Tag Archives: spectrometry

Uncovering the secrets of ancient Wari Empire pottery with lasers and chemistry

This is a little bit outside my usual range but the researchers are using some high end equipment for their analyses so I’m using that as an excuse to make an exception.

Caption: Example ceramic drinking cup from the Wari site of Cerro Baúl, Moquegua, Peru that are similar to the sherds included in the Laser Ablation sampling. Credit: Courtesy Cerro Baúl Archaeological Project, photo by P. R. Williams, Catalog number CB-V001.

From a March 14, 2023 Field Museum (Chicago, Illinois) news release (also on EurekAlert)

Peru’s first great empire, the Wari, stretched for more than a thousand miles over the Andes Mountains and along the coast from 600-1000 CE. The pottery they left behind gives archaeologists clues as to how the empire functioned. In a new study in the Journal of Archaeological Science: Reports, researchers showed that rather than using “official” Wari pottery imported from the capital, potters across the empire were creating their own ceramics, decorated to emulate the traditional Wari style. To figure it out, the scientists analyzed the pottery’s chemical make-up, with help from laser beams.

“In this study, we looked at the idea of cosmopolitanism, of incorporating different cultures and practices into a society,” says M. Elizabeth Grávalos, a postdoctoral researcher at the Field Museum in Chicago and the study’s lead author. “We’re trying to show that potters were influenced by the Wari, but this influence was blended with their own local cultural practices.”

Grávalos says this model of cosmopolitanism is a little like trying to replicate a recipe from another culture, but with a local spin. “If you live in the US and you’re making pad thai at home, you might not have access to all the ingredients that someone living in Thailand would have, so you substitute some things,” she says. “Wari ceramics are a little like thatpeople throughout the empire were interested in Wari material culture, but they weren’t necessarily getting it directly from the Wari heartland. More often than not, we see local people trying to make their own version of Wari pottery.”

Grávalos and her colleagues led archaeological digs throughout Peru, working with local communities to excavate the thousand-year-old remains of households, tombs, and administrative centers, in search of Wari lifeways. The researchers were then granted permission from Peru’s Ministry of Culture to bring samples of ceramics from their excavations to Chicago for analysis.

Clay from different regions has a different chemical makeup, so studying the ceramics’ chemical makeup could tell the researchers if the pots were produced in different places or if they were all imported from the Wari capital.

“We’d take a tiny piece of a pot and used a laser to cut an even tinier piece, basically extracting a piece of the ceramic’s clay paste,” says Grávalos. “Then helium gas carried it to the mass spectrometer, which measures the elements present in the  clay paste.” (The lab set-up didn’t have open laser beams and floating shards of pottery cutting across the room, thoughthe whole process takes place on a microscopic scale inside a big boxy machine.)

The analysis showed that the pots excavated from distinct regions of Peru have different chemical signatures, and were therefore made with distinct clays. That helps show how the Wari culture spread.

Some empires, like the ancient Romans, took a “top-down” approach to spreading their aesthetic, shipping pottery across the Mediterranean so that people throughout the empire were using the official Roman style. Local potters emulating the traditional Wari style in their own work seems to hint at a more “bottom-up” approach.

“Of course, local people in all empires have some degree of agency and creative controlthe only empire that’s truly top-down is the Borg from Star Trek,” says Patrick Ryan Williams, Curator of Archaeological Science and Director of the Elemental Analysis Facility  at the Field Museum and the study’s senior author. “Even the Romans had local people doing things their own way. But what we’re finding in this study is the agency of local peoples and the importance of local economies. In some regions, we find that Wari colonists had their own production centers and were recreating Wari lifeways locally. In other areas, we see that local communities made Wari pottery in their own way. I think that’s what’s really important about this study.”

The researchers say that the patterns revealed by this pottery could help explain why the Wari empire was able to thrive for so long. “Local production, even in a cosmopolitan society with lots of far-flung connections, makes a society more resilient,” says Williams. “If you’re entirely dependent on someone far away sending you things you need, you’re extremely vulnerable.”

Beyond the economic lessons that we might learn from the Wari, Grávalos says that the study matters because “this work challenges some of the assumptions we have about how societies work, particularly Indigenous groups who are often misrepresented or left out of broader narratives of world history. There are many people whose stories haven’t been told, and this study shows their resilience and their accomplishments.”

Here’s a link to and a citation for the paper,

Crafting cosmopolitanism: Ceramic production and exchange during Wari imperialism (600–1000 CE) by M. Elizabeth Grávalos, David A. Reid, Donna J. Nash, and Patrick Ryan Williams. Journal of Archaeological Science: Reports Available online 14 March 2023, 103878 In Press, Correctted proof. DOI: https://doi.org/10.1016/j.jasrep.2023.103878

This paper is behind a paywall.

600 BCE (before the common era) was a very good year for French wine

It’s quite the detective story, almost 20 years to unravel the mystery of where and when viniculture started in France. A Penn Museum June 3 (?), 2013 news release (also found on EurekAlert) provides some fascinating detail about the detective work and about wine,

9,000-year-old ancient Near Eastern ‘wine culture,’ traveling land and sea, reaches southern coastal France, via ancient Etruscans of Italy, in 6th-5th century BCE

Imported ancient Etruscan amphoras and a limestone press platform, discovered at the ancient port site of Lattara in southern France, have provided the earliest known biomolecular archaeological evidence of grape wine and winemaking—and point to the beginnings of a Celtic or Gallic vinicultural industry in France circa 500-400 BCE. Details of the discovery are published as “The Beginning of Viniculture in France” in the June 3, 2013 issue of Proceedings of the National Academy of Sciences (PNAS). Dr. Patrick McGovern, Director of the Biomolecular Archaeology Laboratory at the University of Pennsylvania Museum of Archaeology and Anthropology and author of Ancient Wine: The Search for the Origins of Viniculture (Princeton University Press, 2006) is the lead author on the paper, which was researched and written in collaboration with colleagues from France and the United States.

For Dr. McGovern, much of whose career has been spent examining the archaeological data, developing the chemical analyses, and following the trail of the Eurasian grapevine (Vitis vinifera) in the wild and its domestication by humans, this confirmation of the earliest evidence of viniculture in France is a key step in understanding the ongoing development of what he calls the “wine culture” of the world—one that began in the Turkey’s Taurus Mountains, [sic[ the Caucasus Mountains, and/or the Zagros Mountains of Iran about 9,000 years ago.

“Now we know that the ancient Etruscans lured the Gauls into the Mediterranean wine culture by importing wine into southern France. This built up a demand that could only be met by establishing a native industry, likely done by transplanting the domesticated vine from Italy, and enlisting the requisite winemaking expertise from the Etruscans.”

The news release provides a high level (general with too few details for my taste) description of the technology used for this research,

After sample extraction, ancient organic compounds were identified by a combination of state-of-the-art chemical techniques, including infrared spectrometry, gas chromatography-mass spectrometry, solid phase microextraction, ultrahigh-performance liquid chromatography tandem mass spectrometry, and one of the most sensitive techniques now available, used here for the first time to analyze ancient wine and grape samples, liquid chromatography-Orbitrap mass spectrometry.

All the samples were positive for tartaric acid/tartrate (the biomarker or fingerprint compound for the Eurasian grape and wine in the Middle East and Mediterranean), as well as compounds deriving from pine tree resin. Herbal additives to the wine were also identified, including rosemary, basil and/or thyme, which are native to central Italy where the wine was likely made. (Alcoholic beverages, in which resinous and herbal compounds are more easily put into solution, were the principle medications of antiquity.)

