upper mantle

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upper mantle

The geologist points to a diagram of the Earth's upper mantle.

Definition
  1. Noun:
    • The upper part of the mantle: The solid, rocky layer of the Earth's interior located directly beneath the crust and extending to a depth of approximately 410 miles (660 kilometers). It is a region of the mantle where tectonic plate movement originates.
Usage Examples
  • Noun:
    • Seismic waves change speed as they pass through the upper mantle, helping scientists map its structure.
    • The boundary between the crust and the upper mantle is known as the Mohorovičić discontinuity, or Moho.
    • Convection currents within the upper mantle are a driving force behind plate tectonics.
Advanced Usage
  • "Upper mantle composition": Refers to the specific mineralogy and chemical makeup of this layer, primarily consisting of peridotite.
    • Studies of xenoliths provide direct evidence of the upper mantle composition.
  • "Upper mantle discontinuity": Refers to a boundary within the upper mantle where seismic wave velocities change abruptly, indicating a phase transition in the minerals.
    • The 410-kilometer upper mantle discontinuity marks the transition from olivine to wadsleyite.
Variants and Related Words
  • Mantle (n): The thick layer of hot, solid rock between the Earth's crust and core. The upper mantle is a subdivision of this layer.
  • Asthenosphere (n): The ductile, partially molten region within the upper mantle on which the tectonic plates move.
  • Lithosphere (n): The rigid outer layer of the Earth, comprising the crust and the uppermost, solid part of the upper mantle.
Synonyms
  • No direct single-word synonyms. It is a specific scientific term. Descriptive phrases include:
    • The shallow mantle
    • The outer mantle region
Related Phrases
  • "Upper mantle convection": The slow, creeping motion of solid rock in the upper mantle due to heat from the core, which drives plate movements.
    • The model simulates upper mantle convection patterns.
  • "Upper mantle velocity structure": A description of how the speed of seismic waves varies with depth in this layer, revealing its physical properties.
    • The new tomography study revealed a complex upper mantle velocity structure beneath the continent.
upper mantle

The geologist points to a diagram of the Earth's upper mantle.

Noun
  1. the upper part of the mantle