KIM Report

Bending Clifford’s Rule

Posted by David

In his famed 1966 paper, T.S. Clifford noted that diamond-bearing kimberlite pipes were always ones that intruded regions of ancient continental crust. To be more specific, these regions are Archean in age (>2.5 billion years old) and formed the tectonically stable cores of continents known as cratons. Thus “Clifford’s Rule” states that diamondiferous kimberlites occur in geologic regions that have been tectonically stable (i.e. cratons) since the Archean and that diamond exploration should focus on those areas.

 

However, over the past forty years these regions of high diamond potential have been thoroughly investigated for diamond deposits and a number of world class deposits have been found in this manner, such as those in the Canadian arctic. As time passes, there are fewer and fewer areas of apparent diamond potential that remain unexplored. Diamond prospectors must start looking in places that appear at first not to follow Clifford’s rule. More diamond discoveries are being made in regions where Archean craton is not obvious.

 

Attending this August’s 9^th International Kimberlite Conference, a prevalent theme was diamond exploration and discoveries in atypical areas falling outside of Clifford’s rule. For example, one presentation was regarding the nature of the Arygle mine, owned by Rio Tinto plc. Although situated in a Proterozoic (between 2.5 and 0.542 billion years old) mountain belt, Argyle has probably the highest diamond grade of all operating diamond mines. This presentation suggested the possibility of Archean mantle existing kilometers below the younger material at surface and thus providing the conditions optimal for diamond stability. Another example of developing properties in non-Archean areas is the diamondiferous Carolina kimberlite in Brazil. Located in the 1.8-1.2 billion year old Amazon craton, this kimberlite and others near it are being investigated by Sola Resource Corporation (TSX.V-SL). The characteristics of this kimberlite discovered thus far show no significant deviation from those of kimberlites situated in Archean cratons.

 

Regardless of how the current market environment is treating diamond stocks, the increasing core demand for diamonds has pushed diamond exploration to looking at areas previously considered to be at the fringes. Examples of significant discoveries in these areas include those mentioned above, plus Fort a la Corne, Saskatchewan; and Guaniamo, Venezuela.

 

The rising demand for diamonds has caused the small group of large companies who control the bulk of the rough supply (De Beers, Rio Tinto, BHP Billiton) to raise prices. As with any commodity, when price rises, new technology and new exploration philosophies are employed to discover deposits in previously unexplored areas.

6 Responses to “Bending Clifford’s Rule”

1. Heavymoney Says:
   August 30th, 2008 at 10:09 pm

   Hi David.

   Great site you have here … I’m impressed to see you touch on Sola Resource Corp and their fantastic project in Rondonia. Like for you … Stockhouse was/is a forum for like minded investors such as myself and others that frequent the SL thread to discuss a project of high promise and mutual interest …. however … it would seem that much of Stockhouse is relegated to BS these days. I am impressed with the quality of your articles and would certainly like to see you explore the explosive (my opinion)potential of the Carolina project. Be sure to consider the Chiroca placer field located on the same claim block … the Almir property. Recent discovery of a kimberlite thought to be the source of the Chiroca placer diamonds has added much promise to there being a cluster of economic diamondiferous kimberlites in close proximity of each other … all in a 4km square area being closely examined at present.

   The current bulk sample producing numerous diamonds of up to approx 4ct in size so far, being the first signs that the historic artisanal workings are supported by the findings of Solas modern exploration techniques on the pipe and surrounding area.

   If you do take the time to explore this project in more depth … may I point you to the Santa Elina tech report from OCT/2003 which can be located at Sedar under Vaaldiam and also the Vaaldiam 2007 tech report on the Pimenta Bueno kimberlites which can be found at Sedar or directly on Vaaldiams website. Both of these references give details as to the early evaluation efforts of both Santa Elina and Vaaldiam on the Carolina pipe … efforts taken prior to Sola aquiring the option to the claims (details including microbe analysis data). Vaaldiam wanted her … Sola picked her up.

   Also take a look at the Sola commissioned 2005 Bruce Evans tech report on the Carolina kimberlite … when you put the information available from these sources together and apply them to Dr. Morton and peers KIMBERLITE CONFERENCE academic papers on the Carolina pipe … you start getting a clear picture to the merits behind the conclusions of a typical diamondiferous kimberlite pipe falling in an atypical setting.

   Of particular interest is the quality of diamonds being recovered from the Carolina pipe and area … both from a historic perspective and through current evaluation efforts.

   The Carolina being situated in a Basement setting without any graben covering making possible a much quicker and quite possibly more conclusive evaluation at an early stage … of the economic potential of the Carolina pipe. The last statement being my own conclusion … I’m not nearly the academic study that you are … hopefully my comment has a basis in accuracy.

   Anyway David … take a stab at an article on the Carolina kimberlite … I think you do a fabulous job of expressing your interpretation of diamond deposits and you certainly have the credentials to make your case … myself … I’m a self learned diamond exploration investor … I think I know a bit … but I’m always looking to learn from and consider other perspectives.

