The Mysterious Case Of Columbus' Silver Ore - UPDATE

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                                     The Mysterious Case Of Columbus's Silver Ore







ScienceDaily
(Feb. 20, 2007) —

Silver-bearing ore found at the settlement founded by Christopher Columbus's second expedition
was not mined in the Americas, new research reveals.

The ore that researchers excavated from the settlement, La Isabela, came from Spain, said Alyson Thibodeau, who analyzed the ores.

"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," said David J. Killick. "It's a very different story."

The explorers brought the Spanish ore to La Isabela to use for comparison when assaying the new
ores they expected to find, the researchers surmise. The expedition's purpose was discovering
precious metals.

But by 1497, La Isabela's remaining settlers, having found no gold or silver, were desperate to salvage something of value from the failed settlement. They were reduced to extracting silver from the galena they brought from Spain, the researchers said.

"This part of the story of Columbus's failed settlement is one that couldn't be found in the historical documents," said Thibodeau, a geosciences graduate student at The University of Arizona in Tucson. "We could never have figured this out without applying the techniques of physical sciences
to the archaeological artifacts."

Thibodeau, Killick, a UA associate professor of anthropology, and their colleagues will publish their article, "The Strange Case of the Earliest Silver Extraction by European Colonists in the New World,
" in the early online edition of the Proceedings of the National Academy of Sciences during the week
of February 19.

The other authors are UA's Joaquin Ruiz, John T. Chesley and Ward Lyman; Kathleen Deagan of the University of Florida in Gainesville; and José M. Cruxent (deceased). The National Science Foundation, Direccion Nacional de Parques de la Republica Dominicana, the National Endowment for the Humanities, the National Geographic Society and the Keck Foundation helped fund the research.

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La Isabela, the first European town in the New World, was established by Columbus's second expedition in 1494 on the northern coast of the present Dominican Republic.

The approximately 1500 members of the expedition expected to make their fortunes by finding precious metals but instead found hurricanes, hunger and disease. Columbus was recalled to Spain in 1496, and the few hundred remaining inhabitants abandoned the town in 1498.

Archaeologists excavating the site in the late 1980s and early 1990s found about 100 pounds of galena, a silver-bearing lead ore, and more than 200 pounds of metallurgical slag. The ore and slag were associated with a small furnace near the alhóndiga, a building for the storage and protection of royal property.

Archaeologist Deagan sent pieces of the material to archaeometallurgist Killick for analysis.

The slag turned out to be lead silicate -- the end product of an improvised smelting process, Killick said, adding "Lead silicate is good for nothing." Other smelting processes used at the time could recapture the ore's lead so it could be used for musket balls and as cladding for ships.

"Why waste the lead?" Killick said. "Normally, they would smelt the galena to lead."

Killick and graduate student Ward Lyman examined the slag under a microscope and saw specks of silver, suggesting that Columbus's followers were trying to extract silver from the galena by removing all the lead.

"We thought, 'Fantastic!' The first evidence of Europeans prospecting for silver in the New World."

By reviewing the accounts of Columbus's second voyage, Thibodeau found the expedition had visited islands where geologists now know galena occurs.

It was puzzling that the documents made no mention of finding such ore, Killick said. Maybe it didn't seem to be enough metal to mention or maybe some members of the expedition were trying to hide the discovery.

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Thibodeau then used lead isotope analysis to determine where La Isabela's galena originated. The ratio of the different forms, or isotopes, of lead provides a kind of fingerprint that can indicate the source of a rock.

"We're looking at something about the rock's chemistry and using that to tell us where it came from," she said. "It's like Antiques Roadshow where the appraiser looks at some characteristic of an antique and says, 'This was made by so-and-so at such-and-such a time.'"

Figuring out that the galena came from Spain led to the question, why bring ore? The documents report that the expedition also brought lead.

By contacting an expert in medieval chemistry, the scientists learned that a common practice of the time was mixing galena with powdered ores suspected of having gold or silver. The process provided an assay of the gold or silver in the newly discovered hunk of ore by comparing it with galena containing a known, small quantity of silver.

Given that the expedition purpose was discovering new sources of precious metals, it makes sense that the members toted along materials to assess their discoveries.

"It was a nice detective story," Killick said. "We think we've solved this one."

But there are more archaeological puzzles out there, Thibodeau said.

"Archaeology tells us what might be an interesting question to ask -- and the physical sciences gives us a way to answer the question," Thibodeau said.


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Adapted from materials provided by University of Arizona.

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The Mysterious Case Of Columbus's Silver Ore. ScienceDaily.

Retrieved November 7, 2008, from



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University of Florida archaeologist Kathleen Deagan uses measuring calipers to examine a lead musket ball excavated from La Isabela, Christopher Columbus' first settlement in the New World, in this photo taken Feb. 19, 2007.

