Audio News for January 30th to February 5th, 2011
Welcome to the Audio News from Archaeologica! I'm Laura Kelley and these are the headlines in archaeological and historical news from January 30th to February 5th, 2011.
Legendary Viking sunstone may have been unusual navigational aid
In our first story, researchers are investigating the scientific possibilities behind an ancient sailing saga. Viking legend tells of a gleaming 'sunstone' that, when held up to the sky, revealed the position of the Sun even on a cloudy day. Now scientists who have measured the properties of light in the sky say that polarizing crystals would function in the same way as the myth of the sunstone describes. Such crystals could have helped ancient Viking sailors skillfully cross the Atlantic’s open seas.
Gábor Horváth, an optics researcher at Eötvös University in Budapest, and Susanne Åkesson, a migration ecologist from Lund University, Sweden, reported their investigation into the possibilities in the recent issue of Philosophical Transactions of the Royal Society B. It has long been agreed that the Vikings, who travelled across most of Northern Europe, the British Isles and the northern Atlantic from around AD 750 to 1050, were skilled navigators, managing to cross thousands of miles of open sea between Norway, Iceland and Greenland. But the 24-hour daylight of the far north during the summer would have prevented them from navigating by the stars, and during their era the magnetic compass had yet to be introduced. The question of how they managed to find their way has thus always excited great interest.
Viking legends, including the Icelandic saga about the hero Sigurd, hint that they had a special, supplementary navigational aid at their disposal: a stone called a sólarsteinn, or sunstone. In the Sigurd saga, a passage describes how, during gloomy, snowy weather, King Olaf used a sunstone to look at the sky and see from where the light came. From this, the saga says, he could guess the position of the invisible Sun. The Danish archaeologist Thorkild Ramskou suggested in 1967 that this sunstone could have been a polarizing crystal such as Icelandic spar, a transparent form of calcite that is commonly found in Scandinavia.
Polarizing crystals are naturally occurring filters for the electromagnetic waves in light, which oscillate perpendicularly to the direction of the light's travel. When the oscillations all point in the same direction, the light is polarized. A polarizing crystal such as calcite allows only light polarized in certain directions to pass through it, and can appear either bright or dark, depending on its orientation to the light. Ramskou argued that by holding a crystal such as calcite up to the sky and rotating it to the direction of polarization of the light passing through it, the Vikings could have worked out the position of the sun, even when it was hidden behind clouds or fog, or was just beneath the horizon.
Historians have debated the possibility ever since, with some arguing that the technique would have been pointless, because it would only work if the crystal was pointed at patches of clear sky, and in such conditions it would be possible to estimate the position of the sun with the naked eye, for example from the brightness on the tops of the clouds.
In the newly published research, Horváth and Åkesson report on their tests of the various theories since 2005. In one study, they took photographs of partly cloudy or twilight skies in northern Finland through a 180-degree fisheye lens, and asked test subjects to estimate the position of the Sun. Errors of up to 99 degrees suggested that such naked-eye guesses would not have helped the Vikings estimate the sun's position. To check whether sunstones would work better, they measured the polarization pattern of the entire sky under a range of weather conditions during a crossing of the Arctic Ocean, and found that in foggy or completely overcast conditions the pattern of light polarization was similar to that of clear skies. Even though the polarization was not as strong, they believe it could still have provided Viking navigators with useful information.
Åkesson and Horváth are now planning further experiments to determine whether volunteers can accurately work out the Sun's position using crystals in various weather conditions. According to Christian Keller, a specialist in North Atlantic archaeology at the University of Oslo, the surviving written records indicate that Viking and early medieval sailors crossed the north Atlantic using the Sun's position on clear days as a guide, in combination with the positions of coastlines, flight patterns of birds, migration paths of whales and distant clouds over islands. Keller says he is open to the idea that the Vikings also used sunstones, but is waiting for archaeological evidence.
Antler carving from late Stone Age in Poland interpreted as fertility symbol
In Poland, a Stone Age antler carving has been interpreted as a zigzag drawing of a woman with spread legs, suggesting a fertility ritual or symbol. According to new research, in the upcoming March issue of the Journal of Archaeological Science, the carving on the elk antler is radiocarbon dated to about 10,900 years ago.
According to senior author Tomasz Plonka, a University of Wroclaw archaeologist, the ornament is composed of groups of zigzag lines with several of them joined into a human representation. The rare artifact was unearthed by a farmer at Swidwin, Poland. In beginning their research Plonka and his colleagues noted that the geometrical figure carved onto the antler could have been either a woman or a man, and could have been seen either with their legs spread or as a person raising their arms. The researchers used measurements of the ratio of the stick figure’s limbs in comparison to other early human representations to conclude that the more likely interpretation is that the stick figure is a woman.
Zigzags were popular motifs on artifacts from many cultures throughout the world, with various possible meanings, but Plonka believes the sets of multiple zigzag lines around the figure symbolize water and life. The lines appear to have been carved by different individuals, suggesting a group effort in the creation of the object. Geological study of the Polish site where the artifact was found shows that thawing of ice masses had occurred in the region, increasing the number of water bodies around.
