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A fracture is any separation in a geologic formation, such as a joint or a fault that divides the rock into two or more pieces. A fracture will sometimes form a deep fissure or crevice in the rock. Fractures are commonly caused by stress exceeding the rock strength, causing the rock to lose cohesion along its weakest plane. [1]
Not all named fracture zones are active, indeed only the central portion of those still forming usually is, in an area of active transform faulting associated with a mid-ocean ridge. Classic fracture zones remain significant ocean floor features with usually different aged rocks on either side of the fracture zone due to past tectonic processes.
The fracture zone is thus the junction between oceanic crustal regions of different ages. Because younger crust is generally higher due to increased thermal buoyancy, the fracture zone is characterized by an offset in elevation with an intervening canyon that may be topographically distinct for hundreds or thousands of kilometers on the sea floor.
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth 's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of ...
This glossary of geography terms is a list of definitions of terms and concepts used in geography and related fields, including Earth science, oceanography, cartography, and human geography, as well as those describing spatial dimension, topographical features, natural resources, and the collection, analysis, and visualization of geographic ...
It is the emission of light from the fracture (rather than rubbing) of a crystal, but fracturing often occurs with rubbing. Depending upon the atomic and molecular composition of the crystal, when the crystal fractures, a charge separation can occur, making one side of the fractured crystal positively charged and the other side negatively charged.
The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface, it is called a normal tensile crack or simply a crack ; if a displacement develops tangentially, it is called a shear crack , slip band , or dislocation .
Such fractures occur in planar parallel sets at an angle of 60 degrees and can be of the same size and scale as joints. As a result, some "conjugate joint sets" might actually be shear fractures. Shear fractures are distinguished from joints by the presence of slickensides, the products of shearing movement parallel to the fracture surface. The ...