|Note that all the members on our field excursion to the outback|
found the only two boab trees for hundreds of kilometers around
and at temperatures of 120 degrees F and above, shade was
at a premium.
When I visited the Ellendale lamproite field in Western Australia in 1986, some things were notable - first, it was hotter than Phoenix (but not by much). And the second was that there were a lot of leucite lamproites in the district that were similar to those in the Leucite Hills.
But then there were a couple of other interesting rocks in the Ellendale field that were not exposed at the surface. This was because these particular rocks had considerable olivine. The olivine serpentinized over geological time resulting in the breakdown of the rock. These olivine rich rocks were also diamond-bearing rocks that were buried under thin layers of soil in the outback.
|The Ellendale 7 pipe hidden under a few inches of dirt, but |
has enough diamonds to mine.
|Black Rock butte lamproite plug seen in the background.|
So when I returned to the Leucite Hills, I started searching for olivine. This is how I made the discovery of more than 13,000 carats of peridot in just two anthills at Black Rock.
Then I started sampling some of the olivine leucite lamproites in the area as well as volcaniclastics for diamonds and indicator minerals. AND we recovered diamond-stability chromites from lamproites in the northeastern portion of the Leucite Hills. Diamond-stability minerals have the same chemistry as mineral inclusions found in diamonds - thus, it is thought that such minerals formed at depths in the earth where diamonds exist. Finding such indicator minerals suggests these rocks originated within a portion of the earth's mantle that has diamonds - so it is very likely one will find diamonds in the Leucite Hills (if only someone will seriously look).
But let's use Ellendale as an example. The real rich olivine lamproites in this area are also going to be serpentinized and the host rocks hidden. Where? If I were to search this area, I would start with aerial magnetic/conductivity surveys and start mapping out geophysical anomalies in the northeastern portion of the Leucite Hills. I would bet that there are hidden lamproites in this portion of the field and possibly further north under some of the dune fields.
|Ellendale field with termite mound in foreground|
So why doesn't somebody look? Good question. I tried to get the Director of the WGS to ask the legislature for funding for an airborne survey before I realized this guy was not in this position for the science. So, it never got done. Over the years while I sampled and mapped this region, I did recover one excellent, transparent micro-octohedron with surface trigons. Was it a diamond? Who knows?
We've recently been contacted by nine different TV production companies possibly interested in developing a new show on Hunting for Gemstones. Maybe one day, we'll show you how to find $billions in gemstones, diamonds & gold using sound geological principals.