ALBERT

Description / Table of Contents: Digital signal processing has become more and more an integral part of observational seismology. While it offers unprecedented power in extracting information from seismic signals, it comes at the price of having to learn a variety of new skills. Dealing with digital seismic data requires at least a basic understanding of digital signal processing. Taking the calculation of true ground motion as the guiding problem, this course covers the basic theory of linear systems, the design and analysis of simple digital filters, the effect of sampling and A/D conversion and an introduction to spectral analysis of digital signals. It contains a number of examples and exercises that can be reproduced using the PITSA software package (Scherbaum and Johnson 1993) or similar programs.

Description / Table of Contents: INTRODUCTION The evaporite deposits of the Werra district, especially in the Hattorf mining field, are considered a worldwide unique location for the occurence of numerous basalt dikes and magmatic fluid phases fixed in salt rocks. In spite of the great number of studies dealing with the magmatites in the Werra region, previous investigations have rarely attempted more than a predominantly 'qualitative' description of the basaltic rocks and the effects of volcanism on the evaporites (see Chapter 2). The method of interpreting the mineralogical and chemical composition of the evaporites at the basalt contact is based on previous works (KNIPPING 1984; KNIPPING & HERRMANN 1985). This study should contribute to understanding (i) the mechanism of intrusion of the basaltic rnelts and (ii) the metamorphic processes occurring in the evaporites caused by mobile phases during volcanism. Hence, the following methods were applied: The mineralogical and chemical description of the basaltic rocks with recent nomenclature including the possible differences between individual dikes and between surface- and subsurface-exposed basalts. Seven surface and 48 subsurface exposures at the Hattorf mine of Kali & Salz AG were studied. Application of the most recent knowledge on basalt genesis for interpreting observational and experimental results. Studies on the sulfur and carbon isotope distributions of the native sulfur from several subsurface exposures and the enrichments of gases (predominantly CO2) in the evaporites. Calculation of the spatial and temporal temperature distribution in the evaporite rocks following intrusion of the basaltic melts. For purposes of clarity a few of the terms which will be used frequently here will first be defined: basalt - all of the intrusive rocks studied can be assigned mineralogically and chemically to the basalt family in a broader sense. Thus, the terms basaltic rock or, in short, basalt will be used for these rocks. rock salt - instead of the term salt for halitic rocks the term rock salt is used. Besides, the evaporites are generally designated as host rocks (for the basalt dikes) as well. gases - especially in the German literature the term carbon dioxide or carbonic acid (= Kohlensäure) is frequently used for the gases enclosed in the evaporites of the Werra-Fulda district. ACKERMANN et al (1964) found, in addition to carbon dioxide, considerable amounts of nitrogen and minor amounts of methane. In the following therefore the terms gas mixture or gas will be used. The various basalt dikes found in the Hattorf mining field are described here in terms of their mineralogy and geochemistry for the first time. In doing so it is necessary to number them from east to west. To avoid confusion with older numerations (e.g. SIEMENS 1971) the various dike systems are designated by capital letters (A to P).

