Nearly half a mile of rock retrieved from beneath the seafloor is yielding new clues about how underwater volcanoes are created, and whether the hotspots that led to their formation have moved over time.
have just completed an expedition to a string of underwater volcanoes, or
seamounts, known as the Louisville Seamount Trail, in the Pacific
Ocean. There they
collected samples of sediments, basalt lava flows and other volcanic eruption
materials to piece together the history of this ancient trail of volcanoes. The
expedition was part of the Integrated Ocean Drilling Program (IODP).
out whether hotspots in Earth's mantle are stationary or not will lead to new
knowledge about the basic workings of our planet," says Rodey Batiza,
section head for marine geosciences in the National Science Foundation's (NSF)
Division of Ocean Sciences.
thousands of seamounts exist in the Pacific Ocean.
Expedition scientists probed a handful of the most important of these
sampled ancient lava flows, and a fossilized algal reef," says Anthony
Koppers of Oregon
"The samples will be used to study the construction and evolution of
the expedition aboard the scientific research vessel JOIDES Resolution, along
with co-chief scientist Toshitsugu Yamazaki from the Geological Survey of Japan
at the National Institute of Advanced Industrial Science and Technology.
international research program dedicated to advancing scientific understanding
of the Earth through drilling, coring and monitoring the subseafloor, is
supported by NSF and Japan's
Ministry of Education, Culture, Sports, Science and Technology.
last two months, scientists drilled 3,651 feet into the seafloor to recover 2,644
feet of volcanic rock. The samples were retrieved from six sites at five
seamounts ranging in age from 50 million to 80 million years old.
sample recovery during this expedition was truly exceptional. I believe we
broke the record for drilling igneous rock with a rotary core barrel,"
says Yamazaki. Igneous rock is rock formed through the cooling and
solidification of magma or lava, while a rotary core barrel is a type of
drilling tool used for penetrating hard rocks.
volcanoes found in the middle of tectonic plates, such as the Hawaii-Emperor
and Louisville Seamount Trails, are believed to form from hotspots – plumes of
hot material found deep within the Earth that supply a steady stream of heated
rock. As a tectonic plate drifts over a hotspot, new volcanoes are formed, and
old ones become extinct. Over time, a trail of volcanoes is formed. The
Louisville Seamount Trail is about 2,600 miles long.
volcanic trails like the Louisville Seamount Trail are unique because they
record the direction and speed at which tectonic plates move," says
Scientists Drill Deep into Underwater Volcanoes along Pacific Ocean Seamount Trail
February 18, 2011