Audio news from December 19th to December 25th, 2010.
Welcome to the Audio News from Archaeologica! I'm Laura Kelley and these are the headlines in archaeological and historical news from December 19th to December 25th, 2010.
Sunken cannons retrieved from Confederate wreck
Our first story is from the United States, where a University of South Carolina archaeologist has found the wreck of C.S.S. Peedee, a Confederate gunboat destroyed by its own crew to avoid its capture by Union forces. The discovery in the Pee Dee River comes 18 months after underwater archaeologist Chris Amer confirmed the existence of two of three cannons from the gunboat in the river. The cannons came to light near the site of the former Mars Bluff Navy Yard. One is a Confederate Brooke rifled cannon and the other a Union Dahlgren smooth-bore, 9-inch shell cannon. The boat was not found resting neatly on the river bottom with them, however. As Amer put it, both the remains and the history that put them there are a messy story, one that has until recently been obscure.
The wreck and cannons tell a story about the important yet little-known role that inland Confederate naval yards played in the Civil War. Hidden along interior rivers, the inland naval yards let Confederate forces build gunboats and support vessels in protected locations. Amer had already searched unsuccessfully in July for the missing third cannon, thought to be either under the Dahlgren big gun or under a handful of artillery shells on the river's bottom. In September, Amer returned armed with more clues about the Peedee's location, including data from downstream gathered in 2009 and a personal account by Michael Hartley, an archaeologist in North Carolina, relating that as a 12-year-old in 1954 he watched a group of men salvage a boiler and other parts of the Peedee. Hartley, who was later on staff at USC's South Carolina Institute of Archaeology and Anthropology, gave Amer a file that he had created on the missing ship.
In November, Amer added sonar to the search and found new evidence of the wreck, in the form of ripples on the sand where sediment had built up over debris, magnetic "hits" in straight lines depicting the iron bolts along bedding timbers, and a tree stuck on something substantial on the river's bottom, possibly ship timbers. The fragmentary condition of the wreck was not a surprise. Historical records describe how Confederate commanders set the 170-foot gunboat ablaze and blew it up in 1865, to keep it out of the hands of Gen. William T. Sherman's advancing Union troops. In the early 1900s, the U.S. Army Corps of Engineers further damaged the wreck while clearing the river channel for boat traffic. Additional disruptions occurred in 1925 when propellers were reclaimed, and again in 1954, when Hartley witnessed the salvaging operation. With the remainder of the wreck finally pinpointed, Amer will resume efforts to locate the third cannon. Meanwhile, his colleague, Dr. Jon Leader, is searching for the naval yard. Like the third cannon, the land portion of the Mars Bluff Navy Yard remains elusive. An initial search using ground-penetrating radar and remote-sensing technologies, carried out as part of USC’s and East Carolina University's Program in Maritime Studies field school, uncovered early occupations by Native Americans, but no evidence of the naval yard. Leader believes it may be on neighboring property along the river, which he will investigate this spring.
Ancient Siberian finger bone points to new early human group
On the other side of the world, researchers have confirmed the discovery of a new type of human by sequencing the nuclear genome of an ancient finger bone. The newly defined early human group, who lived in the Altai Mountains in southern Siberia more than 30,000 years ago, is called the Denisovans after the Denisova cave in which the finger bone of the ancient girl was found. Although these people went extinct as a unique group, they had spread widely enough across Asia to interbreed with modern humans before they disappeared, and left behind their traces in the genomes of modern Melanesians.
After archaeologists discovered the bone in 2008, scientists at the Max Planck Institute in Leipzig, Germany, were able to isolate particles of remarkably well preserved DNA. As reported in a publication earlier this year, the team sequenced the finger's mitochondrial DNA, which suggested that the digit did not belong to a Neanderthal or a modern human. The mitochondrial DNA is passed down only through the mother and represents but a small fraction of the total genome. That first analysis didn't provide enough data to draw firm conclusions about the identity of the finger's owner. In the new study, the Max Planck team were able to sequence 70% of the genome in the cellular nucleus and by comparing this with the genomes of Neanderthals and modern humans, they confirmed that the girl was neither human nor Neanderthal. Her DNA was more like that of Neanderthals than that of modern humans, suggesting that Neanderthals and Denisovans are sister groups that shared a common ancestor after they split from the ancestors of modern humans, says evolutionary geneticist and lead author Svante Pääbo. However, they were not Neanderthals, because their DNA apparently split from that of Neanderthals around 640,000 years ago. Also, additional materials that have been found, especially a large molar, are too different in form to belong to a Neanderthal, according to team member David Reich, a population geneticist at Harvard Medical School in Boston.
The researchers also compared different parts of the Denisovan genome with the same segments of DNA in 53 populations of present-day humans. This revealed that the Denisovans shared certain mutations with Melanesians from Papua New Guinea and Bougainville Island, mutations not found in Neanderthals or other modern populations. Melanesians appear to have inherited between 4% and 6% of their DNA from these extinct Denisovans. A likely scenario to fit these data is that after Neanderthals and Denisovans split, Denisovans living in south Asia encountered a group of modern humans heading east from Africa toward Melanesia and interbred with them. As a result, Melanesians now carry DNA from encounters with Denisovans, which means that part of their DNA comes from archaic populations and not from fully modern humans. Yet, archaeologists have reported virtually no sign of the Denisovans, no tools or other indications of how they lived. This might be because sites in Asia haven't been studied as systematically as Neanderthal sites in Europe. Paleoanthropologists now are taking a new look at old fossils in Asia, trying to figure out which ones might be the Denisovans.
New evidence from Iceland shows people arrived before the Vikings
Far to the west in the north Atlantic Ocean, new archaeological discoveries show that Iceland was inhabited around AD 800, nearly 70 years before the traditional dating of its Viking settlement. These early inhabitants may be related to the Irish monastic communities that were found throughout the Scottish islands at that time, and are described in texts from the Viking era and later medieval times. According to team leader Professor Kristján Ahronson of Prifysgol Bangor University in Wales, questions surrounding Iceland’s first settlement in the early medieval period long have been of interest to scholars. The University of Toronto’s Sir Daniel Wilson argued in 1851 that when Norseman first visited Iceland in the latter half of the 9th Century, it was uninhabited, but they discovered traces of the former presence of Irish monks.
The island has revealed nearly 200 caves hollowed out by people. One such discovery is Kverkarhellir Cave in southern Iceland, which measures 7.5 meters or more than 20 feet long. Tool marks on the walls clearly show how it was dug from the soft rock. More importantly, Kverkarhellir also preserves layers of volcanic sediments outside the cave mouth from some of the countless volcanic eruptions that Iceland has experienced. When an eruption takes place, a layer of ashy material known as tephra (TEF-ra) falls to the ground surface and these layers provide a powerful dating tool for past land surfaces and any artifacts buried under the tephra. Tephra layers at Kverkarhellir include one from an eruption known to date around AD 871, which is about the time Vikings first arrived in Iceland. More surprisingly, however, older layers yielded waste material from an episode of early cave construction, which shows occupation older than any other site currently known in Iceland. Using rough but generally accepted estimates on sediment accumulation rates in the area, the team determined a date of around AD 800 for the early activity at the cave.
To learn more about the past environment of the cave area, Ahronson’s team analyzed the layers themselves, looking at such things as how they fell to the ground. Trees or a thick growth of vegetation will interrupt the ash fall, leading to gaps or distinctive features in the tephra layer. The ash also can preserve animal footprints. The team plotted these irregularities in 3D, a new technique involving excavation and mapping, initially tested over a small area. The team achieved clear results and the discovery of possible animal tracks. Ahronson concludes that the size, shape and distribution suggests these were medium-sized herbivores, such as sheep or small to medium size cows. The tracks date back to around AD 871, many decades after the new evidence for people at Kverkarhellir cave, but just about when the large-scale settlement of Iceland by Vikings is generally thought to have begun. The evidence also shows that these animals would have been walking over open grassland, with few trees.
A second cave site at Seljaland, close to Kverkarhellir, also contains possible evidence of early occupation in the form of 19 large and 4 medium-sized Christian crosses carved on its walls. As Ahronson emphasized, it is difficult to firmly date these carvings, but their style show similarities to early medieval crosses seen in western Scotland that predate the Viking Age, in other words AD 800 or earlier. Supporting that is the additional fact that none of the carvings from Seljaland have any parallels in Scandinavian traditions from that time.
Jordan secures agreement to protect field of ancient megaliths from mining
In our final story, hundreds of millennial tombs were spared destruction with the formation of a new archaeological preserve in the Jordan Valley. According to the Jordan Department of Antiquities, the new area protects the Damiya dolmen fields, home to hundreds of megalithic structures dating back to 3000 BC or earlier, which had been threatened by mining activities. Dolmens are Early Bronze Age megalithic table-shaped block formations, which some researchers believe may date back to the Chalcolithic period, also known as the Copper Age, from around 4500 to 3500 BC. Although their exact usage is in dispute, and through various surveys, the dolmens have yielded Iron Age pottery and Early Bronze Age jugs and bowls, leading many to believe they were used for burial and cultic practices.
The average dolmen in Jordan measures three meters long, one meter high and one meter wide, although some reach up to seven meters in length. According to Director General Ziad Saad, a deal was reached with a mining company to set aside a 150-acre area in the northern part of the field that contains most of the dolmens. Under the agreement, 23 dolmens that remain within the mining concession area will be relocated to the protected zone. Between 250 and 300 dolmens are in the Damiyah dolmen field, which was already placed on a World Monuments Fund watchlist in 2009 as a result of adverse affects from rock quarry activities, which left many dolmens vulnerable to collapse. Signage and interpretation will be installed to provide visitors with information on the megalithic structures and indicate which dolmens were artificially relocated, and two of the relocated dolmens will be transported to the new Jordan Museum in Amman, which will open in 2011, for display.
That wraps up the news for this week!
For more stories and daily news updates, visit Archaeologica on the World Wide Web at www.archaeologica.org, where all the news is history!
I'm Laura Kelley and I'll see you next week!