#Convergent boundary definition cracked#

Geophysical Research Letters (2020) CC BY 4.0) (Image credit: Aurélie Coudurier-Curveur Coudurier‐Curveur, A. The depressions are indicative of a strike-slip fault, which is the same kind of fault as the San Andreas Fault in California. This fracture likely formed when the ocean crust was formed, but now it is being turned into a new plate boundary. This map shows the seafloor and deformation below it at a fracture in the Wharton Basin in the Indian Ocean.

#Convergent boundary definition cracked#

However, according to a 2012 article in Nature, earthquakes over the last few decades are evidence that the Indo-Australian plate has cracked over the last 10 million years, creating a separate Indian Plate and Australian Plate which will increase the number of major plates to eight. Geological Service (USGS), and depending on its size, is categorized as 'major,' 'minor' or 'micro.'Īccording to World Atlas, seven major plates exist: the North American, Pacific, Eurasian, African, Indo-Australian, South American and Antarctic tectonic plates. (Imagine it like a cracked egg shell.) Each plate ranges from a few hundred to thousands of kilometers in size, according to the U.S. That's about as fast as your fingernails grow! How many plates are there?īecause Earth is spherical, its tectonic or lithospheric plates are fractured into dozens of curved sections. Tectonic plates move at a rate of one to 2 inches (3 to 5 centimeters) per year, according to National Geographic. California's San Andreas Fault, where the North American and Pacific tectonic plates grind past each other with a mostly horizontal motion, is one famous example of a transform boundary. It’s the slip-sliding motion of plate boundaries that triggers many earthquakes. The final type of plate boundary, transform boundaries, exist where plates move sideways in relation to each other. For example, the Mid-Atlantic Ridge runs directly through Iceland. Underwater mountains and volcanoes can rise along this seam, in some cases forming islands. Hot magma from Earth’s mantle wells up at these ridges, forming new ocean crust and shoving the plates apart. In the ocean, this same process creates mid-ocean ridges. This motion creates giant troughs on land, such as the East Africa Rift.

(Image credit: Kate Ramsayer/AGU.)Īs the name suggests, divergent boundaries are tectonic boundaries where plates 'diverge' or are tugged apart. Volcanic activity and earthquakes are common in the area. Visitors can walk down the rift between the North American plate and the Eurasian plate. Thingvellir Valley in Iceland is only place where the Mid-Atlantic Ridge is above sea level. Plate tectonics are responsible for the Mid-Atlantic Ridge. Erosion also hinders growth by wearing mountains down, but because mountains can grow at a relatively fast rate, erosion typically doesn’t win out, according to the University of Hawai’i at Manoa. However, when a mountain’s mass becomes too large to resist gravity, it will cease to grow. Geologists have discovered the Swiss Alps are being lifted faster than they are being lowered through erosion-and are thus growing every year, according to a 2020 study in the journal Earth-Science Reviews. As the mash-up continues, those mountains grow higher and higher. For example, India and Asia came together about 55 million years ago to create the Himalaya Mountains. Where those plates meet, Earth's crust crumbles and buckles into mountain ranges. There are three ways in which plate boundaries meet, and each one triggers a unique geological feature.Ĭonvergent boundaries occur where plates collide into one another. Related: The Alps are still growing faster than they're eroding They're thought to wrap around the Earth like seams on a baseball.

Geologists refer to the places where segments meet and divide as plate boundaries. Meanwhile, geologists imagine the plates above this roiling mantle as bumper cars they repeatedly collide, stick together, then rip apart. 'It's kind of like a pot boiling on a stove,' Van der Elst said. Hot material near the Earth's core rises, and colder mantle rock sinks. The driving force behind plate tectonics is convection in the mantle. 'Plate tectonics unified all these descriptions and said that you should be able to describe all geologic features as though driven by the relative motion of these tectonic plates.' How plate tectonics works 'Before plate tectonics, people had to come up with explanations of the geologic features in their region that were unique to that particular region,' said Van der Elst.