Plate Tectonics

Definition

Plate tectonics is the scientific theory that explains the movement of Earth's lithosphere, which is divided into tectonic plates that float on the semi-fluid asthenosphere beneath them. This movement shapes the Earth's surface through various processes such as earthquakes, volcanic activity, mountain building, and ocean basin formation.

5 Must Know Facts For Your Next Test

1. There are three main types of plate boundaries: convergent, divergent, and transform, each associated with distinct geological features.
2. The theory of plate tectonics is supported by evidence from seafloor spreading, the distribution of earthquakes and volcanoes, and the matching geological formations across continents.
3. Plate movements can lead to natural hazards such as tsunamis, earthquakes, and volcanic eruptions, which can have devastating effects on human populations and ecosystems.
4. The collision of tectonic plates can create mountain ranges, while their separation can result in ocean basins and rift valleys.
5. Biogeography is influenced by plate tectonics as the movement of plates affects species distribution and evolution by altering habitats and creating barriers.

Review Questions

• How do the interactions between different types of plate boundaries contribute to the formation of specific landforms?
  • The interactions at plate boundaries directly shape landforms. Convergent boundaries lead to mountain building as one plate is pushed over another, while divergent boundaries create rift valleys or ocean ridges as plates pull apart. Transform boundaries can cause fault lines and significant seismic activity. Understanding these interactions helps explain the diverse topography seen around the world.
• Evaluate how evidence from ocean basins supports the theory of plate tectonics.
  • Evidence from ocean basins plays a crucial role in validating plate tectonics. For instance, patterns of magnetic stripes on the seafloor indicate past movements of tectonic plates through seafloor spreading. The age of oceanic crust also supports this theory, as older crust is found further from mid-ocean ridges where new crust is formed. These observations illustrate how the ocean's structure directly corresponds to tectonic activity.
• Assess the implications of plate tectonics on biogeography and species distribution over geological time.
  • Plate tectonics significantly impacts biogeography by influencing habitat availability and species migration. As continents drift apart or collide, ecosystems change dramatically. For example, when landmasses separate, populations can become isolated leading to divergent evolution. Additionally, tectonic activity can create barriers like mountain ranges or oceanic expanses that dictate where species can thrive or migrate, shaping biodiversity across regions throughout Earth's history.

Related terms

Tectonic Plates: Large sections of Earth's lithosphere that move and interact with one another, causing geological phenomena.

Asthenosphere:

The semi-fluid layer of the upper mantle beneath the lithosphere that allows tectonic plates to move.

Subduction Zone: An area where one tectonic plate is being forced under another, often leading to volcanic activity and earthquakes.