Question

Which type of metamorphism involves the fracturing and compression of rocks causing physical damage to minerals without any chemical changes?

• A. Regional Metamorphism
• B. Contact Metamorphism
• C. Dynamic Metamorphism
• D. Thermal Metamorphism

Answer 1

Answer:

C. Dynamic Metamorphism

Dynamic Metamorphism

Characteristics and Processes

• Dynamic metamorphism, also known as cataclastic metamorphism, primarily occurs due to the intense mechanical stress and pressure associated with tectonic plate movements, such as faulting and folding.
• This type of metamorphism is characterized by fracturing, grinding, and shearing of rocks.
• It leads to the physical deformation of minerals and rock structures.
• Key indicators include fault breccia (angular fragments cemented together) and mylonites (finely banded rocks formed under shear stress).
• Crucially, dynamic metamorphism involves minimal to no chemical changes in the minerals. The mineral composition remains largely the same, but their shape, size, and arrangement are altered.
• It often occurs at shallower depths compared to other types of metamorphism like regional or contact metamorphism.

Distinction from Other Metamorphic Types

• Unlike regional metamorphism, which involves heat, pressure, and chemical reactions over large areas, dynamic metamorphism is driven primarily by mechanical forces.
• Compared to contact metamorphism, where heat from igneous intrusions causes changes, dynamic metamorphism relies on mechanical stress.
• The absence of significant chemical recrystallization or the formation of new minerals is a defining feature differentiating it from other metamorphic processes.

Geological Significance

• Areas undergoing significant faulting and crustal deformation are prime locations for dynamic metamorphism.
• It plays a role in understanding the structural evolution of mountain belts and fault zones.