Hello Valuepro
There has been no published petrographic data on these deposits, and I understand from conversations with SUF that opinions have changed as to probable age of them, but I suspect we are talking about kimberlites that are between 80 my old and 100 by old (Middle Cretaceous) like those of Kimberly, Lesotho and Botswana. There could well have been anywhere from 800m of pipe eroded off the top of the M-1 up to 2km; the Sugarbird and Leopard fissures probably represent deeper erosion areas or older kimberlites.
The Klipspringer site appears to generally be very hilly, implying that mountains of some age have been deeply eroded and or the land uplifted in some geologic orogeny probably after emplacement but not necessarily.
Current topography and climate without doubt bare little resemblance to what probably existed in various forms over that time frame. Dolomite is generally the predominant cover rock, but granite appears to be present not too far below surface. This implies that this area was submerged underwater in the not too distant past (Paleozoic?) and was highly eroded cratonic mountain basement before that. SA is known to have undergone ice ages over the millennia but whether these occurred before submersion or after I could not say as I do not have an in-depth paper on SA geologic history at my fingertips.
Regardless, since the kimberlites intrude the dolomite you can get some idea of their age horizon, assuming that they were all emplaced in roughly the same time period. However, how much of the dolomite has been eroded is unknown beyond presumably the highest point of the surround hilltops, which are quite a bit higher than the M-1 site as I read the photos I have seen. Did the hills develop since emplacement? Possibly, but that does not appear to be the case from what meager evidence I have seen.
Either way, wind, ice, rain and flood I am sure have all had opportunity to carry eroded stones over any number of directions, the paleo channel probably only represents the most recent.
The majority are probably in the ocean by now and only the more recently liberated (last million years) are within a few kilometers of the site. It is my understanding that the existing downward slope is predominantly on SUF ground within the known claim area. Whether the paleochannel follows the existing ground slope or one or more slopes that varied throughout time has not been indicated however.
While I doubt Klipspringer kimberlites are older than I have suggested above, it is worth keeping in mind that RSA diamondiferous kimberlites such as the Premier have been found over 1.1 billion years in age and Kuruman over 1.6 billion years old which represents an awful lot of erosion over a very considerable time frame.
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