Tuesday, February 26, 2008

Centuries-old Maya Blue mystery finally solved

Production of the renowned, extremely stable pigment was part of ritual sacrifices at Chichén Itzá

Anthropologists from Wheaton College (Illinois) and The Field Museum have discovered how the ancient Maya produced an unusual and widely studied blue pigment that was used in offerings, pottery, murals and other contexts across Mesoamerica from about A.D. 300 to 1500.

First identified in 1931, this blue pigment (known as Maya Blue) has puzzled archaeologists, chemists and material scientists for years because of its unusual chemical stability, composition and persistent color in one of the world’s harshest climates.

The anthropologists solved another old mystery, namely the presence of a 14-foot layer of blue precipitate found at the bottom of the Sacred Cenote (a natural well) at Chichén Itzá. This remarkably thick blue layer was discovered at the beginning of the 20th century when the well was dredged.

Chichén Itzá, one of the Seven Wonders of the Ancient World, is an important pre-Columbian archeological site built by the Maya who lived on what is now the Yucatán Peninsula of Mexico.

The findings from this research will be published online Feb. 26, 2008, by the prestigious British journal Antiquity and will appear in the print version of the quarterly journal to be released in early March.

According to 16th Century textual accounts, blue was the color of sacrifice for the ancient Maya. They painted human beings blue before thrusting them backwards on an altar (see below for image) and cutting their beating heart from their bodies. Human sacrifices were also painted blue before they were thrown into the Sacred Cenote at Chichén Itzá. In addition, blue was used on murals, pottery, copal incense, rubber, wood and other items thrown into the well.

The new research concludes that the sacrificial blue paint found at this site was not just any pigment. Instead, it was the renowned Maya Blue – an important, vivid, virtually indestructible pigment.

Maya Blue is resistant to age, acid, weathering, biodegradation and even modern chemical solvents. It has been called “one of the great technological and artistic achievements of Mesoamerica.”

Scientists have long known that the remarkably stable Maya Blue results from a unique chemical bond between indigo and palygorskite, an unusual clay mineral that, unlike most clay minerals, has long interior channels. Several studies have found that Maya Blue can be created by heating a mixture of palygorskite with a small amount of indigo, but they have not been able to discover how the ancient Maya themselves actually produced the pigment.

The new research shows that at Chichén Itzá the creation of Maya Blue was actually a part of the performance of rituals that took place alongside the Sacred Cenote. Specifically, the indigo and palygorskite were fused together with heat by burning a mixture of copal incense, palygorskite and probably the leaves of the indigo plant. Then the sacrifices were painted blue and thrown into the Sacred Cenote.

“These sacrifices were aimed at placating the rain god Chaak,” said Dean E. Arnold, Professor of Anthropology at Wheaton College, Research Associate at The Field Museum and lead author of the study. “The ritual combination of these three materials, each of which was used for healing, had great symbolic value and ritualistic significance.

“The Maya used indigo, copal incense and palygorskite for medicinal purposes,” Arnold continued. “So, what we have here are three healing elements that were combined with fire during the ritual at the edge of the Sacred Cenote. The result created Maya Blue, symbolic of the healing power of water in an agricultural community.”

Rain was critical to the ancient Maya of northern Yucatan. From January through mid-May there is little rain – so little that the dry season could be described as a seasonal drought. “The offering of three healing elements thus fed Chaak and symbolically brought him into the ritual in the form a bright blue color that hopefully would bring rainfall and allow the corn to grow again,” Arnold said.

Museum collections play key role

One of the keys to solving the mystery of Maya Blue production was a three-footed pottery bowl (Field Museum catalog number 1969.189262; see below for reference to image) containing rarely preserved copal dredged from the Sacred Cenote at Chichén Itzá in 1904 and traded to The Field Museum in the 1930s. Preserved in the copal were fragments of a white substance and blue pigment. Using The Field Museum’s scanning electron microscope, the authors studied these inclusions and found signatures for palygorskite and indigo. From this they concluded that the Maya produced Maya Blue as part of their sacrificial ceremonies.