Description / Table of Contents: Biolaminated deposits, produced by microbial communities, were studied in modern peritidal environments and in the rock record. The term microbial, mat refers to modern, the term stromatolite to ancient analogs. The term biolaminated deposits was used to encompass both microbial mats and stromatolites. Microbial mat environments studied are the Gavish Sabkha, the Solar Lake, both hypersaline back-barrier systems at the Gulf of Aqaba, Sinai Peninsula, and the "Farbstreifen-Sandwatt" (versicolored sandy tidal flats) on Mellum, an island in the estuary embayment of the southern North Sea coast. Three facies-relevant categories were distinguished: (i) the mat-forming microbiota, (2) environmental conditions controlling mat types and lithology, (3) bioturbation and grazing. Cyanobacteria account for biogenic sediment accretion in all cases studied. Three major groups occur: filamentous cyanobacteria, coccoid unicells with binary fission and those with multiple fission. In the presence of these groups the following mat types evolve: (i) continuously flat (stratiform) L~-laminae (occur in all environments studied); (2) translucent, vertically extended Lv-laminae (only Gavish Sabkha and Solar Lake); (3) nodular granules (only Gavish Sabkha). Basically, the development of mats is controlled by moisture. Thus high-lying parts where the groundwater table runs more than 40 cm below surface are bare of mats. These are: The circular slope and elevated center of the Gavish Sabkha, the shorelines of the Solar Lake and the episodically flooded upper supratidal zone of Mellum Island. The following situations of water supply were found to stimulate mat growth: (i) Capillary movement of groundwater to exposed surfaces, (2) shallowest calm water, both realized in the Gavish Sabkha and the Solar Lake. On Mellum Island, mats form in the lower supratidal zone, which is flooded in the spring tide cycle and wetted during low tide by capillary groundwater. Salinity is almost that of normal seawater, whereas in the Solar Lake, it ranges from 45 °/oo to 180 °/oo and in the Gavish Sabkha, it reaches more than 300 °/oo. Salinity increase is correlated with rising concentrations of magnesium and sulfate ions. In the Gavish Sabkha, episodic sheetfloods cause high-rate sedimentation which is accidental to the living mats. Episodic low-rate sedimentation stimulates the mats to grow through the freshly deposited sediment layer. This occurs predominantly on Mellum Island due to eolian transport. Within the Gavish Sabkha, mineralogy of sediments, community structures, standing crops, redox potentials and pH are highly correlative to the increasing evenness in moisture supply which is realized by the inclination of the system below mean sea level. These conditions bring about a lateral sequence of facies types which include (I) siliciclastic biolaminites at the coastal bar base, (2) nodular to biolaminoid carbonates at saline mud flats, (3) regularly stratified stromatolitic carbonates with ooids and oncoids within the hypersaline lagoon, (4) biolaminated sulfate towardthe elevated center. High-magnesium calcite in facies type 3 precipitates around decaying organic matter and forms also the ooids and oncoids. These occur predominantly within hydroplastic Lv-laminae which provide numerous nucleation centers. Within the Solar Lake, facies type 3 (stromatolitic carbonates with ooids and oncoids) is most important, and grows to extraordinary thickness at the lake's shelf. The regular alternation of dark and light laminae results from seasonally oscillating water depths. These conditions couple back over changing light and salinity intensities to changing dominance structures of mat-building communities. Increasing salinity correlates with decreasing water depth and accounts for the relative abundance of coccoid unicells and diatoms, both active producers of extracellular slimes (Lv-laminae). Water depths locally or temporarily increased favor surface colonization by Mic~ocoleu8 chthonoplastes (Lh-laminae). The biolaminated deposits of the versicolored tidal flats on Mellum Island are similar to facies type 1 of the Gavish Sabkha (siliciclastic biolaminites). Differences exist in the lithology: Sediments upon or through which the mats on Mellum Island grow are made up of clean sand. The grains originate predominantly from re-worked glacial sediments and are rounded to well rounded. By contrast, the strong angularity of siliciclastic grains in the Gavish Sabkha clearly shows their status as primary weathering products. In all environments studied, insects play a significant role. Mainly salt beetles contribute to the lebensspuren spectrum. There is no indication that burrowing and grazing beetles and dipterans are detrimental to the growing mat systems. According to the marine fauna, two distributional barriers exist: (i) physical and (2) biogeochemical factors. Physical barriers are (a) hypersalinity and barrier-closing, which restrict the marine fauna in the Gavish Sabkha and the Solar Lake to a few species, mainly meiofaunal elements such as ostracods and copepods. Only in the Gavish Sabkha, one marine gastropod species occurs which colonizes mud flats of lower salinity. A salinity barrier of about 70 °/oo separates the gastropod habitats from the zones of growing mats. Under reduced salinity, the snails are able to destroy the microbial mats completely. (b) Decreasing regularity of flooding in the microbial mat environment of Mellum Island excludes intertidal deformative burrowers such as cockles and lugworms. However, locally the mats are pierced by numerous dwelling traces. These stem from small polychaetes and amphipod crustaceans which are able to spread over the intertidal-supratidal boundary and settle up to the MHWS-Ievel. Biogeochemical barriers are oxygen depletion within the sediments, high ammonia and sulfide contents, which generate through bacterial break-down of organic matter. Within the highly productive mats of Mic~ocoleu8 chthonoplastes on Mellum Island, dwelling traces of marine polychaetes and amphipod crustaceans disappear due to these conditions. The name of the mat-forming species, Microcoleus chthonoplastes, indicates its capacity to form "soils" (Greek chthonos). While lithology is not altered, the presence of Mic~ocoleu8 mats leads to a habitat change which excludes trace-making "arenophile" invertebrate species and favors "chthonophile" species which do not leave traces. Stromatolitic microstructures studied in rock specimens were interpreted using modern analogs: Microcolumnar buildups in Precambrian stromatolites, ooids and oncoids were compared with those of modern microbial mats. The nodular to biolaminoid facies type found in the Gavish Sabkha was suggested to be an analog to the Plattendolomite facies of Permian Zechstein, North Poland. Studies of the Lower Jurassic ironstone of Lorraine clearly indicate that fungi have been involved in the formation of stromatolites, ooids and oncoids. In conclusion, the comparative study of microstructures in microbial mats and stromatolites reveals a better understanding in both fields. In many cases, it was geology which first revealed the similarity of recent forms to those ancient ones and consequently encouraged research into them.

