ALBERT

Description / Table of Contents: Geochemistry is a science that is based on an understanding of chemical processes in the earth. One of the principal tools available to the chemist for understanding systems at equilibrium is thermodynamics. The awareness and application of thermodynamic techniques has increased at a very fast pace in geosciences; in fact, one may be so bold as to say that thermodynamics in geology has reached the "mature" stage, although much future thermodynamic research is certainly needed. However, the natural processes in the earth are often sluggish enough that a particular system may not reach equilibrium. This observation is being supported constantly by new experimental and field data available to the geochemist e.g. the non-applicability of the phase rule in some assemblages, the compositional inhomogeneities of mineral grains, the partial reaction rims surrounding original minerals, the lack of isotopic equilibration or the absence of minerals (e.g. dolomite), which should be present according to thermodynamics. The need to apply kinetics has produced a large number of papers dealing with kinetics in geochemistry. As an initial response to this growing field, a conference on geochemical transport and kinetics was conducted at Airlie House, VA, in 1973, sponsored by the Carnegie Institution of Washington. The papers there dealt with several kinetic topics including diffusion, exsolution, metasomatism and metamorphic layering. Since 1973 the number of kinetic papers has continued to increase greatly. Therefore, the time is ripe for a Short Course in Kinetics, which brings together the fundamentals needed to explain field observations using kinetic data. It is hoped that this book may serve, not only as a reference for researchers dealing with the rates of geochemical processes, but also as a text in courses on geochemical kinetics. One of us has found this need of a text in teaching a graduate course on geochemical kinetics at Harvard and at Penn State during the past several years. Finally, it is our hope that the book may itself further even more research into the rates of geochemical processes and into the quantification of geochemical observations. The book is organized with a rough temperature gradient in mind, i.e. low temperature kinetics at the beginning and igneous kinetics at the end (no prejudices are intended with this scheme!). However, the topics in each chapter are general enough that they can be applied often to any geochemical domain: sedimentary, metamorphic or igneous. The theory of kinetics operates at two complementary levels: the phenomenological and the atomistic. The former relies on macroscopic variables (e.g. temperature or concentrations) to describe the rates of reactions or the rates of transport; the latter relates the rates to the basic forces operating between the particular atomic or molecular species of any system. This book deals with both descriptions of the kinetics of geochemical processes. Chapter one sets the framework for the phenomenological theory of reaction rates. If any geochemical reaction is to be described quantitatively, the rate law must be experimentally obtained in a kinetically sound manner and the reaction mechanism must be understood. This applies to heterogeneous fluid-rock reactions such as those occurring during metamorphism, hydrothermal alteration or weathering as well as to homogeneous reactions. Chapter 2 extends the theory to the global kinetics of geochemical cycles. This enables the kinetic concepts of stability and feedback to be applied to the cycling of elements in the many reservoirs of the earth. Chapter 3 applies the phenomenological treatment of chapter 1 to diagenesis and weathering. The rate of dissolution of minerals as well as the chemical evolution of pore waters are discussed. The atomistic basis of rates of reaction, transition state theory, is introduced in Chapter 4. Transition state theory can be applied to relate the rate constants of geochemical reactions to the atomic processes taking place. This includes not only homogeneous reactions but also reactions that occur at the surface of minerals. Chapter 5 discusses the theory of irreversible thermodynamics and its application to petrology. The use of the second law of thermodynamics along with the expressions for the rate of entropy production in a system have been used successfully since 1935 to describe kinetic phenomena. The chapter applies the concepts to the growth of minerals during metamorphism as well as to the formation of differentiated layers (banding) in petrology. Chapter 6 describes the phenomenological theory of diffusion both in aqueous solutions and in minerals. In particular, the multicomponent nature of diffusion and its consequence in natural systems is elaborated. Chapter 7 provides the atomistic basis for the rates of reactions in minerals. Understanding of the rates of diffusion, conduction, order-disorder reactions or exsolution in minerals depends on proper description of the defects in the various mineral structures. Chapter 8 provides the kinetic theory of crystal nucleation and growth. While many of the concepts in the chapter can be applied to aqueous systems, the emphasis is on igneous processes occurring during crystallization of a melt. To fully understand both the mineral composition as well as the texture of igneous rocks, the processes whereby new crystals form and grow must be quantified by using kinetic theory. Due to space and time limitations (kinetics!) some topics have not been covered in detail. In particular, the mathematical solution of diffusion or conduction equations is discussed very well by Crank in his book, Mathematics of Diffusion, and so is not covered to a great extent here. The treatment of fluid flow (e.g. convection) is also not covered in the text.

