Search results
Results from the WOW.Com Content Network
Lineations in structural geology are linear structural features within rocks. [1] There are several types of lineations, intersection lineations, crenulation lineations, mineral lineations and stretching lineations being the most common. Lineation field measurements are recorded as map lines with a plunge angle and azimuth.
Foliation in geology refers to repetitive layering in metamorphic rocks. [1] Each layer can be as thin as a sheet of paper, or over a meter in thickness. [ 1 ] The word comes from the Latin folium , meaning "leaf", and refers to the sheet-like planar structure. [ 1 ]
2-dimensional section of Reeb foliation 3-dimensional model of Reeb foliation. In mathematics (differential geometry), a foliation is an equivalence relation on an n-manifold, the equivalence classes being connected, injectively immersed submanifolds, all of the same dimension p, modeled on the decomposition of the real coordinate space R n into the cosets x + R p of the standardly embedded ...
Slender prismatic crystals such as amphibole produce a lineation in which these prisms or columnar crystals become aligned. [1] Tectonites are rocks with minerals that have been affected by natural forces of the earth, which allowed their orientations to change. This usually includes recrystallization of minerals, and the foliation formation.
If the heat is too intense, foliation will be weakened due to the nucleation and growth of new randomly oriented crystals and the rock will become a hornfels. [1] If minimal heat is applied to a rock with a preexisting foliation and without a change in mineral assemblage, the cleavage will be strengthened by growth of micas parallel to foliation.
For instance, the intersection lineation of a S 1 cleavage and bedding is the L 1-0 intersection lineation (also known as the cleavage-bedding lineation). Stretching lineations may be difficult to quantify, especially in highly stretched ductile rocks where minimal foliation information is preserved.
In more advanced states, the later foliation will tend to form distinct foliation planes cross-cutting the earlier foliation, resulting in breaking, warping, and micro-scale folding of the earlier foliation into the new foliation. When the crenulation foliation begins to dominate it may totally or almost completely wipe out the original foliation.
Oblique foliation is a fabric that has achieved a steady state, but does not represent the total accumulated strain.. The structure is thought to result from the interplay of passive flattening and rotation of grains in a non-coaxial flow field on one hand and grain boundary migration destroying the developing shape fabric at the same time on the other hand.