Description / Table of Contents: This volume contains the proceedings of a symposium held at Freiburg im Breisgau, October 7-11, 1990. The symposium was sponsored mainly by the Deutsche Forschungsgemeinschaft (DFG), by the Geological Institute of the University of Freiburg, and by the International Association of Mathematical Geology. We thank these and all other sponsors of the meeting. The symposium whose participants came from more then twenty countries was the first international meeting dedicated entirely to geological applications of threedimensional computer graphics, a rapidly growing field of scientific visualization in geology. The selection of papers in this volume covers a wide range of methods developed in the last decade.

Description / Table of Contents: PREFACE The objective of this book is to introduce the practitioner as well as the more theoretically interested reader into the integration problem of spatial information for Geo-lnformation Syslems. Former Get-Information Systems are restricted to 2D space. They realize the integration of spatial information by a conversion of vector and raster representations. This, however. leads to conceptual difficulties because of the two totally different paradigms. Furthermore, the internal topology of the get-objects is not considered. In recent years the processing of 3D information has played a growing role in Get-Information Systems. For example, planning processes for environmental protection or city planning are dependent on 3D data. The integration of spatial reformation will become even more impoaant in the 3D context and with the development of a new generation of open GISs. This book is intended to respond to some of these requirements. It presents a model for the integration of spatial information for 3D Geo-lnformation Systems (3D-GISs). As a precondition for the integration of spatial information, the integration of different spatial representations is emphasized. The model is based on a three-level notion of space that likewise includes the geometry, metrics and the topology of get-objects. The so called extended complex (e-complex) is introduced as a kernel of the model. Its internal basic geometries are the point, the line, the triangle and the tetrahedron. It is shown how a convex e-complex (ce-complex) is generated by the construction of the convex hull and the "'filling" of lines, triangles and tetrahedra, respectively. As we know from computer geometry, this results in substantially simpler geometric algorithms. Additionally, the algorithms gain by the explicit utilization of the topology of the ce-complex. This book also builds a bridge from the GIS to the object-oriented database technology, which will likely become a key technology for the development of a new generation of open Geo-lnformation Systems. In the so-called GEtmodel kernel "building blocks" are introduced that s~mplify the development of software architectures for geo-applications. A geological application in the Lower Rhine Basin shows the practical use of the introduced geometric and topological representation for a 3D-GIS...

