Is this an APRIL FOOLS JOKE OR IS IT TO GOOD TO BE TRUE? CDR is going to rocket as the Souther Australia Diamond play heats up.
Any comments?
Otherwise, lets sit back and enjoy the ride....
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Insider Report Feature--April 01/98
Home Page: www.stockhouse.com/insider
E-mail: hotline@istar.ca
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DIAMONDS IN SOUTH AUSTRALIA - The Next Argyle Diamond Mine? Part I
The Insider Report is proud to present Part 1 of a 3 part series focusing on The Springfield Basin in Australia. As this area is relatively unknown to the North American junior exploration investing public we feel that early knowledge of what might be the next big diamond area play could be of significance to our readers and is worthy of our attention.
According to a recent Information Sheet, published by the MINES AND ENERGY RESOURCES SOUTH AUSTRALIA (MESA), South Australia hosts macrodiamonds, many of which are gem quality. When it comes to Australian diamonds, most investors think of the world-class Argyle diamond mine and little else. Few realize that Australia boasts five exposed major Archean cratonic nucleii. According to the MESA report, three sites in South Australia have recorded more than 100 diamonds: (a) at Echunga (near Adelaide), 200 diamonds were found by gold panners in the 19th century, but none in the past twenty years; (b) at Eurelia, 140 microdiamonds have been found associated with kimberlites; (c) in the Springfield Basin, 128 diamonds and fragments have been recovered from conglomerates of Permian age.
South Australia hosts the giant Olympic Dam copper-uranium-gold-silver orebody, and has the same terrain that contains the massive Broken Hill lodes. This area had been largely unexplored because of widespread sedimentary and soil cover. Major refinements in aeromagnetic surveying techniques, data processing and computer-aided interpretation now provide a quick and efficient method of exploring these highly prospective terrains. In all, South Australia boasts 93 mines and mineral deposits. Perhaps, there are more to come - a diamond mine, for example?
The tectonic setting and wide range of diamond and lamprophyre occurrences suggest the area east of the Gawler craton is highly prospective. This area is known as the Adelaide Geosyncline. Initial rifting was followed by widespread mafic volcanism that led to the development of the geosyncline. Extensive evaporitic, clastic, glaciomarine and carbonate sedimentation occurred during the Neoproterozoic period. The oldest sediments and volcanics were disrupted and form intrusive breccia bodies. Sedimentation resumed during the Cambrian period with carbonate-dominated units in the shelf and slope environments. Initiation of this extension was associated with mafic intra-plate volcanism and subsequent granite intrusion. Mafic volcanics and Ordovician granites outcrop along the eastern margin of the Adelaide Geosyncline, and these rocks and associated metasediments underlie the Tertiary Murray Basin. At the northeastern corner of the Adelaide Geosyncline, we find the Springfield Basi!
n.
The Springfield Basin is of paramount interest because it may lead to the world's next great diamond exploration stampede. Dr. Kevin Wills reported on the diamond potential of the Springfield Basin, which is thought to be highly prospective. The first differentiation that must be made between Australia and South Africa diamond fields is that, unlike South Africa, Australian diamond source rocks have been found near the margins of Archean cratons. A 1979 study concluded that diamondiferous kimberlite of Permian age or younger would not likely exist in most of southeastern Australia. The exception was the Eurelia province (Springfield Basin) where the kimberlites are thought to have formed at depths of over 125km within the diamond stability field.
The Springfield Project area is located about 50km east of the Torrens Hinge Zone, which is thought to represent the buried margin of the Archean Gawler Craton. Integration of earthquake epicenters, kimberlite and kimberlite indicator mineral distribution clearly outline a major kimberlite province in the mid-north of South Australia. The features controlling diamond emplacement are thought to be the coincidence of structurally and stratigraphically thickened continental crust under the central Adelaide Geosyncline and the presence of pre-existing continent wide fractures that aided mantle tapping during the 300-100Ma period of crustal extension prior to the break-up of Australia and Antarctica. Recent work on mantle and deep crustal xenoliths from southeastern Australia established that gradual warming of the continental crust occurred during this period. This work predicts that the best chances for tapping and preservation of diamond-bearing kimberlites are during the Permia!
n and older periods. It is believed by many that it is only a matter of time before an economic primary diamond deposit is located in central South Australia.
