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В учебно-методическом пособии характеризуются слабо изученные вулканические умереннощелочные и щелочные породы от ультраосновного до кислого состава. Их особенности состоят в том, что они обладают непостоянством минерального состава, широким набором главных породообразующих минералов, составляющих и вкрапленники, и основную массу, что осложняет их диагностику в учебном процессе. Определение этих пород требует комплексного подхода к их изучению, обладания знаниями по геологии региона, особенностями его магматизма и вулканизма, а также по стратиграфии и тектонике вулканической провинции. Петрографическое изучение щелочных вулканитов должно сопровождаться определением химизма пород и кристаллооптическими исследованиями с желательным использованием микрозондового анализа. Только применяя комплексную методику изучения этой группы пород, можно добиться положительных результатов в их познании. Для студентов, аспирантов и молодых специалистов в области изучения магматических, вулканических пород и их комплексов.
ROCKS AND MINERALS are a fundamental part of the Earth’s crust. Collecting and studying them can be both a rewarding and an absorbing hobby. This can involve traveling to exciting places, a lot of research, and some time spent cataloging and displaying finds. As your collection grows, you can exchange material with other collectors and purchase rare or exceptional specimens from mineral dealers <...>
The solid part of the Earth is made up of rocks. Rocks are made up of minerals. A mineral is a naturally occurring inorganic solid. It has a specific chemical composition and a characteristic crystal structure. Quartz is a very common mineral. Most beach sand is composed of quartz. It has the composition SiO2 and forms elongate 6-sided crystals that terminate at a point (Picture 1.1). <...>
Microscopy is a servant of all the sciences, and the microscopic examination of minerals is an important technique which should be mastered by all students of geology early in their careers. Advanced modern textbooks on both optics and mineralogy are available, and our intention is not that this new textbook should replace these but that it should serve as an introductory text or a first stepping-stone to the study of optical mineralogy. The present text has been written with full awareness that it will probably be used as a laboratory handbook, serving as a quick reference to the properties of minerals, but nevertheless care has been taken to present a systematic explanation of the use of the microscope as well as theoretical aspects of optical mineralogy. The book is therefore suitable for the novice either studying as an individual or participating in classwork. <...>
Petrography (from the Greek petra meaning rock and graphus meaning writing or a record) originated over 150 years ago as a technique employed primarily by geologists, who used microscopes to examine rock samples to identify their mineralogical and chemical characteristics. Petrographic techniques have since been applied to a wide range of materials used in construction including building stone, aggregate, soil, cement, concrete, mortar, brick, and bituminous mixtures. The polarising microscope has been used for the examination of cementitious materials since 1887. Almost one hundred years ago a series of six articles'1' in Concrete and Concrete Construction, the forerunner of today's CONCRETE, described the possibilities of using a microscope for examining concrete. In the last 40 years, petrography has become widely used for both research and commercial investigation of concrete structures. Petrographic examination is a laboratory procedure that is unique in that it relies highly on visual inspection of the samples. It requires specialist sample preparation and microscopical equipment and operators with appropriate qualifications and experience. Using the microscope the petrographer can determine the composition of concrete, assess its quality, and investigate the causes and extent of any deterioration. Photographs taken through the microscope (photomicrographs) record petrographic features of concrete samples. <...>
The initial concept of a photographic atlas on fault rocks was developed during informal discussions at the Geological Society of America Penrose Conference "Significance and Petrogenesis of Mylonitic Rocks" held at San Diego, California, in spring 1981, and coconvened by the editors of this book. Many participants felt that a new consensus about mylonites and ductile shear zones had been achieved at the conference, based largely upon the contributions of geoscientists who brought perspectives from the laboratory as well as from the field. In part motivated by the publication (1982) of the Atlas of Deformational and Metamorphic Rock Fabrics (and its predecessor, the Atlas of Rock Cleavage) both edited by G. J. Borradaile, Μ. B. Bayly, and C. McA. Powell, we felt that a collection of photographs of features characteristic of faults and shear zones, ranging in scale from mesoscopic to microscopic to even submicroscopic, together with carefully documented locations and regional (or experimental) information, would provide a valuable reference as well as a teaching device <...>
