Plate Tectonics Flashcards

Study Notes

Theory of Continental Drift

Proposed by Alfred Wegener; suggests all continents were once a single landmass.
Continents have since drifted apart over geological time.

Types of Evidence for the Theory

Fossils found on widely separated continents indicate historical connectivity.
Similar rock formations and geological features across continents support the drift theory.
Fit of continental shores resembles a jigsaw puzzle, hinting at their previous formation as a single mass.

Rock Evidence

Brazilian coal field layers align with those in Africa, demonstrating similar environmental conditions in the past.
Presence of glacial deposits in currently warm regions indicates former colder climates when the continents were joined.

Mid-Ocean Ridge

Characterized by a deep crack in the oceanic mountain ranges.
Site of significant volcanic activity, contributing to the formation of new ocean floor.
Represents a divergent boundary where tectonic plates move apart.

Ocean Floor Spreading

Occurs when lava rises to fill cracks in the ocean floor and solidifies, creating new crust.
Responsible for the continuous renewal of oceanic crust over time.

Earth's Surface Size

The size of Earth's surface remains constant as oceanic crust is recycled; new ocean floor is created at mid-ocean ridges while older crust is subducted.

Oldest Rocks

Found primarily at oceanic trenches, indicating areas where subduction occurs.

Youngest Rocks

Located at mid-ocean ridges where new crust is formed through volcanic activity.

Trench

A deep V-shaped valley on the ocean floor, forming at subduction zones.
Represents the deepest parts of the ocean and is often in proximity to continental regions or islands.
Old oceanic floor is pushed back into the Earth and melted down into the mantle.

Subduction

The process by which one tectonic plate is forced below another, leading to significant geological activity.

Lithospheric Plates

Comprise the Earth's crust and the upper part of the mantle.
There are seven major tectonic plates, including the North American Plate, on which the U.S. is situated, except for California.

Divergent Plate Boundary

Occurs where tectonic plates move away from each other, commonly at mid-ocean ridges.
This separation leads to volcanic formations and the creation of new oceanic crust.

Convergent Plate Boundary

Characterized by plates sliding horizontally past one another, often resulting in earthquake activity and mountain formation.

Description

Test your knowledge on the concepts of Plate Tectonics with these flashcards. Learn about the Theory of Continental Drift, the types of evidence supporting it, and important geological features like the mid-ocean ridge. Perfect for students wanting to deepen their understanding of Earth's structure.