Earth's Structure and Plate Tectonics

These flashcards cover key terms and concepts related to the Earth's structure and plate tectonics from the lecture notes.

Crust

The outermost layer of the Earth, includes oceanic and continental crust.

Lithosphere

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

Asthenosphere

The semi-molten, ductile part of the upper mantle beneath the lithosphere.

Mantle

A thick layer of silicate rock that drives plate movement via convection currents.

Outer Core

The liquid iron and nickel layer that generates Earth's magnetic field.

Inner Core

The solid iron-nickel alloy center of the Earth due to immense pressure.

Mohorovičić Discontinuity (Moho)

The boundary between the crust and mantle, identified by changes in seismic wave velocity.

Oceanic Crust

The segment of Earth's crust that is under the oceans, typically 6-10 km thick and basaltic.

Continental Crust

The thicker part of the Earth's crust that forms the continents, typically 30-50 km thick and granitic.

Sea-Floor Spreading

The process of creating new oceanic crust at mid-ocean ridges as magma rises and solidifies.

Palaeomagnetism

The study of the magnetic properties of rocks to understand historical magnetic field changes.

Divergent Boundaries

Plate boundaries where plates move apart, leading to the formation of mid-ocean ridges.

Convergent Boundaries

Plate boundaries where plates collide, leading to subduction and the formation of mountains, trenches, and volcanoes.

Transform Boundaries

Plate boundaries where plates slide past each other, causing earthquakes without creating or destroying crust.

Explosive Volcanoes

More likely to occur at subduction zones where wet, silicic magma is present.

Shield Volcanoes

Commonly found at divergent boundaries, formed from basaltic magma.

Major Tectonic Plates

The large segments of Earth's lithosphere that move and interact at plate boundaries.

Geological similarities

Evidence for plate tectonics based on shared mountain ranges and rock types across continents.

Fossil Correlations

Evidence for plate tectonics found in similar fossils across different continents.