Many of the problems which arise during a study in structural geology are essentially exercises in three-dimensional geometry. Data acquired from field-observations—strike and dip of planes (beddingplanes, planes of schistosity or cleavage, faults, etc.), the pitch and plunge of lineations (outcrops, slickensides, micro-folds, flow-lines, elongation of mineral components or of inclusions, etc.) and all other related vector data are incorporated in a geological map and in accompanying illustrative sections. Both in the construction of such sections and ofrelated block-diagrams, and in the further study of the structural features of an area, it is frequently necessary to make various calculations. Sometimes, indeed, as in many of the problems of mining geology and in the interpretation of borehole cores, the necessity for calculation arises at an even earlier stage, since such fundamentals as the dip and strike of a bedded series are only indirectly derived from the observed data.<...>

Folds and thrust faults formed by layer-parallel shortening coaxial with extensional structures such as normal dip-slip faults and ductile necking structures with orthorhombic fabric symmetry are usual, but little-recognised structures formed within normal dip-slip shear zones bounding rifts. They are generated because of the shear distribution in a zone of progressive deformation and may be later extended and disrupted depending on which part of the strain ellipsoid they may be located.

Much of our present knowledge of the architecture of molecules has been obtained from studies of the diffraction of X rays or neutrons by crystals. X rays* are scattered by the electrons of atoms and ions, and the interference between the X rays scattered by the different atoms or ions in a crystal can result in a diffraction pattern. Similarly, neutrons are scattered by the nuclei of atoms. Measurements on a crystal diffraction pattern can lead to information on the arrangement of atoms or ions within the crystal. This is the experimental technique to be described in this book

The 5000 lines of FORTRAN code that became known as SHELX-76 had their origins around 1970 when the University of Cambridge replaced the ICL Titan computer with an IBM-370. My previous attempts to write programs used Titan Autocode, a simple but efficient programming language closer to assembler than to a modern high-level language. With the IBM computer came two major innovations: a FORTRAN compiler and punched cards.

Структурная и метаморфическая эволюция синтаксиса Нанга-Парбат, Пакистанские Гималаи, на разрезе ущелья Индус: важность ранних событий

Field relationships are as important as radiometric age data for unravelling the history of polycyclic metamorphic  regions. Field and petrographic data were used to investigate such a region, the Nanga Parbat syntaxis - a major Ntrending transverse structure in the Pakistan Himalayas. Continental rocks of the Indian plate are exposed in the core of  this structure due to uplift relative to the surrounding and structurally higher amphibolites of the overthrust Kohistan Island Arc. In the Indus gorge, the Indian plate gneisses are migmatitic, highly deformed and cut by Himalayan granite sheets. Field relationships show that the migmatization pre-dates the emplacement of a suite of basic intrusive sheets (now amphibolites) which are themselves unlikely to be Himalayan; these amphibolite sheets are cut by the Himalayan granite sheets. There is therefore no genetic link between the granites and the migmatization: the latter might be Precambrian.

The essential difference in the formation between conjugate brittle shear fractures and ductile shear zones is that the intersection angle of conjugate faults in the contractional quadrants in the former is acute (usually w60
) and obtuse (usually 110
) in the latter. The Mohr-Coulomb failure criterion is an experimentally validated empirical relationship, which structural geologists use to interpret the stress directions based on the orientation of the brittle shear fractures. However, a simple application of this criterion assuming that the principal stresses are vertical or horizontal throughout the crust fails to explain crustal scale low-angle normal faults, high-angle reverse faults and certain types of conjugate strike-slip faults that have intersection angles in the compressional quadrants greater than 90
.

Pile design is mostly about application of engineering concepts rather than use of elaborate mathematical techniques. Most pile design work can be done with simple arithmetic. I have provided necessary equations and concepts in a manner so that the reader would be able to refer to them with ease. All chapters are provided with plethora of design examples. The solutions to design examples are given in a step by step basis with many illustrations.

The epithermal Shila-Paula Au–Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E–W vein with secondary N55–60°W veins—two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartz–adularia– pyrite–galena–sphalerite–chalcopyrite–electrum–Mn silicate–carbonate assemblage that fills the main E–W veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartz–adularia–carbonate assemblage that is observed within the secondary N45–60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings.