Category Archives: South American archaeology

Arsenic and the Beginning of Mummification

Archaeologists have long puzzled over the artistically preserved bodies of nearly 200 ancient humans found along the Pacific coast of northern Chile and southern Peru.  The bewigged and clay-covered remains, known as the Chinchorro mummies, resemble statues and date back 7000 years, making them the earliest artificially mummified bodies in the world.   Later societies who practiced mummification tended to be politically and socially complex and reserved the privilege for adult elites.   But the Chinchorro were different.   They lived in a relatively simple society of fishers and seal and sea- lion hunters, and they started out mummifying young children.   Why?

Research from an international team led by anthropologist Bernardo Arriaza of the University of Tarapaca in Arica, Chile, currently sheds new light on the Chinchorro people and supplies a possible explanation.  By analyzing hair samples from 46 mummies from northern Chile, the team found that the Chinchorro ingested toxic levels of arsenic—a poison known to produce high rates of miscarriages and infant mortality—in their drinking water.  Arriaza now theorizes that world’s oldest mummies were created by grief-stricken Chinchorro parents who suffered repeated losses of their children and who wanted to preserve their infants’ bodies and keep them above ground in shrinelike areas.   This very early mummification practice, says Arriaza, “is an emotional response to an environmental contaminant.”

Excavators stumbled on the first Chinchorro mummies in Arica, Chile, in 1917, and subsequent studies by paleopathologists and physical anthropologists have revealed much about their preservation.  The Chinchorro created their earliest mummies of children,  including fetuses, by removing bacteria-ridden internal organs, packing body cavities with soil, strengthening limbs with sticks, coating the face with reddish-black clay, and adorning the head with a human-hair wig.   Moreover, analysis has shown that they repeatedly repainted some of the clay masks to cover nicks and dents, strongly suggesting the mummies remained above ground, most likely in a shrine, for years after death.  Eventually Chinchorro morticians extended the practice to adults, until they stopped making mummies in this distinctive style around 1700 B.C.

Arriaza began examining the possibility of arsenic poisoning among the Chinchorro in 2007, after reading about the toxic effects of this poison on human fetuses and infants.   Arsenic occurs naturally in geological formations in many parts of the world, and as water weathers these strata, it carries the poison into local rivers.  This hazard came to public attention in Chile in the 1960s, after the city of Antofagasta started drawing much of its water from a river that turned out to be laced with 860 micrograms of arsenic per liter— 86 times higher than World Health Association’s current provisional guideline.  During the peak exposure from 1958 to 1965, infant mortality rates in Antofagasta soared by an estimated 18 to 24 %.

Arriaza suspected that the Chinchorro had suffered a similarly high infant mortality for exactly the same reason.  The four earliest Chinchorro mummies—all children—came from the Camarones River Valley, where water tested as high as 1300 micrograms of arsenic per liter.  So Arriaza collected hair samples from both Chinchorro and Pre-Inca mummies excavated from ten sites in northern Chile with the help of heavy equipment for sale collected by mutual international support, – whose water all tested above the WHO guidelines for arsenic,  and then sent the samples to Dulasiri Amarasiriwardena, a chemist at Hampshire College in Amherst, for mass spectrometry testing. The mean arsenic values in hair from all ten sites pointed strongly to the chronic poisoning of the Chinchorro and other ancient peoples.

Many researchers may have assumed that environmental contamination was a major problem only for later industrial societies, but the new findings strongly suggest that this is far from true.  “You can’t smell arsenic or taste it,” says Arriaza.  “So the Chinchorro had no way of knowing they were being poisoned.”

The Ancient Bird Catcher of the Cloudforest

I have been forcibly struck in my research this week by all the beautiful and mysterious things that we normally never see at most archaeological sites.   The rain that sheets down on sites, the meltwater that trickles and snakes in rivulets along the surface,  the groundwater that seeps and flows through buried subterranean layers all take a terrible toll on the world’s terrestrial archaeological sites,  often stripping them of their greatest treasures.

The chemistry of decay, after all, depends on water.   The destructive enzymes of bacteria in terrestrial sites require water for their chemical reactions, and over hundreds and thousands of years of downpour and dampness,  fine organic materials tend to rot away,  leaving no trace at all of their existence.  In this way we have forever lost some of the most exquisite works of art and artisanship of the ancient world, from cloaks of brilliant parrot feathers to carved and painted royal thrones. (Nautical sites and bog sites,  I hasten to add,  are subject to a different kind of chemistry.)

