That's where any co-occurring green olivine, diamonds, and other diamond indicator minerals & mantle-source materials come into play in interpreting the pyroclastics. --I repeat, indicator minerals and a couple clear microdiamonds have already been identified in the region previous.
As I described in my last post, a sought (historically anyway, for diamond expl.) "sub-volcano" or kimberlite will originate from a deep, mantle source (beneath the earth's basement). As the NR points out,
In addition to the pyroclastic horizons, several partly consolidated green sand units were intersected at each of the three targets that yielded the thick pyroclastic. The green color of the sands is due, in part, to the presence of green clay minerals. At this time, prior to analyzing the core, it is unknown whether any of the pyroclastic horizons or the green sand units are related to local mafic or kimberlitic volcanism.
Obviously a very cautious approach given other indications!
Bear in mind all that's so far been discussed, plus this very important information from the NR:
Preliminary observations from drilling indicate that Cretaceous-age shales, sands and mudstones were intersected. The stratigraphic units tested are likely similar in age and character to the succession of sediments that immediately surround or are intercalated with pyroclastic aprons associated with the Buffalo Head Hills kimberlites.
Happy Easter to all!
more morsels later...
-j
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