   I look forward to any comment/article you can put together.

2. Heavymoney Says:
   August 31st, 2008 at 11:17 am

   Hi David.

   Good to see the infamous ‘Diopside’ has moderated and accepted my comment or should I say request/suggestion.

   Can you comment on whether you are open to doing an article on the Carolina project … I’m truly interested in seeing anything you can put together.

   One thing … I’m not looking for an assessment of the management of Sola Resource Corp.

   The credentials of Dr. Morton … Warren Boyd … John Dupuis … the guys with direct technical experience in diamond exploration and evaluation speak for themselves.

   Actually … maybe you can dig into the history of these particular members of the team … our operator … John Dupuis has a most intriguing background in finding the sparkle in the Canadian Northern environment … something definitely a large part of consideration in making an investment in this company.

   The other members of the board bring their own vast experience in the exploration game which certainly rounds out the depth of the management … however … for the purpose of sticking to the ‘hands on’ contingent of management … an outline of their experience as you see it would certainly be worth the read.

   I think from an academic standpoint … mistakes in spelling of technical terms used in company literature may be a ‘red flag’ of some sort as you have pointed out in one of your articles regarding another company but putting that aside … as possibly just oversight on the part of the person reviewing the literature ( I know … pretty careless ) … my request is for your nuts and bolts analysis on the Carolina project from a technical standpoint.

   So what do you say David .. are you up to putting something together?

3. Heavymoney Says:
   September 6th, 2008 at 9:13 am

   Hi David.

   Another point to consider … after reading the 9IKC abstract :

   http://www.cosis.net/abstracts/9IKC/00233/9IKC-A-00233-2.pdf?PHPSESSID=83cbaee00758d5d8da9bfe8da32de8d6

   The paper talks about the possible source of the Macahado River, non-abrated with little resorption diamonds (30%) as being possibly derived from the Carolina or the Pimenta Bueno pipes.

   Carolina being about 40 kms from the Machado River alluvial location and the PB pipes being about 80 kms from the location … what is your thinking on the potential for transport from these two distinct locations in Carolina and the PB pipes.

   If you trace the waterways on GoogleEarth you will see that the waterways passing by each location are significantly different in size … the waterway mutually associated to the PB pipes is much more significant in presence than the waterway associated to the Carolina pipe and Machado alluvial location … transport occuring over a lengthy period … would you not expect to see more of a dispersion trail along the waterway from the Carolina as opposed to the waterway from the PB pipes as the Carolina waterway appears to be of a much lower intensity than the PB pipe associated waterway would be.

   My thinking is you would have more likelihood of finding gravel sheets, potholes or other choice hiding spots for alluvial diamonds in a lower intensity waterway/drainage system than you would in a higher intensity system whereby diamonds may be carried away for long distances without finding a suitable resting spot.

   The Carolina/Chiroca alluvial/placer fields are in close proximity and thought to be directly associated to the pipes in these proximate locales are situated amongst very low intensity waterways and drainage basins.

   The Carolina/Chiroca alluvials-pipes trend towards the Machado alluvial location. The Araras pipes located upstream of that locale are barren and there doesn’t seem to be any evidence of an alluvial trail following the waterway downstream from the PB pipes. That being said … it is intriguing to find Solas property boundaries covering the complete area between Vaaldiams PB pipes and the Machado alluvial location and along trend of the waterways Sola has discovered two high priority anomalies named Nova1 and Nova2 … so it will be interesting to see if Sola establishes any alluvial pockets along the waterways within their land package leading to the Machado alluvial location.

   It reminds me much of the Lajes-Roosevelt River scenario. The vast Roosevelt River alluvial fields are thought to be directly associated to the Lajes River pipes. The PB pipes were ruled out as possible sources for that sparkle as “no alluvial diamonds have apparently been found upstream from the confluence of the Lajes and Roosevelt rivers”.

   Vaaldiams “Pimenta Bueno kimberlite clusters are unrelated to the Lajes-Roosevelt diamonds because the upstream portion of the Roosevelt River that borders the Pimenta Bueno property does not contain alluvial diamonds, and the area that hosts the Cosmos and Pepper clusters does not drain into the Roosevelt River system.”

   I’m wondering if the lack of a defined alluvial trail trending from the PB pipes to the Machado alluvial location is a repeat of the Lajes/Roosevelt River story whereby Carolina/Chiroca will be shown to be the more likely sourcing of the 30% Octahedral class diamonds found in the Machado sampling.

   I suppose only further exploration can answer these questions as Nova1 and Nova2 are still to be fleshed out but I’m really liking the Carolina/Chiroca trend … any thoughts David?

4. propertymad Says:
   September 8th, 2008 at 7:25 am

   Hello David,

   I would like to lend my support to the calls from Heavymoney for you to take a look at Sola’s Carolina pipe…. it would be good to get a geologist to add a ‘professional’ opinion.

