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How do plate tectonics change Earth’s geography over geologic time?
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paleogeography
Watch a time-lapse of Earth changing through geologic time, from the Cambrian Era to the projected period of Pangea Proxima.
In the context of paleogeography, plate tectonics acts as the primary driver of Earth’s changing surface configuration over geologic time. This process reshapes the planet through several key mechanisms:
- Continental Drift and Supercontinents: Plates move across the asthenosphere, carrying continents with them. This leads to the supercontinent cycle, where landmasses periodically assemble into supercontinents like Pangea or Rodinia and subsequently fragment.12
- Ocean Basin Evolution: Seafloor spreading at oceanic ridges creates new crust, widening ocean basins, while subduction consumes older crust, closing oceans and bringing continents together.345
- Orogeny (Mountain Building): When continents collide, the crust thickens and deforms, forcing land upward to create massive mountain ranges like the Himalayas.31
- Sea Level Fluctuations: Tectonic activity alters the volume of ocean basins. Rapid spreading creates buoyant, elevated ridges that displace water, raising sea levels, while the cooling and subsidence of older crust deepen basins, causing levels to drop.5
- Climate Modification: By shifting landmasses across latitudes and altering ocean circulation patterns, tectonics profoundly influences global climate, contributing to events such as the formation of polar ice caps.6