ALBERT

Description / Table of Contents: Contents: Part One: Fundamentals of Soil Formation and Properties of Soils ; 1. Principles of soil formation ; 2. Mineral part of soil and its origin ; 3. Soil physics ; 4. Soil chemistry ; 5. Physical chemistry of soils ; 6. Soil biochemistry ; 7. Elementary processes of soil formation ; Part Two: Natural Factors of Soil Evolution ; 8. Rocks and soil formation ; 9. The relationship between weathering and soil-forming processes under tropical conditions ; 10. Biological factors of soil formation ; 11. Climate and soil formation ; 12. Soil formation as a function of relief and soil age ; Part Three: Classification and Characteristics of Main Soil Types ; 13. Fundamentals of soil classification ; 14. Experience in grouping the soils in the tropics and subtropics ; 15. Siallitic neutral-alkaline soils ; 16. Allitic (ferrallitic) soils ; 17. Podzolic ferrallitic tropical soils ; 18. Yellow quartz-allitic soils ; 19. Red ferritic soils ; 20. Volcanic soils (Andosols) ; 21. Hydromorphic soils (Gleysols) ; 22. Saline (Halomorphic) soils ; 23. Alluvial soils ; 24. Problems of soil conservation ; 25. Problems of soil fertility improvement ; 26. Soil cartography and its practical importance

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Analytical procedures. - Results and discussion. - Bubbles in ice. - Conclusions. - Literature cited.

Description / Table of Contents: Application of the gas law to fourth-place density measurements of ice samples from two deep drill holes at Byrd Station and Little America V, Antarctica, shows that virtually all density increase beyond the pore close-off density (0.830 g/cm^3) can be attributed to compression of the entrapped bubbles of air. Data from Byrd Station also indicate that the lag between overburden pressure and bubble pressure, initially 4-5 kg/cm^2 at pore close-off, diminishes to less than 1.0 kg/cm^2 at about 200-m depth. By substituting the overburden pressure for the bubble pressure in the pressure-density relationship based on the gas law, ice densities below 200 m can be calculated more accurately than they can be measured per se on cores because of the relaxation that occurs in samples recovered from high confining pressures. This relaxation, resulting in a progressive increase in the bulk volume of the ice with time, is generally attributed to decompression of the entrapped air bubbles following removal of the ice from high confining pressures. However, calculations of the stress in ice due to bubble pressure, together with measurements of bubble sizes in cores from various depths at Byrd Station, both tend to indicate that there has'been negligible decompression of the inclosed bubbles. It is suggested that most of this relaxation may be due to the formation of microcracks in the ice. Anomalous bubble pressure-density relations at Little America V tend to confirm abundant stratigraphic evidence of the existence of considerable deformation in the upper part of the Ross Ice Shelf. Studies of crystal-bubble relations at Byrd Station revealed that the concentration of bubbles in ice remains remarkably constant at approximately 220 bubbles per cm^3. Bubbles and crystals were found to be present in approximately equal numbers at pore close-off at 64-m depth, at which level the average bubble diameter was 0.95 mm, decreasing to 0.49 mm at 116 m and to 0.33 mm at 279 m. Despite a tenfold increase in the size of crystals between 64 and 279 m, the bubbles showed no tendency to migrate to grain boundaries during recrystallization of the ice. The observation that most of the bubbles had assumed substantially spherical shapes by 120-m depth points to essentially hydrostatic conditions in the upper layers of the ice sheet at Byrd Station.

Description / Table of Contents: CONTENTS: Introduction. - Test site. - Test procedures. - Equipment. - Unconfined compression tests. - Ring tensile tests. - Test results. - Unconfined compression tests. - Ring tensile tests. - Discussion. - Literature cited. - Appendix A. Calculation of the effect of nonaxial loading of unconfined compression specimens. - Appendix B. Camp Century unconfined compressive strength data at -25C. - Appendix C. Camp Century ring-tensile strength data at -25C. - Appendix D. Unconfined compressive strength of Camp Century vertical snow samples 8.25 in. length, 3.0 in. diam at -25C. - Abstract.

