Hollow rocks

A strange phenomenon is underway in the south Pacific off the coast of New Zealand. Rocks, lots and lots of rocks, but they’re floating! Could this be the end of the world, are the four horsemen saddling up to reap our divine souls? No, there’s a less dramatic, but nevertheless fascinating explanation:

Hindu.com — The gigantic cluster, made up of lightweight pumice expelled from an underwater volcano and spread over 26,000 sq kilometres, has been spotted drifting in the ocean by a military aircraft, about 1,000 kilometres off the coast of New Zealand.

A naval ship had to change direction to avoid the rocks, which were spread out over thousands of square miles. Experts reckon the rocks were formed by lava released from an underwater volcano, the ‘Daily Mail’ reported.

They probably won’t float for too long. Depending on how interconnected the pockets are, the spongy rocks will eventually become water logged and they’ll sink like a … well like a stone.


  1. left0ver1under says

    They would sink? Or are they a different sort of pumice than stones sold for calluses and skin care? I’ve left stones floating in sinks and bathtubs, they’ve never sunk before.

  2. F says

    Well, if they have naval vessels due for a repaint or barnacle removal, maybe they should drive right through the pumice to save time.

  3. geocatherder says

    The vesicles (air bubbles) in the pumice aren’t all interconnected, and some are sealed off. So the water has to actually penetrate the stone itself to reach all the air bubbles, and then displace that air in the rock. Rock can indeed become wet, but it takes a long time for water to permeate most rock. In fact, the seawater may have to react with some of the minerals in the rock and actually change the rock composition. So the pumice will sink eventually… but not for days or weeks or even months, and maybe not for years. Depends on the rocks.

  4. Nice Ogress says

    ..So, if we found a big enough rock, could we have our own floating island?

    And could we put a volcano lair on it? Baking soda’s pretty cheap!

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