What percentage of the Earth's upper crust is water?

Large oceans of water and a rich atmosphere with just the right elements to support life set Earth apart from its close cousins in the solar system. Earth is also the only planet ... Early in its history, however, Earth's crust more closely resembled its cousins with a higher proportion of magnesium. read more

The upper oceanic crust contains 2.68% H2O according to Hart et al. (1999). The upper continental crust in the Canadian shield contains 0.8% H2O according to Wedepohl (1995). read more

Oceanic crust, being so thin, is a very small fraction of the Earth -- about 0.1 percent -- but its life cycle serves to separate the contents of the upper mantle into a heavy residue and a lighter set of basaltic rocks. read more

The evidence comes from a water-loving mineral called ringwoodite that came from the so-called transition zone sandwiched between the upper and lower layers of Earth's mantle, they said in the journal Nature. Analysis shows that 1.5% of the rock comprises molecules of water. read more