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Lost City Expedition: Science

Temperature Extremes in the Earth

There is a vast range in temperatures in the Earth. Deep mantle rocks beneath the mid-ocean ridges reach temperatures in excess of 1400°C (2550F). In contrast, much of the deep ocean waters are at near freezing temperatures of 2°C (37F). The distances over which these temperatures vary, may be extremely long, or short. For example, the distance between the deep mantle, where melting first takes place in the Earth, to the surface of the seafloor is ~ 90-100 km, and temperatures span a range from ~1400°C to 2°C. In contrast, the walls of black smoker chimneys may be only 5-10 cm thick, and temperatures range from 400°C (752F) to 2°C. These differences in distances over which properties (e.g. temperature, fluid chemistry, pressure) change are known as gradients and they are extremely important to both geological and biological processes. In submarine environments, they govern where rocks melt and/or become solid, where liquid water is stable, and where life can exist.