Description / Table of Contents: Es werden geometrische Eigenschaften der räumlichen Bahnkurven der durch die 2 - 10s - Mikroseismik verursachten Bodenschwingungen untersucht. Dabei ergeben sich für Stationen im Inneren des Kontinents ebene, polarisierte Schwingungen, deren Polarisation von der Wetterlage über dem Nordatlantik abhängt. Davon ausgehend wird ein neues Verfahren zur Erhöhung des seismischen Signal-Rausch-Verhältnisses (SNR) entwickelt. Eine Übersicht über das Quellenproblem der Mikroseismik schließt sich an.

Description / Table of Contents: The author has investigated geometrical quantities of the spatial particle orbits of 2 - 10s microseisms. For stations in the interior of the Continent these orbits are plane and polarized. The polarization depends on the weather situation over the Northern Atlantic. The paper presents a new method for signal-to-noise ratio augmentation, which is based on the found polarization phenomenon. A chapter follows on nature and sources of microseisms.

Description / Table of Contents: A new experimental method for measuring the soil-water diffusivity of frozen soil under isothermal conditions is introduced. The theoretical justification of the method is presented and the feasibility of the method is demonstrated by experiments conducted using marine-deposited clay. The measured values of the soil-water diffusivity are found comparable to reported experimental data.

Description / Table of Contents: Réalisation d'un modèle climatique simple tenant compte des principaux processus d'échanges énergétiques (le transfert radiatif est traité en ondes courtes et en ondes longues) dans l'atmosphère et permettant de restituer à l'équilibre les propriétés du profil de température. Un schéma de génération de la nébulosité (la génération de l'épaisseur optique est faite en distinguant 3 étages de nuages) est couplé à la procédure d'ajustement convectif, pour tenir compte de la réponse de la couverture nuageuse. Tests de sensibilité à la constante solaire et à la couverture nuageuse. Attention particulière accordée à la sensibilité de la température et du bilan radiatif de surface à une augmentation de la concentration en CO2. Il serait intéressant de poursuivre le travail en incluant un schéma de dissipation indépendante des flux de chaleur latente et sensible, de façon à se libérer de la contrainte d'un gradient de température convectif.

Description / Table of Contents: This volume contains papers presented at the Geological Society on March 25th and 26th 1981, plus three additional contributions by researchers who were unable to be present at the meeting. The meeting brought together earth scientists with interests in geomorphology, geochemistry, pedology, sedimentology and applied geology. The multidisciplinary approach to the study of residual deposits is reflected in the 25 chapters of this book, which are arranged in four main groups: Weathering processes (chapters 1-3); Kaolinites, laterites and bauxites (chapters 4-11); Red beds (chapters 12-14); Duricrusts: calcretes, silcretes and gypcretes (chapters 15-25). The last two chapters of the book deal with karst related fluorite-baryte deposits, and Cenozoic pedogenesis and landform develop- ment in south-east England. Richard Crockett, Andrew Goudie and Don Highley provided invaluable suggestions during the planning of the meeting that led to this book. R. C. L. WILSON,Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA.

Description / Table of Contents: Although the search for oil and gas in Europe, particularly in the North Sea, has been very successful, it has become progressively more difficult and costly in recent years. The need for continuing exploration success in finding accumulations of hydrocarbons has created a climate which favours the use of modern scientific and technological methods and techniques. Amongst these is petroleum geochemistry. Applications of petroleum geochemistry (integrated with petroleum geology) in petroleum exploration has drastically changed in recent years from a post-mortem science to a widely accepted exploration predictive tool.

Description / Table of Contents: В книге дается очень краткая геологическая и петрофизическая характеристика изученных регионов, характеристика физических аномальных полей, рассматриваются связи аномалий с геологическими объектами, описывается методика изучения глубинного строения земной коры по данным гравиметрической и магнитной съемок, приводится описание мощностей и рельефа поверхностей слоев земной коры, соотношений слоев друг с другом и с аномалиями, а также с рельефом земной поверхности. Диализируются взаимосвязи особенностей структуры различных слоев земной коры с геологическим строением ее приповерхностных зон. На основе выявленных закономерных соотношений между глубинным строением земной коры, с одной стороны, типами геосинклинальных структур, режимом их развития и особенностями их генезиса — с другой, высказываются суждения о составе разных слоев коры и исследуется вопрос об их генезисе. Предлагается и обосновывается гипотеза зарождения и развития земной коры и составляющих ее слоев.

