Ruminations on a Sunday night
I am going to re-post the link that Karl gave recently to the Sudbury craters:
priede.bf.lu.lv
There has been a lot of talk about "twin" anomalies on this website. The two anomalies may both demonstrate gravitational and magnetic similarities, but a reading of the accompanying commentary at the referenced website (listed at the bottom of this post) would seem to rule out any futher connection. What this material states clearly is that the Sudbury structure and the Wanapitei crater are not even distant cousins. The former was one massive meteor which probably changed the course of evolution in North America. It is estimated to be over 50 times as old as the Wanapitei meteor and could possibly have distended mother earth by some 150 lateral miles as she entered her bowels. The Wanapitei crater, on the other hand, is relatively puny (5 mile diameter). The chance that these two hunks of spent star flotsam would be made of the same stuff is remote, given the disparity in composition found at other meteor impact sites around the globe.
What I find far more likely is that the PGM and other mineral values that are being found by Flag and the host of other miners in the area all derive from a single primary source, not from two separate sources. If the estimated size of the Sudbury structure is to be believed, the meteor that created it must have penetrated the earth to great depth, likely instantly melting the native material upon impact.
One of the early posts on this thread mentioned that the high grade ore was believed to lie in the 6000-8000 ft depth range. Maybe these 5 and 7 hundred foot forays are just juicers, and promise no real hope of finding a commercial deposit at these shallow depths. We may have to wait for an
Inco or Implats to find something real at depth.
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"A SIR-B radar image of southern Ontario highlights two juxtaposed but unrelated craters, that are very different in age, in size,and in structural state.
The partially circular lake-filled structure on the right (east) is the 8 km (5 mile) wide Wanapitei crater estimated to have been formed 34 million years ago. The far larger Sudbury structure is evidenced by a pronounced elliptical pattern, more strongly expressed by the low hills to the north. This huge impact crater (some argue it was at least 245 km [150 miles] across when it was circular)was created about 1800 million years ago. It was subsequently deformed by the strong northwestward thrusting of the Grenville
Province terrane against the Superior Province (containing Sudbury) more than 900 million years later. After Sudbury was initially excavated, magmas from deep in the crust invaded the breccia filling to emplace against its walls (some investigators think that the resulting norite rocks are actually melted target rocks). This igneous rock is host to vast deposits of nickel and copper, making this impact structure a multi-billion dollar source of ore minerals." |
