continental Spain (Cabo de Gata) revealed the presence of a deposit of mordenite being industrially commercialized as bentonite. The deposit San José-Los Escullos is located in the concession registered as Los Murcianos, managed by Bentonitas Especiales, S.A. (BENESA) who was extracting bentonite while ignoring the presence of the zeolite. The name San José-Los Escullos refers to the discovery of mordenite in this deposit. The deposit is located in a volcanic area, constituted by pyroxenic andesites, breccias, tuffs, pyroclasts with andesitic and dacitic composition, largely altered by the hydrothermal solutions. The recent discovery of this zeolite with mordenite content up to 97%, has changed the initial vision about that deposit, and new possible uses of this mineral in the pozzolanic cement industry are foreseen. This work intends to give preliminary data on the characterization of this zeolite according to X-ray diffraction (XRD), ICP analyses, and scanning electron microscopy (SEM), as well as to emphasize the pozzolanic properties of this material, using both chemical and mechanical tests.

Transporte hidráulico de misturas bentonita-água em condutos forçados

A argila bentonítica é amplamente utilizada em transporte de sólidos produzidos durante perfuração de poços. Teve por objetivo estudar o escoamento de misturas bentonita-água e determinar suas propriedades reológicas e parâmetros hidráulicos úteis nos projetos de instalações de recalque de misturas sólido-líquido. Foi montado um circuito fechado de tubulações para estudar dados de perda de carga e perfis de velocidade. Realizaram-se ensaios com misturas bentonita-água sob varias concentrações, algumas transportando areia. Observaram-se que a reologia da mistura bentonita-água é melhor descrita pela formulação de Herschell-Bulkley para fluidos não-Newtonianos. O coeficiente de atrito para descrever a perda de carga da mistura bentonita-água observada em tubulações no laboratório coloca-se entre as previsões de Tomita (1959) e Szilas et al (1981). A variação da velocidade da mistura na seção transversal do tubo é melhor aproximada pela equação de Bogue-Metzner (1963).

Propriedades mecânicas e térmicas de nanocompósito híbrido de polipropileno com adição de argila e celulose proveniente de papel descartado.

Este trabalho aborda o estudo do comportamento mecânico e térmico do nanocompósito híbrido de polipropileno com uma argila brasileira bentonítica do Estado da Paraíba (PB), conhecida como \"chocolate\" com concentração de 1, 2 e 5 % em massa com a adição de 1 e 2 % em massa de celulose proveniente de papel descartado. Foi utilizado nesse nanocompósito o agente compatibilizante polipropileno graftizado com anidrido maleico PP-g-AM com 3 % de concentração em massa, através da técnica de intercalação do fundido utilizando uma extrusora de dupla-rosca e, em seguida, os corpos de prova foram confeccionados em uma injetora. O comportamento mecânico foi avaliado pelos ensaios de tração, flexão e impacto. O comportamento térmico foi avaliado pelas técnicas de calorimetria exploratória diferencial (DSC) e termogravimetria (TGA). A morfologia dos nanocompósitos foi estudada pela técnica de microscopia eletrônica de varredura (MEV). A argila, a celulose e os nanocompósitos híbridos foram caracterizados por difração de raios X (DRX), fluorescência de raios X (FRX) e espectroscopia no infravermelho (FTIR). Nos ensaios mecânicos de tração houve um aumento de 11 % na tensão máxima em tração e 15 % no módulo de Young, para o nanocompósito com argila, PPA 5 %. No ensaio de impacto Izod, o nanocompósito com argila, PPA 2 % obteve um aumento de 63 % na resistência ao impacto. Para o nanocompósito híbrido PPAC 1 % houve aumento de 8 % na tensão máxima em tração e para o nanocompósito híbrido PPAC 2 % houve aumento de 14 % na resistência ao impacto.

Nanocompósito de poliestireno reciclado, bentonita sódica e hemi-hidrato de sulfato de cálcio: obtenção e caracterização.