Description / Table of Contents: The book gives a very brief geological and petrophysical description of the studied regions, a description of physical anomalous fields, considers the relationship of anomalies with geological objects, describes a methodology for studying the deep structure of the earth's crust based on gravimetric and magnetic survey data, describes the thicknesses and topography of the surfaces of the layers of the earth's crust, the ratios of the layers with each other and with anomalies, as well as with the relief of the earth's surface. Interrelations between the features of the structure of various layers of the earth's crust and the geological structure of its near-surface zones are dialyzed. On the basis of the revealed regular relationships between the deep structure of the earth's crust, on the one hand, the types of geosynclinal structures, the mode of their development, and the features of their genesis, on the other hand, judgments are made about the composition of different layers of the crust and the question of their genesis is investigated. The hypothesis of the origin and development of the earth's crust and its constituent layers is proposed and substantiated.

Description / Table of Contents: Es werden die Störungen im zeitlichen Ablauf der Amplituden und Phasen zweier auf elastischem Stativ schwingender Schwerependel untersucht. Betrag und Periode der Störungen werden in Abhängigkeit von den Anfangsbedingungen und dem Verhältnis [...] zwischen dem Parameter der elastischen Kopplung und der Verstimmung der beiden Pendel dargestellt. Es zeigt sich, daß die Amplituden und Phasendifferenzen bei [...] = 1 am stärksten gestört sind und mit wachsendem [...] zunehmend von den Anfangsbedingungen beeinflußt werden. Die Ergebnisse absoluter und relativer Pendelmessungen bestätigen den theoretischen Befund.

Description / Table of Contents: Disturbances are investigated which are introduced by the sway effect into the time-functions of amplitudes and phases of two pendulums swinging on the same support. Rate and period of the disturbances are represented as functions of the initial conditions and the quotient [...] formed by the parameter of elastic coupling and the differences of the periods of the two pendulums. Hence it follows that the perturbations of the amplitudes and phase differences are biggest if [...] = 1. With increasing [...] the influence of the initial condi tions is growing up. The results of absolute and relative pendulum measurements confirm the theoretical statements.

Description / Table of Contents: Ice forces on a bridge pier in the Ottauquechee River, in Quechee, Vermont, were measured by installing fourpanels-each capable of measuring forces in the normal and tangential direction - on both sides of a vertical V-shaped pier nose. The measured forces are presented for a short period during an ice run. After the ice run, the thickness and sizes of the ice floes were measured and the compressive strength of the ice was determined in the laboratory from the ice samples collected along the river banks. The water level measurements made at several locations along theriver are also presented for the period of the ice run.

Description / Table of Contents: Recent observations of shore ice pile-up and ride-up along the coast of the Alaska Beaufort Sea are presented. Information is given to show that sea ice movement on shore has overridden steep coastal bluffs and has thrust inland over 150 m, gouging into and pushing up mounds of beach sand, gravel, boulders and peat and, inland, the tundra material. The resulting ice scar morphology was found to remain for tens of years. Onshore ice movements up to 20 m are relatively common, but those over 100 m are very infrequent. Spring is a dangerous time, when sea ice melts away from the shore, allowing ice to move freely. Under this condition, driving stresses of less than 100 kPa can push thick sea ice onto the land.

Description / Table of Contents: The probability density function of the gouge depths into the sediment is represented by a simple negative exponential over four decades of gouge frequency. The exceedance probability function is, therefore, e to the -lambda d, where d is the gouge depth in meters and lambda is a constant. The value of lambda shows a general decrease with increasing water depth, from 9/m in shallow water to less than 3/m in water 30 to 35 m deep. The deepest gouge observed was 3.6 m, from a sample of 20,354 gouges that have depths greater than or equal to 0.2 m. The dominant gouge orientations are usually unimodal and reasonably clustered, with the most frequent alignments roughly parallel to the general trend to the coastline. The value of N(bar) sub 1, the mean number of gouges (deeper than 0.2 m) per kilometer measured normal to the trend of the gouges, varies from 0.2 for protected lagoons to 80 in water between 20 and 38 m deep in unprotected offshore regions. The distribution of the spacings between gouges as measured along a sampling track is a negative exponential. The form of the frequency distribution of N sub 1 varies with water depth and is exponential for lagoons and shallow offshore areas, previously skewed for 10 to 20 m depths off the barrier islands, and near-normal for deeper water. As a Poisson distribution gives a reasonable fit to the N sub 1 distributions for all water depths, it is suggested that gouging can be taken as approximating a Poisson process in both space and time. The distributions of the largest values per kilometer of gouge depths, gouge widths, and the heights of the lateral embankment of sediments plowed from the gouges are also investigated.

