Sunday, September 9, 2012

Pumice plies the waves

Fifteen years after the discovery of an ocean-borne garbage dump twice the size of Texas in the North Pacific, a new, more natural mass has been spotted: a floating raft of loose pumice stones larger than New Jersey in the South Atlantic. It was photographed by the Royal New Zealand Air Force in July and samples were collected by the RNZ Navy (images above and here) the same day. Lieutenant Tim Oscar called the pumice "the weirdest thing I've seen in 18 years at sea." When the ship's spotlight was trained on the rock (another photo here), it lit up like the edge of an ice shelf and extended as far as they could see - 2' thick and riding up and down with the swell. The lightweight pumice posed no danger to the ship, but its source was a mystery until it was traced with the help of earthquake records and satellite imagery to an erupting undersea volcano called the Havre Seamount. The porous rock forms from volcanic lava that cools quickly, trapping gas inside as it hardens. Winds and currents have spread the "raft" into a series of twisted filaments, but the eventual fate of the rock remains uncertain. It may continue to float, be washed ashore, or become saturated and sink.

More floaters:

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