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Showing 81 to 85 of 85 (0.014 seconds)| 81 |
Weiterentwicklung und Anwendung geostatistischer Simulationsverfahren zur unsicherheitsbasierten Modellierung von komplexen, sedimentartig ausgebildeten LagerstättenJohn, André 13 November 2014 (has links)
Die immer komplexer werdenden geologischen Verhältnisse aktueller Lagerstätten, sowie die Umsetzung einer hoch-selektiven Rohstoffgewinnung, machen eine Modellierung auf Basis von geostatistischen Simulationsverfahren in einem modernen Lagerstättenmanagement notwendig, da diese Verfahren die in-situ Variabilität der struktur- und qualitätsbeschreibenden Lagerstättenparameter realistisch vorhersagen und damit auch realitätsnahe betriebswirtschaftliche Risikoabschätzungen zu den Auswirkungen der Unsicherheiten in der Vorhersage, aufgrund eines unvollständigen Kenntnisstandes, ermöglichen. Die Arbeit beschreibt die Weiterentwicklung und Anwendung von Verfahren der geostatistischen Simulation für die Modellierung komplexer, sedimentartig ausgebildeter Lagerstätten in einem praxisrelevanten Umfang und unter Berücksichtigung der besonderen Anforderungen, welche aus der Charakteristik der Lagerstätte und der Zielsetzung einer selektiven Rohstoffgewinnung abgeleitet wurden. Zunächst wird ein geeigneter Ansatz identifiziert, welcher die Grundlage für eine methodische Erweiterung und effiziente Implementierung, hinsichtlich der zu erfüllenden Anforderungen, bildet. Danach wird die komplette Prozesskette für eine zuverlässige Lagerstättenmodellierung untersucht und praktikable Modellierungsstrategien werden vorgestellt. Ein komplexes Anwendungsbeispiel aus dem Braunkohlenbergbau dient der Evaluierung der vorgestellten
Modellierungsverfahren. / The more and more complex geological conditions of current deposits, as well as the implementation of a highly selective extraction of raw materials, require new approaches for the reservoir management. The use of geostatistical simulation methods for modelling the shape and quality of deposits is necessary, because these methods taking into account the natural variability of the deposit attributes and the resulting geological uncertainties. Furthermore this methods allow faithfully and realistic economic risk assessments on the impact of uncertainties in the prediction, due to an incomplete state of knowledge. This work describes the further development and application of geostatistical simulation algorithms for the modelling of complex sediment-like formed deposits in a practically scope, taking into account the special requirements, which are derived from the characteristics of such deposits and the objective of the selective extraction of raw material. First an appropriate simulation approach is identified, which then forms the basis for a methodical expansion and efficient implementation, in terms of fulfilling requirements. In addition, the complete process chain for reliable reservoir modelling is studied and a viable modelling strategy is presented. A complex application example from the lignite mining is used for evaluation of the presented modelling methods.
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Numerical simulation of selected geologic processes based on Discrete Element MethodLiu, Yuan 14 January 2019 (has links)
This study presents numerical modeling of geologic processes based on Discrete Element Method (DEM), including modeling of pull-apart basin development based on Particle Flow Code (PFC) and simulation of deformation and earthquake potential of Ordos Block (China) under present tectonic stress regime based on Universal Distinct Element Code (UDEC).
A scale-independent modeling approach based on PFC2D has been established to simulate the development of pull-apart basins. The micro-scale PFC models are used to investigate crack propagation and basin development in releasing sidestep systems with pure strike-slip, transtensional, and transpressional master faults, respectively. In each system, three typical models including 30° underlapping, 90° non-overlapping, and 150° overlapping releasing sidesteps are chosen. The modeling results are compared with pull-apart basins in nature. The geometric differences of pull-apart basins result from both the initial strike-slip fault geometries and its various evolution stages. Rhomboidal basins which have larger basin length than the amount of motion form in overlapping systems and do not progress through the spindle-shaped and lazy-Z-shaped stages such as the Dead Sea basin. Rhomboidal basins with cross-basin faults tend to form in underlapping systems. Finally, the origin of rhomboidal pull-apart basins, depocenters of pull-apart basins, cross-basin faults and their significances, models for pull-apart basin development, and minimum displacements and ages to form pull-apart basins are discussed.
A two-dimensional UDEC model involving Ordos Block and adjacent areas is set up. Boundary conditions based on present tectonic regime are assumed. Block rotations, shear stress and displacement on faults, ratio of shear to normal force are simulated. Slip tendency which represents the assessment of the potential for causing slip on individual faults and earthquake-prone of the faults is predicted. Modeling results are compared with geologic evidences.
