Search results
Results from the WOW.Com Content Network
Systematic joints are planar, parallel, joints that can be traced for some distance, and occur at regularly, evenly spaced distances on the order of centimeters, meters, tens of meters, or even hundreds of meters. As a result, they occur as families of joints that form recognizable joint sets.
Columnar jointing is a geological structure where sets of intersecting closely spaced fractures, referred to as joints, result in the formation of a regular array of polygonal prisms (basalt prisms), or columns. Columnar jointing occurs in many types of igneous rocks and forms as the rock cools and contracts.
Basalt columns seen on Porto Santo Island, Portugal. Columnar jointing of volcanic rocks exists in many places on Earth. Perhaps the most famous basalt lava flow in the world is the Giant's Causeway in Northern Ireland, in which the vertical joints form polygonal columns and give the impression of having been artificially constructed.
Conjugate Joints occur when the joints intersect each other at angles significantly less than ninety degrees. Systematic Joints are joint systems in which all the joints are parallel or subparallel, and maintain roughly the same spacing from each other. Columnar Joints are joints that cut the formation vertically in (typically) hexagonal ...
Various geological processes create discontinuities at a broadly regular spacing. For example, bedding planes are the result of a repeated sedimentation cycle with a change of sedimentation material or change in structure and texture of the sediment at regular intervals, folding creates joints at regular separations to allow for shrinkage or expansion of the rock material, etc. Normally ...
In geology and geomorphology, a tessellated pavement is a relatively flat rock surface that is subdivided into polygons by fractures, frequently systematic joints, within the rock. This type of rock pavement bears this name because it is fractured into polygonal blocks that resemble tiles of a mosaic floor, or tessellations. [1]
One way in particular that joints can be formed is due to fluid pressure, as well as at the crest of folds in rocks. This occurs at the peak of the fold or due to the fluid pressure because a localized tensile stress forms, eventually leading to jointing. [2] Another way in which joints form is due to the change in the weight of the overburden ...
This example is made more complex by the Galapagos Microplate which is a small separate plate on the rise just to the southeast of the triple junction. Chiapas coast off Tapachula where Guatemala, North America and Pacific join and small earthquakes occur weekly. This is pushed eastward by the Cocos plate.