Nesta Tese foram preparados, em solução, filmes híbridos de argila e poliestireno provenientes de copos descartáveis comercializados no mercado brasileiro, com acetato de etila e glicerol. Posteriormente, foi adicionado o Hemi-hidrato de sulfato de cálcio como carga de reforço. Tanto a argila quanto o glicerol, assim como o hemihidrato de sulfato de cálcio, foram utilizados nos percentuais relativos à massa do poliestireno fragmentado correspondendo a 1%,2%, 3%,4%, 5% e 7%. Dos filmes, nos percentuais 3, 4, 5 e 7, exclui-se o percentual de 4% e os demais foram fragmentados e submetidos a extrusão, com resfriamento natural, à seco, produzindo-se grãos com os quais foi avaliado o índice de fluidez e injetados para a moldagem de corpos de prova rígidos. O desempenho dos corpos rígidos, foi comparado com os resultados do HIPS 484, e o GPPS comercializados no mercado brasileiro. Os filmes foram caracterizados por difração de raios X, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), além dos testes de resistência à tração, fluorescência de raios X, EDS e FTIR. Amostra do filme, ultrafino, obtido a partir da solução com o percentual de 5% foi observada ao microscópio ótico e no microscópio eletrônico de transmissão, assim como amostras de corpos rígidos microtomizadas. Nos corpos rígidos, além das análises instrumentais citadas, foram avaliadas a resistência à flexão, modulo de flexão, resistência à tração, alongamento e resistência ao impacto Izod. O desempenho sob chama foi avaliado em amostras de filme e também do corpo rígido. Resultados do DRX, e da MET foram coerentes com a bibliografia para nanocompósitos argila-polímero e, associado às respostas dos demais ensaios, indicaram um material de boa qualidade morfológica e boas propriedades mecânicas comparadas ao HIPS 484 e ao GPPS. Sob a chama o material produzido apresentou maior resistência à queima avaliado pela quantidade aparente de material residual para um mesmo tempo sob fogo. Constatou-se, também, uma boa dispersão das cargas na matriz polimérica, assim como uma adequada interação entre os elementos orgânicos e inorgânicos do material, a delaminação parcial da argila e quebra da estrutura do hemi-hidrato. Isto resultou em um bom desempenho mecânico e térmico do compósito que pode ser atribuído, tanto a uma forte influência dos íons metálicos presentes nas cargas inorgânicas, quanto às adições presentes na formulação dos copos descartáveis.

Mineralogy and chemistry of bentonitic clays from the Wombat and Exmouth Plateaus

Bentonites (i.e., smectite-dominated, altered volcanic ash layers) were recovered in Berriasian to Valanginian hemipelagic sediments of the Wombat Plateau (Site 761) and southern Exmouth Plateau (Site 763). They are compared to coeval bentonites in eupelagic sediments of the adjacent Argo Abyssal Plain (Sites 261 and 765) and Gascoyne Abyssal Plain (Site 766). A volcaniclastic origin with dacitic to rhyolitic ash as parent material is suggested by the abundance of well-ordered montmorillonite, fresh to altered silicic glass shards, volcanogenic minerals (euhedral sanidine, apatite, and long-prismatic zircon), and volcanic rock fragments, and by a vitroclastic ultrafabric (smectitized glass shards). We distinguish (1) pure smectite bentonites with a white, pink, or light gray color, a waxy appearance, and a very homogeneous, cryptocrystalline smectite matrix (water-free composition at Site 761: 68.5% SiO2, 0.27% TiO2, 19.1% Al2O3, 3.3% Fe2O3, 0.4%-1.1% Na2O, and 0.6% K2O) and (2) impure bentonitic claystones containing mixtures of volcanogenic smectite and pyroclastic grains with terrigenous and pelagic components. The ash layers were progressively altered during diagenesis. Silicic glass was first hydrated, then slightly altered (etched with incipient smectite authigenesis), then moderately smectitized (with shard shape still intact), and finally completely homogenized to a pure smectite matrix without obvious relict structures. Euhedral clinoptilolite is the latest pore-filling or glass-replacing mineral, postdating smectite authigenesis. Volcanic activity was associated with continental breakup and rapid subsidence during the "juvenile ocean phase." Potential source areas for a Neocomian post-breakup volcanism include the Wombat Plateau, Joey and Roo rises, Scott Plateau, and Wallaby Plateau/Cape Range Fracture Zone. Westward-directed trade winds transported silicic ash from these volcanic source areas to the Exmouth Plateau into the adjacent abyssal plains. The Wombat Plateau bentonites are interpreted as proximal ash turbidites.

