Plate Tectonics: Earth's Lithosphere and Plate Boundaries

Study Notes

Plate tectonics is the theory that the Earth's lithosphere is broken into large plates that move relative to each other.

Lithosphere: The outermost solid layer of the Earth, including the crust and upper mantle.
Asthenosphere: The upper mantle beneath the lithosphere, which is capable of flowing over long periods of time.

Divergent Boundary: Where two plates move apart from each other, resulting in the creation of new crust.
- Examples: Mid-ocean ridges, East African Rift System
Convergent Boundary: Where two plates move towards each other, resulting in subduction or collision.
- Examples: Andean mountain building, Himalayan orogeny
Transform Boundary: Where two plates slide past each other horizontally, without creating or destroying crust.
- Examples: San Andreas Fault, North Anatolian Fault

Seafloor Spreading: The process by which new oceanic crust is created at mid-ocean ridges.
Subduction: The process by which one plate is forced beneath another plate.
Continental Drift: The movement of continents relative to each other.

Fit of the Continents: The observation that the continents fit together like a puzzle.
Mid-Ocean Ridges: The presence of volcanic mountain ranges at the boundaries of tectonic plates.
Magnetic Reversals: The alternating polarity of magnetic minerals in rocks, indicating changes in the Earth's magnetic field.
Paleomagnetism: The study of the orientation of magnetic minerals in rocks, providing evidence for continental drift.
Seismicity: The distribution of earthquakes, which is related to plate boundaries and tectonic activity.

The Earth's outermost solid layer is called the lithosphere, comprising the crust and upper mantle.
The asthenosphere is the upper mantle beneath the lithosphere, capable of flowing over long periods of time.

Divergent Boundary: Plates move apart, creating new crust, with examples including Mid-ocean ridges and the East African Rift System.
Convergent Boundary: Plates move towards each other, resulting in subduction or collision, with examples including Andean mountain building and the Himalayan orogeny.
Transform Boundary: Plates slide past each other horizontally, without creating or destroying crust, with examples including the San Andreas Fault and the North Anatolian Fault.

Fit of the Continents: The continents fit together like a puzzle.
Mid-Ocean Ridges: Volcanic mountain ranges exist at tectonic plate boundaries.
Magnetic Reversals: Alternating polarity of magnetic minerals in rocks indicates changes in the Earth's magnetic field.
Paleomagnetism: The study of magnetic minerals' orientation in rocks provides evidence for continental drift.
Seismicity: Earthquake distribution is related to plate boundaries and tectonic activity.