Description / Table of Contents: The unconfined compressive strengths [Sigma]c and the ring-tensile strengths [Sigma]T of snow and ice specimens from the Inclined Drift at Camp Century, Greenland, were determined. The specimen densities varied over essentially the complete natural density range of polar snow and ice (0.340 to 0.890 g/cm^3). The specimens were loaded rapidly to failure with times varying between 0.2 and 1.4 sec. During loading, head speeds varied between 5.1 and 23.6 cm/min, although during individual tests they were constant. Even the low density specimens failed in the brittle mode. Although a plot of [Sigma]T vs [Gamma] is linear, [Sigma]c vs [Gamma] is clearly nonlinear. This nonlinearity may result from either changes in the level of the internal stress concentrations associated with the voids in the snow or from changes in the ratio (bulk porosity/effective porosity of the failure surface) with density. Both tangent and secant moduli are linear functions of [Gamma]. There is no pronounced change in [Sigma]c with changes in strain rate. A significant increase in [Sigma]T, [Sigma]c and the modulus values was noted at bulk densities greater than 0.830 g/cm^3. This increase is presumably caused by the close-off of the air passages.

Description / Table of Contents: CONTENTS: Preface. - List of symbols. - Introduction. - Structure of ice and ice sheets. - Ice as a mineral. - Lake and sea ice. - Chemistry and phase relations. - Dislocations,cracks,and stress concentrators. - Direct observation of dislocations. - Crackformation. - Stress concentration. - Theoretical considerations. - Experimental results. - Compressive strength. - Indentation failure. - Tensile strength. - Flexural strength. - Shear strength. - Impact strength. - Scale effects. - Strength deterioration in the spring. - Recommended research. - Summary. - Selected bibliography. - Abstract.

Description / Table of Contents: The increased activity in cold regions has made a thorough understanding of fracture in lake and sea ice quite desirable, inasmuch as this information has application to a number of problems of geophysical as well as engineering importance. This survey starts with a discussion of the structure of ice I and the macro- and microstructure of sea and lake ice as well as their chemistry and phase relations. Recent work on the direct observation of dislocations as well as the formation of cracks in ice is summarized. Formal ice-brine-air models for analyzing variations in ice strength are also reviewed. The results of the different types of tests are discussed and cornpared (compressive, indentation, direct and ring-tension, small beam flexure and in situ cantilevers and simple beams, shear, and impact). Scale effects are considered as well as the rapid strength deterioration experienced by ice sheets in the spring. Finally, a number of recommendations are made concerning future research in this field.

Description / Table of Contents: CONTENTS: Introduction. - Regional variations in density. - Monthly increase in density. - Nomograph to estimate average snow-cover density. - Test and application of the nomograph. - Discussion. - Literature cited. - Appendix A: Observed, weighted snow-cover densities for stations in Table 1.

Description / Table of Contents: Analysis of snow-cover observations made during November - March at 27 stations in Alaska, Canada and the northern United States for a 2 to 11 year period showed that the average snow density can be classified in four general categories: Category 1 (density 0.20 to 0.23 g/cm^3 ), inland stations reporting light winds; Category 2 (0.24 to 0.27 g/cm^3), stations reporting moderate winds; Category 3 (0.28 to 0.30 g/cm^3), inland and coastal locations with stronger winds; Category 4 (0.32 to 0.36 g/cm^3), cold and windy stations of the Arctic. Skewness coefficients computed for each station showed bias toward lower densities for cat. 1 and 2, and bias toward higher densities for cat. 3 and 4. A nomograph in which the average winter air temperature and wind speed are the independent variables makes it possible to estimate the average snow-cover density for any location in the Arctic, subarctic and North Temperate Zones. A comparison between observed and estimated densities for ten other test stations yielded a correlation coefficient of 0.91 with a standard error of estimate of 0.016 g/cm^3. An average snow density map of North America was drawn and the continent was divided into areas based on the four categories.

Description / Table of Contents: CONTENTS: Introduction. - Previous work. - Conduct of the research. - Fundamental properties of snow. - Derived properties of snow. - Environmental effects. - Conclusions. - Literature cited. - Abstract.

Description / Table of Contents: One of the great deficiencies in snow science is the lack of an analytical framework for much of the snow cycle. Snow research to date has largely consisted of measuring index properties of snow, such as bulk density and snow strength, and correlating them. This is useful, particularly for engineering purposes, but it does not grapple with the basic problem of what fundamental properties of snow determine the magnitude of the index properties and how these properties respond to environmental conditions. This study was an attempt to measure, quantitatively, the fundamental properties of grain size, shape, and fabric (relationship between grains) and relate these to the index or derived properties of bulk density, shear and tensile strength, permeability for air, and the dielectric static permittivity and loss tangent. Despite numerous difficulties in defining fabric and quantifying it, it was possible to show that: 1) snow strength is a function of bond area with a relationship in the low density range that is described by: [Sigma]f = [Sigma]i exp - (0.14nf) where [Sigma]f is failure strength, [Sigma]i is the final strength of ice, and nf is the porosity on the failure surface; and 2) the rate of densification of low density snow can be explained in part by high stress concentrations (on the order of 10^7 dynes /cm^2) at intergranular contacts and by such factors as riming on crystals. The effect of the environmental factors of time, temperature, and gravitational stress is difficult to study in situ because they are not independent variables. However, it appears that their study is simplified when we study the fundamental properties of snow as opposed to index properties.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Analytical procedures. - Results and discussion. - Literature cited.

