« previous next »

Author Question: What is metamorphic grade, and present an example of how a rock reaches its metamorphic grade? What ... (Read 62 times)

SGallaher96

  • Hero Member
  • *****
  • Posts: 509
on: Jul 15, 2018
What is metamorphic grade, and present an example of how a rock reaches its metamorphic grade? What will be an ideal response?

Question 2

What are index minerals, and what are they used for? Give an example of minerals that would be
  found in a low-grade, intermediate, and high-grade metamorphosed shale. What will be an ideal response?



djofnc

  • Sr. Member
  • ****
  • Posts: 318
Reply #1 on: Jul 15, 2018
Answer to Question 1

Metamorphic grade is a term that characterizes the degree to which a rock has undergone metamorphic
change. When shale is metamorphosed, chlorite first begins to crystallize at about 200C. If the
metamorphism stops there, the rock will be low grade. If temperatures and pressures increase, new
minerals replace chlorite, and if temperatures exceed 500C, sillimanite will appear.



Answer to Question 2

Index minerals are minerals that are known to form only within specific temperature and pressure
ranges. Their presence allows geologists to establish the metamorphic grade of a rock because the
highest-grade mineral indicates the temperature and pressure the rock was at for some time. Low-grade
minerals include chlorite, muscovite, and biotite; intermediate include muscovite, biotite, garnet,
staurolite, and kyanite; and sillimanite indicates high grade



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
« previous next »
 

Did you know?

Anesthesia awareness is a potentially disturbing adverse effect wherein patients who have been paralyzed with muscle relaxants may awaken. They may be aware of their surroundings but unable to communicate or move. Neurologic monitoring equipment that helps to more closely check the patient's anesthesia stages is now available to avoid the occurrence of anesthesia awareness.

Did you know?

Though Candida and Aspergillus species are the most common fungal pathogens causing invasive fungal disease in the immunocompromised, infections due to previously uncommon hyaline and dematiaceous filamentous fungi are occurring more often today. Rare fungal infections, once accurately diagnosed, may require surgical debridement, immunotherapy, and newer antifungals used singly or in combination with older antifungals, on a case-by-case basis.

Did you know?

Drugs are in development that may cure asthma and hay fever once and for all. They target leukotrienes, which are known to cause tightening of the air passages in the lungs and increase mucus productions in nasal passages.

Did you know?

According to the Migraine Research Foundation, migraines are the third most prevalent illness in the world. Women are most affected (18%), followed by children of both sexes (10%), and men (6%).

Did you know?

Cyanide works by making the human body unable to use oxygen.

Synaptic transmission. (a) Action potential reaches synapse; (b) neurotransmitter released synaptic ... Synaptic transmission. (a) Action potential reaches synapse; (b) neurotransmitter released synaptic ...
Granite and Granitic Rock Granite and Granitic Rock
Directional Selection in Rock-Pocket Mice Directional Selection in Rock-Pocket Mice
Tree grade 1 Tree grade 1
Grade 1 math Grade 1 math
Grade 1 drawing Grade 1 drawing
Video: Hemoglobin's affinity with oxygen - carbon dioxide, temperature and bisphosphoglycerate (BPG)

For a complete list of videos, visit our video library