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  2. Structural geology - Wikipedia

    en.wikipedia.org/wiki/Structural_geology

    Fold axis plunge is measured in dip and dip direction (strictly, plunge and azimuth of plunge). The orientation of a fold axial plane is measured in strike and dip or dip and dip direction. Lineations are measured in terms of dip and dip direction, if possible. Often lineations occur expressed on a planar surface and can be difficult to measure ...

  3. Strike and dip - Wikipedia

    en.wikipedia.org/wiki/Strike_and_dip

    Linear features are similarly measured with trend and plunge, where "trend" is analogous to dip direction and "plunge" is the dip angle. [3] Strike and dip are measured using a compass and a clinometer. A compass is used to measure the feature's strike by holding the compass horizontally against the feature.

  4. Geologic map - Wikipedia

    en.wikipedia.org/wiki/Geologic_map

    Trend and plunge are used for linear features, and their symbol is a single arrow on the map. The arrow is oriented in the downgoing direction of the linear feature (the "trend") and at the end of the arrow, the number of degrees that the feature lies below the horizontal (the "plunge") is noted.

  5. Glossary of geology - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_geology

    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 ...

  6. Rake (geology) - Wikipedia

    en.wikipedia.org/wiki/Rake_(geology)

    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.

  7. Carlin Unconformity - Wikipedia

    en.wikipedia.org/wiki/Carlin_Unconformity

    Carlin Trend, shown with other alignments of sediment-hosted gold deposits in Nevada.Source: USGS. Newmont's Gold Quarry mine in 2009, on the Carlin Trend. The Carlin Unconformity or Carlin Trend is a geologic feature in northeastern Nevada which represents a period of erosion or non-deposition likely associated with a collision between a tectonic crustal block called a terrane and the North ...

  8. Geological compass - Wikipedia

    en.wikipedia.org/wiki/Geological_compass

    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.

  9. Geobiology - Wikipedia

    en.wikipedia.org/wiki/Geobiology

    The origin of life from non-living chemistry and geology, or abiogenesis, is a major topic in astrobiology. Even though it is fundamentally an earth-bound concern, and therefore of great geobiological interest, getting at the origin of life necessitates considering what life requires, what, if anything, is special about Earth, what might have ...