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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]
d = run Δh = rise l = slope length α = angle of inclination. 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.
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.
For example, the Earth's mean specific gravity (5.515) is far higher than the typical specific gravity of rocks at the surface (2.7–3.3), implying that the deeper material is denser. This is also implied by its low moment of inertia (0.33 M R 2, compared to 0.4 M R 2 for a sphere of constant density). However, some of the density increase is ...
Deformations are numbered according to their order of formation with the letter D denoting a deformation event. For example, D 1, D 2, D 3. Folds and foliations, because they are formed by deformation events, should correlate with these events. For example, an F 2 fold, with an S 2 axial plane foliation would be the result of a D 2 deformation.
Cleavage, in structural geology and petrology, describes a type of planar rock feature that develops as a result of deformation and metamorphism. [1] The degree of deformation and metamorphism along with rock type determines the kind of cleavage feature that develops.
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.