“This study documents the analytical value of museum collections for resolving long-standing research questions,” said Gary Feinman, Curator of Anthropology at The Field Museum and co-author of the study.

But other knowledge was necessary to understand the significance of the bowl and the hardened copal it contains.

“This study required documentary, ethnographic and experimental research to establish the full context and use of the artifacts,” Feinman said. “Our work emphasizes the potential rewards of scientific work on old museum collections. It also shows that scientific analysis is necessary but not sufficient for understanding museum objects.”

It is this broad knowledge coupled with the scientific analysis that has enabled the scientists to finally – after more than 100 years – explain the thick layer of blue precipitate at the bottom of the Sacred Cenote at Chichén Itzá.

Already knowing that Maya Blue was central to Maya ritualistic sacrifices together with discovering that the pigment was produced right beside the Cenote solved the mystery of the 14-foot layer of blue precipitate: So many sacrifices – from pots to more than 100 human beings – were thrown into the Sacred Cenote that ultimately a layer of the pigment washed off the sacrifices and settled at the bottom of the well. (Although fully formed Maya Blue is extremely durable, it can be washed off with water, especially if there is no binder to help it adhere to the object on which it is placed.)

Other objects in The Field Museum’s collections may reveal more information about Maya Blue, the scientists said. For example, identification of the plant materials on the bottom of the copal incense in other bowls dredged from the Sacred Cenote at Chichén Itzá could reveal which portions of the indigo plant were used to make Maya Blue.

“The Field Museum’s collection was critical in solving this mystery,” Arnold concluded. “This bowl has been in the collection for 75 years yet only now have we been able to use it in discovering the ancient Maya technology of making Maya Blue.”

Monday, February 25, 2008

Viking Women Dressed Provacatively

Vivid colors, flowing silk ribbons, and glittering bits of mirrors - the Vikings dressed with considerably more panache than we previously thought. The men were especially vain, and the women dressed provocatively, but with the advent of Christianity, fashions changed, according to Swedish archeologist Annika Larsson.

"They combined oriental features with Nordic styles. Their clothing was designed to be shown off indoors around the fire," says textile researcher Annika Larsson, whose research at Uppsala University presents a new picture of the Viking Age.

She has studied textile finds from the Lake Mälaren Valley, the area that includes Stockholm and Uppsala and was one of the central regions in Scandinavia during the Viking Age. The findings, some of which were presented in her dissertation last year, show that what we call the Viking Age, the years from 750-1050 A.D., was not a uniform period. Through changes in the style of clothing we can see that medieval Christian fashions hit Sweden as early as the late 900s and that new trade routes came into use then as well. The oriental features in clothing disappeared when Christianity came and they started to trade with the Christian Byzantine and Western Europe.

"Textile research can tell us more about the state of society than research into traditions. Old rituals can live on long after society has changed, but when trade routes are cut off, there's an immediate impact on clothing fashions," says Annika Larsson.

She maintains that Swedish Viking women in the pre-Christian period probably dressed much more provocatively than we previously believed. She bases her theory on a new find uncovered in Russian Pskov, close to Novgorod and the eastward trade routes then plied from Sweden. The find consists of extensive remnants of a woman's attire, which Annika Larsson claims does not square with the traditional picture of how Viking women dressed.

Previously it was thought that Viking women wore a long suspender (brace) skirt, with both the front and back pieces consisting of square sections, held together by a belt. Clasps, often regarded as typical of the Viking Age, were attached to the suspenders roughly at the collar bone. Under this dress they wore a linen shift, and on top of it a woolen shawl or sweater.

"The grave plans from excavations at Birka outside Stockholm in the 19th century show that this is incorrect. The clasps were probably worn in the middle of each breast. Traditionally this has been explained by the clasps having fallen down as the corpse rotted. That sounds like a prudish interpretation," says Annika Larsson.