Geochemistry, minerals, color, rare earth elements and d18O at DSDP Hole 92-504B

Investigations of borehole waters sampled in Hole 504B during Leg 92 revealed changes in major-ion composition similar to changes observed previously (during Leg 83). The uniformity of chloride concentrations with increasing depth suggests efficient downhole mixing processes along density gradients caused by large temperature gradients. Chemical and mineralogical studies of suspended drilling mud (bentonite) suggest that this material has undergone substantial alteration and that CaSO4 (anhydrite/gypsum) has precipitated in the deeper parts of the hole. Rare earth element studies suggest contributions of both the bentonites and the basalts to the REE distributions. Studies of the isotopic composition (87Sr/86Sr) of dissolved strontium indicate a strong contribution of basaltic nonradiogenic strontium, although differences between the Leg 83 and Leg 92 data indicate an influence of bentonite during Leg 92. The oxygen isotope composition of the water does not change appreciably downhole. This uniformity can be understood in terms of high water-rock ratios and suggests that the chemical changes observed are due either to alteration processes involving bentonites and basaltic material from the walls of the hole or to exchange with formation fluids from the surrounding basement, which may have altered in composition at relatively high water-rock ratios.

Dam break wave of thixotropic fluid

Thixotropy is the characteristic of a fluid to form a gelled structure over time when it is not subjected to shearing, and to liquefy when agitated. Thixotropic fluids are commonly used in the construction industry (e.g., liquid concrete and drilling fluids), and related applications include some forms of mud flows and debris flows. This paper describes a basic study of dam break wave with thixotropic fluid. Theoretical considerations were developed based upon a kinematic wave approximation of the Saint-Venant equations down a prismatic sloping channel. A very simple thixotropic model, which predicts the basic theological trends of such fluids, was used. It describes the instantaneous state of fluid structure by a single parameter. The analytical solution of the basic flow motion and theology equations predicts three basic flow regimes depending upon the fluid properties and flow conditions, including the initial degree of jamming of the fluid (related to its time of restructuration at rest). These findings were successfully compared with systematic bentonite suspension experiments. The present work is the first theoretical analysis combining the basic principles of unsteady flow motion with a thixotropic fluid model and systematic laboratory experiments.

Development of an animal repellent - selection, efficacy and presentation

Under some circumstances it may be desirable to repel herbivorous pests (e. g. goats and wallabies) from plants (e. g. horticultural or forestry seedlings) rather than to kill them. These circumstances may include using these animals as a resource at a later time, and there may also be welfare, public perception or legislative issues where repelling animals from particular plants or area is preferable to killing them. The first experiment tested the efficacy of 5 different materials (tiger fecal extract, maggot brew-the liquid exudate from a flyblown goat, capsaicin, dog urine, and burnt goat hair, skin and carcass+fat) to repel groups of goats in a feedlot pen from 1 trough of feed when another trough of feed was available to them to eat. Each repellent was tested on 5 groups of mixed age female goats for periods of 3 days. All 5 groups were exposed to the 5 repellents. Both tiger fecal extract and maggot brew reduced intake of feed from the 'protected' feed trough and significantly (P < 0.05) delayed 'normal' feeding behaviour by more than 5 h from that trough. The repellents became less effective with repeated use even with different groups of goats. The reduction in effectiveness was indicated by higher intakes of feed and earlier feeding from the protected trough. This habituation to the repellents, where the effectiveness is reduced with repeated exposure, is of concern. In the second experiment, we selected the most effective repellent (tiger fecal extract) and tested its efficacy under similar conditions, after the repellent had been mixed with a carrier (bentonite) in an endeavour to increase the duration of its effectiveness. This repellent was significantly more effective in repelling groups of 3 goats in a feedlot pen from 1 trough of feed for 3 days, when another trough of feed was available to them to eat.

The effect of organic mulch amendments on the physical and chemical properties and revegetation success of a saline-sodic minespoil from central Queensland, Australia

Saline-sodic clay minespoil materials excavated during open-cut coal mining in central Queensland, Australia, pose significant challenges for revegetation, particularly where suitable topsoil capping is not available. We examined the ability of sawdust or straw mulch amendments to ameliorate the adverse properties of these minespoils and improve the success of revegetation efforts. In laboratory studies, mulch application improved infiltration, increased soil moisture retention and reduced surface crust strength. In the field, mulches incorporated to a depth of 0.15 m at application rates of at least 20 t/ha straw or 80 t/ha sawdust were needed to mitigate against capillary rise of salts during drying cycles and support satisfactory vegetation cover. Further research is needed to determine whether improvements are maintained beyond the 4-year trial period reported here.

