EARTH'S PAST CHANGING POLARITY

FROM:  NATIONAL SCIENCE FOUNDATION 

Geomagnetic reversal: Understanding ancient flips and flops in Earth's polarity
Researcher boards R/V Sikuliaq to gather data about Earth's geomagnetic history
Imagine one day you woke up, and the North Pole was suddenly the South Pole.

This geomagnetic reversal would cause your hiking compass to seem impossibly backwards. However, within our planet's history, scientists know that this kind of thing actually has happened...not suddenly and not within human time scales, but the polarity of the planet has in fact reversed, which has caused scientists to wonder not only how it's happened, but why.

This week, as the National Science Foundation (NSF) research vessel R/V Sikuliaq continues its journey towards its home port in University of Alaska Fairbanks' Marine Center in Seward, Alaska, she detours for approximately 35 days as researchers take advantage of her close proximity to the western Pacific Ocean's volcanic sea floors. With the help of three types of magnetometers, they will unlock more of our planet's geomagnetic history that has been captured in our Earth's crust there.

"The geomagnetic field is one of the major physical properties of planet Earth, and it is a very dynamic property that can change from milliseconds to millions of years. It is always, always changing," said the expedition's chief scientist, Masako Tominaga, an NSF-funded marine geophysicist from Michigan State University. "Earth's geomagnetic field is a shield, for example. It protects us from magnetic storms--bursts from the sun--so very pervasive cosmic rays don't harm us. Our research will provide data to understand how changes in the geomagnetic field have occurred over time and give us very important clues to understand the planet Earth as a whole."

Flipping and flopping

Reportedly, the last time, a geomagnetic reversal occurred was 780,000 years ago, known as the Brunhes-Matuyama reversal. Bernard Brunhes and Motonori Matuyama were the geophysicists who identified that reversal in 1906.

Researchers Tominaga, Maurice Tivey (from Woods Hole Oceanographic Institution) and William Sager (from University of Houston) have an interest that goes further back in history to the Jurassic period, 145-200 million years ago when a curious anomaly occurred. Scientists originally thought that during this time period, no geomagnetic reversals had happened at all. However, data--like the kind that Tominaga's team will be collecting--revealed that in fact, the time period was full of reversals that occurred much more quickly.

"We came to the conclusion that it was actually 'flipping flopping,' but so fast that it did not regain the full strength of the geomagnetic field of Earth like today's strength. That's why it was very low," Tominaga explained. "The Jurassic period is distinctive. We think that understanding this part of the geomagnetic field's behavior can provide important clues for computer simulation where researchers have been trying to characterize this flipping and flopping. Our data could help predict future times when we might see these reversals again."

Better tools equal better data

For approximately three decades, researchers like Tominaga have been probing this area of the western Pacific seafloor. With her cruise on R/V Sikuliaq, Tominaga and Tivey come with even more technology in hand.

Thirty years ago, researchers didn't have access to autonomous underwater vehicles (AUV) that could go to deeper, harder-to-reach ocean areas. However, that is just one of three ways Tominaga's team will deploy three magnetometers during its time at sea. One magnetometer will be towed at the seasurface from R/V Sikuliaq. Another will trail behind the ship at mid-water depth, and the third will be part of the AUV at near the seafloor.

"The seafloor spreading at mid-ocean ridge occurred because of volcanic eruption over time. And when this molten lava formed the seafloor, it actually recorded ambient geomagnetic data. So when you go from the very young ocean seafloor right next to the mid-ocean ridge to very, very old seafloor away from the mid-ocean ridge, a magnetometer basically unveils changes in the geomagnetic field for us," Tominaga said. "The closer we can get to the seafloor, the better the signal. That's the rule of thumb for geophysics."

With the help of R/V Sikuliaq's ship's crew, Tominaga and Tivey, a cruise archivist who is also a computer engineer/scientist, and seven students (three of whom are undergraduates), the team will run 24 hours a day/seven days a week operations, deploying underway geophysics, the magnetometers, collecting data and then moving on to the next site.

Naturally, the weather can waylay even the best plans. "Our goal is always about the science, but the road likely will be winding," Tominaga said. "The most enjoyable part of this work is to be able to work together with this extremely diverse group of people. The Sikuliaq crew, the folks at UAF and those connected to the ship from NSF have all been committed to seeing this research happen, which is incredibly gratifying.... When we make things happen together as a team, it is really rewarding."

Focus on fundamentals

Not surprisingly, this kind of oceanographic research is among some of the most fundamental, serving as a foundation for other research where it might correlate or illuminate. Additionally, because the causes and impacts of these geomagnetic changes are unknown, connections to currents, weather patterns, and other geologic phenomenon can still be explored also.

