Audio News for May 30th to June 5th, 2010.
Welcome to the Audio News from Archaeologica! I'm Laura Kelley and these are the headlines in archaeological and historical news May 30th to June 5th, 2010.
Stone Age Ochre Production Site Unearthed in South Africa
In our first story, archaeologists have revealed a large-scale 58,000-year-old ochre powder production site in South Africa. The site consisted of four cemented hearths containing the ochre powder. The discovery offers a glimpse into what early humans valued and used in their everyday lives. The findings also mark the first time that any Stone Age site has yielded evidence for ochre powder processing on cemented hearths, which was inventive for that era.
White ash from hearths can cement and become rock hard, providing a sturdy work surface. The cement workstations could have held grindstones or served as storage vessels for the powder.
Ochre consists of naturally tinted clay that contains mineral oxides. According to project leader Lyn Wadley, ochre occurs in a range of colors that include orange, red, yellow, brown, and varying shades of these colors. Yellow and brown ochre transform to red by heating them at temperatures as low as 250 degrees Celsius. Wadley said that they found ochre on bone awl tools, which early humans probably used for working leather, making it possible that the ancients wore decorated colorful leather clothing and other leather goods.
In addition to coloring objects, ochre makes a compound adhesive when mixed with other ingredients, such as plant gum and animal fat. Wadley explains that this glue could have attached stone spear or arrowheads to hafts, or blades to handles for cutting tools. Other roles of ochre include use as a body paint and makeup, as a preservative and as a medicinal component, so it could have served many different purposes during the Stone Age.
Wadley analyzed the ochre factory at the large Sibudu rock shelter north of Durban, South Africa. She believes the natural material came from just over a half a mile away from the site. Based on the nature of the cemented ash and the geology at the site, Francesco d'Errico, director of research at the National Center of Scientific Research at the University of Bordeaux, believes that people 58,000 years ago intended to produce large quantities of red pigment in a short time frame.
Tomb of 19th Dynasty Egyptian general rediscovered after 125 years
Moving now to the opposite end of the African continent, in Egypt, researchers from Cairo University have unearthed the lost tomb of an Egyptian general and scribe in the ancient necropolis of Saqqara, 125 years after its initial discovery.
The tomb of 19th Dynasty official Ptahmes (pTA mees), is over 70 meters long and features several chapels. No one recorded its location when Egyptologists discovered it in 1885, leaving it to disappear beneath the desert sands. Most of the tomb's possessions are already in museums located in The Netherlands, Italy, and the United States. However, the latest discoveries revealed several stelas including an unfinished image of Ptahmes himself. Another shows his family before the “Theban Triad” of gods Amun, Mut and Khonsu. Investigators also found a painted head of Ptahmes' daughter or wife, alongside shabti (SHAB tee) figurines, amulets and clay vessels. Despite excavation efforts to find the tomb’s main shaft and burial chamber, Ptahmes’ sarcophagus remains missing.
The 19th Dynasty, when Ptahmes lived, covered the time from 1203 to 1186 BC. Ptahmes, a high-ranking official of his time, served several important roles in the empire, including mayor of Memphis, royal scribe and supervisor of the temple of Ptah. His tomb was located on the south side of the Pyramid of King Unas, a highly cherished spot reserved for the burial of ancient Egypt's top government officials.
The tomb’s design is similar to that of the tomb of Ptah Im Wiya, (pTAH em Weeya) a royal seal bearer who lived during the reign of Pharaoh Akhenaten, discovered in 2007 by Dutch archaeologists. Saqqara, the location of the tomb, dubbed the “City of the Dead,” is a major necropolis 40km south of Cairo.
Jamestown residents survived drought by eating oysters
We move now across the Atlantic Ocean to the United States, where oyster shells excavated from a well in Jamestown, Virginia, strengthen the belief that the first colonists suffered an unusually deep and long-lasting drought. Jamestown was the first permanent British settlement in North America. Colonists established the outpost in 1607.
