936116 Composite magnetic anisotropy fabrics: experiments, numerical models, and implications for the quantification of rock fabrics

347A 936112 Factors influencing the transport and fate of contaminants in the subsurface Brusseau, M L J Hazard Mater V32, N2/3, Dec 1992, P137-143 A brief review of the present state of knowledge of transport of contaminants in the subsurface is first presented. Factors causing transport to be non-ideal are introduced: nonlinear sorption, irreversible sorption, non-equilibrium sorption, sorption capacity variation, facilitated transport, and hydraulic conductivity variation. Only solution-phase processes are considered in this case. Available models which can accommodate multifactor non-ideality are discussed.

936113 Strain and magnetic remanence Borradaile, G J J Struct Geol V15, N3-5, March-May 1993, P383-390 Specimens of limestone, sandstone, and Portland cement containing haemetite or magnetite were deformed in a triaxial rig under controlled conditions and relations between strain and magnetic remanence studied. Three theoretical models have been used to analyse the experimental data. Using Wettstein's equation, excellent agreement with passive line theory of magnetic remanence rotation is obtained within the strain range applied.

936114 Magnetic hysteresis of limestones: facies control? Borradaile, G J; Chow, N; Werner, T Phys Earth Planet Inter V76, N3/4, March 1993, P241-252 Samples of non-red, non-metamorphosed limestones of age from Proterozoic to Recent were collected from 92 sites. Laboratory data indicate remanence is carried by magnetite in pseudo single domain (PSD) or small multidomain (MD) size. Definite association of rock magnetic characteristics with sedimentary facies was found. Results suggest pelagic limestones are paramagnetic as a result of detrital clay contamination and have larger PSD size of magnetite, which may imply a lesser suitability for carrying stable remanence. Comparatively few samples had sufficient SD or superparamagnetic magnetite, usually suspected to be of biogenic origin, to dominate their ferromagnetic response.

936115 Physico-chemical effect on compressibility of tropical soils. Technical note Sridharan, A; Rao, S M; Murthy, N S Soils Found V32, N4, Dec 1992, P156-163 Residual montmoriilonite and kaolinite clay soils from India have been examined. Liquid limit, equilibrium void ratio, and compression index of the kaolinitic soils correlated well with shrinkage limit values, which in turn are related to clay fabric. The corresponding properties of the montmorillonitic soils correlated well with exchangeable sodium content. On wetting at nominal pressures, the kaolinitic soils showed no volume change, montmorillonitic soils considerable swelling. In situ moisture content, density, and degree of saturation also influence the void ratio sustained at a given stress level.

936116 Composite magnetic anisotropy fabrics: experiments, numerical models, and implications for the quantification of rock fabrics Housen, B A; Richter, C; van der Pluijm, B A Tectonophysics 1/220, N1/4, April 1993, P1-12 The magnetic anisotropy ellipsoids of multi-mineral rocks may arise from addition of two or more component fabrics. Numerical modelling and laboratory experiments with epoxy/magnetite disks demonstrate that these composite magnetic fabrics do not directly reflect the shapes and/or orientations of individual fabrics. Criteria for recognition and interpretation of composite fabrics in natural rocks are presented. Magnetic fabrics have been modelled for shales and slates of the Martinsburg Formation, Pennsylvania. 936117 In-situ determination of air permeability and diffusion properties of helium in sedimentary iron ore Pahl, A; Liedtke, L Proc 3rd International Symposium on Field Measurements in Geomechanics, Oslo, 9-11 September 1991 V2, P595-602. Publ Rotterdam: A A Balkema, 1991 To evaluate the gastightness of chamber seals at the proposed low level waste repository in the disused Konrad iron ore mine, it was necessary to examine the air permeability and diffusion properties of the coral oolite host rock. Two 15m long parallel boreholes, 1.5m apart, were drilled at depth about 1000m. Air permeability was measured at lm intervals to assess the influence of the loosened zone round the drift. Cross-borehole helium leakage tests were used to provide the basis for material transport calculations. 936118 Consolidation of a deep homogeneous clay stratum subjected to a surface temperature change Savvidou, C; Booker, J R Proc Ninth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Bangkok, 9-13 December 1991 V1, P425-429. Publ Thailand: Southeast Asian Geotechnical Society, 1991 If an element of a saturated soil is heated, temperature of both the soil skeleton and pore fluid will change. A closed form solution is developed to describe the effects of heating on a deep stratum of fine grained soil. Heat transfer by conduction alone and pore fluid transport coupled with temperature are assumed. The solution gives predictions in satisfactory agreement with experimental data. High pore pressures are generated close to the surface but dissipate fairly quickly. Both pore pressure changes and surface movements are more severe in less permeable materials. 936119 Geochemical modeling of water-rock interaction: past, present, future Plummer, L N Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 V1, P23-33. Publ Rotterdam: A A Balkema, 1992 Geochemical modelling has advanced over the past 30 years through application of chemical thermodynamics to geochemical systems. Computer codes are now available to assist modelling over a wide range of conditions. Inverse modelling, using water and rock compositions to predict geochemical reactions, and forward modelling, using hypothesised geochemical reactions to predict rock and water composition, are

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