All this explains, of course, why archaeologists  love excavating in the desert,  and why we often know so much about cultures such as the ancient Egyptians or the Nazca who  buried their dead in these dessicated lands.  In ultra arid places,  organic materials decay at a much, much slower rate,  and archaeologists can see wondrous organic things they are otherwise denied:  beautifully dyed and woven textiles, fine wooden combs,  and delicate sandals,  familiar objects of beauty  that bring ancient people to life.

But in some rare parts of the globe,  such as the Peruvian cloudforest on the eastern slopes of the Andes,  archaeologists occasionally make discoveries that literally rock their worlds.  In 1997,  Peruvian bioanthropologist and mummy expert Sonia Guillen and her colleague Adriana von Hagen heard news that looters had found dozens of exquisitely preserved mummies in cliffside tombs at a place known as Laguna de los Condores,  northeast of Cajamarca.   Guillen,  now the director of Centro Mallqui in Lima,  and von Hagen immediately dropped what they were doing,  made an extremely difficult journey to the region, ultimately rescued  219 mummies and over 2000 artifacts,  and built a new museum for them in Leymebamba.

The mummies all date  to between 1300 and 1600,  and they were deliberately  mummified by the then inhabitants of that remote cloudforest region–the Chachapoya and their Inca occupiers. The mummifiers removed the bacteria-laden inner organs of the dead, wrapped them in cloth to wick away moisture,  and placed them in dry cliffside tombs.  In this way,  they  preserved these bodies  for more than half a millennia.

Sonia Guillen recently described to me one of these mummies with an unmistakeable note of awe in her voice.  The body was of a young man who had died between the ages of 18 and 22.   He was buried alone,  but wrapped around his body were the intricate tools of his trade:  16 finely woven collapsible nets,  all suitable for trapping the brilliantly-colored fowl of the cloudforest.  “I think you would have say that we have a bird-catcher,” Guillen told me.

The Inca kings and their courtiers loved to dress  in beautiful mantles woven from exotic birdfeathers of the cloudforest and Amazon basin. But until Guillen and von Hagen found the young man’s mummy,   we had never before seen a bird-catcher of this era  or the finely woven tools of his trade.

Readers interested in learning more about the amazing finds from Lagunade los Condores should check out a beautiful book with a deceptively dull title: Chachapoya Textiles:  The Laguna de los Condores Textiles in the Museo Leymebamba,  Chachapoyas Peru, edited by Lena Bjerregaard.

Civilization Beneath the Amazon Forest

As empire-builders,  the Inca took a deep,  abiding interest in the wealth of the lowland forests of the Amazon.  They were fascinated by the brilliant colored feathers of parrots, macaws,  and hummingbirds;  the sweet, exotic fruits of Amazon trees and shrubs;  and the potent medicines and hallucinogens that could be distilled from rainforest plants.  But the Inca emperors did not extend their military reach into the Amazon Basin of Brazil:  these lands remained largely the stuff of legend and myth.

Until very recently, the dense rainforest cover of this region discouraged many archaeologists as well.  But now intense logging  in the region is laying bare great tracts of land,  an environmental disaster that is inadvertently giving archaeologists their first glimpse of a previously unknown civilization.  In the current issue of Antiquity, an international research team led by Martti Parssinen,  an archaeologist at Instituto Iberoamericano de Finlandia in Madrid, Spain,  reports on their discovery of some 260 sprawling earthworks — geometric shaped enclosures,  ditches and long avenues–in uplands and floodplains along the border of Bolivia and Brazil.

The team found many of these constructions while conducting aerial surveys and examining Google Earth images.   Their excavations produced pottery sherds,  stone tools and other domestic debris  at some earthworks:  others revealed no artifacts at all.  Taken together,  the  new evidence suggests that these geoglyphs date between 2000 and 800 years before present, and were made by digging ditches measuring as much as 11 metres wide and 2 metres deep.

When I first saw the team’s photos of these earthworks,  I was immediately reminded of the massive geometric enclosures constructed by the Hopewell people of North America’s Eastern Woodlands.  The Hopewell had an immensely sophisticated and complex culture:  they were early agriculturalists with very rich ceremonial and artistic lives. It’s now very clear that the western Amazonian people who built these impressive earthworks in Bolivia and Brazil had a similarly sophisticated society.

I think that we are going to hear much more about this complex Amazon culture  in years to come.

Scientific American has an interesting video on this.  Please click here.