Geothermics : An Introduction The constantly growing demand for energy as well as the realization during the past decade that fossil energy reserves to satisfy ever­ increasing energy consumption are limited have helped as part of the search for alternative energy sources to bring the subject of geothermics to its present level of significance. Practical geothermics is concerned with prospecting for and develop­ ment of geothermal heat. General geothermics deals with the thermal state of our Earth as a whole. Both divisions of this field however contribute practical insights and improved methods of temperature esti­ mation have helped to give us a better picture of detailed thermal condi­ tions. It is difficult for readers interested in this field to obtain an overview from the numerous specialized papers that have been written on geother­ mics. This book is meant to provide a thorough introduction to the subject although the coverage is not exhaustive is detail. Geothermics is taught at universities and technical institutes as part of the curriculum in geology. This introduction to geothermics is directed especially to students of geophysics and is meant to be used as a supple­ ment to their lectures. of this work must be given to my Special thanks for the completion teacher Prof. Dr. O. ROSENBACH. His lectures in geophysics inspired my interest in geothermics which is still my main research area. 1 Physical Basis of Heat Transfer 1.1 Temperature and Temperature Gradient 1.2 Heat Flow Density Thermal Conductivity and Thermal Diffusivity 1.3 The Heat Conduction Equations 2 Thermal Properties of Common Rocks 2.1 Thermal Conductivity 2.2 Specific Heat 2.3 Radiogenic Heat Production 3 Analytical Treatment of Conductive Cooling in the Crust 3.1 Thermal Equilibration in the Homogenous Half Space 3.2 Temperature Equilibration in Model Bodies 4 Thermal State of the Earth’s Interior 4.1 Thermal State of the Upper Crust 4.2 Thermal State in the Lower Crust and Deeper Interior 4.3 Thermal Aspects of Plate Tectonics 5 Methods for Determining Temperature 5.1 Geothermometers for Evaluating Reaction Temperatures 5.2 Geophysical Methods for Determining Temperatures 6 Geothermal Heat as an Energy Source 6.1 Prospecting Methods for Thermal Reservoirs 6.2 Utilization of Geothermal Energy 7 Appendix 7.1 Error Function 7.2 Answer to the Problems 8 References 9 Subject Index.