Dawn Levy, News Service (650) 725-1944; e-mail: firstname.lastname@example.org
All the world's a laboratory to a globetrotting geologist
Stanford geologist Elizabeth Miller experienced a moment of panic when she saw the airplane that would take her research team into the Siberian wilderness. The sagging body of the Russian-made Antonov-2 was a patchwork of stained aluminum panels. The pilot, a swashbuckling Siberian cowboy-type, had alcohol on his breath.
On top of the world, Miller got a bird's-eye view of the folds and thrusts of the Verkhoyansk belt. By discovering the age of these mountains, Miller can learn about the geologic forces that shaped eastern Russia.
If this had been Miller's first time in northeastern Russia, she might never have boarded the plane. But she knew better than to refuse the flight in an area where summer storms could ground planes for days. Once airborne, she looked down at the taiga forest, a luxurious mat of Siberian larch. When the plane lurched and bucked, Miller was one of the few who kept her lunch.
Miller and a team of geologists were on a six-week trip during the summer of 1999 to study a remote but impressive geologic feature called the Verkhoyansk fold and thrust belt. The team included Stanford postdoctoral researcher Jaime Toro (now an assistant professor at West Virginia University) and three Russian geologists, Andrei Prokopiev, Vladimir Tarabukin and Valery Alpatov, from the Institute of Geological Sciences, Russian Academy of Sciences, in Yakutsk. Miller and Toro will return to the Verkhoyansk belt this summer to continue their studies.
"Our studies will tell us a lot about the basic geologic framework for natural resources in this region," says Miller.
Russian geologists have mapped the region, but questions remain as to how the Verkhoyansk belt formed. Scientists think the belt could provide clues to understanding the motion of continental plates. Miller also hopes to learn more about the formation of the Sea of Okhotsk.
In addition to academic interest, geologists have a practical reason to explore the area: ExxonMobil Corp., one of Miller's funders, is prospecting for oil on nearby offshore islands. "From studying what happens on land nearby, we can infer what happens offshore," Miller says.
Miller prepares to board the weathered Antonov-2.
Photos courtesy of Elizabeth Miller
But on Miller's trip to Siberia, getting the information she needed was not easy. The geologists endured bumpy rides over unpaved roads and camped in mosquito-infested wilderness. They survived on tshonka (canned meat) and grishka (buckwheat); their only fresh food was the wild chives and rhubarb they gathered. They hiked and rafted to some of the most remote regions on the planet in search of geological samples.
Studying the Earth's geology from the ground can be as challenging as a flea studying the surface of a dog. But for Miller and other geologists, fieldwork is essential. Satellite pictures tell much about present geology, but little about the past. Instead, geologists take trips to strategic places to gather the most information they can in a manageable amount of time.
When the world is your laboratory
When the plane set down on a grass landing strip outside the Russian town of Eldican, the truck the researchers had hired was nowhere to be seen. They had trekked two miles toward town before the truck rumbled up and out jumped the driver, Valodya, or "Tiger." Miller soon would learn that Valodya's name suited his aggressive driving style.
The six-wheel-drive, triple-axle truck had wheels that stood higher than Miller's waist. Behind the cab was a 20-foot-long room that would be the researchers' mobile base camp for the next month. During a "welcome to Siberia" feast, replete with lots of vodka shots, at Valodya's house, Miller and her colleagues watched satellite-fed Brazilian soap operas dubbed in Russian, which made Brazilian-born Miller feel strangely at home.
The next day the group set out eastward on the main dirt highway that connects the mining camps that dot the Verkhoyansk belt. The belt stretches from the Sea of Okhotsk on Russia's eastern coast to the Arctic Circle, a distance comparable to the span between the United States' Mexican and Canadian borders. From the air, the region looks like an S-shaped series of tightly aligned valleys and ridges. At lower latitudes the belt is forested, but as one moves northeast the furrowed land protrudes from the forest to form steep, snow-dusted mountains.
Although on a map they look like two separate land masses, geologists now know that both North America and Eastern Russia occupy a single continental plate. The Pacific Ocean plate lies between the continents and pushes against their edges. Miller and Toro hope to compare the formation of the Verkhoyansk belt to structures such as the Rocky Mountains and the Wyoming-Montana thrust belt. The gold-bearing quartz veins that ripple through the Verkhoyansk belt are similar to those of the mother lode belt of the western Sierra Nevada. The geologists want to find out if similar plate motions create mountain ranges on both sides of the Pacific.