Description / Table of Contents: PREFACE In the geologic record, vertical crustal uplift has often resulted in erosional removal of huge thicknesses of sedimentary strata. If the uplift is of a broad regional nature or the uplifted strata remain relatively undeformed and sediments deposited after the uplift are not preserved, the magnitude of uplift and subsequent erosion may be difficult to quantify. This may lead to misinterpretation or omission of chapters of geologic history of a region. Fortunately, a number of indirect methods can be used to infer the thicknesses of missing strata and reconstruct the geologic history. Our book titled "Thick Post-Devonian Sediment Cover Over New York State: Evidence from Fluid-Inclusion, Organic Maturation, Clay Diagenesis and Stable Isotope Studies" uses four techniques of paleotemperature measurements in sedimentary rocks in order to determine burial depths of the existing Paleozoic strata in New York State. Since every technique has its own analytical and interpretative uncertainties, the use of four techniques allowed us to place a better constraint on our results. We show how regionally extensive paleotemperature data can be used to estimate the thicknesses of strata lost from an uplifted sedimentary basin. We also provide a tentative tectonic-, paleogeographic- and depositional history of New York State after the Devonian when the missing strata were deposited...

Description / Table of Contents: INTRODUCTION While the complex mechanical properties of rocks and soils are studied for quite a while, it is only in the last decades that sound established mathematical models were developed based on accurate experimental data. Some rheological properties of geomaterials as for instance creep, were studied for a long time but the experimental data reported were incomplete and, as a consequence, the models developed have missed either the generality necessary for the solving of engineering problems or some of the major specific mechanical properties possessed by these materials as for instance dilatancy and/or compressibility , long term damage etc. Generally, these very particular empirical models were made for a specific test only and therefore are not appropriate for solving problems involving general loading histories. Let us remind that due to the presence of a great number of cracks and/or pores existing in roks and soils, the mechanical behaviour of geomaterials is quite distinct from that of other materials as for instance metals or plastics. That is why rock and soil rheology has some specific aspects. It must also be mentioned that the solving of various problems of rock and soil mechanics posed by modern technology was not possible by using time-independent models, thus the study and development of rehological models become absolutely necessary. In the last decade or so, very accurate experimantal data became available as a result of the development of experimental techniques and of the growing interest for this field of research in the scientific community. These data, in turn, have made possible the development of genuine models for geomaterials, mainly rheological models, able to describe such properties as creep, dilatancy and/or compressibility during creep, long term damage and failure occurring after various time intervals, slip surface formation etc. Today it is clear that no accurate constitutive equation for rocks can be formulated unless the dilatancy phenomena and the time effects are not included. Another idea is the need of a better description of the concepts of damage and failure of rocks, again using in someway the concepts of irreversible dilatancy or another related notion. In soil rheology it is clear that the scale effect may be taken into consideration in order to obtain a corect information from the routine tests. Also in writing the constitutive equations for soils it is neccessary to take into account the microscopic or local phenomena, because there is a great variety of types of saturated or nonsaturated soils, granular or cohesionless soil etc. The aim of the Euromech Colloquium 196 devoted to Rock and Soil Rheology and therefore that of the present volume too, is to review some of the main results obtained in the last years in this field of research and also to formulate some of the major not yet solved problems which are now under consideration. Exchange of opinions and scientific discussions are quite helpful mainly in those areas where some approaches are controversial and the progress made is quite fast. That is especially true for the rheology of geomaterials, domain of great interest for mining and petroleum engineers, engineering geology, seismology, geophlsics, civil engineering, nuclear and industrial waste storage, geothermal energy storage, caverns for sports, culture, telecommunications, storage of goods and foodstuffs (cold, hot and refrigerated storages), underground oil and natural gas reservoirs etc. Some of the last obtained results are mentioned in the present volume...

Description / Table of Contents: PREFACE Sedimentation as a Three-Component System describes the most common styles of deposition in marine environments as they relate to sediment composition. Three components, organic matter, carbonate, and siliciclastic sediment, may settle concurrently, but at different rates, intermixing on the sea floor to form a particular sediment composition. A change in the flux of one component is capable of relatively diluting or concentrating the other two components, which can be expressed in the characteristic ratio of organic carbon to carbonate in the resulting sediment. The basic concept of this book is to address organic carbon-carbonate associations in terms of depositional inputs and time spans. In addition, the three-component system describes organic carbon changes related to major facies transitions. Examples include models of the genesis of carbonaceous sediments, with their various laminated to bioturbated lithotypes, and numerical organic carbon prediction. I hope that this book will encourage stimulating discussions and promote a new approach to quantitative stratigraphy...