Weapons like this were crafted from lead extracted from galena, a silver-bearing lead ore. Researchers excavated nearly 200 pounds of galena in association with a smelting operation at La Isabela, located in what is now the Dominican Republic.

A new study shows the settlement’s inhabitants desperately tried to extract sliver from the galena before abandoning the site in 1498.

(Credit: Image courtesy of University of Florida)

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             Inhabitants Of Columbus' First Settlement Were Desperate To Find Metals, Study Finds






ScienceDaily
(Feb. 25, 2007) —

A new study provides evidence that the last inhabitants of Christopher Columbus’ first settlement desperately tried to extract silver from lead ore, originally brought from Spain for other uses, just before abandoning the failed mining operation in 1498. It is the first known European extraction of silver in the New World

University of Florida archaeologist Kathleen Deagan co-authored the study and led the fieldwork at La Isabela, founded in 1493 on modern day Dominican Republic’s north coast. Deagan collaborated with geoscientists and metallurgists to interpret a smelting operation at the site that appeared to have used nearly 200 pounds of galena, a silver-bearing lead ore.

Findings will be published in the Proceedings of the National Academy of Sciences Feb. 27 print edition.

“We first thought they mined the galena locally to extract lead for weapons, such as lead shot and musket balls or ship sheathing,” said Deagan, a distinguished research curator at the Florida Museum of Natural History. “But an isotope analysis showed it was actually from Spain. And metallurgical analysis shows they were trying to extract silver. The archaeological evidence suggested just how desperate the last settlers at the colony were to get precious metal before abandoning the settlement.”

Columbus established La Isabela on his second expedition, which Deagan says was a quest for precious metals. Mining and metallurgy were central elements to the settlement of about 1,500 people — almost all men.

“Columbus really expected and needed to find gold,” she said. “Anytime we recovered evidence for metallurgy — like ore, slag or equipment for smelting — it was important.”

Deagan and her team excavated the galena inside a structure they identified as the royal storehouse, near the front entry. Just outside the entry, they excavated more than 440 pounds of metal slag material. Deagan said it was associated with a fire pit likely used for heating metals.

“All the galena was in the last stratigraphic layer of the storehouse,” Deagan said. “The smelting was one of the last activities to take place.”

Deagan collaborated with other researchers to understand how the settlers processed the materials. She contacted archaeometallurgist David Killick at the University of Arizona and provided samples and funding for his laboratory.

Alyson Thibodeau, a geosciences graduate student working with Killick and lead author of the paper, performed an isotope analysis.

“We found that the samples from La Isabela were extremely consistent with galena found in Spain near the port where the second expedition sailed from,” Thibodeau said.

Deagan was surprised to learn the galena was not mined locally. “So the question was: Why did they haul this heavy, unrefined lead ore all the way from Spain when they could have brought processed lead?” Deagan said.

By consulting with Spanish experts in medieval metallurgy, the team discovered other past uses for galena. In medieval times, they learned, galena was used as flux to draw precious metals from ore matrices and to test their purity. This is likely how La Isabela’s settlers used it.

Killick pieced together the settler’s unconventional use of the galena when he identified the excavated slag as lead silicate — the end product of an improvised smelting process. He discovered tiny specks of silver upon examining the lead silicate with optical and scanning electron microscopy.

“That’s when the penny dropped,” he said. “I realized they were wasting all the lead trying to separate out the silver.”

Deagan said the metal analysis showed the settlers didn’t quite know what they were doing. “They were clearly trying to get the silver out of it,” Deagan said. “But the byproducts showed they had too much of one chemical, but not enough of another. Someone knew a little bit, but not enough.”

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Ann Ramenofsky, an archaeologist at the University of New Mexico, reviewed the study.

“Given there was someone on the expedition who knew how to do these extractions suggests metallurgy was significant, even though Isabela ultimately failed,” Ramenofsky said. “Deagan deserves high praise for a beautiful excavation. It’s changed our understanding of the Spanish conquest of the Americas.”

Additional authors are Joaquin Ruiz, John Chesley and Ward Lyman of the University of Arizona; and José Cruxent of Universidad Nacional y Experimental Francisco de Miranda in Venezuela. The project was funded by the National Science Foundation, Direccion Nacional de Parques de la Republica Dominicana, the National Endowment for the Humanities, the National Geographic Society and the Keck Foundation.


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Adapted from materials provided by University of Florida. Original article written by DeLene Beeland.
Need to cite this story in your essay, paper, or report? Use one of the following formats:
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 MLA University of Florida (2007, February 25). Inhabitants Of Columbus' First Settlement Were Desperate To Find Metals, Study Finds. ScienceDaily.

Retrieved November 7, 2008, from




http://www.sciencedaily.com­ /releases/2007/02/070223143515.htm