Question

Which of the following statements about Dynamic Metamorphism is true?

1. It is also known as pressure-induced metamorphism.
2. It leads to the chemical alteration of mineral structures.
3. It involves the destruction and fracturing of minerals.

• A. 2, 3
• B. 1, 3
• C. None of these
• D. 1 only

Answer 1

Answer:

B. 1, 3

Dynamic Metamorphism: Key Concepts

Also Known As:

• Dynamic metamorphism is also referred to as stress metamorphism or cataclastic metamorphism. It is distinct from regional and contact metamorphism.

Primary Processes:

• This type of metamorphism is primarily driven by mechanical deformation under conditions of high pressure and temperature, but with a significant emphasis on directed stress.
• It involves the physical breakdown of rocks and minerals due to immense pressure, leading to the destruction and fracturing of pre-existing mineral grains.
• This physical process results in the formation of textures like mylonites, which are characterized by fine-grained, foliated rock structures.

Chemical Alteration:

• While physical deformation is the dominant process, some chemical recrystallization can occur. However, it is not the primary driver as seen in other forms of metamorphism.
• It does not primarily lead to the extensive chemical alteration of mineral structures in the same way as hydrothermal or contact metamorphism. The focus is on mechanical effects.

Conditions and Locations:

• Dynamic metamorphism is typically associated with areas of intense tectonic activity, such as fault zones and the roots of mountain belts where rocks are subjected to shearing and crushing forces.
• The heat involved aids in the deformation process but is often secondary to the mechanical stress.