May 7, 2002 GSA Release No. 02-28

Are There Diamonds in Iron Mountain?

Looking for diamonds in kimberlite deposits can be an Indiana Jones-type adventure. In Wyoming's Iron Mountain, for example, rattlesnakes abound.

"Many of the kimberlites, a rock type that has been successfully mined for diamonds, are infested with rattlesnakes. Some days you can walk across them and hear the rattlesnakes rattle in their holes under your feet," geologist Dan Hausel said. "It really keeps your eyes peeled to the ground."

Hausel, an economic geologist for the Wyoming State Geological Survey, has been investigating potential diamond sources in the state. He's discovered that the kimberlite district at Iron Mountain contains 50-60 percent more kimberlite than was previously mapped. Furthermore, Hausel's recent geochemical analyses suggest that a large portion of the deposits may be a potential diamond source. The kimberlite district in Iron Mountain is one of the two largest in the United States.

In another treasure hunt, Hausel discovered a deposit of gem-quality rubies, sapphires, and iolites in the Laramie Range. (Sorry, Indiana, these gems won't go in a museum. A Colorado company filed mining claims on the site and will sell these gems for jewelry.)

"After realizing that there was a connection between these gemstones and the type of rock that it was found in (vermiculite), I began investigating other vermiculite occurrences and found that a few others in Wyoming also contained corundum," Hausel said. "In Wyoming, corundum is sometimes formed in vermiculite. Gem-quality corundum is known as either sapphire or ruby depending on its color."

Hausel will present these findings in two presentations May 9 at the Geological Society of America's Rocky Mountain Section Meeting at Southern Utah University.

So, what about those diamonds in Iron Mountain?

"We tested the chemistry of the kimberlites and most appear to be favorable to host diamonds," Hausel said. "One sample collected in the early 1980s was reported to contain one diamond. We have another district about 45 miles to the south known as the State Line district where there are at least 40 diamondiferous kimberlites that have produced more than 130,000 diamonds including gemstones up to 28.3 carats."

But we won't know for sure about the diamonds in Iron Mountain. Funding for the project was discontinued.

Contact information:

Dan Hausel

Wyoming State Geological Survey

P.O. Box 3008, University of Wyoming

Laramie, WY 82071

dhause@wsgs.uwyo.edu

307-766-2286

Abstracts:

  gsa.confex.com/gsa/2002RM/finalprogram/abstract_33545.htm

  gsa.confex.com/gsa/2002RM/finalprogram/abstract_33540.htm

Geological Society of America
Rocky Mountain Section Meeting
May 7-9, 2002
Southern Utah University, Cedar City, Utah

For information and assistance during the meeting, please call the GSA registration desk at 435-865-8437.

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