The Plate Tectonics Paradigm

The Plate Tectonics Paradigm is a unifying concept in geology that explains the large-scale motions of Earth’s lithosphere.
Consisting of the continental and oceanic crust as well as the outermost layer of the mantle, the lithosphere is divided into a series of plates.
These plates float and move on the fluid-like (viscous) asthenosphere beneath, with their motion driven by convection currents caused by Earth’s internal heat.

Plate boundaries are regions where two plates interact and are categorised as being either convergent, divergent, or transform.
Convergent boundaries occur when plates collide into one another, leading to the subduction of the denser plate or continental collision.
Divergent boundaries are where plates move apart, typically under oceans, leading to seafloor spreading and the creation of new crust from upwelling molten material.
Transform boundaries involve plates sliding past one another and are the sites of earthquakes, such as the San Andreas fault in California.

Seismic activity, including earthquakes and volcanic eruptions, is intimately related to plate tectonics due to the movement and interaction of the plates at their boundaries.
Plate tectonics is also responsible for mountain formation. For instance, the Himalayas were formed from the collision of the Indian and Eurasian plates.
The movement of plates can cause the opening and closing of oceans — an example being the Atlantic Ocean, which continues to widen due to the divergence of the North American and Eurasian plates.

The plate tectonics paradigm evolved from the earlier concept of continental drift, proposed by Alfred Wegener in the early 20th century.
The theory of seafloor spreading put forth by Harry Hess along with additional evidence from rock magnetism (paleomagnetism) greatly contributed to the development of the modern theory of plate tectonics.

Plate tectonics not only shapes the physical environment but also significantly influences life on Earth by affecting climate, evolution, and the distribution of resources.
Biogeography, the study of the distribution patterns of living organisms, can often be explained by the historical movements of tectonic plates.
Earth’s rich natural resources and mineral deposits such as gold, diamonds, and other precious metals are often found at plate boundaries where geologic activity concentrates these materials.