Description / Table of Contents: Conductivity measurements have been made on snow and ice samples from pits and deep drillholes at a number of localities in Antarctica and Greenland. Conductivities of the order 1-2 [My]mho/cm only were recorded at the inland sites. Data from deep cores representing more than 1900 years of continuous snow accumulation at Byrd Station, Antarctica, and more than 400 years deposition at Inge Lehmann, Greenland, showed no significant variations of conductivity with time. Measurements of freshly precipitated snow from a single coastal location in McMurdo Sound, Antarctica, also yielded relatively low conductivities of the order 3-4 [My]mho/cm. The substantial increase observed in the conductivity of core samples from near the surface of the Ross Ice Shelf at Little America V can be attributed most probably to windborne salts of marine origin that had accumulated on the surface after the snow was deposited. A peak conductivity of 49 [My]mho/cm was recorded in snow estimated to have been deposited within 20 km of the seaward edge of the Ross Ice Shelf and the maritime effect could still be detected in samples deposited more than 40 km from the ice front. For samples deposited at distances of greater than 200 km from the edge of the Ross Ice Shelf conductivities never exceeded 2 [My]mho/cm. The very low conductivities observed in ice cores from near the bottom of the Ross Ice Shelf confirm earlier conclusions based on detailed petrographic studies oi the cores that the 258-m-thick ice shelf at Little America V is composed entirely of glacial ice.

Description / Table of Contents: CONTENTS: Preface. - Introduction. - Previous work. - Study area. - Field procedures. - Results and discussion. - Conclusions. - Literature cited. - Abstract.

Description / Table of Contents: A modern ice-push ridge on the northwest shore of Gardner Lake in southeastern Connecticut is 0.6 - 1.2 m high and 1.2 - 3.1 m wide. In February and March 1967, the positions of survey stakes placed on the lake ice were measured periodically. During the same period, air and ice temperature and solar radiation intensity were also recorded. Analysis of the data supports the hypothesis that thermal expansion of the lake ice rather than wind action, was the principal cause of ice push. An ice temperature change of approximately 1°C/hr increase for 6 hr was sufficient to induce ice thrust. In a 30-day period, the average net shoreward movement of the surveyed area of the ice surface was 1.0 m. During the 1966-67 winter, approximately 14 m^3 of beach material was reworked and deposited, forming a discontinuous ice-push ridge along 260 m of shoreline.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Previous work on unsteady rectilinear motion of a sphere. - Experiments with a circular path. - Conclusion. - Literature cited. - Appendix A: Comparisons of the measured and calculated forces.

Description / Table of Contents: Forces on a sphere moving unsteadily along a circular path in a viscous fluid are measured, and it is found that within the experimental range the formula valid for rectilinear motion has to be modified to account for the curvature of the path.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Theory. - Discussion. - Conclusion. - Literature cited.

Description / Table of Contents: A diffusion equation is obtained that describes the mechanical dispersion of a dilute mixture of solid particles within an ice matrix that is undergoing deformation. It is shown that within the limits of time intervals and strain rates appropriate to the movement of glaciers and ice sheets the dispersal distance usually is no larger than a distance about one order of magnitude greater than the size of the particles themselves.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Description of the anemometer. - Temperature effects and their compensation. - Input-output relations. - Vibration isolation and compensation. - Wind tunnel tests. - Conclusions.

Description / Table of Contents: A triaxial semiconductor strain-gage anemometer measuring wind velocities in three directions and thereby also determining the direction of the wind was designed and subjected to many crucial tests under various conditions. It was found that the measurements were affected by temperature and vibrations. Temperature compensation in two directions was made and wind tunnel tests on an almost vibration-free platform were performed. The results show that this type of instrument can be successfully used to measure large-scale turbulences. Throughout this report, emphasis is placed on the compensation necessary for temperature and vibration effects and the determination of input-output relationships. It is concluded that it is possible to design a practical triaxial strain-gage anemometer with high-frequency response and high sensitivity and to measure wind velocities accurately with this type of instrument when temperature and vibration compensations are properly made.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Theory. - Application to ice sheets and ice shelves. - Summary. - Literature cited.

