Strike and dip refer to the orientation or attitude of a geologic feature. Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit The strike of a stratum or planar feature is a line representing the intersection of that feature with the horizontal. In Geology and related fields a stratum (plural strata) is a layer of rock or Soil with internally consistent characteristics that distinguishes On a geologic map this is represented with a short straight line segment oriented parallel to the compass direction of the strike. A geologic map or geological map is a special-purpose Map made to show Geological features Strike is usually given as a compass bearing (N25°E for example) in terms of east or west of north, or as a single three digit number representing the azimuth, where the lower number is usually given (where the example of N25°E would simply be 025, and the other value of 205 is discarded). Azimuth ( is a mathematical concept defined as the angle usually measured in degrees (° between a reference plane and a point. The dip gives the angle below the horizontal of a tilted stratum or feature. The symbol is a short line attached and at right angles to the strike symbol pointing in the direction of inclination. Typically the angle of dip is included on a geologic map.
Strike and dip are determined in the field with a compass and clinometer or combination known as a Brunton compass. An inclinometer or clinometer is an instrument for measuring angles of Slope (or Tilt) Elevation or Inclination of an object with A Brunton compass, properly known as the Brunton Pocket Transit, is a type of precision Compass made by Brunton
Another way of representing strike and dip is by dip and dip direction, where the latter is simply the azimuth of the dip. It can be obtained from strike by simply counting 90° around in the relevant direction. For example, for strata dipping 45º to the south and striking east-west, the strike and dip value would be 45ºS/090, which converts to a dip and dip direction reading of 45/180. Compass-clinometers which measure dip and dip direction in a single operation (as pictured) are often called "stratum" or "Klar" compasses after a German professor.
Any planar feature can be described by strike and dip. This includes sedimentary bedding, geologic faults and fractures, cuestas, igneous dikes and sills, metamorphic foliation and any other planar feature in the Earth. Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement In Structural geology and Geomorphology, a cuesta (from Spanish: "slope" is a Ridge formed by gently tilted Sedimentary rock Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock A dike or dyke in Geology is a type of Sheet intrusion referring to any geologic body that cuts Discordantly ' across planar In Geology, a sill is a tabular Pluton that has intruded between older layers of Sedimentary rock, beds of Volcanic Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic Linear features are measured with very similar methods, where "plunge" is the dip angle and "trend" is analogous to the dip direction value.
See also
Translation summary:
References
- Lahee, Frederic H. In Geomorphology, an escarpment is a transition zone between different physiogeographic provinces that involves a sharp steep Elevation differential characterized A dip slope is a geological formation often created by Erosion of tilted strata. In Structural geology and Geomorphology, a cuesta (from Spanish: "slope" is a Ridge formed by gently tilted Sedimentary rock , 1961, Field Geology, 6th ed. , McGraw-Hill
- Tarbuck, Edward J. and Frederick K. Lutgens, 2002, Earth: an Introduction to Physical Geology, 7th ed. Prentice Hall, ISBN 0-13-092025-8
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic