Volcanic pools ooze from ocean floor

TOKYO, July 16 (UPI) -- Japanese scientists have found young basalts along the seaward slope of the Japan Trench oozed to the surface through so-called petit-spot volcanism.

In 1997, some basalts within 130 million-year-old oceanic crust were sampled and found to be unexpectedly young -- only about 6 million years old.

Noting there are no known hotspots in that vicinity, Toshiya Fujiwara, Natsue Abe and Kaoru Takizawa of Japan's Institute for Research on Earth Evolution, along with Naoto Hirano of the University of Tokyo, sought to understand more about the unknown intra-plate volcanics, dubbed "petit-spot" volcanism, suggested by the discovery.

They conducted a seismic reflection survey of the region and found the young basalt pooled between sedimentary layers and oozed to the surface through cracks and vents. The researchers expect their findings -- and surveys of other petit-spot volcanism areas -- will help scientists better understand the evolution and modification of old oceanic crust.

The research appears in the journal Geophysical Research Letters.