Featured Research

from universities, journals, and other organizations

Scientists explore origins of 'supervolcanoes' on the sea floor: Ancient goliaths blamed for multiple mass extinctions

Date:
April 10, 2010
Source:
National Science Foundation
Summary:
"Supervolcanoes" have been blamed for multiple mass extinctions in Earth's history, but the cause of their massive eruptions is unknown.

JOIDES Resolution departing from Yokohama, Japan, on the Shatsky Rise expedition.
Credit: John Beck, IODP/TAMU

"Supervolcanoes" have been blamed for multiple mass extinctions in Earth's history, but the cause of their massive eruptions is unknown.

Despite their global impact, the eruptions' origin and triggering mechanisms have remained unexplained. New data obtained during a recent Integrated Ocean Drilling Program (IODP) expedition in the Pacific Ocean may provide clues to unlocking this mystery.

To explore the origins of these seafloor giants, scientists drilled into a large, 145 million-year-old underwater volcanic mountain chain off the coast of Japan.

IODP Expedition 324: Shatsky Rise Formation took place onboard the scientific ocean drilling vessel JOIDES Resolution from September 4 to November 4, 2009. Preliminary results of the voyage are emerging.

"'Supervolcanoes' emitted large amounts of gases and particles into the atmosphere, and re-paved the ocean floor," says Rodey Batiza, marine geosciences section head in the National Science Foundation (NSF)'s Division of Ocean Sciences, which co-funded the research.

The result?

"Loss of species, increased greenhouse gases in the atmosphere, and changes in ocean circulation," says Batiza.

In fall 2009, an international team of scientists participating in IODP Expedition 324 drilled five sites in the ocean floor. They studied the origin of the 145 million-year-old Shatsky Rise volcanic mountain chain.

Located 1,500 kilometers (930 miles) east of Japan, Shatsky Rise measures roughly the size of California.

This underwater mountain chain is one of the largest supervolcanoes in the world: the top of Shatsky Rise lies three and a half kilometers (about two miles) below the sea's surface, while its base plunges to nearly six kilometers (four miles) beneath the surface.

Shatsky Rise is composed of layers of hardened lava, with individual lava flows that are up to 23 meters (75 feet) thick.

"Seafloor supervolcanoes are characterized by the eruption of enormous volumes of lava," says William Sager of Texas A&M University, who led the expedition with co-chief scientist Takashi Sano of Japan's National Museum of Nature and Science in Tokyo. "Studying their formation is critical to understanding the processes of volcanism, and the movement of material from Earth's interior to its surface."

About a dozen supervolcanoes exist on Earth; some are on land, while others lie at the bottom of the ocean. Those found on the seafloor are often referred to as large oceanic plateaus.

Current scientific thinking suggests that these supervolcanoes were caused by eruptions over a period of a few million years or less--a rapid pace in geologic time.

Each of these supervolcanoes produced several million cubic kilometers of lava--about three hundred times the volume of all the Great Lakes combined--dwarfing the volume of lava produced by the largest present-day volcanoes in places like Hawaii.

Since the 1960s, geologists have debated the formation and origin of these large oceanic plateaus. The mystery lies in the origin of the magma, molten rock that forms within the Earth.

A magma source rising from deep within the Earth has a different chemical composition than magma that forms just below Earth's crust. Some large oceanic plateaus show signs of a deep-mantle origin. Others exhibit chemical signatures indicative of magma from a much shallower depth.

The IODP Shatsky Rise expedition focused on deciphering the relationship between supervolcano formation and the boundaries of tectonic plates, crucial to understanding what triggers supervolcano formation.

A widely-accepted explanation for oceanic plateaus is that they form when magma in the form of a "plume head" rises from deep within the Earth to the surface.

An alternative theory suggests that large oceanic plateaus can originate at the intersection of three tectonic plates, known as a "triple junction."

Shatsky Rise could play a key role in this debate, because it formed at a triple junction. However, it also displays characteristics that could be explained by the plume head model.

"Shatsky Rise is one of the best places in the world to study the origin of supervolcanoes," says Sager. "What makes Shatsky Rise unique is that it's the only supervolcano to have formed during a time when Earth's magnetic field reversed frequently."

This process creates "magnetic stripe" patterns in the seafloor. "We can use these magnetic stripes to decipher the timing of the eruption," says Sager, "and the spatial relationship of Shatsky Rise to the surrounding tectonic plates and triple junctions."

Sediments and microfossils collected during the expedition indicate that parts of the Shatsky Rise plateau were at one time at or above sea level, and formed an archipelago during the early Cretaceous period (about 145 million years ago).

Shipboard lab studies show that much of the lava erupted rapidly, and that Shatsky Rise formed at or near the equator.

As analyses continue, data collected during this expedition will help scientists resolve the 50 year-old debate about the origin and nature of large oceanic plateaus.

The JOIDES Resolution is one of the primary research vessels of IODP, an international marine research program dedicated to advancing scientific understanding of the Earth through drilling, coring, and monitoring the subseafloor. The vessel is operated by the U.S. Implementing Organization of IODP, consisting of the Consortium for Ocean Leadership, Texas A&M University, and Lamont-Doherty Earth Observatory of Columbia University.

IODP is supported by two lead agencies: the U.S. National Science Foundation and Japan's Ministry of Education, Culture, Sports, Science, and Technology.

Additional program support comes from the European Consortium for Ocean Research Drilling (ECORD), the Australian-New Zealand IODP Consortium (ANZIC), India's Ministry of Earth Sciences, the People's Republic of China (Ministry of Science and Technology), and the Korea Institute of Geoscience and Mineral Resources.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "Scientists explore origins of 'supervolcanoes' on the sea floor: Ancient goliaths blamed for multiple mass extinctions." ScienceDaily. ScienceDaily, 10 April 2010. <www.sciencedaily.com/releases/2010/04/100409131419.htm>.
National Science Foundation. (2010, April 10). Scientists explore origins of 'supervolcanoes' on the sea floor: Ancient goliaths blamed for multiple mass extinctions. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2010/04/100409131419.htm
National Science Foundation. "Scientists explore origins of 'supervolcanoes' on the sea floor: Ancient goliaths blamed for multiple mass extinctions." ScienceDaily. www.sciencedaily.com/releases/2010/04/100409131419.htm (accessed September 18, 2014).

Share This



More Earth & Climate News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins