Peridotite

Definition

Peridotite is a dense, coarse-grained igneous rock primarily composed of olivine, with lesser amounts of pyroxene and other minerals. It is significant as the main rock type found in the Earth's mantle, providing insights into the composition and processes occurring deep beneath the Earth's crust.

5 Must Know Facts For Your Next Test

1. Peridotite is predominantly found in ophiolite complexes and is crucial for understanding mantle dynamics and composition.
2. The high magnesium and iron content in peridotite gives it a unique density, making it significantly heavier than rocks found in the Earth's crust.
3. Peridotite can undergo partial melting, resulting in the formation of basalt, which is a common volcanic rock.
4. The study of peridotite samples brought up by mantle plumes can provide valuable information about mantle convection and plate tectonics.
5. In addition to being a key mantle rock, peridotite also contains valuable minerals like diamonds and chrome, making it economically significant.

Review Questions

• How does the mineral composition of peridotite influence its role in understanding the Earth's mantle?
  • Peridotite's mineral composition, primarily consisting of olivine and pyroxene, directly reflects the conditions and processes occurring in the Earth's mantle. Its high magnesium and iron content suggest that it forms under high-pressure environments deep within the Earth. By studying peridotite, scientists can gain insights into mantle composition, temperature, and the mechanisms of plate tectonics, making it a crucial rock for geologists.
• Evaluate the significance of peridotite in the context of mantle dynamics and volcanic activity.
  • Peridotite plays a significant role in mantle dynamics as it is involved in processes such as partial melting and magma formation. When peridotite undergoes partial melting due to high temperatures and pressures, it generates basaltic magma, which can lead to volcanic eruptions at the surface. Understanding these interactions helps geologists assess volcanic hazards and offers insight into how material from the mantle moves to the Earth's surface, influencing geological activity.
• Synthesize information about how peridotite contributes to our understanding of plate tectonics and Earth’s geological history.
  • Peridotite provides essential information about plate tectonics and Earth’s geological history through its association with both mantle dynamics and crust formation. By analyzing peridotite samples from various geological settings, researchers can trace the movement of tectonic plates and understand how these movements have shaped continents over millions of years. Additionally, studying how peridotite transforms into other rock types during tectonic processes reveals critical aspects of Earth's evolution, helping to reconstruct its complex geological history.

Related terms

Olivine: A green mineral that is a primary component of peridotite, often responsible for its distinctive color and characteristics.

Mantle: The layer of the Earth located between the crust and the core, composed mainly of silicate minerals including peridotite.

Asthenosphere: A semi-fluid layer within the upper mantle that allows tectonic plates to move and is composed largely of peridotite.