Convergent Plate Boundaries: The Collision of Plate Tectonics
Convergent plate boundaries cause violent catastrophes on Earth. It’s where plates collide together in red. It’s common to see convergent plates along the edge of continents. Likewise, you’ll see large chains of mountains and volcanoes.
For example, the Pacific Ring of Fire has some of the most violent earthquakes in history. If you scroll down this page, you’ll see the similarities between the convergent plate boundaries map and the Pacific Ring of Fire map.
For Earth’s 7 major plate tectonic boundaries (and 10 or so minor ones), they interact with each other in 3 ways:
- Divergent plates pull apart from each other
- Convergent plate boundaries push plates together
- And conservative (transform) plate boundaries slide across from each other
Today, let’s explore convergent plate boundaries. For example, where can we find them? And what type of landforms do they generate when they collide?
Plates push into each other at convergent boundaries
Convergent boundaries or subduction zones are where two plates collide into each other. Because matter cannot be destroyed, it forces one of the plates into the mantle underneath.
Convergent boundaries have some of the most violent catastrophes and geology on Earth. When plates smash together, it has created chains of volcanoes.
For example, almost all along the Pacific Ring of Fire, plates collide and sink into the ocean floor at zones of subduction. But continents don’t always collide with oceans.
Sometimes, continents collide with other continents, which is part of the formation of mountains. You can find examples around the world. For example, the Nazca plate has created the Andes mountain range. It’s just that erosion wears it away fairly quickly.
For example, the Appalachians use to be 5 miles higher, when Africa collided with North America. But over 300 million years, weathering and erosion have torn them down and washed them through streams.
Convergent plate boundaries dominate the Pacific Ring of Fire
81% of earthquakes occur along the Pacific Ring of Fire. Despite the slow movement of plate tectonics (just 5-10 cm every year), they release a tremendous amount of energy. For example, Indonesia is known for having one of the most active chain of volcanoes in the world.
Most of the Ring of Fire’s tectonic plates collide and sink into the ocean floor at zones of subduction. This causes violent earthquakes and volcanoes.
It’s not only the Pacific Ring of Fire, but you can look all around the world and find examples. For example, the Nazca plate has created the Andes mountain range.
It’s just that erosion wears it away fairly quickly. For example, the Appalachians use to be 5 miles higher, when Africa collided with North America.
But over 300 million years, weathering and erosion have torn them down and washed them through streams.
How mountains are made
Plate tectonics are deceptively slow. But they’re never idle. When convergent plates collide, plates thrust upwards to build mountains.
This geologic process of vertical upheaving are the orogenies or mountain building events. For example, the Laramide orogeny lifted the Rocky Mountains about 80–55 million years ago.
Since the beginning of Earth, plate tectonics have carved out chains of mountains which have reshaped the landscape inside and out.
While young rock appear and disappear, cratons are stable pieces of continent that have lasted over 1 billion years old.