According to Howard Spero, a geochemist at the University of California Davis, the shells reveal that water in the James River near the colony, where colonists harvested oysters, was much saltier then than along that stretch of the estuary today. For the water to be so briny, the river must have flowed slower than it does today, a sign that precipitation was dramatically lower when those oysters were growing.
Many accounts by Jamestown’s early settlers, including journal entries and letters home, chronicled the drought. So did the region’s trees. Previous studies based on tree rings and original documents revealed that the first colonists’ arrival coincided with the beginning of a drought that included the driest seven-year period in almost 800 years. Oysters independently confirm the tale from trees and historical accounts.
Excavataors unearthed the telltale oysters from a well that sat within the fort at Jamestown, about 100 yards from the river. Among other material dumped into the well, the shells came from three distinct layers up to 3.5 meters deep. The well’s water level originally sat deeper, at a depth of about 4 meters, so Spero and his colleagues suggest that the settlers abandoned the well because it ran dry or salty groundwater infiltrated it. In either case, settlers converted it into a trash pit.
Historical accounts suggest that settlers dug the well sometime between 1609 and 1617, but items unearthed from the well narrow that window considerably. A ratio of different forms, or isotopes, of oxygen in the shells suggests that settlers harvested these mollusks before the drought ended in late 1612. One artifact found beneath the oyster shells, a ceremonial item linked to a particular nobleman from England, couldn’t have been present in Jamestown before he arrived in June 1610 and probably wouldn’t have been discarded in the well until after that nobleman’s return to England in April 1611. Those data, plus the pattern of isotope variations in the oyster shells, which reveal the season when residents harvested the mollusks, hint that the settlers gathered and ate the mollusks between late fall 1611 and summer 1612.
Analysis of the oyster shells has raised another mystery. The oxygen-isotope ratios in the middle layer of shells are substantially different from those in the upper and lower layers, which other data suggest the Jamestown settlers gathered locally. That disparity indicates that in March and April of 1612, Jamestown residents gathered these oysters elsewhere. Further analyses of trace elements in those shells should reveal whether the settlers gathered the oysters in another part of the James River watershed or if sailors on an English supply ship collected them elsewhere along the Mid-Atlantic coast and brought to Jamestown.
Sticky rice used to create super-strong mortar
In our final story, a new study suggests sticky rice, a staple in many modern Asian dishes, was also the secret ingredient in super-strong mortar used in China 1,500 years ago. According to the American Chemical Society, the sweet-rice mixture was probably the world's first composite mortar. Mortar, a paste used to bind and fill gaps between bricks, stone blocks and other construction materials, remains the best available material for restoring ancient buildings. Builders used the material to construct important structures like tombs, pagodas and city walls, some of which still exist today.
Builders made the super-strength mixture by combining sticky rice soup with a standard mortar ingredient called slaked lime, or limestone that the workers heated to a high temperature and exposed to water, according to study researcher Bingjian Zhang, a professor at the Department of Chemistry at Zhejiang University in China.
Analytical study shows that the ancient masonry mortar is a kind of special organic-inorganic composite material. The inorganic component is calcium carbonate, and the organic component is amylopectin, which comes from the sticky rice soup added to the mortar. This secret ingredient, which makes the mortar so strong and durable, is a type of polysaccharide, or complex carbohydrate. The mortar's potency is so impressive that restorers can still use today as a suitable restoration mortar for ancient masonry.
To determine whether sticky rice can aid in building repair, Zhang and colleagues prepared lime mortars with varying amounts of sticky rice and tested their performance compared with traditional lime mortar. Test results of the modeling mortars show that sticky rice-lime mortar has more stable physical properties, has greater mechanical strength, and is more compatible, which make it a suitable restoration mortar for ancient masonry. In fact, the mortar works so efficiently as a bonding agent that some of the structures that the ancient Chinese built using it remain strong enough to shrug off the effects of modern bulldozers and powerful earthquakes.
That wraps up the news for this week!
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I'm Laura Kelley and I'll see you next week!