Revised 04 / 10

Economic Geology

Tonight: a free for all...


Natural Resources (DEFINE)

The other 84 elements...

Very important

Name something not associated with minerals or other earth materials


Earth concentrates materials through several processes

Average crustal abundance

The human time-stratigraphic horizon

The possible longer-term impact of concentrating radioactive materials

Ore vs. Waste

Does the gold/silver in seawater constitute an ore deposit?


Primary vs. Secondary Industry

Creation of new wealth vs. redistribution

Inflation: the ultimate result of a reduction of primary industry

The making of a mine: a tough mix of competing (and often conflicting) variables

GeoTechnical / Economic / Political / Environmental


Primary vs. Secondary Deposits


Primary deposits

Formed directly from the creation and/or crystallization of magma

And other limited types of deposits

Often the result of "residual fluids"

Black smokers, hydrothermal vein deposits, etc.


Secondary deposits

Re-worked primary deposits

Placer gold, etc.: your basic 49'er


The importance of energy

As a mineral resource (i.e. fossil fuels)

As a concentrating agent

Geothermal energy - primary hydrothermal deposits

Energy of moving water - secondary placer deposits

Ultimately, the sun (again)


Several main categories

Fossil fuels (petroleum)

Coal, oil, gas

Industrial materials

Sand and gravel, building stone, etc.

Metallic deposits

Precious vs. base metal deposits


Fossil fuels

Origins of petroleum


(74 m.y.)






Did a lower % of O2 retard decomposition?

An evolving atmosphere, indeed!


The criminal waste of using gasoline

Climate change

Rapid evolution of the atmosphere as we return the carbon

But not just the environmental degradation

Plastics, pesticides, fertilizer... a long list!


Industrial materials

Sand and gravel - the big one for sure

Concrete - man-made conglomerate

Building stone

Art, sculpture, etc.


Metallic deposits

Placer deposits - everyone's favorite mine

Most, however, are primary

Bowen's Reaction Series (REVIEW)

Plate tectonics (REVIEW)

We end up with four (4) magmas and two (2) boundaries

Magma Type Plate Boundary
UltraMafic Divergent
Intermediate Convergent

We'll take them by magma type


Ultramafic magmas and rocks

High pressure and temperature environments

Strategic metals

Lateritic deposits - Gasquet Mtn., Cleopatra, Red Flat

Use of refractive seismology

Chromite - banded vs. podiform

Emma Belle


Mafic magmas and rocks

Hydrothermal vents

Black (and white) smokers

Volcanogenic massive sulfide deposits

Turner-Albright deposit

Island Mountain deposit


Intermediate magmas and rocks

Subducted and re-worked mafic deposits?

Porphyry copper deposits

Chuquicamata (Chile)

Bingham Canyon, et al. (US)


Felsic magmas and rocks

Residual fluids

Fluid penetration of overlying strata

Mother Lode (California)

Pala pegmatites (and others!)

Carlin epithermal deposits

Continental rifting?


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