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How did the formation and closure of ocean basins create mountain belts during the Proterozoic Eon?
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geologic history of Earth
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During the Proterozoic Eon, mountain belts were primarily formed through the cyclic process of supercontinent assembly and breakup, driven by plate tectonics.1
The creation of these mountain belts followed a sequence similar to the Wilson cycle:
- Rifting and Ocean Formation: The rifting of supercontinents created new ocean basins as continental fragments drifted apart.1
- Subduction: These oceans were subsequently destroyed in subduction zones, where oceanic crust was consumed beneath continental margins, often leading to the development of island arcs.12
- Continental Collision: As the ocean basins closed, continental blocks collided. Because buoyant continental crust cannot be easily subducted, the leading edges were scraped off, stacked, and thrust upward, creating major mountain belts.13
Notable examples include the Grenville belt (1.3 to 1.0 billion years old) and the Trans-Hudson belt (1.8 billion years old), which formed through these collisional processes. These events were fundamental in welding smaller cratons into larger landmasses like Columbia and Rodinia.124