Plate boundaries are the dynamic zones where Earth's tectonic plates interact. These boundaries come in three main types: divergent, convergent, and transform. Each type creates unique geological features and landforms, shaping our planet's surface.

Understanding plate boundaries is crucial for grasping Earth's ever-changing landscape. From mountain ranges and deep ocean trenches to volcanic arcs and rift valleys, these boundaries are responsible for many of the planet's most dramatic geological features and natural hazards.

Types of Plate Boundaries

Types of plate boundaries

• Divergent boundaries create new crust as plates move apart enabling seafloor spreading and rift valley formation (Mid-Atlantic Ridge)
• Convergent boundaries destroy or uplift crust as plates collide producing subduction zones and mountain ranges (Andes Mountains)
• Transform boundaries slide plates horizontally past each other without creating or destroying crust often forming strike-slip faults (San Andreas Fault)

Features of plate boundaries

• Divergent boundaries form mid-ocean ridges through magma upwelling and seafloor spreading creating underwater mountain ranges (East Pacific Rise)
• Convergent boundaries create deep oceanic trenches as one plate subducts beneath another leading to volcanic arc formation (Mariana Trench)
• Transform boundaries produce linear fault zones with horizontal displacement causing offset features and shallow earthquakes (Alpine Fault)

Landforms from plate interactions

• Mountain ranges form at convergent boundaries through continental collision uplifting and deforming rock layers (Himalayas)
• Volcanic activity occurs at convergent boundaries through subduction-related processes and at divergent boundaries via fissure eruptions (Mount Fuji)
• Earthquakes happen at all boundary types varying in depth and intensity based on plate interactions (San Francisco 1906 earthquake)
• Basins develop at divergent boundaries as rift basins and at transform boundaries as pull-apart basins (East African Rift Valley)

Global distribution of boundaries

• Pacific Ring of Fire encompasses convergent boundaries surrounding the Pacific Ocean concentrating volcanoes and earthquakes (Mount St. Helens)
• Mid-Atlantic Ridge runs through the Atlantic Ocean as a divergent boundary separating American plates from Eurasian and African plates
• Alpine-Himalayan Belt extends from Mediterranean to Southeast Asia marking convergent boundary between Eurasian and African-Indian plates (Mount Everest)
• San Andreas Fault System represents transform boundary between Pacific and North American plates posing high seismic risk in California
• East African Rift System demonstrates divergent boundary on continental crust potentially forming future ocean basin
• Plate boundary evolution changes plate motion over geologic time opening and closing ocean basins through Wilson Cycle