Admin Table of Contents
- 1 What do we call metamorphic rocks in which mineral grains are not arranged in bands?
- 2 What is the texture called where a metamorphic rock shows alignment of mineral grains?
- 3 How are foliated metamorphic rocks different from non-foliated metamorphic rocks?
- 4 What is foliated texture?
- 5 Why is migmatite classified as a metamorphic rock?
What do we call metamorphic rocks in which mineral grains are not arranged in bands?
Chapter 6: Rocks (Flashcards, Matching, Concentration, Word Search)
| A | B |
|---|---|
| foliation | the metamorphic rock texture in which mineral grains are arranged in planes or bands |
| nonfoliated | the metamorphic rock texture in which mineral grains are not arranged in planes or bands |
What is an alignment of minerals called in a rock?
Foliation is produced in a rock by the parallel alignment of platy minerals (e.g., muscovite, biotite, chlorite), needle-like minerals (e.g., hornblende), or tabular minerals (e.g., feldspars). This parallel alignment causes the rock to split easily into thin layers or sheets.
Which metamorphic rock has mineral alignment?
Foliated Metamorphic Rocks
Foliated Metamorphic Rocks: Foliation forms when pressure squeezes the flat or elongate minerals within a rock so they become aligned. These rocks develop a platy or sheet-like structure that reflects the direction that pressure was applied.
What is the texture called where a metamorphic rock shows alignment of mineral grains?
foliation
foliation, planar arrangement of structural or textural features in any rock type but particularly that resulting from the alignment of constituent mineral grains of a metamorphic rock of the regional variety along straight or wavy planes.
Why are metamorphic rocks called metamorphic?
Metamorphic rocks form from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock. The word “metamorphic” comes from Greek and means “To Change Form”.
What is non foliated metamorphic rocks?
Overview. 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.
How are foliated metamorphic rocks different from non-foliated metamorphic rocks?
Foliated metamorphic rocks such as gneiss, phyllite, schist and slate have a layered or banded appearance that is produced by exposure to heat and directed pressure. Non-foliated metamorphic rocks such as hornfels, marble, quartzite and novaculite do not have a layered or banded appearance.
What is mineral alignment?
Minerals can become aligned due to the circumstances of their environment. The process has been given the name foliation to describe when minerals become aligned.
Is serpentinite foliated or Nonfoliated?
Amphibolite: a metamorphic rock dominated by hornblende + plagioclase. Amphibolites may be foliated or non-foliated. The protolith is either a mafic igneous rock or graywacke. Serpentinite: an ultramafic rock metamorphosed at low grade, so that it contains mostly serpentine.
What is foliated texture?
Foliation is described as the existence or appearance of layers. Foliated textures result from a parallel arrangement of flat, platy minerals. This is usually a result of mineral recrystallization in the presence of a directed pressure. Very flat foliation that resembles mineral cleavage.
What type of metamorphic rock has large grains?
Similar to phyllite but with even larger grains is the foliated metamorphic rock schist, which has large platy grains visible as individual crystals. Common minerals are muscovite, biotite, and porphyroblasts of garnets.
What is metamorphic texture?
Metamorphic texture is the description of the shape and orientation of mineral grains in a metamorphic rock. Metamorphic rock textures are foliated, non-foliated, or lineated are described below.
Why is migmatite classified as a metamorphic rock?
With its curling light and dark veins, migmatite can be very picturesque. Yet even with this extreme degree of metamorphism, the minerals are arranged in layers and the rock is clearly classified as metamorphic.
What type of chemical reactions occur during metamorphism?
Chemical reactions of many sorts occur during metamorphism. Different parent-rock compositions produce different kinds of metamorphic rocks. The composition of the parent rock determines the metamorphic minerals and rocks that may form.