Description / Table of Contents: An analysis is made of the rate of bubble coalescence in a deforming ice mass. A total strain of at least 8 is required before appreciable coalescence occurs, The analysis has.been applied to deforming ice shelves and ice sheets. No appreciable coalescence is expected in ice shelves but coalescence should occur in ice sheets (or glaciers) if the shear strain rate at the bottom surface is of the order of 0.075/yr or larger. Measurements of bubble concentration are capable of setting limits on paleo-strain rates of the present ice sheets. Bubble migration down temperature gradients presents complications to the study of bubble coalescence.

Description / Table of Contents: CONTENTS: Preface. - Nomenclature. - Introduction. - Basic equations. - Constitutive relations. - Elastic region. - Plastic region. - Stability of the differential equation. - Stability of the difference equation. - Literature cited.

Description / Table of Contents: An analysis is made of the stability of difference approximation to one-dimensional shock wave propagation in elastic-plastic media. The necessary condition for stability is obtained.

Description / Table of Contents: The flow of a compressible fluid through a deep layer of a porous medium with non-uniform permeability was analyzed. The volumetric behavior of the fluid was described first by the perfect gas law, then by the van der Waal's equation of state. Darcy's law was assumed to be valid. For illustration, the model of air flowing through a deep bed of naturally compacted snow was used to carry out numerical computation. The permeability of snow was considered as a function of depth. The nonlinear partial differential equation obtained by combining the continuity equation with Darcy's law was solved by finite difference technique. A time dependent exponential decay boundary condition was used which included the step-rise constant boundary condition as a limiting case. Pressure distributions in the porous medium calculated from the assumption of ideal gas and van der Waal's gas were compared. The data were presented in dimensionless variables.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Theoretical considerations. - Method of canopy evaluation. - Application to forest problems. - Forest blowdown. - Radioactivity gradient. - Phenology. - Forest types and structure. - Distribution of leaves and canopy gaps. - Light quality. - Discussion and summary. - Literature cited.

Description / Table of Contents: A technique for evaluating forest canopies was developed based on the use of a divergent lens system to obtain hemispherical photographs of tree crowns. The photography was processed from 35 mm film and enlarged as a silhouette, and the light transmission was measured with a specially fabricated macrodensitometer. It is concluded that the amount of forest canopy can be expressed as canopy closure index (CCI) at a precision of approximately 5%. It is shown by application to a variety of problems in diverse geographical areas that this technique can be used for measuring both temporal and spatial changes in the canopy, for estimating the shade light climate, and for specifying the probability of target detection through a canopy. Data are presented to analyze changes caused by explosions, radioactivity, growing season, and vegetation types. The geometry of gaps in tree crowns is discussed and the nature of shade light quality under forests is illustrated.

Description / Table of Contents: CONTENTS: Preface. - Introduction. - Review of dielectric properties of soils and rocks. - Methods and measurements. - Introduction. - Dispersion. - Experimental procedures. - Introduction. - Apparatus. - Correction for stray fields. - Material. - Results. - The dielectric properties of Na-montmorillonite suspensions as a function of concentration. - The dielectric properties of K-montmorillonite water suspension. - Conclusions. - Outlook. - Literature cited.

Description / Table of Contents: The dielectric properties of Na- and K- montmorillonite suspensions with concentrations varying from 2.5% to 0.10% by weight were measured at 25°C in the frequency range of 50 Hz to 20 kHz. Effects of electrode polarization were minimized by using the same stainless steel electrodes at different interelectrode distances and a correction was applied to compensate for stray fields. This investigation establishes the fact that the high dielectric constants of clay suspensions at audio frequencies are real and not the result of electrode polarization. The polarization that determines the dispersion is an interfacial phenomenon between the ionic atmosphere and the negatively charged clay particle. The results of this study show that clay suspensions have the same dispersion as soil samples, indicating the probability that the dispersion of wet soils in the frequency range from 50 Hz to 20 kHz is similar for most soils. The actual value of the dielectric constant, however, cannot yet be predicted.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Theoretical background. - Experimental apparatus and procedures. - Results and discussion. - Conclusions. - Literature cited.

Description / Table of Contents: The transition in the mode of heat transfer from conduction to convection in a layer of water formed continuously by melting ice from below has been determined experimentally. This was accomplished by locating the inflection point on the curve relating the water-ice interface (or melting front) and time. Thus, the critical Rayleigh number, Rac, at which convective heat transfer started can be correlated empirically as a function of warm plate temperature, Ts, by Rac= 14,200 exp(-6.64 x 10^-2 Ts). This relation is valid for Ts varying from 7.72 to 25.50°C. The initial ice temperature T0 was varied from -4.8 to -22.00°C. The effect of T0 was found to be insignificant. Homogeneous, bubble-free ice was prepared and used in all the experiments.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction and statermnt of problem. - Solution of problem shown in Figure 3. - Solution of problem shown in Figure 4. - The negligibility of the effects of buoyancy and incompressibility of the sealed liquid. - Literature cited.