   For additional reference you should also look at the following sources of information….

   http://www.vsacapital.com/pdf/Sola%20Research%20note%20print%20final.pdf

   http://www.reportonmining.com/ReportOnMiningSpring2008.pdf

   http://dumbfukistan.org/pdf/sola07.pdf

   Out of interest, does the Argyle really break/bend Cliffords Rule seeing as its a lamproite as opposed to a Kimberlite? Sola’s Carolina could be special in more ways than one?

   Thanks,

   P

5. propertymad Says:
   September 8th, 2008 at 7:41 am

   David,

   see below an abstract from the Yellowknife GAC conference May 2007… not sure how much of this was repeated at 9IKC……

   THE FORMATION OF UNCONVENTIONAL DIAMOND
   DEPOSITS – A CASE STUDY ON THE CAROLINA KIMBERLITE IN BRAZIL

   Hunt, L.C., lchunt@ualberta.ca, Stachel, T., University of Alberta, 1-26 Earth Sciences Building, Edmonton, AB, T6G 2E3, and Morton, R., Sola Resource Corp, 120-3442 118th Avenue SE, Calgary, AB, T2Z 3X1

   The Carolina kimberlite is located in Brazil, a country with a long history of diamond exploration and mining. Between 1730 and
   1870, Brazil was the world’s leading diamond supplier with its production derived from alluvial deposits. The Carolina 41 kimberlite is located in the southeastern portion of the state of Rondônia. Here alluvial diamond deposits have been mined from the Pimenta Bueno and Comemoração rivers since the 1930s. Exploration for the primary source of these diamonds only began in 1974, with the Carolina kimberlite itself not being found until 2002.

   Exploration for primary diamond deposits is based upon the assumption that diamondiferous kimberlites are associated exclusively with cratonic areas that have remained stable since
   the Archean (i.e. for at least the past 2.5 Ga).

   The South American platform, which underlies Brazil, is an assemblage of two cratons, the Amazon craton and the São Francisco craton.
   The Rondônia kimberlite province with the Carolina pipe is located on the Amazon craton within basement rocks of presumed Proterozoic age (1.8 to 1.2 Ga). This occurrence of a
   diamondiferous kimberlite within presumably Proterozoic lithosphere thus appears to contradict current thinking on the normal location of primary diamond deposits and is the premise for this research.

   The Carolina pipe is an olivine phlogopite kimberlite, containing abundant garnet xenocrysts. It is these xenocrysts that have
   been the focus of study to date. The kimberlite is unusual through an overwhelming predominance of G9 (lherzolitic) garnets. 308 garnets analyzed so far have all been shown to be G9 in character. This lack of harzburgitic (G10) garnets is
   consistent with a post-Archean signature, which is in agreement with Proterozoic age dates for the Amazon Craton.

   Heavy mineral concentrate from the Carolina kimberlite shows almost exclusively peridotitic garnets with <1% being eclogitic in nature. This indicates that the subcratonic lithosphere is
   dominated by peridotite, with only a very minor eclogitic component. The almost complete lack of eclogitic garnets appears to contradict diamond formation in a post-Archean subduction related setting (as observed e.g. for the Buffalo Hills
   in Alberta, Canada). The absence of G10 garnets, on the other hand, is unique amongst primary diamond deposits derived from peridotic mantle sources. A more detailed understanding of this
   setting may eventually reveal alternative target areas for diamond exploration in unconventional settings.

6. propertymad Says:
   September 8th, 2008 at 9:15 am

   David, final post on the issue of cratonic age and kimberlite characteristics….. I promise!

   see below in relation to the Sola Carolina pipe and Dianors Leadbetter deposit…..

   Lucy Hunt, Thomas Satchel and Roger Morton arrived at the conclusion that the absence of G10′s in Carolina was consistent with the relatively young nature of the Amazon craton within which our pipe is found……

   Yellowknife GAC conference May 2007 – Carolina

   The kimberlite is unusual through an overwhelming predominance of G9 (lherzolitic) garnets. 308 garnets analyzed so far have all been shown to be G9 in character. This lack of harzburgitic (G10) garnets is consistent with a post-Archean signature, which is in agreement with Proterozoic age dates for the Amazon Craton.

   However, have a look at the top of page 29 of the Dianor leadbetter preliminary tonnage report (available on their website http://www.dianor.com) which states the following….

   The majority of garnets recovered from the Leadbetter samples fall into the Iherzolite field of paragenesis (i.e. “G9”).

   Since the leadbetter stones have been dated as some of the oldest diamonds on the planet (2.7 billion years old), and given the fact that the leadbetter conglomerate exhibits the same predominance of G9′s as Carolina, then that would suggest that the Hunt/Stachel/Morton defined linkage between cratonic age and G9′s is flawed?

   what do you reckon? Am I missing something here….

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