The Diamonds of the Wyoming Craton

Bedrock map of North America   USGS

This is a tale about how riches were overlooked in Colorado, Montana and Wyoming by gold seekers in days of yore.  In these three states a whole diamond province has been overlooked in the kimberlites by the hundreds that underlie these states.  The diamonds can also be found in lamproites, lamprophyres and other cryptovolcanic structures that are associated by the Wyoming Craton underlying these three states.  Many of the larger targets lie right next to I-80 between Cheyenne and Laramie that remain unexplored.  This area was originally discovered by early gold miners who discovered it contained little or no gold so they passed it on.

Subsequent discoveries indicate this may be one of the most unexplored diamond provinces in North America where the diamonds can be found in the carbonate rich sediments found in a Archean gneiss.  More then fifty depressions have been discovered here suggesting cryptovolcanic activity that lie east of the State Line diamond district.  It is thought these depressions could be kimberlites containing possibly large amounts of diamonds. 

Ongoing exploration suggests that the Wyoming Craton contains a world-class diamond province and like the diamond province near Marathon, Ontario also contains large deposits of colored gemstones as rubies and sapphires.  This craton is found covering a large portion of Canada.

The Wyoming Craton aside from covering several western states also includes exposures in Alberta and Saskatchewan. Diamonds have been discovered in both the kimberlites and lamprophyres in Montana, Wyoming, Colorado, Kansas and Nebraska as well as Canada.

Another potential place where you can look is in any conglomerates that are derived from the lamprophyres and kimberlites of the Wyoming Craton.  One of my prospecting buddies has found a diamond deposit like this near Marathon, Ontario.  Another Canadian prospecting buddy that lives in western Ontario has also found probable diamonds in his part of the province.

It isn’t just diamonds that can be found there; recently one of the world’s largest deposits of rare earth metals was found in Nebraska,  When you start poking around in this ancient craton you never know what you’re likely to find.

The Wyoming Craton has the greatest southwestern outcrops of Archean rocks in North America.  Theoretically terranes like this have deep roots in the lithosphere that according to Clifford’s rule this deep keel is necessary for the formation of kimberlites with their association with diamonds.  Although this terrane wasn’t deformed during the

Ancestral Rockies Orogeny it was pervasively deformed during the Laramide Orogeny and one theory has it that its deep keel was removed partially or wholly allowing it to be deformed during the Cretaceous or later.