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The three-dimensional orientation of a line can be described with just a plunge and trend. The rake is a useful description of a line because often (in geology) features (lines) follow along a planar surface. In these cases the rake can be used to describe the line's orientation in three dimensions relative to that planar surface.
A horizontal line would have a plunge of 0°, and a vertical line would have a plunge of 90°. [3] [7] A linear feature which lies within a plane can also be measured by its rake (or pitch). Unlike plunge, which is the feature's azimuth, the rake is the angle measured within the plane from the strike line. [3]
Structural geology is a critical part of engineering geology, which is concerned with the physical and mechanical properties of natural rocks. Structural fabrics and defects such as faults, folds, foliations and joints are internal weaknesses of rocks which may affect the stability of human engineered structures such as dams , road cuts, open ...
The grade (US) or gradient (UK) (also called stepth, slope, incline, mainfall, pitch or rise) of a physical feature, landform or constructed line is either the elevation angle of that surface to the horizontal or its tangent. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper ...
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
Classic geological compass (Brunton), sideview Classic geological compass (Brunton), topview. There are a number of different specialized magnetic compasses used by geologists to measure orientation of geological structures, as they map in the field, to analyze and document the geometry of bedding planes, joints, and/or metamorphic foliations and lineations.
Lineations in structural geology are linear structural features within rocks. [1] There are several types of lineations, intersection lineations, crenulation lineations, mineral lineations and stretching lineations being the most common. Lineation field measurements are recorded as map lines with a plunge angle and azimuth.
In geology, a dike or dyke is a sheet of rock that is formed in a fracture of a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock.