Question

What type of metamorphic grade is responsible for the conversion of granite into granitic gneiss?

- Low Grade
- Very Low Grade
- High Grade
- Medium Grade

Please explain!

Answer 1

Answer: High Grade

Explanation:
Gneiss forms as a result of high-grade, regional metamorphic conditions. High grade refers to metamorphism occurring at over 320 degrees Celsius and relatively high pressure. As the grade increases, the hydrous minerals lose H20, and non-hydrous minerals become more common. The regional metamorphism results in the heavy foliation in gneiss.

Answer 2

High grade

Explanation:

• Granite is converted into granitic gnesis in high grade of metamorphic phase
• The high grade refers to the temperature above 50°C or 323K around.
• Because increasing temperature decreases water crystals in granite