Mighty Viking Ax Discovered in Tomb of Medieval ‘Power Couple’

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Mighty Viking Ax Discovered in Tomb of Medieval ‘Power Couple’

Mighty Viking Ax Discovered in Tomb of Medieval 'Power Couple'

One of the largest Dane axes ever found, recovered by archaeologists from a 10th-century Viking tomb near Silkeborg in central Denmark.

Credit: Silkeborg Museum

Archaeologists have discovered one of the largest Viking axes ever found, in the tomb of a 10th-century “power couple” in Denmark.

Kirsten Nellemann Nielsen, an archaeologist at the Silkeborg Museum who is leading excavations at the site near the town of Haarup, said Danish axes like the one found in the tomb were the most feared weapons of the Viking Age.

“It’s a bit extraordinary — it’s much bigger and heavier than the other axes. It would have had a very long handle, and it took both hands to use it,” Nielsen told Live Science.

Viking site

Credit: Silkeborg Museum

The simplicity of the mighty ax, without any decorations or inscriptions, suggests this fearsome weapon was not just for show. “It’s not very luxurious,” she said.

And the man in the tomb was buried with his ax alone. “He didn’t have anything else buried with him, so I think you can say he identified himself as a warrior above anything else,” Nielsen said.

The ax was one of the artifacts recovered from the Haarup Viking tomb, or dødehus, which means “death house” in Danish. The tomb consisted of a wooden palisade or roofed structure, about 13 feet (4 meters) wide and 43 feet (13 m) long, which was constructed around the two graves.

One of three people found in the tomb was a wealthy Viking woman, who was buried in a wooden cart similar to this reconstruction at Silkeborg Museum.

Credit: Silkeborg Museum

The tomb was built around A.D. 950 for the burial of a man and a woman of evident distinction, Nielsen said. The individuals were identified by their clothing and belongings, and the only human remains that survived the centuries was a single black human hair found in the woman’s clothing.

The woman was buried lying in a wooden wagon, which was a tradition for women of noble birth at the time, and a pair of keys found in the tomb indicated that she was one of the leading people in the community, according to the archaeologists.

Tomb layout

Credit: Silkeborg Museum

Keys were a symbol of authority and distinction for women in Denmark and elsewhere in Europe in theMiddle Ages, and the tradition likely dated back to an earlier time, Nielsen said. “If you are an important woman, with a lot of fine artifacts with you in the grave, then you also have a key,” she said.

Grave goods

Credit: Silkeborg Museum

One of the keys was for a small wooden casket, bound with iron brackets, that was buried beside her.

“She also had gold and silver threads woven into her clothing, so this is quite fine,” Nielsen said.

Nielsen said the man and woman in the tomb may not have been husband and wife, but they were clearly the local “power couple.” [Fierce Fighters: 7 Secrets of Viking Seamen]

“The special thing about this tomb is that these two people, each in their own grave, are put inside the same structure,” she said. “I can’t say it isn’t a brother and sister, or it could be [a] husband and wife relationship. But definitely, these two were the ones in charge, the noblest people of the local area.”

Far and wide

Credit: Silkeborg Museum

At some point in time, after the first man and woman were buried, a second man was buried in a grave inside a wooden structure that was added to the original tomb. This man was also buried with his ax, although it was not as large as the ax from the original burial, the researchers said.

Nielsen thinks the second man could have been a relative or successor of the first man. “He was definitely a warrior,” she said. “Both men had Dane axes made for fighting, and both were definitely warriors.”

The tomb at Haarup was unlike any other Viking tomb in Denmark and the other Viking burials uncovered at the same site, she said.

“This is unique — the only one of its kind that I know of,” Nielsen said. “It’s a special place.”

Other finds from the tomb, and other sites in Haarup, show that the local Vikings likely had some international connections, whether through trade or travel, the archaeologists said. [In Photos: Viking Voyage Discovered]

The woman in the tomb was buried with a decorated ceramic cup that originated in the Baltic region, Nielsen said. Two silver coins of a Middle Eastern type called “dirhams,” thought to be from an area that is now in Afghanistan, were found in the grave of another Viking woman buried nearby.

Viking warriors

Credit: Silkeborg Museum

Nielsen has been working at Haarup since the site was unearthed during the construction of a motorway in 2012. As more construction goes on in the area, more archaeological discoveries are being made, including artifacts from the Iron Age and Danish medieval periods, as well as the Viking 10th century.

“From the Vikings, we have only found their burials — we haven’t found their houses yet, so we know them only from their graves,” Nielsen said. “They most definitely lived there, but we just haven’t found the place yet.”

Future archaeological research from Haarup will focus on the four different types of woven cloth found in the graves, the construction of the small casket in the leading woman’s grave, and the single black hair found in her clothing — the only human remains that have survived, and potentially a source of DNA that could provide more clues about its owner, Nielsen said.

A report on the discoveries at Haarup, titled “Dead and Buried in the Viking Age,” can be read online (in Danish) at Academia.edu.

Original article on Live Science.

A major step to predicting when supervolcanoes will explode

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A major step to predicting when supervolcanoes will explode

1/06/14 5:20pm


Scientists have learned that massive caldera volcanoes, like the one stewing beneath Yellowstone, are ruled by geological processes far different than the ones governing conventional volcanoes. These massive reservoirs of magma can explode spontaneously — an important piece of insight that can help us predict a future disaster.

Super-eruptions are extremely rare, occurring once every 100,000 years or so. Disturbingly, these cataclysmic geological events aren’t archaic phenomena; we know of at least 20 supervolcanoes on Earth, including Yellowstone, LakeToba in Indonesia, Lake Taupo in New Zealand, and the Phlegraean Fields in Italy. Scientists say it’ll only be a matter of time before the next Big One — an event that could eject upwards of 1,000 cubic kilometers of ash into the sky.

