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Although joints can occur singly, they most frequently appear as joint sets and systems. A joint set is a family of parallel, evenly spaced joints that can be identified through mapping and analysis of their orientations, spacing, and physical properties. A joint system consists of two or more intersecting joint sets. [1] [2] [3]
Columnar jointing in Giant's Causeway in Northern Ireland Columnar jointing in the Alcantara Gorge, Sicily. 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.
In metamorphic geology, a compatibility diagram shows how the mineral assemblage of a metamorphic rock in thermodynamic equilibrium varies with composition at a fixed temperature and pressure. Compatibility diagrams provide an excellent way to analyze how variations in the rock's composition affect the mineral paragenesis that develops in a ...
[[Category:Geology templates]] to the <includeonly> section at the bottom of that page. Otherwise, add <noinclude>[[Category:Geology templates]]</noinclude> to the end of the template code, making sure it starts on the same line as the code's last character.
In geology and geophysics, thermal subsidence is a mechanism of subsidence in which conductive cooling of the mantle thickens the lithosphere and causes it to decrease in elevation. This is because of thermal expansion : as mantle material cools and becomes part of the mechanically rigid lithosphere, it becomes denser than the surrounding material.
The thin parts are the oceanic crust, which underlies the ocean basins (5–10 km) and is mafic-rich [9] (dense iron-magnesium silicate mineral or igneous rock). [10] The thicker crust is the continental crust , which is less dense [ 11 ] and is felsic -rich (igneous rocks rich in elements that form feldspar and quartz ). [ 12 ]
The letters A and B at the top correspond to the line labeled A--B on the smaller map. In this example, the vertical scale is exaggerated compared to the horizontal scale. A cross section or cross-section , in geology , is a diagram representing the geologic features intersecting a vertical plane , and is used to illustrate an area's structure ...
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. [1] [2] In this aspect the most common device used to date is the analogue compass.