Nearby, an ancient pressing platform, made of limestone and dated circa 425 BCE, was discovered. Its function had previously been uncertain. Tartaric acid/tartrate was detected in the limestone, demonstrating that the installation was indeed a winepress. Masses of several thousand domesticated grape seeds, pedicels, and even skin, excavated from an earlier context near the press, further attest to its use for crushing transplanted, domesticated grapes and local wine production. Olives were extremely rare in the archaeobotanical corpus at Lattara until Roman times. This is the first clear evidence of winemaking on French soil.

Here’s what the ancient wine press looks like,

Caption: This is an ancient pressing platform from Lattara, seen from above. Note the spout for drawing off a liquid. It was raised off the courtyard floor by four stones. Masses of grape remains were found nearby. Credit: Photograph courtesy of Michael Py, copyright l'Unité de Fouilles et de Recherches Archéologiques de Lattes.

Caption: This is an ancient pressing platform from Lattara, seen from above. Note the spout for drawing off a liquid. It was raised off the courtyard floor by four stones. Masses of grape remains were found nearby.
Credit: Photograph courtesy of Michael Py, copyright l’Unité de Fouilles et de Recherches Archéologiques de Lattes.

Here’s how McGovern describes his work and its relationship to the history of viniculture in Europe and the ancient Near East, from the news release,

For nearly two decades, Dr. McGovern has been following the story of the origin and expansion of a worldwide “wine culture”—one that has its earliest known roots in the ancient Near East, circa 7000-6000 BCE, with chemical evidence for the earliest wine at the site of Hajji Firiz in what is now northern Iran, circa 5400-5000 BCE. Special pottery types for making, storing, serving and drinking wine were all early indicators of a nascent “wine culture.”

Viniculture—viticulture and winemaking—gradually expanded throughout the Near East. From the beginning, promiscuous domesticated grapevines crossed with wild vines, producing new cultivars. Dr. McGovern observes a common pattern for the spreading of the new wine culture: “First entice the rulers, who could afford to import and ostentatiously consume wine. Next, foreign specialists are commissioned to transplant vines and establish local industries,” he noted. “Over time, wine spreads to the larger population, and is integrated into social and religious life.”

Wine was first imported into Egypt from the Levant by the earliest rulers there, forerunners of the pharaohs, in Dynasty 0 (circa 3150 BCE). By 3000 BCE the Nile Delta was being planted with vines by Canaanite viniculturalists. As the earliest merchant seafarers, the Canaanites were also able to take the wine culture out across the Mediterranean Sea. Biomolecular archaeological evidence attests to a locally produced, resinated wine on the island of Crete by 2200 BCE.

“As the larger Greek world was drawn into the wine culture, “ McGovern noted, “the stage was set for commercial maritime enterprises in the western Mediterranean. Greeks and the Phoenicians—the Levantine successors to the Canaanites—vied for influence by establishing colonies on islands and along the coasts of North Africa, Italy, France, and Spain. The wine culture continued to take root in foreign soil—and the story continues today.”

Where wine went, so other cultural elements eventually followed—including technologies of all kinds and social and religious customs—even where another fermented beverage made from different natural products had long held sway. In the case of Celtic Europe, grape wine displaced a hybrid drink of honey, wheat/barley, and native wild fruits (e.g., lingonberry and apple) and herbs (such as bog myrtle, yarrow, and heath

I wonder why wine displaced Celtic Europe’s hybrid honey drink. Did wine taste better and/or did get folks drunk faster?

For anyone who’s interested in the research, here’s a link to and a citation for the paper,

Beginning of viniculture in France by Patrick E. McGovern, Benjamin P. Luley, Nuria Rovira, Armen Mirzoiand, Michael P. Callahane, Karen E. Smithf, Gretchen R. Halla, Theodore Davidsona, and Joshua M. Henkina. Published online before print June 3, 2013, doi: 10.1073/pnas.1216126110 PNAS June 3, 2013

The paper is behind a paywall.