The Springfield Project is already a successful diamond exploration project. To come from nowhere in the mid 1960's, to a kimberlite province containing diamond-bearing rocks, is a significant exploration achievement. Unfortunately for the previous explorers, they did not hit the jackpot. The diamonds at Springfield and Eurelia indicate this is the right geological terrain. Earlier work suggests that the best chances for economic success will be in Permian or older kimberlites. The bulk of any such intrusions should still be preserved near the present land surface. There is evidence for at least two different primary source rocks in the area.
Previous exploration ultimately failed because bulk sampling was conducted on secondary diamond populations, not the primary source rocks or recent alluvials. Secondaries are likely to be sorted and diluted, which led to the initial sub-economic results and earlier exploration failure. Since then, exploration techniques have been refined.
Dr. Wills compared what previously happened in the Springfield Basin to earlier efforts in Australia and Venezuela. He wrote:
"CRA and its predecessors in the Ashton JV initially missed the diamonds in Smoke Creek altogether. On their second pass, with much improved sampling techniques, diamonds were recovered and this rapidly led to the Argyle discovery. In Venezuela, alluvial diamonds had been known since 1887. In the first pass, no indicators were returned. In the second pass, when concentrates
were observed to -0.2mm, abundant kimberlitic pyropes were recognized that rapidly led to the primary sources."
The strengths of Springfield Basin are as follows:
1) The Central Adelaide Geosyncline area is the most likely part of southeastern Australia to contain Permian and older kimberlites that are thought to have passed through the diamond stability field and picked up diamond-bearing xenoliths.
2) The Springfield project area is one of few in Australia to contain over 100 macrodiamonds. They are hosted by Upper Permian conglomerates. The associated indicators are very fresh.
3) The Springfield area is located near the intersection of several major continent-wide linear features and where continental crust was thickened during the Delamerian Orogeny and thinned prior to the break-up of Australia and Antarctica.
4) The diamonds, indicator freshness and concentration and the associated polished boulders all suggest that a primary source is relatively close to the Springfield Basin.
5) The Springfield diamonds contain some broken crystal suggesting larger diamonds are present. The small size located to date may be a reflection of the primary source.
6) Taken together, there is evidence for at least five undiscovered kimberlites on the Springfield Resources Syndicate's tenements. These are the diamondiferous Springfield and Boolcunda populations and the Kimberlitic Round Hill, Springfield Basin North and Kanyaka site.
According to Dr. Kevin Wills, his conclusions justify a new exploration program aimed at locating diamondiferous primary kimberlites on the Springfield Tenements. The only Canadian junior exploration company that has a joint venture in the Springfield Tenements is Tiger Resources trading on the Vancouver
Stock Exchange. Ticker Symbol: TGR. Tiger Resources has embarked on diamond exploration in the highly prospective Springfield Basin. Because of the past 25 years of grassroots exploration in this basin and the exceptional number of macrodiamonds that were recovered, Tiger's exploratory work tends closer to the
advanced exploratory phase of this area.
Dr. Kevin Wills prepared the Springfield Project report. He has spent nearly 30 years exploring for gold, base metals and diamonds. During 1977-80, Dr. Wills worked on CRA Exploration's successful diamond exploration
programs, organizing the follow-up sampling after Argyle was recognized. He was involved in the initial heavy-media plant bulk sampling of Argyle and carried out the first geological mapping of the deposit. Dr. Wills graduated with an Associate of the Royal School of Mines (UK) in 1970 and completed his doctorate at Durham University (UK) on island arc volcanism. Since migrating to Australia, he has worked in various positions from junior geologist to Exploration Manager for several mining companies, including CRA Exploration, Metana
Minerals and Dominion Mining.
We will release Part II of this feature on Thursday after the close of the market.
Insider Group
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