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Gold/Mining/Energy : Donner Minerals (DML.V) -- Ignore unavailable to you. Want to Upgrade?

To: Ed Pakstas who wrote (789)	10/31/1997 7:17:00 PM
From: VAUGHN	Read Replies (4) \| Respond to of 11676

Hello Ed Thanks Please keep in mind that I am no geologist, and Terry or someone more qualified should perhaps be the one who explains this subject, as I am only suggesting what may have happened based on my limited knowledge, but here goes. It is my understanding that there are two continental blocks here that have essentially collided. The Nain Province (Nain Plutonic Suit-Archean aged gneisses and granitoids) having collided with the Churchill Province (Lower Proterozoic - metasendimentary gneisses and granitoid rocks). Simply put, 2.9 billion year old metamorphisized rocks collided with 1.1 billion year old metamorphisized sendimentary and granitic rocks. The deposit is theorized to have been emplaced through a magmatic sulfide intrusion hosted in mafic rock (olivine gabbro, norite, troctolite). I was suggesting that the collision may have been the event the precipitated the magmatic intrusion. In effect the collision may have either weakened the rock, fractured it allowing the magmatic fluids to seap and inject into the voids and weaknesses, or, the Nain Province rocks may have hosted the sulfide deposit from an intrusive event prior to the collision, but the heat of the collision might have remobilized the sulfides into resulting fractures. Since previous NR's mentioned prolific breccia zones (intruded rock scoured from a deeper source essentially in a volcanic pipe) it sounds as if the magmatic sulfide ore may have been intruded after the collision rather than remobilized, but that is just my guess. Published technical data for the Voisey Bay deposit shows that small mafic intrusions (troctalite) and associated dyke and sill like features are important targets in the search for massive sulfide ore. Geological mapping and available drill data shows that the olivine gabro intrusions (troctalite) are generally east dipping. These rocks form outliers on the basement gneisses (Churchill Suite I believe) however, they also appear to dip beneath the gneisses in places and the area is complicated by faulting which can cause displacement of the contact with the basement rocks. Does that make any more sense? Now I would imagine one of the complications is if the magmatic intrusion occurred after the collision not during it, and possibly after the faulting, then the ore would have deposited into the faulting as well as the seams and fractures between the two provinces. On the other hand, if it injected and then was subsequently offset by faulting, then the ore targets may be displaced from one another. Terry, feel free to step in here and correct me please and/or add your two sense and expertise. So are you baffled with BS now Ed? Have a good weekend. Regards