select the correct answer. which rock has the highest metamorphic grade? a. rock formed at 500°c and 8…

select the correct answer. which rock has the highest metamorphic grade? a. rock formed at 500°c and 8 kilobars of pressure b. rock formed at 1,200°c and 20 kilobars of pressure c. rock formed at 400°c and 12 kilobars of pressure d. rock formed at 700°c and 10 kilobars of pressure

select the correct answer. which rock has the highest metamorphic grade? a. rock formed at 500°c and 8 kilobars of pressure b. rock formed at 1,200°c and 20 kilobars of pressure c. rock formed at 400°c and 12 kilobars of pressure d. rock formed at 700°c and 10 kilobars of pressure

Answer

Explanation:

Step1: Understand metamorphic grade

Metamorphic grade increases with higher temperature and pressure.

Step2: Compare given options

We compare the temperature and pressure values of each option.

  • Option A: $T = 500^{\circ}C$, $P=8$ kilobars
  • Option B: $T = 1200^{\circ}C$, $P = 20$ kilobars
  • Option C: $T = 400^{\circ}C$, $P=12$ kilobars
  • Option D: $T = 700^{\circ}C$, $P = 10$ kilobars Option B has the highest temperature and one of the highest pressures among the options.

Answer:

B. rock formed at 1,200°C and 20 kilobars of pressure