Giant “Raft” of Floating Lava Rock in Pacific

A huge “raft” of very lightweight rocks called pumice is floating across the South Pacific Ocean. These rocks came from an undersea volcano and are expected to reach Australia in seven to 12 months.

Pumice is a very light rock formed when super-hot, liquid rock is ejected from a volcano. As the rock cools quickly, millions of tiny bubbles form, creating a light, foam-like rock that often floats.

Giant “Raft” of Floating Lava Rock in Pacific — Pumice is an extremely light rock made when super-hot, liquid rock is thrown out of a volcano. Millions of tiny bubbles form as the rock cools quickly, leaving a light, foam-like rock that can often float.
(Source: deltalimatrieste [Public domain], via Wikimedia Commons.)

Pumice rafts aren’t unusual. Scientists say they happen about once every five years. Lava from underwater volcanoes usually cools quickly, creating lots of pumice.

The pumice raft spotted in the South Pacific is enormous, covering around 58 square miles (150 square kilometers). One part of the raft is about 1.5 miles (2.5 kilometers) wide and 22 miles (35 kilometers) long. Another part is about 31 miles (50 kilometers) long.

The pumice raft spotted in the South Pacific is huge. The raft covers around 58 square miles (150 square kilometers). One section of the raft, shown in the satellite image above, is about 1.5 miles (2.5 kilometers) wide and 22 miles (35 kilometers) long.
(Source: NASA Earth Observatory.)

The raft was first noticed by sailors on August 9, about 70 miles (113 kilometers) from Tonga. A small ship called “Olive” came across “ribbons” of pumice on the sea’s surface. One of the ship’s officers, Rachel Mackie, said the ship was soon “surrounded as far as the eye could see.”

On August 9, a small ship called “Olive” came across “ribbons” of pumice on the sea’s surface. One of the ship’s officers, Rachel Mackie, said the ship was soon “surrounded as far as the eye could see.”
(Source: Rachel Mackie, OliveOcean.com.)

Ms. Mackie reported that the raft was about a foot (30 centimeters) deep and had some large lumps as big as 32 inches (80 centimeters) across. It took the ship two hours to pass through the pumice.

On August 15, a sailing boat called “Roam” also encountered the pumice. Sailors Michael Hoult and Larissa Brill found pumice stones of various sizes – some as small as marbles and others as large as basketballs. They said the raft covered the sea so completely that they couldn’t see the water.

The raft was about a foot (30 centimeters) deep and was made of pumice rocks of different sizes – some as small as marbles, others as large as basketballs. It took the Olive two hours to pass through the pumice.
(Source: Rachel Mackie, OliveOcean.com.)

Both boats noticed a smell of sulfur, which is closely associated with volcanoes and smells a bit like matches.

Scientists believe the pumice raft came from an underwater volcano that erupted on August 7. This volcano also erupted in 2001 but has never been named.

As the raft moves with the ocean currents, it is slowly breaking up and heading toward Australia.

As the raft is pushed by the movement of the ocean, it’s slowly breaking up and moving toward Australia. In the satellite photo from NASA above, an image of New York’s Manhattan Island has been added in the upper right corner to give an idea of how large the raft is.
(Source: NASA Earth Observatory.)

Scott Byron from Queensland University of Technology in Australia says the pumice will collect various tiny creatures and plant life as it drifts across the ocean. He mentions it may bring along “algae, barnacles, corals, crabs, snails, and worms.”

Byron hopes the pumice raft might help Australia’s Great Barrier Reef, the world’s largest coral reef system. This vital underwater area has lost over half of its corals since 1985, mainly due to climate change.

The Great Barrier Reef is an important underwater area that has lost over half of its corals since 1985, mainly because of climate change. The picture shows a dying coral in front of a healthy one. Scott Byron hopes the pumice raft might bring some healthy corals to the reef.
(Source: Wikipedia.org.)

The pumice raft could bring new, healthy corals, potentially helping to restore the reef. However, some of the creatures hitching a ride on the pumice could harm the reef or other areas in Australia.

The sailors from the Roam are bringing pumice samples to Mr. Byron for further study.

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