Plate Boundaries Flashcards
(10 cards)
What are plate boundaries?
Plate boundaries are the edges where two tectonic plates meet. They are zones of intense geological activity like earthquakes, volcanoes, and mountain formation. There are three main types: convergent, divergent, and transform.
Types of plate boundaries include: convergent, divergent, transform.
What happens at a convergent boundary?
Two plates move toward each other. Depending on the crust types involved, different features form such as mountains, trenches, volcanoes, or island arcs.
Features formed can vary based on crust type: mountains, trenches, volcanoes, island arcs.
What forms at a continental-continental convergent boundary?
Tall mountain ranges form (e.g., the Himalayas). Neither plate subducts because both are low-density continental crust. The crust folds and thickens.
Example: Himalayas.
What forms at an oceanic-continental convergent boundary?
The denser oceanic plate subducts under the continental plate, forming deep ocean trenches and volcanic mountain chains (e.g., the Andes Mountains).
Example: Andes Mountains.
What forms at an oceanic-oceanic convergent boundary?
One oceanic plate subducts under another, forming deep-sea trenches and volcanic island arcs (e.g., the Mariana Trench and the islands of Japan).
Examples: Mariana Trench, islands of Japan.
What happens at a divergent boundary?
Plates move away from each other. New crust forms from rising magma, creating features like mid-ocean ridges and rift valleys.
Key features: mid-ocean ridges, rift valleys.
What forms at a divergent boundary between oceanic plates?
Mid-ocean ridges form (e.g., the Mid-Atlantic Ridge) through seafloor spreading. New oceanic crust is created.
Example: Mid-Atlantic Ridge.
What forms at a divergent boundary between continental plates?
A continental rift valley forms (e.g., the East African Rift). If spreading continues, it may become a new ocean basin.
Example: East African Rift.
What happens at a transform boundary?
Plates slide past each other horizontally. This motion causes faults and frequent earthquakes (e.g., the San Andreas Fault). No crust is created or destroyed.
Example: San Andreas Fault.
What are some key differences between the three types of plate boundaries?
- Convergent: Plates collide → mountains, trenches, volcanoes
- Divergent: Plates move apart → ridges, rift valleys
- Transform: Plates slide past → faults, earthquakes
Summary of boundary types and their geological features.