She maintains instead that the Birka women's skirts consisted of a single piece of fabric and were open in front. The suspenders held up the train and functioned as a harness that was fastened to the breasts with the clasps. Annika Larsson's theory is strengthened by that fact that a number of female figures have been preserved whose outfits both have trains and are open in front. But if we are to believe the archeological finds, this style of clothing disappeared with the advent of Christianity.

"It's easy to imagine that the Christian church had certain reservations about clothing that accentuated the breasts in this way and, what's more, exposed the under shift in front. It's also possible that this clothing was associated with pre-Christian rituals and was therefore forbidden," she believes.

Royals weren't only builders of Maya temples

An intrepid archaeologist is well on her way to dislodging the prevailing assumptions of scholars about the people who built and used Maya temples.

From the grueling work of analyzing the “attributes,” the nitty-gritty physical details of six temples in Yalbac, a Maya center in the jungle of central Belize – and a popular target for antiquities looters – primary investigator Lisa Lucero is building her own theories about the politics of temple construction that began nearly two millennia ago.

Her findings from the fill, the mortar and other remnants of jungle-wrapped structures lead her to believe that kings weren’t the only people building or sponsoring Late Classic period temples (from about 550 to 850), the stepped pyramids that rose like beacons out of the southern lowlands as early as 300 B.C.

“Preliminary results from Yalbac suggest that royals and nonroyals built temples,” said Lucero, a professor of anthropology at the University of Illinois.

In fact, judging by the varieties of construction and materials, any number of different groups – nobles, priests and even commoners – may have built temples, Lucero said, and their temples undoubtedly served their different purposes and gods.

That different groups had the wherewithal – the will, resources and freedom – to build temples suggests to Lucero that “the Maya could choose which temples to worship in and support; they had a voice in who succeeded politically.”

Yalbac’s location on the eastern periphery of the southern Maya lowlands and its distance from regional centers may explain its particular dynamics and its “relative political independence,” Lucero said.

The archaeologist’s new propositions challenge academic thinking on Maya temples.

“Maya scholars have basically assumed that rulers built all the temples,” she said. “No one has questioned this, although cross-cultural comparison alone would suggest otherwise.”

To be sure, the historic record is largely silent on why the Maya, a complex culture with many mysteries still to unravel, had several temples in any given center, which is why Lucero, among others, believes that archaeologists must seek answers from the buildings themselves and “construct more creative ways to assess what temple attributes can reveal about their non-material qualities.”

Lucero’s latest findings are detailed in the most recent issue of Latin American Antiquity in an article titled “Classic Maya Temples, Politics, and the Voice of the People.”

Lucero is the leading expert on Yalbac and the sole authorized archaeologist on the site, authorized by the Belize Institute of Archaeology. She has conducted research in the area since 1997, and on the Yalbac site since 2002. The work Lucero is doing will provide the basis for her next book project, an exploration of temples as text.

While largely unknown – except to looters and loggers – Yalbac is a rich site. In addition to the six temples, it also includes two plazas, a large royal residence or acropolis, and a ball court. Several of the temples are likely royal, three likely residential or memorial. None so far has been cleared of surface debris. Only one of the temples has escaped looting.

Looters, ironically, paved the way for Lucero’s work to map, excavate and analyze Yalbac’s Late Classic period temples. Over the years, thieves have carved nine trenches into the site in their pursuit of priceless booty. These same trenches have become Lucero’s access routes to the temples. Still, in order to reduce additional invasion and damage to the historic site, Belizean authorities restrict her excavation beyond the trenches.

Some of the evidence she is accumulating is in the tons of fill – cobbles, boulders and stone pebbles, some in the tons of mortar – marl, plaster, and various kinds of loam.

Lucero – either on her own or leading groups of archaeology field school students – has been able to map the Yalbac site, including its structures, looters’ trenches and stelae – upright marker stones, sometimes inscribed, erected by the Maya over the millennia.

