Plate Tectonics and Earth Crust Movement

A theory explaining how Earth's surface is shaped by large-scale movements of tectonic plates.

The idea that continents have moved over time, leading to the arrangement of landmasses we see today.

A supercontinent that existed millions of years ago, comprising all of Earth's landmasses.

Alfred Wegener, a German meteorologist, proposed the idea of continental drift in 1915, but his work faced significant criticism.

Geological structures, fossils, and climate data that support the theory of continental drift.

A key insight that ultimately led to the acceptance of plate tectonics, despite initial skepticism.

The process of mountain building, often caused by collisions between tectonic plates.

Occurrences of earthquakes, volcanic eruptions, and other Earth surface processes that are related to tectonic plate movements.

The process where new oceanic crust is formed at mid-ocean ridges, then moves laterally away from the ridge, being replaced by newer crust.

A crack-like valley running through the Mid-Atlantic Ridge, marking where the seafloor is pulling apart.

The rigid outer layer of Earth, consisting of both crust and the uppermost mantle, broken into large pieces called tectonic plates.

Areas where tectonic plates interact, resulting in various geological activities like earthquakes, volcanic eruptions, or mountain formation.

The freshwater reptile Mesosaurus, whose fossils are found on both South America and Africa, provides evidence for the theory of continental drift. The fact that these fossils don't exist elsewhere suggests these continents were once connected.

Alfred Wegener proposed the theory of continental drift, but he lacked a plausible explanation for the force that could move continents apart.

Convection currents within the Earth's mantle are the driving force behind continental drift and seafloor spreading. These currents create a push-and-pull effect that moves the continental plates.

The Mid-Atlantic Ridge is a deep crack-like valley running down the crest of the Atlantic Ocean. This feature is evidence of seafloor spreading, where new oceanic crust is being formed.

After World War II, extensive exploration of the ocean floor revealed that the seafloor is primarily composed of young basalt, not old granite, as some geologists initially believed.

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Mapping the Mid-Atlantic Ridge revealed a deep crack-like valley, or rift, running down its crest, providing further evidence for seafloor spreading.

The rigid outermost layer of Earth, broken into large pieces called plates.

A layer in Earth's mantle below the lithosphere, characterized by semi-molten rock that allows plates to move.

A region where two tectonic plates move apart, creating new lithosphere as magma rises and solidifies.

A region where two tectonic plates collide, causing one to subduct beneath the other, resulting in volcanic activity and mountain building.

A region where two plates slide past each other horizontally, causing earthquakes but not volcanoes.

The Pacific Plate, the largest tectonic plate, is located in the Pacific Ocean basin.

Small tectonic plates, like the Juan de Fuca Plate, can be found between larger plates.

Continental fragments, like the Anatolian Plate, can form small plates.