Definition

Noun: - A type of rock that has been transformed from its original form (igneous, sedimentary, or older metamorphic rock) by the effects of heat, pressure, and chemical activity, usually deep within the Earth's crust. This process, called metamorphism, changes the rock's mineral composition and texture without melting it.

Usage

• As a subject or object in a sentence: The term is used to identify or describe a specific class of rocks formed through metamorphism.
• In geological contexts: It is a fundamental category in the rock cycle, alongside igneous and sedimentary rocks.

Examples

• Noun:
  • Marble and slate are common examples of metamorphic rock.
  • The mountain range contains extensive bands of metamorphic rock formed during a continental collision.
  • Geologists study metamorphic rock to understand the history of pressure and temperature in a region.

Advanced Usage

• "Metamorphic rock" as a mass noun: Often used without an article to refer to the material in general.
  • The cliff face is composed of metamorphic rock.
• Specifying the parent rock: The original rock type can be mentioned.
  • This metamorphic rock originated as limestone.

Variants and Related Words

• Metamorphism (n): The process that forms metamorphic rock.
  • Regional metamorphism occurs over large areas.
• Metamorphic (adj): Describing rocks formed by metamorphism or the process itself.
  • The metamorphic changes created new mineral grains.

Synonyms

• Metamorphite (n): A less common technical synonym for metamorphic rock.
• Altered rock: A descriptive phrase emphasizing the transformation.

Related Phrases

• Parent rock / Protolith: The original rock from which a metamorphic rock forms.
  • The protolith for this schist was likely shale.
• Foliated metamorphic rock: A subtype where minerals are aligned in parallel layers or bands (e.g., schist, gneiss).
• Non-foliated metamorphic rock: A subtype with no layered structure (e.g., marble, quartzite).

Noun

1. rock altered by pressure and heat