Early Footprints Kick Up a Storm

Human occupation of the Americas is not supposed to be much older than 12,000 years. A spear point found in mammoth remains in 1932 has long been the earliest solid evidence of humans living in the New World. The find was rigorously dated to about 11,200 years ago and came from a culture called the Clovis. In 1977 anthropologist Tom Dillehay of Vanderbilt University in Tennessee found the remains of a human settlement at Monte Verde, Chile, that was at least 1,000 years older. Since then, mounds of disputed evidence have been unearthed, from Pennsylvania to the Amazon, in the search for signs that someone got here even earlier. The latest and most controversial candidate surfaced when a team of investigators led by Sylvia Gonzalez of Liverpool John Moores University in England announced in August the discovery in central Mexico of human footprints that they claim are at least 40,000 years old.

The evidence came to light in 2003 when Gonzalez, along with David Huddart of LJMU and Matthew Bennett of Bournemouth University in England, were studying a formation of volcanic ash in the Valsequillo Basin, south of Puebla. There they spotted lines of small depressions in an area of hardened ash that had long been quarried by locals. Gonzalez spent the next two years studying the depressions. She and her team dated the site by several methods with several dating laboratories and announced that some of the marks were footprints made by ancient humans. The study has been accepted for publication in Quaternary Science Reviews.

Many scientists have challenged the conclusions. Mike Waters, an archaeologist at Texas A&M University, and Paul Renne, a geologist with the University of California at Berkeley and the Berkeley Geochronology Center, visited the site and examined the markings. Waters says the proposed footprint tracks cross several different layers of ash and in some cases form rectangular patterns.

This suggests that the marks may not be footprints at all but rather modern quarry marks left when workers cut and extracted rectangular slabs of the concretelike ash. "I found some quarry workers who told me they made those marks with steel digging tools," Waters says. "They even offered to show me how they did it." Renne said that the site was too disturbed by modern human activity to yield conclusions; for the evidence to be convincing, Gonzalez would have to find such prints in a completely undisturbed context. Renne, Waters, and others have questioned the dating techniques and the age of 40,000 years. They believe the ash layers are much older, making them even less likely to hold human footprints.

Gonzalez says she knew from the outset that any finding that challenged the Clovis and Monte Verde dates would be controversial. She aims to return to the site in 2006, with the support of a sizable U.K. government grant, for further investigation. With the publication of her paper in Quaternary Science Reviews, the scrutiny—and the stakes—will increase.—Michael W. Robbins

NASA Imaging Technology Illuminates Ancient Egyptian Manuscripts

Between 300 B.C. and A.D. 800, Egyptians in the city of Oxyrhynchus discarded books, scrolls, and other documents with their household garbage in a dump on the outskirts of town. Some 1,100 years later, a pair of Oxford University undergraduates uncovered roughly half a million fragments of papyrus at the site. In the century or so since then, only 1 percent of the text (5,000 documents) has been published. But this year archaeologists used an innovative technology called multispectral imaging to reveal a treasure trove of writing by the likes of Sophocles, Euripides, and Hesiod. Among the finds is a poem by the seventh-century B.C. Greek poet Archilochus. "And this came out of a papyrus that was simply a wretched piece of crap, really," says Dirk Obbink, director of the recovery efforts. "Everyone who worked on the collection had looked at it and simply thrown it back in the box in despair."

Multispectral imaging was originally developed by NASA to peer at the surface of planets through their roily atmospheres using wavelengths of both ultraviolet and infrared light. Archaeologists discovered it was a useful tool in 1999, when it was used to expose the text of scrolls blackened by the eruption of Vesuvius in A.D. 79. Even with the help of the advanced technology, however, deciphering the Oxyrhynchus papyri remains a herculean task. These days, all documents are kept at the Sackler Library at Oxford, where cupboards open to reveal box after box of papyri bits wrapped in century-old copies of the Oxford University Gazette. "It's like building a city," says Nick Gonis, curator of the collection, "and the city, at the moment, can function. But there's no end in sight."  —Anne Casselman

Are Incan Knots A Crackable Code?

The Incas didn't leave any written words behind, but they did leave behind khipus—knotted, colored, and twisted textile strings that seemed to serve as a record-keeping system for the largest state in the ancient New World. Until this year, the function of khipus was more presumed than proven. In August Harvard University anthropologist Gary Urton and his colleague Carrie Brezine reported the first clear signs of shared information embedded in 7 of 21 khipus from Puruchuco, an Incan palace and administrative center on the coast of Peru. "For the first time we've been able to see khipus that are communicating with each other," says Urton.

Urton and Brezine also found a series of three figure-eight knots repeated in some of the seven Puruchuco khipus. They believe this redundant element may code for the town itself or its khipu keeper. Finding information that extends beyond administrative inventory is especially tantalizing, given that the only extant description of the Incan empire was penned by Spanish conquerors.

"If we learn how to read and interpret these khipus, it will for the first time allow us to see inside the empire from the point of view of the people who lived in those times themselves," says Urton. "And if it turns out to be a system of writing, then it sort of throws open the question of what writing is." 

Historian Leland Locke first determined in the 1920s that khipus contained numerical data. By the 1970s Cornell University anthropologist Robert Ascher, and his wife, mathematician Marcia Ascher at Ithaca College, concluded that more than
20 percent of the khipus were nonnumerical. In 2002 Urton began consolidating minutiae about more than 700 surviving khipus as part of the Khipu Database Project. "Ultimately, what we want to do is decipher the khipus or at least determine whether they are decipherable or not," he says. "And that's a question that's still open."—Anne Casselman