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A joint system consists of two or more intersecting joint sets. [1] [2] [3] The distinction between joints and faults hinges on the terms visible or measurable, a difference that depends on the scale of observation. Faults differ from joints in that they exhibit visible or measurable lateral movement between the opposite surfaces of the ...
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.
A discontinuity may exist as a single feature (e.g. fault, isolated joint or fracture) and in some circumstances, a discontinuity is treated as a single discontinuity although it belongs to a discontinuity set, in particular if the spacing is very wide compared to the size of the engineering application or to the size of the geotechnical unit.
Igneous rock – Rock formed through the cooling and solidification of magma or lava; Metamorphic rock – Rock that was subjected to heat and pressure; Sedimentary rock – Rock formed by the deposition and cementation of particles; Structural geology – Science of the description and interpretation of deformation in the Earth's crust
Exfoliation joints underlying a dam foundation can create a significant leakage hazard, while increased water pressure in joints may result in lifting or sliding of the dam. Finally, exfoliation joints can exert strong directional control on groundwater flow and contaminant transport.
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 columns. These tend to be a result of cooling and contraction in hypabyssal intrusions or lava flows.
A McKelvey diagram or McKelvey box is a visual representation used to describe a natural resource such as a mineral or fossil fuel, based on the geologic certainty of its presence and its economic potential for recovery. The diagram is used to estimate the uncertainty and risk associated with availability of a natural resource.
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.