3-D structural geology. A practical guide to surface and subsurface map interpretation / 3-D структурная геология. Практическое руководство по интерпретации карт поверхности и недр

Many important decisions, ranging from locating an oil prospect or a land-fill site to determining the location and size of an earthquake-producing fault, are based on geological maps. Because a map-scale structure is never completely sampled in three dimensions, geological maps and the cross sections derived from maps are always interpretations. The interpretation may be complicated by direct structural observations, like bedding attitudes, that are misleading because they represent a local structure, not the map-scale structure. Some data may simply be wrong. The interpretation of the geometry of even a single horizon, therefore, always involves inferences about the validity and meaning of the observations themselves as well as the nature of the geometry between the observation points . How is an accurate interpretation to be constructed and how is it to be validated once complete? The objective of this book is to demonstrate the concepts and techniques required to obtain the most complete and accurate interpretation of the geometry of structures at the map scale.The methods are designed primarily for interpretations based on outcrop measurements and subsurface information of the type derived from welllogs and two-dimensional seismic reflection profiles. These forms of information all present a similar interpretive problem, which is to define the geometry from isolated and discontinuous observations. The underlying philosophy of interpretation is that structures are three-dimensional solid bodies and that data from throughout the body should be integrated into an internally consistent interpretation. The techniques presented here are drawn from the best and most practical methods of surface and subsurface geology and provide a single methodology intended to be appropriate for both . Because computers are widely used for interpretation and drafting, quantitative techniques and computer-oriented methods are emphasized. The techniques are developed using approaches that can be done with a pencil, a piece of paper, and a pocket calculator, because an understanding of the methods is best achieved by working through at least a few examples by hand. Most of the methods are also presented in analytical forms suitable for implementation on a computer. The final equations are given in the body of the text with the derivations placed at the end of the chapters so that the text can concentrate on the applications <...>