Description / Table of Contents: After a brief description of the circumstances which led to the investigation of the title problem and discussion of some related previous investigations, exact solutions are derived for a circular plate which seals an incompressible liquid, is clamped along the boundary and is subjected at an arbitrary point to a lateral concentrated force P. For the case when the plate is covered by a thin liquid layer the solution is obtained in closed form. When this liquid layer is absent, the solution is obtained as an infinite series. The paper concludes with a study of the range of the parameter ([Lambda] a) for which the effort of buoyancy is negligible upon the deflections and stresses in the plate.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Snow crystals in Greenland. - Microspherules. - Microspherules in snow and ice-fog crystals. - Concentration and radii of spherules. - Discussion and conclusions. - Literature cited.

Description / Table of Contents: Spherules found in snow crystals, ice-fog crystals, fallout particles, and fly ash were studied with an electron microscope using the electron diffraction method. The central part of the residues of 1004 specimens of natural snow crystals from Greenland, the United States, and Japan were examined; 14 spherules 0.1 to 1.5? in radius were found among them. The residues of 658 artificial ice-fog crystals formed from water vapor in flue gases of coal-burning electric power plants at Fairbanks, Alaska, were also examined; nine spherules were found. Spherules similar to those found in ice-fog residues were found in furnace-produced fly ash fallout at Fairbanks, Alaska. Electron and optical microscope examination of spherules found in Greenland snow reveals a size distribution of the form dN/d(log r) = Cr-ß where ß approximately 3. The properties of spherules and the mean mass of snow crystals from Greenland are described. The electron microscope study indicated that less than 0.7% of the 1004 snow crystals contained spherules of possible extraterrestrial origin, and that snow crystals are formed mainly on clay mineral particles by heterogeneous nucleation.

Description / Table of Contents: CONTENTS: Introduction. - Methods. - Results. - Ground and aerial photography. - Hemispherical photography. - Light quality. - Discussion. - Literature cited. - Abstract.

Description / Table of Contents: Aerial and ground photographs were taken over a 2-year period of sites in the El Verde rain forest to record the consistency of the vegetational patterns in untreated sites and the changes that occurred following gamma irradiation. Four emulsions were used: panchromatic infrared, false color transparency and color transparency. Densitometry was used to evaluate color film and the vegetation response to 3 months of radiation. The color emulsions provided the sharpest indication of damage to vegetation and the succession following treatment. Hemispherical photography of the canopy was evaluated in terms of a canopy cover index defined as percent of light passing through the negative in a 90-degree cone area. Control stations were remarkably constant in all photography, establishing the stability and slow natural changes in rain forest structure. Spectral light measurements within the forest confirmed the predominance of far red shade light. Compared to similar studies on the chronic irradiated forest at Brookhaven National Laboratory the El Verde results were less distinct.

Description / Table of Contents: The attenuation of visible light by falling snow was studied by making simultaneous attenuation measurements and snow concentration measurements. The attenuation coefficient was calculated from photometric measurements and from visual observations. Snow concentration in the air was evaluated by two methods: from Formvar replicas collected during the snowfall, and by mass accumulation of snow in collecting pans. The snowflakes were arbitrarily classified by crystal types according to their estimated fall velocity. It was found that the correlation between extinction coefficient (attenuation) and snow concentration was generally much higher by types than when all snowflakes were considered together regardless of crystal components and degree of riming. Two types, apparently improperly classified, displayed lower correlations than the overall group. When no fog is present during the snowfall, the experimental results coincide well with attenuation theory if a reasonable correction is applied to the values obtained in the measurement of snowflake diameters. Measurements of mass flux indicate that for a given intensity the attenuation caused by snow is an order of magnitude greater than that caused by the same mass flux of rain.

