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Analytical Chemistry

Columbus' Silver Mining Debunked

Chemistry rewrites history of precious-metal processing in New World

by Bethany Halford
February 26, 2007 | A version of this story appeared in Volume 85, Issue 9

Galena and lead pieces unearthed at LaIsabela.
Credit: James Quine
Credit: James Quine

CHEMICAL ANALYSIS of metallurgical artifacts from La Isabela—the settlement Christopher Columbus founded on his second trip to the New World in 1494—is challenging the long-held notion that the site is where Europeans first mined and processed precious metals in the New World. A recent lead isotope analysis of La Isabela artifacts reveals that the settlers were not, as archaeologists thought, extracting silver from Caribbean ores but were trying to pull the metal out of materials they'd brought from Spain (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.0607297104).

The discovery provides new evidence of how desperate La Isabela's inhabitants were to extract something of value from their disastrous time in the New World, says Alyson M. Thibodeau, the geosciences graduate student at the University of Arizona who spearheaded the research.

La Isabela has a legacy of disappointment. When Columbus returned to Spain in 1493 from his first expedition to the Americas, he spoke exuberantly of a New World glimmering with golden treasure. His tales convinced Spain's King Ferdinand and Queen Isabella to finance a much larger second expedition. As many as 1,500 settlers joined Columbus, no doubt tempted by the promise of riches.

These starry-eyed adventurers established La Isabela, the first European town in the New World, on the northern shore of what is now the Dominican Republic. They did not, however, find any precious-metal ores there. Instead, the settlers found hunger, disease, hurricanes, mutiny, and conflicts with the local Taíno natives. By 1498, La Isabela had been abandoned.

While excavating La Isabela in the late 1980s and early 1990s, archaeologists unearthed evidence of silver extraction. They found more than 100 lb of galena, a silver-containing lead ore, as well as hundreds of pounds of slag, which, upon close inspection, contained tiny specks of silver. This, the archaeologists thought, indicated the settlers' early silver-prospecting efforts.

But one question remained: Why didn't the settlers' records mention any discoveries of ore? Thibodeau decided to compare the lead isotope ratios from galena deposits in the Caribbean with those from the galena from La Isabela. They didn't match. But lead isotope ratios from the La Isabela galena did match those of Spanish samples of the ore, leading Thibodeau to conclude that the settlers brought the material with them, probably to compare with the anticipated local ores for a rough assay of silver content.

"What appeared to be the earliest evidence of European finds of precious metals in the New World turned out not to be that at all," says David J. Killick, an anthropology professor at Arizona, who participated in the research. "It's a very different story."

Piecing together what's known about La Isabela's final doomed months and the poorly processed galena, Thibodeau's group hypothesizes that the settlement's last desperate survivors were trying to salvage anything of value before abandoning the site.

"This part of the story of Columbus' failed settlement is one that couldn't be found in the historical documents," Thibodeau says. "We never could have figured this out without applying the techniques of physical science to the archaeological artifacts."


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