Economic Geology: Rocky resources/mining in
4/11/2013 5:36:00 AM
Economic Geology – brings a lot of people into Geology..
Companies look for people that look for training (differentiation between
rocks and minerals) – logging core. drillers go and take long drills of rock,
and you must tell them what it is.
The Geology of Ontario – 4 layers (from Toronto Rocks by Eyles)
Layer Cake Diagram (see slide) 4 layers of Ontario Geology in it. The oldest
layer is the one at the bottom, Layer 1- that layer in Ontario is more than a
billion years old. Precambrian and aged – comes from plate collision and
mountains. Most rocks are metamorphic rocks. Metamorphic rocks in this
stage; made when old boundaries existed – old plates existed and formed
old mountains in that area. (GNEISS – roots of an old mountain that no
longer exists – mountain has been worn away by erosion)
Layer 2 – Tropical Seas Paleozoic – hot and tropical; near the equator;
however, over time the erosion wore it down to relatively flat.
Peneplenation – there was a rugged surface and it got worn down almost flat
– it was being eroded by all those elements. Coral reefs started to flourish –
so we already know coral reefs make a rock called (sedimentary rock) –
limestone. Layer 2 has lots of limestone. It also has other sedimentary
rocks. Totally different from Layer 1 – lots of Limestones, but also has (coral
reef needs a lot of light) if there isn‟t, coral reef dies out, and you produce
KLASTIC sedimentary rocks – Sandstone, shale, etc.
Interbedding – layer of limestone, layer of clastics, layer of limestone, etc.
Repeated cycles of rock types – in this case clastics, and non clastics.
Because of changes in the environment.
Thick black line – surface of erosion – the great unconformity – missing time
in the geologic record!!
Black line between blue and yellow – the BIG GAP – another unconformity…
more missing time in the geologic record. For a while, layer 2 was the
surface, so the sedimentary rocks wwere the surface for a long time, getting
eroded. They were on top. Eventually something else got deposited on
top (the yellow stuff) all that yellow stuff represents is what Toronto
area is really famous for (glacial and interglacial sediments – NOT
ROCKS) Layer 3 – covered by a KM or more of ICE – 20,000 of ice.
We are at an interglacial time right now (between times of ice cover)
We are going to talk about the economic geology – in terms of the various
layers. .. Layer 1 is different than Layer 2 and Layer 3 is different.
History – First geologic map produced for King Ramses to find Gold –Gold
mining district in Eastern Sahara. IT was written on papyrus, amazing that it
lasted for this long – valley of mini baths.
This is the area – Mediterranean Sea and the Red Sea on the eastern side.
Pink = layer 1, and Brown and Green = Layer 2, and White = Layer 3 The
reason for the map, was to find way back to the Gold resource.
Beckenstone – ornamental stone and the Ancient Egyptians prized it as an
Before Georgius Agricola – people thought minerals had magical properties,
thought that rocks and minerals were dragons tears, they were alive, living
things, all sorts of properties were ascribed. Georgius Agricola – he was an
observer – he liked to go out and spend time looking and observing. He was
lucky enough to live in Germany – it was an area that had silver mines; lived
on the property of one who had one of the best silver mines.
Geology – he wrote a book that talked about not only his thoughts about
geology of the area and mines – but about the diseases slaves got in the
mine…he was way ahead of his time – it wasn't appreciated at that time, it
was a handbook of those working in the industry – it was appreciated long
after his death. Bring a scientific approach to geologic resources.
William Strata Smith – canal engineer in Britain = principal of using fossils –
to figure out with layer is older. In 1815, he made a geologic map (first map
of Britain) = father of stratigraphy (study of layers) or father of modern
geology – this map changed the world the way people study geology. He
really thought about how the rocks relate to one another, he actually showed
what was below the surface not just what was above the surface.
Sir William Logan – task it was to find coal.. for upper and lower Canada –
Ontario and Quebec. Looking to find coal, and there wasn't coal to be had –
so he made a map of Canada and found coal in the eastern provinces –
particularly in Nova Scotia. Needed coal to build railway – Sponsored by
Molson Canadian – and Sir William Logan and his map and his search for
coal were directly responsible for confederation – including eastern provinces
of what we now call Canada!
Inuit Mining – 2000 years old rocks – oil lamps (Newfoundland)
(see slide) – Green Areas – are part of Layer 1, some of the oldest crust that
we have in Canada. “greenstone”
Metamorphic Rock – Greenstone
If you have an area of Greenstone – it's a great place to search for resources
such as Gold. Really old areas of the crust from really old collisions –
excellent places to search for Gold.
VMS – Volcangenic Mass Sulfides (short answer question)
- you get seawater, and near to the mid ocean ridge, that sea water gets
into the cracks – and, it gets heated up, as that water gets heated, and goes
through the rocks, it ends up exchanging oxygen, potassium, calcium
sulfate, magnesium, between water and the rock – sometimes its losing to
the rock, and gaining things from the rock – as it gets really really hot, it
picks up IRON, SULFUR, ZINC, and COPPER. Because water is hot, its able
to hold on to those things, eventually the water makes its way out of the
rocks, comes back out into the cold sea… Its temperature cools down, and
can no longer hold on to those copper, zinc, etc and precipitate out as
Economic geology brings a lot of people into geology Companies look for people that look for training (differentiation between rocks and minerals) logging core. Drillers go and take long drills of rock, and you must tell them what it is. The geology of ontario 4 layers (from toronto rocks by eyles) Layer cake diagram (see slide) 4 layers of ontario geology in it. The oldest layer is the one at the bottom, layer 1- that layer in ontario is more than a billion years old. Precambrian and aged comes from plate collision and mountains. Layer 2 tropical seas paleozoic hot and tropical; near the equator; however, over time the erosion wore it down to relatively flat. Peneplenation there was a rugged surface and it got worn down almost flat. It was being eroded by all those elements. Coral reefs started to flourish so we already know coral reefs make a rock called (sedimentary rock) limestone.