Elegant proof that Earth 'swiftly' recycles old surface through volcano eruptions

Earth's surface is continuously recycled as plates are buried, melted at depth and spit out by volcanos to form new surface.   Instead of 2 billion years, research has shown it "only" takes 1/2 a billion years to do the loop.  Ancient seawater was trapped in the plates as they began to sink some kilometers below the earth's surface.  This crystal below formed after a modern lava eruption and preserved traces of that ancient seawater in tiny pockets.  The ratio of strontium isotopes in that speck of water dates the original subsidence.

These are olivine crystals from Mauna Loa volcano, Hawaii, with a width of less than 1 mm. The brown ovals are solidified, glassy inclusions trapped as droplets of melt by the growing olivine crystal. They contain strontium isotope ratios which are inherited from 500-million-year-old seawater. 

A reminder this is ongoing: New Eruption at Undersea Volcano  Mile-wide brand-new lava flow found off California's coast.