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Gold/Mining/Energy : Gold Price Monitor -- Ignore unavailable to you. Want to Upgrade?

To: long-gone who wrote (88813)	8/15/2002 7:42:02 PM
From: E. Charters	Read Replies (1) \| Respond to of 116759

I thought they had a gas pipeline into the Hawaiin volcanoes just for tourists. I don't think the volcanic eruptions are significant until the go St. Helens or Pinatubo. Wasn't St. Helen's magnificent? I used to map volcanic rock all over Canada. Flow, tuffs, pillows, agglomerates, pyroclastics. Then to see the real pyroclastic thing in living colour! Really widespread ash flows just like geology 101! Genuine Phreatomagmatism. Sure livens up the field trip. I will never think of a tuffisite or nuee ardente as boring again. That is what all the Kimberlites are,(diamond hosts) tuffistic volcanoes that exploded just like St. Helen's. More or less. There are some important differences but the explosion part is the same. That is what yellow ground is. Crater facies rock - a diatremic explosive volcanic centre. CDN geos map volcanic eruptions that are 3 billion years old. I lived on rock that was formed by hundreds of island chain volcanoes that exploded underwater before the earth had an atmosphere. Timmins Ontario is the centre of the largest outpouring of volcanic rock the world has ever seen. Perhaps 90 thousand square miles of solid lava flows. Subdury Ontario is the centre of the largest area of explosive "acid" volcanism in the world. This is not too widely known although many geologist know the scale of the Sudbury irruptive is not small. On its east were mountains formed like the Rockies, by compression uplift along the granitic Grenville front and they were 30,000 feet from base to top, making Everest look miniscule. BTW, the hot water vents related to the Cascades Range volcanism on the west coast extrudes copper orebodies 5000 feet deep on the sea floor, in the Straits of Juan de Fuca perhaps 250 miles from the nearest active shore volcano. This is how all orebodies were formed that we know in Canada. Moderately deep on the sea floor by hot water circulation, either into crevices or onto the sea floor, and close to an active volcano and a type of rock called porphyry. This process is called subaqeous hydrothermal vent deposition. The signs or evidence of underwater volcanoes revealing proximal orebodies, has been known since Roman times. All gold mines seem to be near volcanoes that were builders of islands like Hawaii. That is why prospectors look for what are called pillow lavas, This is a sign that the lava extruded underwater in blobs that settle in a characteristic pillow shape. Nearby there is nearly always a coarse grained colourful rock of varying composition, but almost always carrying quartz and feldspar in coarse crystals. The rock the gold is contained in is a tuff or fine clastic sedimentary ash bed that is heavily sheared by being uplifted by compression. The ash bed is sandwiched in between the pillow lava and the porphyry 90% of the time. When the mine is drilled, you can lay heavy odds that the drill shack is set up on the pillow lava, and the drilling goes through the tuff and ends up in the porphyry. All the gold drilled thusly in Ontario is purported to be within a 200 million year band from 2.8 to 2.6 billion years old. I differ on this and think that gold in the Geraldton belt may be proterozoic in age as the nickel in Sudbury. (1.8 billion years old. I think this because the deformation of the quartz vein structures displaces the Hearst dyke swarm and I believe this dyke swarm dates the gold. EC<:-}