Tuesday, September 30, 2008

Gravel Fossils and Alluvial Diamonds

As a geology student at what was then Northeast Louisiana State College, I concentrated on partying as much as I did “cracking the books.” Being a small department, all the professors and students knew each other and we all looked forward to the geology picnic held every spring at a camp on Lake Cheniere - hot dogs, hamburgers and a keg or two of beer provided the usual fare.

One memory I have of these seasonal events is witnessing a geology professor – goaded by several grad students – attempting to drink the last gallon from the keg. He didn’t make it, and thank goodness final grades for the year were already posted.

The camp on Lake Cheniere was near a large gravel pit, a strip mining operation that had already removed tons of gravel for construction and road building. The pit was a favorite with geology students because it was a virtual endless repository of what we called gravel fossils. What kind of fossils? Silicified, Paleozoic fossils of the marine variety – brachs, corals, bryozoans, cephalopods, etc. Well, you get the picture.

How did these three hundred to five hundred million year old fossils end up populating geologically young Louisiana alluvium? In the case of the gravel pits near Monroe, they were eroded and washed down dip from Paleozoic deposits in the Ouachita Mountains of Arkansas.

There were rumors that alluvial diamonds were also sometimes found in the gravel – rumors because I never talked to anyone that had actually found a diamond, or knew anyone that had. Still, the possibility is legitimate since Murfreesboro in the Ouachita Mountains is the location of a known diamond deposit, with diamonds exposed at the surface of the earth there.

Is it possible that a large, undiscovered alluvial diamond deposit exists in north Louisiana? Consider this – such a deposit is very real in South Africa where alluvial diamonds are found in gravel deposits, much like those in Louisiana. From 1926 to 1984 over 667,000 carats were produced from this part of South Africa known as the Ventersdorp Alluvial Diamond District.

Where would you look if you wanted to find this elusive north Louisiana diamond deposit? That gravel pit near Lake Cheniere might be a good place to start. Hey, and invite me along as I would love to find one of those elusive glitterers.

Eric's Website

1 comment:

Anonymous said...

I would very much like to get in touch with you about this post in blogger. Please let me know if I can get in touch via email ,as I haven't been able to find an email address here. Thanks. Michael