Smaller volcanoes, like Mt. Pinatubo, are typically triggered by earthquakes or other external factors; they’re powered as magma shoots into the volcanic chamber, increasing internal pressure to the point when an explosion occurs. But supervolcanoes, which consist of massive reservoirs of magma deep beneath the surface, are ruled by considerably different processes.

A recent study conducted by a Swiss team from ETH Zurich now shows that the mechanism behind these eruptions is buoyant magma — the same force that makes it difficult to hold a basketball underwater. To reach this conclusion, the researchers simulated the intense pressure of heat in the caldera of a supervolcano by using an experimental station called a high pressure beamline. They filled synthetic magma into a diamond capsule and shot high-energy X-rays inside to monitor changes as the mixture reached critically high pressures. By doing so, they could calculate the amount of pressure required to induce a spontaneous eruption (their samples reached pressures of up to 36,000 atmospheres and temperatures of nearly 1,700°C — similar to the conditions inside a magma chamber).

Results showed that the mounting pressure caused by magma buoyancy can crack more than 6 miles (10 km) of the Earth’s crust above the volcano chamber. Eventually, the magma penetrating these cracks will reach the Earth’s surface. But as it rises, it expands violently, causing a tremendous explosion. Discouragingly, this research shows that supervolcanic eruptions could happen 10 to 100 times more often than previously assumed.

The good news — such that it is — is that we will be able to see this disaster coming, particularly at Yellowstone. Speaking to the BBC, geologist Wim Malfait said the ground would probably rise hundreds of meters. He believes that Yellowstone currently has 10-30% partial melt, and that the overpressure required for an eruption requires at least 50%. What’s more, it can take hundreds of millions of years for this buoyancy force to create the pressure required for an explosion. It doesn’t appear that Yellowstone is going to blow any time soon. But given this new insight, geologists can now start to monitor the conditions within this and other calderas in hopes of predicting a future eruption.

Read more at BBC; and the entire study at Nature Geoscience: “Supervolcano eruptions driven by melt buoyancy in large silicic magma chambers.”

We’ll Only Have a Year to Prepare For a Cataclysmic Super-Eruption

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We’ll Only Have a Year to Prepare For a Cataclysmic Super-Eruption

Yesterday 1:02pm

Image: GFZ German Research Centre for Geosciences

Volcanic super-eruptions are bad. Like really bad. Scientists warn of such a potentially civilization-ending catastrophe in our future, but as a new study shows, we’ll only have a year to prepare once the signs of an impending eruption become visible.

A new microscopic analysis of quartz crystals taken from the site of a massive volcanic eruption that occurred 760,000 years ago in eastern California suggests we’ll only have about a year’s worth of advance warning before a devastating super-eruption. In a paper published in PLOS ONE, Guilherme Gualda from Vanderbilt University and Stephen Sutton from the University of Chicago show that super-eruptions don’t require much time to blow their tops, even though they’re tens of thousands of years in the making.

The Long Valley Caldera in eastern California, the result of a super-eruption 760,000 years ago. (Image: NASA/JPL)

Unlike “conventional” eruptions, these explosions are among the most devastating on the planet, unleashing destruction that can flatten continents, trigger new ice ages, and potentially put an end to human civilization as we know it. They happen when the magma in the mantle rises into the crust, but is unable to breach the surface. The ensuing pressure builds and builds in an ever-growing magma pool until the crust can no longer contain the pressure. The results of the ensuing explosion are nothing short of catastrophic. In the most severe cases, a supervolcano can eject upwards of 1,000 cubic kilometers of ash into the sky.

Our planet has experienced several super-eruptions in the recent geological past. The Taupo Volcanic Zone in New Zealand erupted 26,500 years ago, and Campi Flegrei in Italy erupted 40,000 years ago. Other noteable super-eruptions include Indonesia’s Toba super-eruption in Sumatra 75,000 years ago and the Tambora eruption in 1815. Wyoming’s Yellowstone has super-erupted three times in the past million years, and there’s fear it could happen again. As these episodes show, super-eruptions are still a part of Earth’s geological fabric. It’s not a matter of if they’ll happen again, but when.

As these timelines suggest, super-eruptions evolve over relatively long timescales. But as the new study by Gualda and Sutton shows, the final stage doesn’t take very long at all.

“The evolution of a giant, super-eruption-feeding magma body is characterized by events taking place at a variety of time scales,” noted Gualda in a release. It typically takes tens of thousands of years to “prime” the crust with the requisite amounts of magma. Once these pools are established, the giant magma bodies swell and fester for a few millennia or even just a few centuries. “Now we have shown that the onset of the process of decompression, which releases the gas bubbles that power the eruption, starts less than a year before eruption,” said Gualda.

A quartz crystals used in the analysis. (Image: Guilherme Gualda/Vanderbilt University)

Gualda and Sutton reached this conclusion by analyzing small quartz crystals in pumice taken from the site of the Long Valley Caldera that formed nearly a million years ago. This allowed the researchers to measure the distinctive surface rims found at the sites of super-eruptions. By measuring the size and growth rates of these rims, the researchers were able to determine the length of time it took for an explosion to happen once the collapse phase begins. Analysis showed that more than 70 percent of rim growth times were less than a year, indicating that quartz rims mostly grow in the days and months prior to an eruption.

According to the researchers, we’ll likely be able to detect the signs of a pending super-eruption by noticing the bloating effects of the expanding magma body on the surface. More work is needed to know more about thesewarning signs, but this new study suggests that these signals will start to appear within a year of an eruption. And they’ll intensify as the explosion gets closer.