divergent boundaries

The Mid-Atlantic Ridge is located at the juncture of crustal plates that form the floor of the Atlantic Ocean; it is considered a “slow-spreading” ridge by earth scientists.

The dates revealed that the Atlantic Ocean was opening by seafloor spreading from the Mid Atlantic Ridge at a rate of about 0.02 metres per year. This means that North America and Europe are moving away from each other at about the rate it takes for your fingernails to grow.

Pacific Ocean

Where is active sea floor spreading occurring today? Seafloor spreading is the movement of old rock that is being pushed by the new young oceanic crust. This would be a divergent since the plates are separating from each other. Active seafloor spreading is occurring at mid-ocean ridges.

Seafloor spreading occurs at divergent plate boundaries. As tectonic plates slowly move away from each other, heat from the mantle’s convection currents makes the crust more plastic and less dense. The less-dense material rises, often forming a mountain or elevated area of the seafloor.

The main driving force of plate tectonics is gravity. If a plate with oceanic lithosphere meets another plate, the dense oceanic lithosphere dives beneath the other plate and sinks into the mantle. However, convection also drives plate tectonics.

The mechanism behind Plate Tectonics. The main features of plate tectonics are: The ocean floors are continually moving, spreading from the center, sinking at the edges, and being regenerated. Convection currents beneath the plates move the crustal plates in different directions.

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Plate tectonics, which has so profoundly influenced geologic thinking since the early 1970s, provides valuable insight into the mechanisms by which the Earth’s crust and mantle have evolved as well as into how the Earth has cooled.

This process of plate tectonics is one of Earth’s defining characteristics. Humans mostly experience it through earthquakes and, more rarely, volcanoes. “Plate tectonics is what modulates our atmosphere at the longest timescales.

If all plate motion stopped, Earth would be a very different place. Erosion would continue to wear the mountains down, but with no tectonic activity to refresh them, over a few million years they would erode down to low rolling hills.

Without plate tectonics, Earth would not have its diverse geography, which provides a wide range of habitats. Plate tectonics is also responsible for hydrothermal vents on the ocean floor.

— There may be more habitable planets in the universe than we previously thought, according to Penn State geoscientists, who suggest that plate tectonics — long assumed to be a requirement for suitable conditions for life — are in fact not necessary. Planets without tectonic plates are known as stagnant lid planets.

The study, published this month in Gondwana Research, has provoked controversy, and some experts argue that we can never accurately predict the end of plate tectonics. But scientists largely agree that such an end will arrive one day, putting Earth on a path to a geologic standstill.

A tectonic plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere. Like icebergs, only the tips of which are visible above water, continents have deep “roots” to support their elevations.