Earth Resources
“Resources are like air, of no great important until you are not getting any.”
Human society relies on Earth resources for health and prosperity
Through time, the type and amount of resource use has changed and expanded, including both raw and synthetic materials
Earth’s population is a major driving force in the use of development of resources
How will we feed all these people? Where will they live? What living standards will be available?
Renewable Resources: materials that are replenished on short timescales of a few months or years
Plant and animal products
Solar, tidal wind, geothermal, biomass, and hydropower
Renewable resources must be used sustainably to provide a sustainable yield
Non-renewable resources: materials of which Earth contains a fixed quantity and which are not replenished by natural processes operating on short timescales
Coal, oil, natural gas, uranium
Copper, lead, zinc, gold, etc.
Although new fossil fuels are being produced continuously, our rate of use far exceeds the rate of production
Water is a renewable and a non-renewable resource
Energy resources
Since the 1973 energy crisis (the oil embargo), much attention has focused on the cost and availability of future energy resources
Fossil fuels vs. green energy
Metallic resources
Metals are the key resource in the development of human society (Bronze Age, Iron Age)
Abundant metals (aluminum, iron, silicon, manganese, magnesium, titanium) are found in enormous quantities although spatially discontinuous
Scarce metals (copper, lead, zinc, molybdenum, silver, gold, mercury…) are found in small and isolated concentrations, and future availability is questionable
Non-metallic resources
Minerals and substances used for fertilizers, abrasives, construction, industry, etc.
Crushed stone, sand, and gravel are used to make cement
Some are used solely to provide the resources needed to make chemicals (e.g. halite is an important source of sodium (Na) and chlorine (Cl)
Water and soil resources
Although 70% of Earth’s surface is covered by water, only 2% is freshwater, and only ¼ of that is accessible for use
Although soil covers nearly all the lands surface of Earth, only 10% is suitable for agriculture
Various geochemical cycles control the production and availability of Earth resources – e.g. the rock cycle
Geothermal energy drives tectonic processes which build mountains, while solar energy creates climate which wears mountains down
Throughout this cycle, resources are being produced and brought to the surface to be available for our use
By using resources, we can interrupt the natural geochemical cycles – e.g. the carbon cycle

Every natural resource we use results in changes to the geochemical cycle that produces or control the availability of that resource
The changes can be large or small scale, long lasting or temporary, pleasant or unpleasant
The results of the changes are often called pollution, environmental degradation, or environmental disaster
Resources can become reserves if:
The price of extraction drops below the market price (increased profitability)
New technology can access previously inaccessible concentrations
New land use laws allow for the extraction of the material
Reserves can become resources if:
The price of extraction exceeds the market price
New land use laws restrict the extraction of the material
New geologic evidence downgrades the quality of the material
The reserve base is the part of the resource that has a reasonable potential for becoming economically available within planning horizons beyond those that assume proven technology and current economics

Origin of Earth Resources
4 Processes responsible for the formation of Earth resources:
1. Subsurface igneous and metamorphic processes
2. Surface processes
3. Shallow subsurface and diagenetic processes
4. Marine processes

Subsurface Igneous and Metamorphic Processes
Generally, the continents are underlain by