Description / Table of Contents: A 4-summer hydrologic record from a 1.6 km^2 drainage basin at Barrow, Alaska is analyzed. The watershed, a drained lake basin, is underlain by continuous permafrost within 0.3m of the tundra surface and is covered by ice-wedge polygons and numerous small shallow ponds. Considerable variations from the 20-yr means of summer climate (thaw period 88 days, precipitation 67 mm) are represented in the data: 1963 - cold, extremely wet; 1964 - cold, extremely dry; 1965 - cool, dry; 1966 - cool, wet. Runoff varied greatly from storm to storm, occurring primarily through and over the tundra mat and through an intricate system of polygonal troughs and ponds. As a result of the subdued coastal topography, varying areas (0.3 km^2 to 1.6 km^2) contribute to runoff from different storms. Analyses of hydrographs revealed: 1) lag times generally from 3 to 10 hr; 2) recession constants of about 50 hr, but occasionally as much as 160 hr; and 3) runoff from individual storms between 1 and 70%. About 5% of the thaw season precipitation normally runs off. Comparison of total thaw season precipitation between the U.S. Weather Bureau and a shielded gage located on the watershed indicated no major differences. If "trace" precipitation is considered, only 90% of the actual precipitation may be recorded. Pan evaporation for an average thaw season is about 160 mm and evapotranspiration which is essentially in balance with precipitation is about 60 mm. Conductivity of runoff water varied from 250 [My]mhos during sustained discharge to more than 500 [My]mhos during low flows in dry years. Precipitation chemistry showed no correlation with storm direction. Assuming all winter precipitation runs off, and the data are spatially and temporally representative, about 50% of the measured annual precipitation in this region runs off into the Arctic Ocean.

Description / Table of Contents: CONTENTS: Preface. - Abstract. - Introduction. - Physical properties of ice fog. - Mie scattering computations. - Results. - Literature cited.

Description / Table of Contents: Ice-fog crystals consisting of many spherical particles, and some hexagonal plates and columns, were observed at ambient temperatures of about -40°C in the Fairbanks, Alaska area during mid-winter. The concentrations and the size distributions of the ice-fog crystals were measured. The attenuation and backscattering of infrared radiation by ice-fog crystals were computed for optical wavelengths of 2.2[My], 2.7[My], 4.5[My], 5.75[My], 9.7[My] and 10.9[My] using the Mie theory. The minimum attenuation coefficients and backscattering functions of ice fog were found to be at 9.7[My] wavelength in the observed wavelengths. Optical attenuation coefficients and volume backscattering functions of water fogs were also computed using the Mie theory. The minimum attenuation coefficients and backscattering functions of water fog were found to be at 10.9[My] wavelength in the region of 2.2[My], 2.7[My], 4.5[My], 5.75[My], 9.7[My] and 10.9[My]. Both the attenuation coefficients and backscattering functions of ice fog are within the same order of magnitude as water fog for equivalent fog concentrations and wavelengths.

Description / Table of Contents: CONTENTS: Preface. - Summary. - Introduction. - Theory. - Discussion. - Literature cited.

Description / Table of Contents: Steady-state temperature profiles are calculated for the borehole drilled through the Greenland ice sheet at Camp Century. The profiles are found by modifying Robin's theory through the addition of several correction terms. One of these terms is the internal heating arising from creep deformation. The importance of this term was emphasized by Lliboutry. The new theoretical profiles do not differ appreciably from the profile derived from Robin's theory. The theoretical profiles do differ substantially from the Camp Century profile measured by Hansen. It is concluded that Hansen's observations are evidence that factors such as accumulation rate and the upper surface temperature are not in a long-term steady-state condition. Better agreement between theoretical and measured curves is obtained if it is assumed that the accumulation rate was about 40% smaller in the past and that the mean annual surface temperature varied by about 0.5°C over the past 1000 years.

Description / Table of Contents: This book provides a synthesis of Archaean and Proterozoic crustal evolution in the North Atlantic Region. There is particular reference to Proterozoic collisional tectonics. The main topics include: Archaean crustal growth; Proterozoic crustal growth; orogenic processes during the Proterozic; geochronology of Proterozoic tectono-thermal processes; and provenance of Proterozoic sediments.

Description / Table of Contents: Contents: Nonlinear hyperbolic systems in one space dimension.- Gas dynamics and reaction flows.- Finite Difference Schemes for one-dimensional systems.- The case of multidimensional systems.- An Introduction to Boundary conditions.

