Search for a command to run...
With the threat of depletion of conventional sources of energy there has been increased interest in harnessing geothermal energy for mans use in many countries. However, there are comparatively few people with wide experience in the science and technology of developing this new energy resource. Geothermal training programs are therefore being organized by many governments, universities, and industries, and there is a need for literature that summarizes the current state of knowledge in various facets of the work. We have drawn upon our background as geochemists with experience in many New Zealand and overseas geothermal areas, to provide information on the theories and methods used in the geochemical aspects of geothermal work. We also describe and seek to place in context the contributions from other sciences in a geothermal development program and provide, as a background, descriptions of the nature and occurrence of geothermal areas. While aimed at geothermal specialist training, the book may also provide useful material in graduate earth science courses, as well as be of general interest to geologists, geophysicists, chemists, and chemical engineers. The first two chapters review the extent of geothermal development throughout the world and outline the geological and hydrological features of geothermal areas. With this introduction, the chemistry of geothermal fluids is then described in detail, and the reasons for the various fluid compositions are interpreted through the chemical and mineralogical reactions that occur in the geothermal systems. A brief description of the physical and chemical nature of high-temperature water solutions follows to aid this understanding. Procedures of geochemical field and laboratory work are considered in detail in Chapters 5 and 6 with particular reference to New Zealand experiences. The basic information, theory, and data required for the chemical work are provided. The approach is practical with many examples. Recomended sequences are given for the geological, geophysical, and geochemical work required in investigating a new geothermal area. Chapter 7 gives examples of the calculations necessary to interpret geochemical results, and methods of storing, retrieving, and interpreting data. The use of chemistry to monitor changes in a geothermal fields is described.