Chemical and physical characterization of clay bodies

Suitable methods for the assessment of the effect of freeze-thaw action upon ceramic tiles have been determined. The results obtained have been shown to be reproducible with some work in this area still warranted. The analysis of Whichford Potteries clays via a variety of analytical techniques has shown them to be a complex mix of both clay and non-clay minerals. 57Fe Mössbauer spectroscopy has highlighted the presence of both small and large particleα-Fe203, removable via acid washing. 19F MAS NMR has demonstrated that the raw Whichford Pottery clays examined have negligible fluorine content. This is unlikely to be detrimental to ceramic wares during the heating process. A unique technique was used for the identification of fluorine in solid-state systems. The exchange of various cations into Wyoming Bentonite clay by microwave methodology did not show the appearance of five co-ordinate aluminium when examined by 27Al MAS NMR. The appearance of Qo silicate was linked to an increase in the amount of tetrahedrally bound aluminium in the silicate framework. This is formed as a result of the heating process. The analysis of two Chinese clays and two Chinese clay raw materials has highlighted a possible link between the two. These have also been shown to be a mix of both clay and non-clay minerals. Layered double hydroxides formed by conventional and microwave methods exhibited interesting characteristics. The main differences between the samples examined were not found to be solely attributable to the differences between microwave and conventional methods but more attributable to different experimental conditions used.

Chemical modification of smectite clays

Today, speciality use organoclays are being developed for an increasingly large number of specific applications. Many of these, including use in cosmetics, polishes, greases and paints, require that the material be free from abrasive impurities so that the product retains a smooth `feel'. The traditional `wet' method preparation of organoclays inherently removes abrasives naturally present in the parent mineral clay, but it is time-consuming and expensive. The primary objective of this thesis was to explore the alternative `dry' method (which is both quicker and cheaper but which provides no refining of the parent clay) as a process, and to examine the nature of the organoclays produced, for the production of a wide range of commercially usable organophilic clays in a facile way. Natural Wyoming bentonite contains two quite different types of silicate surface (that of the clay mineral montmorillonite and that of a quartz impurity) that may interact with the cationic surfactant added in the `dry' process production of organoclays. However, it is oil shale, and not the quartz, that is chiefly responsible for the abrasive nature of the material, although air refinement in combination with the controlled milling of the bentonite as a pretreatment may offer a route to its removal. Ion exchange of Wyoming bentonite with a long chain quaternary ammonium salt using the `dry' process affords a partially exchanged, 69-78%, organoclay, with a monolayer formation of ammonium ions in the interlayer. Excess ion pairs are sorbed on the silicate surfaces of both the clay mineral and the quartz impurity phases. Such surface sorption is enhanced by the presence of very finely divided, super paramagnetic, Fe2O3 or Fe(O)(OH) contaminating the surfaces of the major mineral components. The sorbed material is labile to washing, and induces a measurable shielding of the 29Si nuclei in both clay and quartz phases in the MAS NMR experiment, due to an anisotropic magnetic susceptibility effect. XRD data for humidified samples reveal the interlamellar regions to be strongly hydrophobic, with the by-product sodium chloride being expelled to the external surfaces. Many organic cations will exchange onto a clay. The tetracationic cyclophane, and multipurpose receptor, cyclobis(paraquat-p-phenylene) undergoes ion exchange onto Wyoming bentonite to form a pillared clay with a very regular gallery height. The major plane of the cyclophane is normal to the silicate surfaces, thus allowing the cavity to remain available for complexation. A series of group VI substituted o-dimethoxybenzenes were introduced, and shown to participate in host/guest interactions with the cyclophane. Evidence is given which suggests that the binding of the host structure to a clay substrate offers advantages, not only of transportability and usability but of stability, to the charge-transfer complex which may prove useful in a variety of commercial applications. The fundamental relationship between particle size, cation exchange capacity and chemical composition of clays was also examined. For Wyoming bentonite the extent of isomorphous substitution increases with decreasing particle size, causing the CEC to similarly increase, although the isomorphous substitution site: edge site ratio remains invarient throughout the particle size range studied.

Multi-media filtration for removal of petroleum contamination

A pilot scale multi-media filtration system was used to evaluate the effectiveness of filtration in removing petroleum hydrocarbons from a source water contaminated with diesel fuel. Source water was artificially prepared by mixing bentonite clay and tap water to produce a turbidity range of 10-15 NTU. Diesel fuel concentrations of 150 ppm or 750 ppm were used to contaminate the source water. The coagulants used included Cat Floc K-10 and Cat Floc T-2. The experimental phase was conducted under direct filtration conditions at constant head and constant rate filtration at 8.0 gpm. Filtration experiments were run until the filter reached its clogging point as noted by a measured peak pressure loss of 10 psi. The experimental variables include type of coagulant, oil concentration and source water. Filtration results were evaluated based on turbidity removal and petroleum hydrocarbon (PHC) removal efficiency as measured by gas chromatography. Experiments indicated that clogging was controlled by the clay loading on the filter and that inadequate destabilization of the contaminated water by the coagulant limited the PHC removal. ^