Undersea columns of basalt have been found near an uninhabited islet off Penghu County and are believed by the finder to be the only such formations in the world.
Jeng Ming-hsiou (鄭明修), a researcher from Academia Sinica, came across the formations in May when he was diving off Dayao Islet — north of the main Penghu island — to study the mass death of fish there early last year.
Jeng said that the columns were about 200m long and 10m high.
Because of strong undersea currents, Jeng said he could not take pictures of the columns, although he dove twice to measure their size.
The undersea columns, with the clear five-sided or six-sided structure typical of basalt formations, are covered in barnacles and coral, Jeng said. The formations have partly collapsed but are otherwise unspoiled, he said.
After consulting experts, Jeng said he was “pretty sure” the undersea basalt columns were the only ones known in the world.
Jeng said that with Taiwan trying to gain UN acknowledgement of Penghu — an archipelago formed by basalt — as a world natural heritage site, he hoped his discovery would lend credit to the attempt.
Basalt is formed by hardened lava from volcanoes or cracks under the sea. It consists chiefly of pyroxene and plagioclase feldspar.