Linear and planar features in geology. Almost all work on geologic structures is concerned in one way or another with lines and planes. The following are examples of linear features that one might observe in rocks, together with some kinematic deductions from them: glacial striae (which reveal the direction of ice movement);

2021年4月12日 · Lineations in structural geology are linear structural features within rocks. There are several types of lineations, intersection lineations, crenulation lineations, mineral lineations and stretching lineations being the most common.

Lineation is one of the most significant fabric elements and it should be included in all complete structure maps. The attitude of a linear structure is described by its trend, which is the compass direction of the lineation projected on a horizontal plane, and its plunge.

The following are examples of linear features that one might observe in rocks, together with some kinematic deductions from them: glacial striae (which reveal the direction of ice movement); the fabric or lineation produced by alignment of amphiboles seen in metamorphic rocks (which reveal the direction of stretching acquired during deformation);

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.

Linear structures can be penetrative or non-penetrative. Penetrative linear structures occur throughout the rock mass and at all scales, indicating they are also a type of fabric element. Common examples include stretched or aligned minerals, fossils, and other inclusions.

Although most geologic structures are generally either curvilinear or curviplanar, they can be approximated as either linear or planar at specific scales or domains. For example, a primary linear structure such as the crest of ripple marks or flute …

Hinges of cylindrical folds are linear structures. 3- Stretching lineation Formed by the parallel alignment of individual detrital grains such as elongated pebbles during the presence of currents. 6 5- Mineral lineation Metamorphic minerals often grow with a preferred crystallographic and dimensional orientation,

2016年3月16日 · A linear structure resembles a geometric line rather than a plane; examples of linear structures include scratches or grooves on a rock surface. Geologists specify the orientation of a line by giving its plunge and bearing (figure above d). The plunge is the angle between a line and horizontal in the vertical plane that contains the line.

(a) Using a compass-clinometer, measure the trend of a linear structure. To do this, hold the compass in a horizontal plane so that the needle swings freely in the Earth’s magnetic field. Then place the compass so that its horizontal edge is over the plunging line, keeping the compass level.