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Lost City Expedition: Science

Can Mountains be Built as a Result of Hydration?

Atlantis Massif
Another important consequence of the formation of serpentine during hydration of mantle rocks is that the density of the rocks change form about 3.3 grams per cubic centimeter (g/cm3) to about 2.7 g/cm3 and the volume of the rocks can increase up to about 40%. The change in density and the expansion of the rocks during serpentinization has the effect that the mountain becomes lighter and needs more room as it swells up, and thus “lifts” itself to greater elevations. The expansion of the rocks also leads to a greater number of cracks and ultimately causes mass wasting along steep slopes.

This in turn creates new fractures that allow seawater to penetrate further into the mountain and react with new portions of rock that contain fresh olivine. Another goal of our expedition is to better understand how processes of faulting, volume expansion, and mass wasting influence the ability of seawater to alter the mantle peridotites and keep the Lost City hydrothermal system going.