Over the years, she has dated ceramics found at Yalbac from about 300 B.C. through A.D. 900; her plaza test pit excavations have exposed floors that date to the same period, “a typical occupation history for Maya centers.”

“We also have placed test units throughout the site to get an idea as to monumental architecture construction histories and functions.”

To date she has taken four New Mexico State University field school classes to Yalbac. She will take her first U. of I. field school class this May for a six-week hands-on course in archaeological survey and excavation. Lucero joined Illinois’ department of anthropology last August, after a decade at NMSU.

The focus this summer will be on profiling the temple looters’ trenches and test excavations. Lucero and 10 undergraduates and two graduate assistants will collect data from the six temples in order to compare temple frequency, size differences, location, layout, accessibility, history of use, construction patterns, surface decoration and ritual deposits.

“We also will expand the trenches to see if the looters missed caches – artifacts consisting of shell, jade, ceramics, lithics, etc. – that may provide clues as to temple function and purpose.”

Lucero doesn’t spend much time worrying about looters.

“While looting is still a problem, the relatively new management of the land-owning company, Yalbac Cattle and Ranch Co., which logs the 200,000 acres they own, have armed patrols that protect the area from illegal poachers, loggers and looters.”

Because Yalbac is directly behind the guardhouse, she said, “the site is very well protected, as are the students and staff.”

“We have been surveying the area for years without any problems,” she said. “Often the loggers show us sites they have found in the process of searching for mahogany, cedar and rosewood.”

Friday, February 15, 2008

Mobile Neanderthals

A 40,000-year-old tooth has provided scientists with the first direct evidence that Neanderthals moved from place to place during their lifetimes. In a collaborative project involving researchers from the Germany, the United Kingdom, and Greece, Professor Michael Richards of the Max Planck institute for Evolutionary Anthropology in Leipzig, Germany and Durham University, UK, and his team used laser technology to collect microscopic particles of enamel from the tooth. By analysing strontium isotope ratios in the enamel - strontium is a naturally occurring metal ingested into the body through food and water - the scientists were able to uncover geological information showing where the Neanderthal had been living when the tooth was formed .

The tooth, a third molar, was formed when the Neanderthal was aged between seven and nine. It was recovered in a coastal limestone cave in Lakonis, in Southern Greece, during an excavation directed by Dr Eleni Panagopoulou of the Ephoreia of Paleoanthropology and Speleology (Greek Ministry of Culture). The strontium isotope readings, however, indicated that the enamel formed while the Neanderthal lived in a region made up of older volcanic bedrock. The findings, published in the Journal of Archaeological Science, could help answer a long-standing debate about the mobility of the now extinct Neanderthal species.

Some researchers argue that Neanderthals stayed in one small area for most of their lives; others claim their movements were more substantial and they moved over long distances; and others say they only moved within a limited area, perhaps on a seasonal basis to access different food sources.

Professor Richards said: "Strontium from ingested food and water is absorbed as if it was calcium in mammals during tooth formation. Our tests show that this individual must have lived in a different location when the crown of the tooth was formed than where the tooth was found. The evidence indicates that this Neanderthal moved over a relatively wide range of at least 20 kilometres or even further in their lifetime. Therefore we can say that Neanderthals did move over their lifetimes and were not confined to limited geographical areas."

"Previous evidence for Neanderthal mobility comes from indirect sources such as stone tools or the presence of non-local artefacts such as sea shells at sites far away from the coast. None of these provide a direct measure of Neanderthal mobility." said Dr Katerina Harvati of the Max Planck Institute, in Germany, who initiated the study.

The researchers believe the laser ablation technique used to collect the minute particles of enamel will allow the measurement of other rare Neanderthal remains to see how the result compares in other regions and at other time periods.

The technique could also allow scientists to look at very small scale migrations, which is not possible with traditional research methods, and could possibly be applied to research into early humans.