Read an Academic Passage

The Theory of Plate Tectonics

The theory of plate tectonics is the foundational concept in modern geology that explains the large-scale movements of Earth's lithosphere. The lithosphere, which is the planet's rigid outer layer, is broken into several large and small pieces called tectonic plates. These plates are not static; they are constantly moving, floating on the semi-fluid asthenosphere beneath them. The movement is slow, typically only a few centimeters per year, but over millions of years, it has dramatically reshaped the planet's surface.

The idea of moving continents was first proposed in the early 20th century by Alfred Wegener as "continental drift," but it was not widely accepted. Wegener provided evidence such as the jigsaw-puzzle fit of continents like South America and Africa, fossil similarities across oceans, and corresponding rock formations. However, he could not provide a plausible mechanism to explain how the continents moved. It was not until the 1960s, with the discovery of seafloor spreading, that the theory of plate tectonics gained scientific consensus.

The movement of these plates is responsible for most of Earth's major geological features and events. At plate boundaries, where plates interact, phenomena such as earthquakes, volcanic eruptions, and the formation of mountain ranges occur. For example, the Himalayas were formed by the collision of the Indian Plate with the Eurasian Plate. The theory of plate tectonics provides a unified framework for understanding these diverse geological processes and continues to be a vital area of research.