Salts form 3.5% (more commonly stated as 35 ppt) of seawater by mass. If you evaporate seawater, the following minerals precipitate out in this order (the reverse of their solubility):
1) Calcite (CaCO3)
2) Gypsum (CaSO4 * 2H2O)
3) Halite (NaCl)
4) Sylvite (KCl)
You can remember the order because it's alphabetical!
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The ocean floor forms at seafloor spreading centers, where basaltic magma pushes out through cracks. This magma ultimately comes from the mantle. What would you see if we could punch out a 8 km deep tube from the sea floor? Unfortunately, that isn't yet possible, but thanks to ophiolites, which are parts of the seafloor that have been uplifted to where we can study them, we have an idea of what it would look like. Read more →
The Perpetual Ocean video by NASA is absolutely hypnotic, and lets the viewer appreciate large-scale and smaller-scale surface circulation patterns. The visualization was created using a model crunching satellite and in-situ data collected from June 2005 to December 2007. You can download the full-version at NASA's website.
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