Sorry that was a bit of a confusing paragraph. What I'm saying is that diamonds from the kimberlite in question (L259) could have contributed to the diamonds in the Calonda gravels when they formed about 66 million years ago and also be washing down the modern alluvial river beds and that the ancient Calonda diamonds could easily also become mixed into more modern river channels by erosion and mobilisation from higher terrace positions (relative to the lower more modern river beds).
For me the formation of the Calonda sediment pile is more distant in time so less of a reliable guide when it comes to the exploration of the source of its diamonds. The picture with the Calonda Formation is also complicated because of tectonic displacement of these placers after their formation due to subsidence of the Congo tectonic depression.
If I was coming fresh to this project my (amateur) strategy would be to map out the locations of all modern diamondiferous gravels along the river system to try and find the source of the diamonds. I personally don't think the Calonda gravels can lead you to the pipe without making major assumptions.
As far as your comments about the facies of the kimberlite pipe my reading currently doesn't extend far enough to allow me to comment much.
But I have found this interesting paper that has studied trace elements found in individual crystal grains found in 6 known kimberlites located in north eastern Angola (Tchiuzo, Anomaly 116, Catoca, Alto Cuilo-4, Alto Cuilo-63 and Cucumbi-79). Samples were collected to depths of upto 800m in some of the pipes sampled and they discuss the differing crater and diatreme facies in which the crystals were found and there significance to the understanding of the petrogenetic evolution of the kimberlites in northeastern Angola and the implications for diamond exploration.
Can you please further explain or provide a reference for this statement that you have made.
"and of interest is LOMs statement that the SRVK and RVK are in fact upper facies levels of kimberlite pipes but are not prospective for large diamonds and that the PK kimberlite is better suited as a source - problem with this is that a lot of the kimberlites to date are 80-90% covered by upper facies and therefore their contribution to the alluvials old or new seems limited -( this does not mean they are not prospective - they are if the interpretation is correct on the RVK and SRVK but they could not have contributed much in way of diamonds to the alluvials at this point in time."
Also can you please explain in every day language how do sand diluted resedimented volcaniclastic kimberlites SRVK and RVK come into being and can you please provide any data or information you have on diamond grades or qualities in such formations and why you think diamonds from these kimberlite facies wouldn't be capable of being concentrated in modern river systems to economic levels.
Eshmun
LOM Price at posting:
50.5¢ Sentiment: Hold Disclosure: Held
