Plate tectonics is the scientific theory explaining the movement of Earth's lithosphere, which is divided into several plates.
Table of Contents
Lithosphere and Asthenosphere
Lithosphere: It is the rigid outer layer of the Earth, consisting of the crust and the upper mantle.
Asthenosphere: It is the semi-fluid layer beneath the lithosphere, allowing the plates to move.
Tectonic Plates
Earth's lithosphere is broken into major and minor plates (e.g., Pacific Plate, North American Plate).
These plates float on the semi-fluid asthenosphere.
Plate Movements
Plates move due to convection currents in the mantle, slab pull, and ridge push.
Movements can be divergent (moving apart), convergent (coming together), or transform (sliding past each other).
Types of Plate Boundaries
Divergent Boundaries: Plates move apart, creating new crust (e.g., Mid-Atlantic Ridge).
Convergent Boundaries: Plates collide, leading to subduction or mountain formation (e.g., Himalayas).
Transform Boundaries: Plates slide horizontally past each other (e.g., San Andreas Fault).
Geological Activities
Earthquakes: Caused by the release of energy as plates move.
Volcanic Activity: Occurs at divergent and convergent boundaries.
Mountain Building: Result of convergent plate interactions.
Historical Development
Alfred Wegener's continental drift hypothesis laid groundwork.
Further evidence from sea-floor spreading and paleomagnetism solidified the theory.
Significance
Explains distribution of earthquakes, volcanoes, mountain ranges, and oceanic trenches.
Fundamental for understanding Earth's geological history and processes.
