Geology and Earth Sciences Review

These flashcards cover key terms and concepts related to geology and earth sciences, including Earth's structure, types of rocks, and plate tectonics.

Inner core

Solid part of the Earth's core, composed mainly of iron and nickel. It’s kept solid due to extremely high pressure despite very high temperatures.

Outer core

Liquid layer of the Earth's core, also made up of iron and nickel.

Lithosphere

Uppermost layer of the Earth, consisting of the crust and the upper mantle; rigid and broken into tectonic plates.

Asthenosphere

Zone of the upper mantle beneath the lithosphere where rocks can flow plastically.

Element

Substance that cannot be broken down into simpler substances by heating or chemical reactions, consisting of atoms.

Mineral

Naturally occurring solid with a definite chemical composition.

Cleavage (in minerals)

The tendency of a mineral to break along specific planes of weakness.

Igneous rocks

Rocks formed from the solidification of magma or lava.

Extrusive rocks

Igneous rocks that solidify from lava quickly on the Earth's surface.

Intrusive rocks

Igneous rocks formed from the slow solidification of magma beneath the Earth’s surface.

Felsic rocks

Igneous rocks with more than 66% SiO2, such as granite and rhyolite.

Mafic rocks

Igneous rocks with 45-52% SiO2, such as gabbro and basalt.

Sedimentary rocks

Rocks formed from the cementation and compaction of sediments.

Metamorphic rocks

Rocks that have been changed from their original form due to heat and pressure.

Lithification

The process of turning sediments into solid rock through compaction and cementation.

Clastic sediments

Sediments composed of fragments of pre-existing rocks.

Folds

Bends or curves in rock layers resulting from tectonic forces.

Faults

Fractures in rock where there has been displacement.

Epicenter

The point on the Earth's surface directly above where an earthquake originates.

P waves

Primary seismic waves that are compressional and travel through solids, liquids, and gases.

S waves

Secondary seismic waves that are shear and can only move through solids.

Tsunamis

Large ocean waves typically caused by underwater earthquakes or volcanic activities.

Plate tectonics

The theory explaining the movement of the Earth's plates on the viscous mantle underneath.

Isotasy

The equilibrium between segments of the Earth's crust floating on the underlying mantle.

Caldera

A large depression formed after a volcanic eruption when a magma chamber is emptied.

Hot spots

Areas of volcanic activity resulting from plumes of hot mantle material breaking through the crust.

Crust (Continental and Oceanic)

The outermost layer of the Earth; continental crust is less dense and high in silica, while oceanic crust is denser and low in silica.

Seafloor spreading

The process where new oceanic crust is created at mid-ocean ridges, pushing older crust away.