Description / Table of Contents: An evaluation of an impulse radar system for detecting cavities under concrete pavement is discussed, and field results are presented. It was found that a dual antenna mode of surveying was ideal for void detection. In this mode one antenna operated in a transceive mode and a second, offset from the first, operated in a receive-only mode. This arrangement allowed a refraction-type profile survey to be performed, which enabled subpavement voids to be easily detected. Field trails were held at Plattsburgh Air Force Base, where 28 cavities were detected and mapped. Drilling of holes verified that a cavity existed and allowed cavity depth to be measured. The cavities varied from 1.5 in. to 23 in, depth and were up to 20 ft. long.

Description / Table of Contents: This paper documents the development and verification of two finite difference models that solve the general two-dimensional form of the heat conduction equation, using the alternative-direction implicit method. Both can handle convective, constant flux, specified temperature and semi-infinite boundaries. The conducting medium may be composed of many materials. The first program, ADI, solves for the case where no change of state occurs. ADIPC solves for case where a freeze/thaw change of phase may occur, using the apparent heat capacity method. Both models are verified by comparison to analytical results.

Description / Table of Contents: A review on past experimental and theoretical work indicates a need for additional experimentation to characterize the response of snow to inelastic pressure waves. Pressure data from previously conducted explosion tests are analyzed to estimate the elastic limit of snow of 400 -kg/cu m density to be about 36 kPa. This pressure corresponds to a scaled distance of 1.6 m/cu.rt.kg for charges fired beneath the surface of the snow, and to a scaled distance of 1.2 m/cu.rt.kg for charges fired in the air. The effects of a snow cover on the method of clearing a minefield by using an explosive charge fired in the air above the snow surface are also discussed and recommendations are given for further work in this area. Explosive pressure data are used to estimate the maximum effective scaled radius for detonating buried mines at shallow depth to be 0.8 m/cu.rt.kg. Fuel-air explosive will increase this effective radius significantly because of the increase in the size of the source region.

Description / Table of Contents: The presence of snow on the ground can impose limitations on the mobility of wheeled and tracked vehicles. Snow depth and density are the two most easily measured snow properties that can be related to mobility over snow. Existing models of snowpack accumulation and ablation processes and models of internal snowpack structure were examined to determine if a model of the snowpack can be developed for use in predicting the snow parameters that affect mobility. Simple models, such as temperature index models, do not provide sufficient snowpack details, and the more detailed models require too many measured inputs. Components of the various models were selected from a basis of a snowpack model for predicting snow properties related to mobility over snow. Methods of obtaining the input data from some components are suggested, and areas where more development is needed are described.

Description / Table of Contents: A sea ice model was applied to the East Greenland Sea to examine a 60-day ice advance period beginning 1 October 1979. This investigation compares model results using driving geostrophic wind fields derived from three sources. Winds calculated from sea-level pressures obtained from the National Weather Service's operational analysis system resulted in strong velocities concentrated in a narrow band adjacent to the Greenland coast, with moderate velocities elsewhere. The model showed excessive ice transport and thickness build-ups in the coastal region. The extreme pressure gradient parallel to the coast resulted partially from a pressure reduction procedure that was applied to the terrain-following sigma coordinate system to obtain sea-level pressures. Additional sea-level pressure fields were obtained from an independent optimal interpolation analysis that merged FGGE buoys drifting in the Arctic basin with high latitude land stations and from manual digitization of the NWS hand-analyzed Northern Hemisphere Surface Charts. Modeling results using winds from both of these fields agreed favorably.

Description / Table of Contents: An analysis of ice fracture that incorporates dislocation mechanics and linear elastic fracture mechanics is discussed. The derived relationships predict a brittle to ductile transition in polycrystalline ice under tension with a Hall-Petch type dependence of brittle fracture strength on grain size. A uniaxial tensile testing technique, including specimen preparation and loading system design was developed and employed to verify the model. The tensile strength of ice in purely brittle fracture was found to vary with the square root of the reciprocal of grain size, supporting the relationship that the theory suggests. The inherent strength of the ice lattice and the Hall-Petch slope are evaluated and findings discussed in relation to previous results. Monitoring of acoustic emissions was incorporated in the tests, providing insights into the process of microfracture during ice deformation.

Description / Table of Contents: Ice accreted on high-speed rotors operating in supercooled fog can be thrown off by centrifugal force, creating severe unbalance and dangerous projectiles. A simple force balance analysis indicates that the strength of accreted ice and its adhesive strength can be obtained by measuring the thickness of the accretion, the location of the separation, the rotor speed, and the density. Such an analysis was applied to field and laboratory observations of self-shedding events. The results agree reasonably well with other observations.