« previous next »

Author Question: What is metamorphic grade, and present an example of how a rock reaches its metamorphic grade? What ... (Read 67 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?

Every 10 seconds, a person in the United States goes to the emergency room complaining of head pain. About 1.2 million visits are for acute migraine attacks.

Did you know?

The highest suicide rate in the United States is among people ages 65 years and older. Almost 15% of people in this age group commit suicide every year.

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?

There are approximately 3 million unintended pregnancies in the United States each year.

Did you know?

The newest statin drug, rosuvastatin, has been called a superstatin because it appears to reduce LDL cholesterol to a greater degree than the other approved statin drugs.

Atlatl mammoth ivory "creeping hyena", found in La Madeleine rock shelter, dated back to c Atlatl mammoth ivory "creeping hyena", found in La Madeleine rock shelter, dated back to c
Listening to loud music with headphones or at rock concerts is a frequent cause of hearing loss amon Listening to loud music with headphones or at rock concerts is a frequent cause of hearing loss amon
Evolution of the Sun's luminosity, radius and effective temperature compared to the present Sun Evolution of the Sun's luminosity, radius and effective temperature compared to the present Sun
Volcanoes Are Rock Factories Volcanoes Are Rock Factories
Golden sonic grade 1 drawing Golden sonic grade 1 drawing
Grade 1 achievement certificate Grade 1 achievement certificate
Video: Interview with Person who has Schizophrenia

For a complete list of videos, visit our video library