Almost like being there
Polar Rock Repository offers access to samples from Antarctica without leaving lab
Posted October 17, 2014
More than 99 percent of Antarctica is covered by ice. The few places where rocks do poke through the vast continental ice sheets are generally remote, requiring long hours travelling on planes, helicopters, or snowmobiles to reach.
Yet hardy geologists and other scientists will venture to such forsaken places to collect rock specimens that may reveal clues about Antarctica’s past geologic and possibly climate history.
Or they could just get samples of gneiss from the Transantarctic Mountains or volcanic rocks from the slopes of Erebus through the Polar Rock Repository at the Byrd Polar Research Center, which is located at The Ohio State University. The repository even ships for free.
“Samples from Antarctica are unique, and they can provide information in a way that scientists wouldn’t be able to get otherwise,” noted Anne Grunow, a senior research scientist at OSU and curator of the Polar Rock Repository.
The repository was built 11 years ago with support from the National Science Foundation’s Division of Polar Programs. The first collections were primarily rock provided by retiring scientists and institutions with little room to store boxes of granite and other heavyweight stones collected by research faculty and students.
Over the past decade, the repository’s collection has grown to more than 34,000 samples, some dating back to the 1950s.
The current collection is completely archived online. The repository’s website allows researchers to search for samples by the location or a description of the type of specimen they’re interested in seeing.
“Our hope is to have a good representation of rock samples from around the continent and also dredges from off-shore to provide for research use,” said Grunow, who conducted her own studies in Antarctica for about a dozen years in the 1980s and 1990s.
Grunow said the facility is also hoping to encourage research teams to provide a split of their rock samples or dredges after a project has been completed, a move supported by the National Science Foundation, which helps fund the repository.
“The primary value of the repository to me is that it is a centralized collection of rock samples available to the whole world and allows new investigators to get a glimpse of the potential for future studies,” said Philip Kyle, principal investigator for the Mount Erebus Volcano Observatory, a long-term project that studies Antarctica’s southernmost active volcano.
Once a skeptic of the repository, Kyle said he has become a convert. Over the last two years, he has examined volcanic rock cores drilled during the early 1970s by the Dry Valley Drilling Project. Now housed in the repository, the cores still provide valuable material to understand the region’s geologic and volcanic history, according to Kyle.
The last volcanic eruption near the present-day location of U.S. Antarctic Program’s McMurdo Station occurred about 400,000 years ago.
“The [rock] core allows the nature of this eruptive activity to be understood much better,” Kyle explained. “There remains a reasonable probability that further small basaltic eruptions could occur in the vicinity of McMurdo Station in the future.”
Kyle is currently in the process of preparing his and his students’ collections – spanning nearly four decades of research as part of the U.S. Antarctic Program – to be donated to the Polar Rock Repository.
In the next few months, he expects to ship more than 40 boxes of rocks that contain specimens ranging from volcanic rocks from Northern Victoria Land, along the Hallett Coast, and most of the volcanic centers in the McMurdo Sound region.
“Samples from the unique and undescribed 180-million-year-old Butcher Ridge area south of McMurdo will allow other people to develop new research proposals to examine and understand this unusual rock body,” he said.
The repository’s collection has also enabled research on other planetary surfaces such as Mars or provided samples for investigations into the terrestrial nature of Antarctica without ever leaving the laboratory.
Photo Courtesy: Anne Grunow
The shelves at the Polar Rock Repository contain samples from around the Antarctic, including the seafloor around the continent.
Mark Salvatore, in collaboration with the Polar Geospatial Center at the University of Minnesota, has developed a special kind of map of a region in the Transantarctic Mountains by using multispectral imagery that was collected by a satellite in orbit.
[See related article — Coloring outside the lines: Spectral mapping technique offers new view of old rocks in Antarctica.]
Multispectral images capture data at specific wavelengths across the electromagnetic spectrum, including those beyond the visible light range, such as infrared. In this case, spectral imaging can extract information about the types of rocks found in the Transantarctic Mountains.
The technique is not perfect, and Salvatore analyzed more than 450 specimens from the Polar Rock Repository to help refine his map of the Shackleton Glacier region.
“You’re getting the basic rock types pretty well with what you see from the repository,” explained Salvatore, a postdoctoral research associate at Arizona State University who specializes in studying planetary surfaces with remote-sensing techniques.
The nontraditional method of ground-truthing the satellite data with rock samples from the repository saves the time and expense of planning an expedition to the mountains, which nearly bisect the Antarctic continent.
“At the moment, it’s a lot cheaper, a lot easier to go to Ohio than it is to go to the Shackleton region,” Salvatore noted.
Grunow estimates that between 2012 and 2014, based on the number and types of loans made through the repository, the amount of money that would have been needed to collect and ship samples back to the United States from Antarctica would be nearly $4 million.
And that estimate is just ship time aboard research vessels for dredging rocks from the seafloor and the cost of transporting samples from the field using large fixed-wing aircraft. It doesn’t include the price tag of the actual grants or the money required to support scientists while in Antarctica, from housing and feeding them to the workforce required to run research stations and field camps.
“Antarctica is remote in the first place. Some of these places are a five-hour [plane] flight. That’s a pretty expensive trip,” Grunow noted.
The work for Grunow and her one student assistant doesn’t end once the rocks arrive at the repository. Every sample is weighed and photographed. Additional notes are made about each specimen, aside from what might be found in a field journal that accompanied the donation.
“It is a time-consuming process,” she said. Still, about 3,500 samples are processed each year, and use of the facility has increased every year since it was built. It is currently at about half of its intended capacity, with room for expansion to hold 140,000 samples.
Rocks aren’t just available for loan to scientists for research. In 2010, the repository began an outreach program to send boxes of rocks to classrooms across the country. Last year, Grunow shipped 45 boxes, which include samples of igneous, metamorphic, and sedimentary rocks, along with fossils and minerals.
The focus, of course, remains on scientists who may need samples for studies or to serve as clues as to where to plan their next expedition to some remote corner of Antarctica.
“We’re just trying to keep encouraging geologists to look here and at least get an idea of what they’re going to be seeing in the field,” Grunow said.