After traversing the ridges in the western portion of the belt, the group arrived in Allakh Hun, a town of boarded-up wooden houses, rusted vehicles and broken picket fences. With the Russian government unable to pay salaries, workers survive on potatoes, cabbage and other vegetables grown during the short summers. This year the annual shipment of diesel had failed to arrive, so the electricity plant ran only two hours a night. "The place was turning into a ghost town," Miller recalls.
The plan was to spend a week at a gold-mining camp across the river, from which the researchers could launch expeditions. But here they ran into their first major obstacle. The river was too high for even fearless Valodya to drive across. After a spirited conversation in Russian, of which Miller understood only parts, a decision was reached. They'd cross by boat. At the camp, they were welcomed by the caretaker, an aging Chuckhi (native Siberian) man who kept a baby bear as a pet.
Each day the geologists trekked among granites and dark, slatey rocks streaked with quartz veins inlaid with gold. They collected samples that would provide them with highly precise ages of the biotite and zircon mineral grains found in the belt's granite rocks. To determine the ages of biotite, Miller uses a technique that detects the radioactive decay of potassium to argon.
Another technique, known as SHRIMP (for Sensitive High Resolution Ion MicroProbe), detects uranium and lead in the tiny zircon grains. As the rock ages, the uranium turns to lead by radioactive decay. By comparing the relative abundance of the original isotopes to their decay products, scientists can determine the age of the sample. The age of these minerals may tell Miller how tectonic plate movements affected the formation of the Verkhoyansk belt.
Unfortunately, the granite lay in high mountain regions, reached by few or no roads. The group had to use foot power to reach the peaks of the mountains. "What an amazing and also painful day!" Miller wrote in her journal. "The sun beating down and I'm soaking with sweat and we haven't even started up hill really yet." They ate Snickers bars to keep up their energy.
"We go up up up until we are in rocky ridges with views of snow-capped peaks and cirques and high ridges behind us," Miller wrote. To the east, north and south,
snow-dusted black peaks rose and fell like waves with whitecaps.
The trip down the mountain was easier, sort of. "The way down was a steep but soft descent on spongy tundra that tripped you up for the occasional face-plant," wrote Miller. They arrived at camp to find waiting a warm meal and a heated sauna, or banya.
Returning to Allakh Hun, Miller and the team spent the next several days driving up and down the nearby river to chip bits of rock off the faces of cliffs with hammers and chisels. They collected samples for later analysis of the cooling history of the rocks involved in folds and thrust faults.
One technique for dating rocks is fission-track dating. The rocks in this region contain a crystal called apatite that in turn contains trace amounts of uranium. When this radioactive element undergoes spontaneous division, called fission, it releases daughter fragments that rip through the crystal and leave tracks in their wake. These tracks heal when the rock is heated to more than 100 degrees Celsius. By counting the number of trails in an apatite crystal, geologists can tell when the rock cooled and determine the approximate age of uplift by folding and faulting.
When the geologists reached the southernmost part of their journey, they found their path blocked. A spring flood had knocked out a key bridge support.
Time for Plan B. "The river moved about the right pace to view the rocks," says Toro. The geologists inflated their rubber rafts and launched them onto the swirling green water. From boats, they made sketches of the pattern of folds and faults that ripple through the Precambrian and Paleozoic sediments. These sediments were crumpled into the folds and faults of the Verkhoyansk. Miller and Toro will combine their sketches with geothermal dating to construct a model of how the land buckled to form ridges and valleys. Their sketches also detail how erosion shaped the land.
More adventures ahead
Miller, Toro and Prokopiev plan to return to the Verkhoyansk belt this summer to continue collecting samples for their studies. This time, Toro and Prokopiev will head north, collecting samples and making observations to test Miller and Toro's initial thoughts on the timing of formation of the belt. Meanwhile, Miller and Stanford graduate student Jeremy Hourigan will fly by helicopter to the interior of the high mountain range close to the Sea of Okhotsk. They will hike 70 miles to a point along the Dyanyshka River where they will collect rubber rafts and other supplies previously dropped by helicopter. Then they will launch the boats and study the rock formations as they float by them.
From above, they'll look like tiny specks in an incredibly vast wilderness. "You are too small and the Earth is too big to go everywhere," says Miller. "You must pick where you go carefully." After doing fieldwork in Siberia, she should know.
Catherine Zandonella is an intern at Stanford News Service.
By Catherine Zandonella