GEO 110: Lecture 3 - Earth Layers and Plate Tectonics

Flashcards covering key concepts related to Earth's layers, tectonic movements, and related geological concepts.

Differentiation

The process by which a planet evolves from a magma ocean stage to having a core, mantle, and crust.

Lithosphere

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

Asthenosphere

The weak layer of the mantle that flows due to convective heating.

Geothermal gradient

The rate at which temperature increases with depth in the Earth.

Subduction zone

An area where one tectonic plate dives beneath another, often associated with oceanic and continental plate interactions.

Continental Drift

The theory proposing that continents were once connected and have since drifted apart, supported by fossil and geological evidence. Coined by Wegener.

Phase Diagrams

Graphs that show the relationship between pressure and temperature for different phases of a substance (solid, liquid, gas).

Seismic waves

Energy waves generated by earthquakes or other geological events, used to study the internal structure of the Earth.

Tectonic plates

Large sections of the lithosphere that move and interact at their boundaries, causing geological activity.

Earth's magnetic field

A magnetic field generated by the dynamics of the liquid outer core and the heat from the inner core.

Crust

The outermost layer of the Earth, comprising continental and oceanic crust, distinguished by its thickness and composition. Contains silicon (Si), titanium (Ti), aluminum (Al), oxygen (O), iron (Fe), calcium (Ca), sodium (Na), and potassium (K).

Transform faults

Fractures in the Earth's crust where two plates slide past each other, often associated with seismic activity. Generates small earthquakes.

P and S waves

Primary waves (P waves) are compressional waves that can travel through solids and liquids; Secondary waves (S waves) are shear waves that can only travel through solids, creating a shadow zone for liquids.

Why is core solid and liquid?

At elevated pressure, liquids want to transition to a solid. This process is known as crystallization or solidification, where substances change from liquid to solid states under specific temperature and pressure conditions.

Mantle

2900 km thick from base of crust to top of the core (largest layer by volume). Mostly Solid. It is composed of silicate minerals and plays a key role in tectonic activity. Made of silicone (Si), aluminum(Al), iron (Fe), magnesium (Mg), and oxygen (O),.

Continental crust

The outermost layer of the Earth's crust, consisting primarily of lighter, granitic rocks, and making up the continents. It is generally thicker than oceanic crust and forms the landmass of the planet. It is also less dense than oceanic crust, allowing it to rise above sea level.

Oceanic crust

The layer of the Earth's crust that underlies the oceans, primarily composed of denser basaltic rocks. It is thinner than continental crust and is continuously formed at mid-ocean ridges.

Physcial layers of Earth

Lithosphere, asthenosphere, mesosphere, outer core, and inner core. 

plate movement

Interaction of lithosphere and asthenosphere drive ____.

Mid-Ocean Ridge

an underwater mountain range formed by plate tectonics, where new oceanic crust is created. Warm, newly formed rocks close to the center of the spreading ridge are younger and thinner. 

Trench

a deep depression in the ocean floor formed by the subduction of one tectonic plate beneath another, often associated with volcanic activity.