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In a recent review article, Groves et al. (1998) suggested that lode-gold deposits worldwide, which have been variously termed mesothermal, turbidite-hosted, slate-belt hosted, greenstone-hosted, Mother lode-type or gold-only deposits, are a coherent group of gold deposits with a common origin.
Secondary alteration of rocks and their contained minerals is common in nature. Alteration reflects the interaction of fluid, typically dominated by water, with rock at temperatures that range from warm (< 100°C) to hot (>500°C). For geologists who wish to study the primary mineralogy and chemistry of rocks, alteration is a nuisance to be avoided. Alteration mineralogy, however, documents the post-formation history of the rock, information that has practical implications. In particular, alteration is ubiquitous in and around hydrothermal mineral deposits. The distribution and mineralogy of this alteration relates to the hydrothermal environment, and hence, the type of mineral deposit. More importantly for mineral exploration, hydrothermal alteration around mineral deposits commonly forms halos that provide a target which is much larger than the deposit itself. The mineralogy and in some environments the chemical composition of the alteration provide an indication of the proximity of mineralization, or in the ideal case, a vector towards mineralization. Interpretation of alteration is, therefore, a routine part of exploration for hydrothermal mineral deposits. Similarly, as a product of geothermal activity, the mineralogy of hydrothermal alteration provides information on reservoir and fluid characteristics, and the evolution of the geothermal system. These data are used in conjunction with other information to evaluate potential geothermal resources.
Although it is generally understood that the Antarctic Ice Sheet plays a critical role in the changing global system, there is to date still a lack of generally available information on the subject. Climatic change and the role of the polar areas are often discussed in the media.
Our knowledge of metamorphic and deformational rock fabrics has been acquired largely by studying the products of deformation in ancient fold belts. As such, our understanding of how rock fabrics form has been built up from inferences about, rather than direct observations of, processes that might have operated, and many of those inferences have proved incorrect.
Orogens in space and time are the potential sources of information in understanding the mechanism of episodic global material circulation on a whole-mantle-scale. They represent the hallmarks of the interaction among lithospheric plates. The word “orogen” is derived from Greece (oros for “mountain,” genesis for origin). The term “orogen” or “orogenic belt” has been traditionally described as a mountain belt composed of different types of rocks or rock strata forming a complex of variable size, typically tens to hundreds of kilometres wide and several thousand kilometre long, later fragmented during younger geological time due to various processes (e.g., Miashiro, 1961). In modern terminology, an orogen can be defined as a major linear deformed zone, sandwiched between cratons with prolonged deformational history, repeatedly reactivated and associated with different events of magmatic pulses and metamorphic episodes in space and time (Dewey and Bird, 1970). An orogen or orogenic belt develops when a continental plate crumples and is pushed upwards to form one or multiple mountain ranges. This involves a series of geological processes called “orogenesis.” <...>
Air, sea, surface water and soil support life, from which comes our food; the fossil remains of life, that is: coal, oil and gas, together with solar and terrestrial radiation provide energy; but almost all the artifacts of human civilization are made from substances taken from the earth's crust.
The study of rocks in thin section using a petrographic microscope is an essential part of any undergraduate course in geology. This is the fourth volume in a series of photographic atlases of minerals and rocks in thin section. As in previous volumes the main purpose of the book is to provide the student with a handbook for use in practical classes to enable him or her to become familiar with the more common mineral associations and textures to be found in metamorphic rocks. In addition, some more unusual rocks which have given rise to particular significant ideas about metamorphism are also illustrated; the aim of this atlas is however to complement, not replace, a theoretical course in metamorphism.
Mineral resources are of great strategic significance since they matter in every aspect of social and economic development. However, existing mineral resources are unlikely to support sustainable economic development given the planning and construction of urbanization in China.