"NSF, along with the entire science community, has waited years for this unique state-of-the-art Arctic vessel, and the timing couldn't be more critical," said Rose DuFour, NSF program director. "Our hope is to use R/V Sikuliaq to help carry out the abundant arctic-based seagoing science missions that go beyond NSF-funded science and extend to those from other federal agencies, like Office of Naval Research as well."

Tominaga notes that another key part to the cruise's mission is record keeping; it's why an archivist is part of her team. He even will blog daily (with pictures). As foundational research, it's important to "keep every single record intact," and she believes this broadcasting daily narrative will assist in this effort.

"Without going there, getting real data--providing ground truth--how do we know what is going on?" Tominaga said, explaining fieldwork's importance.

Tominaga is quite clear on what prompts her to keep one of the busiest fieldwork schedules, even during a season usually reserved for family and friends, sipping eggnog or champagne. "I was 'raised' as a scientist/marine geophysicist, and I don't just mean academically," she said. "I really looked up to my mentors and friends and how they handed down what they know-so unselfishly. And when I was finishing my Ph.D., I realized that there will be a time I will hand down these things to the next generation. Now, as a professor at Michigan State University, I'm the one who has to pass the torch, if you will--knowledge, experience, and skills at sea. That's what drives me."

-- Ivy F. Kupec
Investigators
Masako Tominaga
Maurice Tivey
William Sager
Related Institutions/Organizations
Woods Hole Oceanographic Institution
Locations
Western Pacific Seafloor , Hawaii
Related Programs
Marine Geology and Geophysics

100TH ANNIVERSARY OF RACE TO THE SOUTH POLE

Photo:  Supply Delivery To Antarctica.  Credit:  U.S. Air Force.
FROM:  NATIONAL SCIENCE FOUNDATION
May 31, 2012
A Legacy of the Race to the South Pole: New Scientific Discoveries in Antarctica
Forbidding though Antarctica is, the stations located there are nevertheless irresistibly inviting to scientists, as Antarctica supports a cornucopia of unique life forms, geologic wonders, and marine and atmospheric conditions

This winter marks the 100th anniversary of the race to the South Pole. After crossing Antarctica-the coldest, windiest, driest continent on Earth-the Norwegian explorer Roald Amundsen and his team arrived at the geographic South Pole on Dec. 14, 1911, the first people in history to reach the bottom of the Earth.

About one month later, on January 17, 1912, the British explorer Navy Captain Robert Falcon Scott and his party arrived at the South Pole to discover that Amundsen had beaten them there. Sadly, Scott died on the ice while attempting to return from the Pole. Nevertheless, the work of the Scott team on their trek to and from the Pole-including hauling 35 pounds of rock and fossil specimens on their return journey-helped lay the foundation for modern Antarctic science.

If Amundsen and Scott could somehow magically be transported back to the South Pole now, they would probably be amazed and honored to discover that the National Science Foundation's (NSF) Amundsen-Scott South Pole Station, a massive, two-story, science-support structure, overlooks the spot they worked so hard to reach. Nearby is a 10-meter radio telescope that is currently being used to study the nature of mysterious dark matter.  Below the surface of the ice sheet ice is a cube-shaped detector--a kilometer on each side--searching for elusive subatomic particles called neutrinos.

Amundsen-Scott is one of three year-round stations operated by the U.S. Antarctic Program (USAP), which is managed by NSF under terms of Presidential Memorandum 6646. The other stations are McMurdo Station on Ross Island and Palmer Station on Anvers Island in the Antarctic Peninsula Region.

Forbidding though Antarctica is, the Amundsen-Scott South Pole Station, McMurdo Station and Palmer Station are nevertheless irresistibly inviting to scientists because Antarctica supports a cornucopia of fantastic life forms, geologic wonders, and marine and atmospheric conditions that are found nowhere else on Earth.

For example, researchers are studying adaptations that enable various life-forms-from microorganisms to penguins to seals-to survive in Antarctica, and how research into those adaptations may ultimately benefit human health. Researchers are even looking at the living and working conditions of research teams already in Antarctica to get a better understanding for how people can survive in such extreme ecosystems.

Some Antarctic species, despite their adaptations, are under particular stress. The retreat of sea ice in some parts of Antarctica are critically affecting two penguin species with particularly restricted ranges, and recent warming of water temperatures may be influencing the proliferation of undersea giants, including extremely large sea stars, jellyfish and sea spiders.

                                          Photo:  Break-up Of Antarctic Sea-Ice,  Credit:  NASA 

Scientists are also investigating global changes for which Antarctica provides an ideal study site, such as the current state of our planet's ozone layer, which protects us from ultraviolet radiation, and the impacts that are emerging as global climate changes. Observations of Antarctica's response to a warming globe-such as ocean acidification and the calving of glaciers off of continental ice sheets-are important for understanding such factors as the effects of ice retreat on global sea level and, more broadly, serve as bellwethers for the planet as a whole.