Description / Table of Contents: Microorganisms cause mineral precipitation and dissolution and control the distribution of elements in diverse environments at and below the surface of the Earth. Conversely, mineralogical and geochemical factors exert important controls on microbial evolution and the structure of microbial communities. This was the rationale for the Short Course on Geomicrobiology presented by the Mineralogical Society of America on October 18 and 19, 1997, at the Alta Peruvian Lodge in Alta, Utah. Minerals have been known and honored since humans realized their essential contributions to the "terra firma" and stone tools thrust our species on the path of cultural evolution. Microbes are the oldest living creatures, probably inhabiting at least a few salubrious environments on the earth as early as 3.8 billion years ago. At this moment in history we are only beginning to appreciate the intimate juxtaposition and interdependence of minerals and microbes. We have been nudged into this position by the realization that our earth is finite, and the recognition of many global environmental problems that minerals and microbes contribute to, both positively and negatively. In addition, our globe may not be the only site in the solar system where 'life' arose, or may persist. What all of these concerns enunciate is that we as scientists only dimly comprehend our own dynamic "terrestrial halls." This short course and volume have been generated with great enthusiasm for grasping as much as possible of the whole panorama of possibilities that involve both the inorganic and biologic realms . Over 3600 mineral species have been defined and their relationships to each other and the environments in which they form have been documented. This vast data base, collected over the past several hundred years and constantly added to and upgraded, is a monument to the research efforts of many geoscientists focused on the inorganic realm. Much of this data has come from investigators intrigued by the novelty, beauty, and versatility of minerals, direct expressions of the chemistry and physics of geologic processes. We are now adding a new dimension to questions of mineral formation, dissolution, and distribution: what were, are, and will be the contributions of microbes to these basic components of the environment. Microbes have also been known for hundreds of years. However, their small size (0.5 to 5 µm in diameter) and the difficulties associated with identifying a species unless it was grown in the laboratory (cultured), precluded thorough analysis. The advent of molecular biology has only recently made it possible to evaluate microbial evolutionary relatedness (phylogeny) and physiological diversity. These techniques are now being applied to study of microbial populations in natural environments. It is becoming very clear that the surface of Earth is populated by far more species of microbes than there are types of minerals. We are now exploring every portion of the globe and finding the relationships under the rubric "geomicrobiology." The ocean deeps are characterized by a diversity of microorganisms, including those associated with manganese nodules. The profusion and concentration of minerals created at ocean ridges and vents matches the variety of microorganisms, large animals, and plants there. The snowy tops of mountain ranges and glaciers of Antarctica harbor not just ice but whole bacterial communities whose cellular types and activities need elucidation. The equatorial jungles and the deserts, with their enormous diversity of ecological niches, further challenge us. The diversity of geographic, geologic, and biologic environments, including some contributed by humans (e.g. mines, air-conditioning equipment), can now also be explored in detail. Modern studies use protocols developed to preserve or measure in situ chemical and physical characteristics. Electron microscopes allow direct characterization of mineral and biological morphology and internal structures. Spectroscopic techniques permit complimentary chemical analysis, including determination of oxidation states, with very high spatial resolution. Other studies quantitatively measure isotopic abudances. These data serve to distinguish biologically mediated, or biologically controlled formation of the mineral from an abiotic process and mechanism. Each ecological niche requires accurate characterization of the mineralogic and biologic entities in order for us to begin to understand the range of dynamic relationships. We can pose many questions. Is the mineral only a substrate, or is its occurrence and stability impacted by microbiologic activity and metabolic requirements? Which minerals are of microbiological rather than inorganic origin and what are the mechanisms by which organisms dictate the morphology and structure of the solid phase formed? How do organic metabolic products bind metals and change their form and distribution, with implications for metal toxicity and geochemical cycles? How do inorganic reactions such as mineral dissolution and precipitation impact microbial populations through control of their physical and chemical environments? Clearly, new and excitingly research areas exist for all varieties of scientists. Although published by the Mineralogical Society of America, the authors of this volume include microbiologists, molecular biologists, biochemists, biophysicists, bioengineers as well as biomineralogists. Here, they bring together their respective expertise and perspectives to provide disciplinary and interdisciplinary background needed to define and further explore the topic of geomicrobiology. The volume is organized so as to first introduce the nature, diversity, and metabolic impact of microorganisms and the types of solid phases they interact with. This is followed by a discussion of processes that occur at cell surfaces, interfaces between microbes and minerals, and within cells, and the resulting mineral precipitation, dissolution, and changes in aqueous geochemistry. The volume concludes with a discussion of the carbon cycle over geologic time. In detail: Nealson and Stahl acquaint us with the basic properties of prokaryotes, including their size and structure. They define the types and ranges of microorganisms and their metabolisms and describe their impacts on some important biogeochemical cycles. Barns and