Table of Contents
What is Lineation foliation?
Foliation is the result of the parallel arrangement of (micas, etc.) in a plane perpendicular to the maximum principal applied stress. A lineation is caused by a similar growth of elongate minerals (eg. hornblende) in this plane. Slate, schist, and gneiss are three common foliated metamorphic rocks.
Is burial metamorphism foliated?
Burial metamorphism occurs when sediments are buried deeply enough that the heat and pressure cause minerals to begin to recrystallize and new minerals to grow, but does not leave the rock with a foliated appearance.
What is burial metamorphism?
Burial Metamorphism (Fig. 8.3): occurs when sedimentary rocks that had undergone diagenesis are buried even deeper. Diagenesis grades into burial metamorphism, a relatively mild type of metamorphism resulting from the heat and pressure exerted by overlying sediments and sedimentary rocks.
What is non foliated metamorphic rocks?
Nonfoliated metamorphic rocks lack foliated texture because they often lack platy minerals such as micas. They commonly result from contact or regional metamorphism. Examples include marble, quartzite, greenstone, hornfel, and anthracite.
What causes lineation geology?
Lineation may be formed during deformation by the parallel alignment of minerals, fossils, or pebbles; by parallel crenulation cleavages; or by striations and grooves resulting from the movement of a rock over a plane, e.g. a fault surface (see SLICKENSIDE), or flexural slip during folding.
What is an example of burial metamorphism?
A good example of low-pressure–high-geothermal-gradient burial metamorphism is seen in the rocks of the Tanzawa Mountains, Japan where the metamorphism varies from zeolite to amphibolite facies (Seki et al., 1969). The low-grade rocks are undeformed and made up of andesitic and basaltic material.
What are the 3 types of foliation?
There are three types of foliated rocks: slate, schist, and gneiss. Each type varies based on the size of the mineral grain and how foliation is characterized.
Which of the following causes the foliation or lineation among deformed rocks?
Differential stress (pressure) is the main force causing minerals to align parallel to each other and create a texture that is foliated or lineated.
What causes lineation in metamorphic rocks?
A lineation is caused by a similar growth of elongate minerals (eg. hornblende) in this plane. Slate, schist, and gneiss are three common foliated metamorphic rocks.
What is meant by foliation in metamorphic rocks?
Foliation in metamorphic rocks is related to the orientation of the applied stresses and not the original sedimentary or earlier metamorphic structures. The original shale bedding (relict bedding) is sometimes preserved as color contrasts in a slate. In most cases the slate’s fracture cleavage lies at some angle to the original bedding plane.
What are the three most common foliated metamorphic rocks?
Slate, schist, and gneiss are three common foliated metamorphic rocks. Slate is a hard, fine-grained rock with a well-developed rock cleavage or slaty cleavage caused by the incipient growth of platy (micaceous) minerals, due to metamorphism of fine-grained clastic sediments such as shale and siltstone and also volcanic tuffs.
What is the process of metamorphism?
Metamorphism is the process that changes existing rocks (called protoliths) into new rocks with new minerals and new textures. Increases in temperature and pressure are the main causes of metamorphism, with fluids adding important mobilization of materials. The primary way metamorphic rocks are identified is with texture.