The speed of spreading affects the shape of a ridge – slower spreading rates result in steep, irregular topography while faster spreading rates produce much wider profiles and more gentle slopes. As the plates separate, molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt. Mid-ocean ridges occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. The majority of the system is underwater, with an average water depth to the top of the ridge of 2,500 meters (8,200 feet). The massive mid-ocean ridge system is a continuous range of underwater volcanoes that wraps around the globe like seams on a baseball, stretching nearly 65,000 kilometers (40,390 miles). This system forms the longest and largest mountain range on Earth, winding its way between the continents. New ocean crust, shown in this map in red, forms along the divergent plate boundaries of the ridge system.

The nearly continuous, global mid-ocean ridge system snakes across the Earth’s surface like the seams on a baseball. Diversity, Equity, Inclusion, and Accessibility.

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