2 - The Earth's Layers: Compositional and Mechanical Structures

A collection of vocabulary flashcards covering key terms and concepts related to the Earth's layers and geological structures.

Continental Crust

The thicker part of the earth's crust that forms the continents, generally between 10-70 km thick.

Oceanic Crust

The thinner part of the earth's crust that forms the ocean floor, typically 5-7 km thick.

Mantle

The layer of the Earth between the crust and core, comprising a majority of Earth's volume.

Lithosphere

The rigid outer layer of the Earth composed of the crust and the upper mantle.

Asthenosphere

The semi-fluid layer beneath the lithosphere on which tectonic plates float.

Moho Discontinuity

The boundary between the Earth's crust and the underlying mantle, marked by an increase in seismic wave velocity.

Xenoliths

Fragmental pieces of rock that are distinct from the surrounding rock, often found in igneous rocks.

Ophiolite

A section of the Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed.

Isostasy

The equilibrium of the Earth's crust floating on the denser, underlying mantle.

Granodiorite

An intrusive igneous rock that is a mixture of granite and diorite, commonly found in the Earth's crust.

Seismic Reflection

A geophysical technique for exploring subsurface structures by analyzing reflected seismic waves.

Seismic Refraction

A method used to determine the structure of the Earth by analyzing the refracted waves after seismic waves hit different materials.

Plutonics

A type of igneous rock formed from the cooling and solidification of magma below the Earth's surface.

Ringwoodite

A high-pressure form of olivine, found in the Earth's transition zone, important for understanding mantle composition.

P-Waves

Seismic waves that compress and expand the ground, can travel through both solid and liquid.

S-Waves

Seismic waves that move the ground up and down or side to side, can only travel through solid materials.

D-'' Layer

The heterogeneous region of the lower mantle, possibly related to temperature variations and partial melts.

Geotherm

The temperature distribution within the Earth, often visualized as a function of depth.