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Minerogeny of the Pan-African Volta Basin of GhanaBoamah, Kwame 10 April 2017 (has links) (PDF)
Within the framework of this research, the complex geological history of the Pan African-Volta basin has been systematically reconstructed. Based on a broad review of literature and new data, 5 stages of geological-tectonic development have been identified. For the first time a systematic review of the mineral potential of the Pan-African Volta Basin was executed. Known and potentially existing mineralization have been related to the geotectonic history and metallogenetic conclusions have been drawn.
Based on the findings of this research, the folded thrust belt located at the eastern rim of the Volta basin has been identified as the most prospective area for the ultramafic rocks with chromite, nickel mineralization and PGEs, hydrothermal gold and banded iron formation (BIF) but this will require further work.
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Minerogeny of the Pan-African Volta Basin of GhanaBoamah, Kwame 04 March 2017 (has links)
Within the framework of this research, the complex geological history of the Pan African-Volta basin has been systematically reconstructed. Based on a broad review of literature and new data, 5 stages of geological-tectonic development have been identified. For the first time a systematic review of the mineral potential of the Pan-African Volta Basin was executed. Known and potentially existing mineralization have been related to the geotectonic history and metallogenetic conclusions have been drawn.
Based on the findings of this research, the folded thrust belt located at the eastern rim of the Volta basin has been identified as the most prospective area for the ultramafic rocks with chromite, nickel mineralization and PGEs, hydrothermal gold and banded iron formation (BIF) but this will require further work.:Table of contents
Table of contents iii
List of tables v
List of figures 1
Introduction 5
Summary of work done 6
Acknowledgements 6
1 In the Geology and regional geotectonic development of the West African Shield 7
1.1 Introduction 7
1.2 The basement of the Proterozoic sedimentary platform cover 9
1.3 Connection of West African Shield to Brazil 10
1.4 The Neoproterozoic sedimentary sequence and the extent of the Volta Basin 13
1.4.1 Introduction 13
1.4.2 The Neoproterozoic Sedimentary Sequence 15
1.5 The Pan-African Mobile Belt 23
1.5.1 The Buem Fold and thrust belt 23
1.5.2 New defined units 30
1.6 Interpretation of the deep structure of the Volta Basin 35
1.7 Metallic Minerals 37
1.7.1 Introduction 37
1.7.2 Iron (Fe) 39
1.7.3 Aluminium (Al) 46
1.7.4 Manganese (Mn) 50
1.7.5 Lead (Pb) 52
1.7.6 Copper (Cu) 55
1.7.7 Mineralisation related to ultramafic rocks 57
1.7.8 Gold (Au) 69
1.7.9 Tantalum (Ta) 72
1.7.10 Zirconium (Zr) 73
1.7.11 Heavy minerals in sands of Paleochannels 76
1.8 Non-metallic minerals 83
1.8.1 Introduction 83
1.8.2 Limestone (CaCO3) 84
1.8.3 Magnesite (MgCO3) 91
1.8.4 Barite (BaSO4) 93
1.8.5 Diamonds 97
1.8.6 Bitumen 100
1.9 Mineral Prediction with advangeo® Prediction Software 102
2 Minerogeny 109
2.1 Mineralisation controls and indicators 109
2.1.1 Geochemical Properties of selected stratigraphic units 109
2.1.2 Intrusive rocks 114
2.1.3 Volcanic rocks 118
2.1.4 Fault structural controls 119
2.1.5 Reactive Rocks 121
2.1.6 Other sedimentary controls: placers and paleoplacers 122
2.1.7 Laterites 122
2.1.8 Control of diamond occurrences 132
2.2 Key stages of metallogenic development 132
3 Discussion and recommendations 136
3.1 Recommendations 138
4 List of References 139
5 Appendices 144
5.1.1 Sample G113RK1 144
5.1.2 Sample G109RK1 145
5.1.3 Sample G116RK1 147
5.1.4 Sample G121RK1 149
5.1.5 Sample G121RK2 151
5.1.6 Sample G121RK3 152
5.1.7 Sample G131RK1 154
5.1.8 Sample G144RK2 155
5.1.9 Sample G145RK1 156
5.1.10 Sample G147RK1 157
5.2 Thin Sections 159
5.3 Deep drilling Data 174
5.4 Geophysical Datasets 176
5.5 Geochemical properties of volcanic rocks 181
5.6 Regional Geochemical Datasets (MSSP) 186
5.6.1 Methodology of data processing 188
5.7 Geochemical analysis – Electronic Dump 190
5.8 Geochemical properties of selected geo-tectonic units 190
5.8.1 Epicratonic basin 190
5.8.2 Foreland Basin 195
5.8.3 Thrusted continental margin 202
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Geochemie Porifera-reicher Mud Mounds und Mikrobialithe des Mittel- und Oberdevons (Westaustralien, Nordfrankreich) / Geochemistry of Porifera-rich mud mounds and microbialites of the Middle and Upper Devonian (Western Australia, Northern France)Hühne, Cathrin 07 November 2005 (has links)
No description available.
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