Nierzwicki-Bauer document the phylogenetic relationships and evolution of microorganisms, begging some fundamental questions that might be now just beyond our grasp: What was the 'last common ancestor'? The physiology, biochemistry and ecology of hyperthermophilic, and the many diverse geologically important microbial species from the lithosphere and hydrosphere, as well as some of the techniques employed, are presented. Banfield and Hamers describe and integrate the processes acting on minerals and at surfaces relevant to microorganisms, examining the factors that control mineralogy, mineral forms, and the stability of phases. Surface properties and reaction rates for dissolution, precipitation, and growth of important classes of minerals are discussed. The possible role of mineral surfaces in formation of prebiotic molecules needed to explain the origin of life is examined. Little, Wagner and Lewandowski describe biofilms, an essential interface between microbes and minerals. They demonstrate that these membranes, with their unique morphological and structural attributes, are sites where much activity related to dissolution and/or formation of minerals takes place. Biology makes it possible to move molecules and elements against a gradient. Many questions regarding the transfer of elements from minerals to microbes at this important heterogeneous interface remain. Fortin, Ferris and Beveridge review surface-mediated mineral development by bacteria. Fresh or oceanic waters, anaerobic or aerobic environments provide discretely different ecologies, bacterial entities, and resulting mineralogies. It is obvious from this presentation that investigators have just scratched the surface of microbial mineralization processes. Bazlinski and Moskowitz review the magnetic biominerals and provide insights into the environmental and biological significance of these few tens of nanometer-sized mineral products. The magnetosome chemistry and biochemistry is probably the best understood of any biologically precipitated mineral. Their formation and unique properties underscore the roles these biomaterials play in the rock magnetic record and in geochemical cycles. Tebo, Ghiorse, van Waasbergen, Siering and Caspi contribute data on the roles of Mnminerals and Mn(II) oxidation in geologic environments. Their chapter encompasses molecular genetic and biochemical investigations. Manganese oxides and oxyhydroxides are notoriously difficult to identify and the crystal chemistry of these phases is a research effort on its own. The prospect of learning how microbes utilize the multiple oxidation states of Mn (2+, 3+ and 4+) as a source of energy sharpens the motivation for interdisciplinary study. Manganese is also known as a cofactor in the production and activation of the enzymes that digest large biomolecules that must be the source of the smaller molecular species and ultimately the building blocks of C, N, 0, H required by all species. How have the mechanisms identified in the bacterial systems been transferred up the phylogenetic tree to plants and humans? This is an expanding and intriguing area for further investigation. DeVrind-de Jong and de Vrind address silicate and carbonate deposition by algae (eukaryotic photosynthetic microorganisms). This chapter documents the mechanisms of biomineralization of diatoms and coccoliths. These abundant aquatic organisms are responsible for huge volumes of siliceous sediments and calcium carbonate deposits world wide. The implications of algal biomineralization for climatic variation throughout much of the Earth's history may be quite significant. Stone leads us though a quantitative approach to evaluating reactions between organic molecules and cations. He considers available extracellular organic ligands and the roles these play in uptake of metals. He documents the basic chemical speciation and complexation for several elements, making metal to metal comparisons. Remaining challenges involve coordinating the organic and inorganic results of biologic activity. Following the discussion of biomineralization and interactions between organic compounds and cations, Silver discusses the strategies microorganisms have evolved to deal with toxic metal concentrations in solution. Beyond the fundamental biological significance, this has important implications for understanding microbial populations in contaminated environments. The impact on the geochemical form (speciation) and distribution of elements is also discussed. Nordstrom and Southam summarize sulfide mineral oxidation and dissolution kinetics and devote considerable effort to describing the specific contributions of microorganisms, mostly bacteria. Despite the vast amount of accumulated information, many unanswered questions remain. Barker, Welch and Banfield address weathering of silicate minerals. This topic encompasses not only mineralogy but geomorphology, microbiology, and geochemistry. The necessary interdisciplinary mode of these investigations is highlighted by discussion of the role(s) of bacterial nutrition, groundwater chemistry, and biochemistry. There are obvious implications for hazardous waste storage, a currently daunting and politicized topic that requires predictions over thousands to millions of years. Finally, Des Marais treats the long term evolution of the carbon cycle, adopting a biogeochemical view. He discusses the sources, sinks and the transfer of the element over geologic time. Consideration of such a basic series of questions relating to the partitioning of carbon necessitate interdisciplinary crossovers. It is a fitting conclusion to a dialogue in progress.

Description / Table of Contents: Lithological, faunal, radiocarbon and amino acid data are presented for ten new occurences of in situ or redeposited pre-Holocene marine material in western Greenland, and further data on four previously described ones, bringing the total known occurences to 22 - 23. The new and older data suggest that this material dates from a number of periods of marine inundation from the Early to Late Quaternary, the exact number being uncertain. A succession of marine events are designated for two regions of western Greenland. From the occurence of the Chlamys islandica - Mytilus edulis faunal assemblage the subarctic West Greenland Current is considered to have existed during several of these marine events of different age.