Cell phone microscopy

You can make a microscope or a spectrometer out of your cell phone for about $20, say researchers at the University of California at Los Angeles and the University of California at Davis. Here’s an image contrasting standard microscopy with cell phone microscopy,

Images of several commercially prepared microscope slides featuring stained samples. Top row, commercial microscope. Bottom row, cell phone microscope. Left column, pollen grains. Right two columns, plant stems. (copied from PLoS article: DOI: 10.1371/journal.pone.0017150

There’s a serious note to this activity (from the March 11, 2011 news item on Nanowerk),

With health care costs increasing throughout the world, there is a pressing need for reducing the cost and complexity of biomedical devices. Additionally, with growing demand for high-quality health care in regions of the world where medical infrastructure is below levels found in developed countries, portable devices that can transmit relevant data to remote experts are likely to have a large impact on quantity and quality of care. To this end, several groups have focused on the development of low-cost and rapidly deployable technologies that address common diseases afflicting the third world and common tests performed in both hospital and field environments.

Researchers at UCLA have constructed a modified lensless cell phone that enables holography-based digital microscopy, while researchers at UC Berkeley have constructed a complex objective attachment that also transforms a cell phone into a microscope. Additionally, a patent was recently awarded for the use of a cell phone as a spectrometer. However, there is still a need for more research directed towards utilizing cell-phone cameras to record images or spectra of biological samples.

Dave Mosher’s March 11, 2011 article for Wired magazine offers instructions on how to create the cell phone microscope,

Using tape, rubber and a tiny glass ball, researchers transformed an iPhone into a cheap, yet powerful microscope able to image tiny blood cells. They’ve also added a clinical-grade cellphone spectroscope that might be able to measure some vital signs.

And with a few dollars and some patience, you can do the same to your own phone. (See instructions below.)

“It still amazes me how you can build near-research-grade instruments with cheap consumer electronics,” said physicist Sebastian Wachsmann-Hogiu of the University of California at Davis, leader of a study March 2 in PLoS ONE. “And with cellphones, you can record and transmit data anywhere. In rural or remote areas, you could get a diagnosis from a professional pathologist halfway around the world.”

Cellphone Microscope – Step 1

Grab any cellphone with a camera, but note models that use touchscreen focusing and/or have manual focus options are best.

Find some thin, dark, rubbery material and poke a small hole in it (less than 1 millimeter in diameter). This can be done using a pin or needle.

Cellphone Microscope – Step 2

Order a 1-millimeter-diameter ball or half-ball lens. One from Edmund Optics costs between $15 and $25.

Note that lenses with larger diameters can be used, but they will provide a smaller magnification.

Cellphone Microscope – Step 3

Carefully mount it to the iris, covering as little of the lens as possible.

Cellphone Microscope – Step 4

Center the iris with the ball lens tucked in the middle over the camera of the cellphone (above).

From black electrical tape, cut out a hole larger than the diameter of the ball lens, but smaller than the diameter of the iris (below [image omitted, see Wired article]).

Cellphone Microscope – Step 5

Attach the iris to the camera body using the electrical tape mask. You may need to adjust the position of the iris to ensure the microscope images are centered in the camera’s field of view.

As with a standard microscope, use plenty of light to illuminate your sample. Liquid samples should be placed between a glass slide and coverslip.

Mosher’s article also provides instructions on how create a cell phone spectrometer. Or you can read the research article on the Public Library of Science website (open access):

Cell-Phone-Based Platform for Biomedical Device Development and Education Applications

Zachary J. Smith, Kaiqin Chu, Alyssa R. Espenson, Mehdi Rahimzadeh, Amy Gryshuk, Marco Molinaro, Denis M. Dwyre, Stephen Lane, Dennis Matthews,  and Sebastian Wachsmann-Hogiu

PLoS ONE, Vol. 6, Issue 3. March 2, 2011. DOI: 10.1371/journal.pone.0017150

Sometimes I find it all kind of amazing. I mean, whodathunk you could create a microscope with a phone?