Giant elk, whose antlers were used for the carvings, were the most imposing animals of the European Plain, and thus may have symbolized the power of life to the peoples of the plain. Internal structure of the antler indicates its growth stage was spring or summer. The scientists believe the elk might have been selected and killed for the purpose of making the object, which may have served a role in rituals for many years. Co-author Krzysztof Kowalski of the National Museum in Szczecin (Sh che sheen) said that one of two possible groups, the Federmesser or the Ahrensburg cultures, were the likely artists.
The Federmesser culture is known for its distinctive flint blade tools, while the Ahrensburg people have left much evidence of their animal hunting. Finds of Ahrensburgian reindeer skeletons with arrowheads in their chests suggest some sacrifice during rituals. The researchers aren't yet certain if the images on the carved antler are associated with Venus figurines, statuettes of women with exaggerated sexual features that date to as early as 35,000 years ago. Some Venus figurines have been found in Poland, not too far from the Swidwin site.
Conservation project in Peru includes finds of new temple and tombs
Now we go to Peru, where an important religious temple of the Mochica (moh-CHEE-ca) culture has been discovered, along with a group of tombs from all the cultures that inhabited the northern coast from 1,500 BC up to the Spanish conquest. According to Edgar Bracamonte (ed-GAR bra-ca-MOHN-tay), the lead archaeologist on the project, the new finds in the Lambayeque (lom-bye-YAY-kay) area indicate that the region, best known for the discovery of the outstanding tomb of the Lord of Sipan (see-PAHN), has many more surprises in store. Work began on the group of finds last November as part of a series of projects that include some new explorations, but also involve work to protect sites from the weather and to prevent looting.
Notable finds unearthed to date include 14 tombs, completely intact, dating back to such cultures as the Chimu (chee-MOO), Lambayeque and Inca, as well as other burial sites found opened and damaged, not by today’s archaeological tomb robbers but by the same ancient cultures that settled the area over the centuries. According to Bracamonte, the site displays a complete sequence of cultural occupation in the Lambayeque Valley on the northern coast of Peru from its primitive origins until the time of the Incas; in other words, from 1500 BC until the arrival of Spaniards in the area. For the archaeologist, the great quantity of remains from all these cultures shows the importance of the site and suggest that the place was a point of control and exchange between the mountains and the coast.
The newly documented Mochica temple dates to the period from AD 550 to 800. Named the Temple of Clay for the construction technique used, it differs from the traditional adobe used in the rest of the area’s ancient structures. The numerous offerings found along with the altars and platforms seem to indicate the religious importance of the area. Exploration will continue at the temple in hopes of shedding light on cultural evolution in the northern region of Peru.
Norwegian burial mound reveals unusual petroglyphs within
Our final story is from Norway, where what was thought to be a routine excavation of a burial mound turned up something unusual: Bronze Age petroglyphs. Archaeologists from the Norwegian University of Science and Technology’s Museum of Natural History and Archaeology carried out the work in Stjørdal, just north of Trondheim, in advance of destruction by a gravel pit.
Project archaeologists did not anticipate that the dig would be very complicated, and budgeted just three weeks to the effort. Then came the surprise. It turned out that mound builders had used an existing hill as a starting point to save them time and effort. The hill itself made the burial mound even larger and more monumental than it might have otherwise been. However, researchers supposed there might be another reason for the choice of the hilltop when they uncovered the remains of two cremations, or rather a fire layer that also contained bits of bone. Underneath this were a number of petroglyphs, including eight drawings that show the soles of people’s feet, and five shallow depressions. Two boat drawings and several other drawings of feet soles with toes were also found just south of the burial mound.
Museum researcher and project manager Anne Haug believes these are very special as no similar finds from Trøndelag County are known to exist. She theorizes that the tomb might have been intentionally constructed over the petroglyphs, probably as part of funeral ritual. Based on the drawing style, especially the drawings of the foot soles, the art is dated to the Bronze Age, about 1800-500 BC in this area. Why there are foot sole drawings beneath the cremation layer is a puzzle. However, if interpreted in terms of a fertility cult, it may be that the soles represent God and life-giving power, meaning that you can have both life and death represented in one place, Haug noted.
Haug says that there was a similar discovery in Østlandet County where petroglyphs depicting foot soles were found under a tomb dating back to the Bronze Age. Nordic archaeology includes several other sites where burials were combined with rock art, including petroglyphs of foot soles found at Bohuslän, a World Heritage site in Sweden. It’s not yet clear if the new grave was built at the same time as the petroglyphs were carved, but the analysis is ongoing. The scientists have found about 900 grams of burned bone, probably from one or more individuals, and they hope to be able to carry out C-14 dating of the material along with other analyses, to discover the gender and the age of the individuals.
It is unclear whether the original burial site contained two grave mounds, or whether there was just one large burial area. Historians and archaeologists had described a burial ground in the area in 1818, and again in 1879. It is likely that the graves excavated in the most recent dig are the last remaining portion of this site.
That wraps up the news for this week!
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I'm Laura Kelley and I'll see you next week!