This document discusses water as a finite resource and provides details about groundwater systems. It notes that water is a regionally renewable resource, but not always locally. Groundwater flows underground and is recharged very slowly over long timescales. Pumping groundwater lowers the water table and can cause issues like subsidence. The document also discusses soil resources and issues like erosion, as well as mineral resources and the global distribution and demand issues for certain minerals.

1. NOAA:
National
Oceanic and
Atmospheric
Administration
Midwest US: local anomalies make us one of the only “cold
spots” on earth

2. Big cliché #1
All geologic resources are finite
Once it‟s gone, it‟s gone
Long before that, it‟s scarce
Big cliché #2
mined
If it isnt grown, it must be ______

3. Water as a resource
Our supply
Groundwater sources and uses
Regional supply and demand
Solutions

4. water is a resource: it is important for domestic use,
agriculture, and industry
Water is a finite resource
Just like most other geologic resources
Fresh water on earth:
a very small
percentage of total
• Polar ice
• Groundwater
• Surface water –
a distant third
{ closed system }
Water is a regionally renewable resource – but not always locally!
Geology affects the quality and quality of water in a region

5. Sick of this yet?
Groundwater portion:
Water will flow down until it hits the
saturated underground zone – surface at
the water table
Water table approximately follows
topography but also depends on
sediments, barriers etc
Groundwater will slowly
flow or stay
underground for up to
millions of years

6. Water will flow along streams,
through cracks, and directly into
porous sediments and soils
Porosity and permeability describe
the amount of space between
grains and the ability of
rocks/sediments/soils to contain
fluid and to allow fluids to pass
through them
Aquifer = place with good storage
and movement as above = good
source for water
Porous, but
NOT
permeable!

7. Recharge can take place over large timescales

8. Pumping ground water will lower the water
table and form a cone of depression
Aquifer rocks may compact after ground
water is withdrawn, leading to subsidence
Result: seawater intrusion, sinkholes
Urbanization causes both higher withdrawal
and lower recharge
• Pavement and parking lots reduce
recharge capacity
• Building on wetlands reduces recharge,
water storage, and water quality

9. A mixture of younger surface and older, rocky
aquifer sources
Quaternary – glacial sand and gravel
Cretaceous – marine sediments limestone
Older – sandstone and hard metamorphic
rocks
BIG range of recharge times, pollution rates,
and demand
Issues: pollution ! Pollution ! pollution !!
Lots of surface water
sources too

10. A geopolitical issue - global water usage
• Too many people
• Too much demand
• Not many places to
find more water
Conservation is growing
in importance, but not
enough
Desalination is also
growing in importance
Mali, Afghanistan, Somalia, Nigeria, DR Congo

11. Hi and lo tech:
•Cloud seeding
•Interbasin transfer
•Recycling
Conservation – a must do
strategy in U.S.
Water is wasted every
day in different ways
Interbasin Water Transfer
Moving surface waters
from one stream
system‟s drainage
basin to another‟s
Desalination
Ground water recharge can be enhanced by incorporating various artificial
recharge strategies
Build artificial recharge basins
Retention strategies

12. Soil as a resource
Soils defined – characteristics
Soil formation process, weathering, erosion
Minnesota soil issues
Soil solutions

13. Soil :
- Unconsolidated material
overlying bedrock
- Material capable of
supporting plant growth
- Connected biological –
geological system
Rocks x climate x plants x time
Color: dark or light
Dark soils tend to be rich in
organic matter
Texture: size – sand/silt/clay
Sand-sized (2-0.05 mm)
Silt-sized (0.05-0.002 mm)
Clay-sized (less than 0.002
mm)
Structure:
Blocks or „peds‟ , crumbs,
etc

14. Soil is produced by weathering - chemical, physical, biological
Climate, topography, source composition, and time are factors
Calcium Carbonate and some
silicates dissolve in water
Organic acids and acid rain from
sulfates break down minerals
Biological activity - roots &
burrowers – aids weathering
Erosion is the physical removal & transport
of weathered material
…creates and destroys the raw materials for soil
Erosion >>>formation

15. Mineral   organic
Soil blanket shows zones of different colors, chemical
compositions, & properties
Topsoil [„E Horizon‟] rooted and organic
A Horizon - exposed to heavy leaching
B Horizon - accumulation / deposition + leaching
C Horizon - Very coarsely broken-up bedrock
R horizon: bedrock material
Most soils are defined
by the combination of
their profiles

16. Climate x usage x population
Impacts are processes such as:
•
•
•
•
•
Desertification
Erosion
Deterioration of tropical soil
Contamination
Chemical change - farming
Result: the loss of soil, loss of soil quality, and degraded acreage left to
grow enough food for a hungry world.
…Land area is finite

17. Loads of wetland soils
Tend to be rich in accumulated organic matter  acidic
because decaying organic matter consumes oxygen
Provide vital habitats for birds and other organisms
Retain flood waters easily and often trap sediments
Also serve as pollution traps
Intimately associated with farmland
Farmland soils have their own problems
• Nutrient degradation and buildup
• Erosion and runoff

18. Nearly all solutions involve keeping the soil unharmed and in place
Protect the soil from fast moving wind
Plant wind breaks perpendicular to wind
Protect the soil from fast moving water
Reduce the slope so runoff is slowed
Terrace and contour farming
Encourage the growth of rooty plants

19. Mineral resource basics
Demand and dependence
Occurrence on the earth
Costs and steps in recovery
Distribution and resource
bottlenecks
Case studies in mineral resources

20. „if it isn‟t grown, it must be mined‟
Aluminum & Iron – appliances and
vehicles
„rare earth‟ metals - semiconductors
Gems, gold, and silver – jewelry
Lead, zinc, metal coatings
Copper for many electrical uses
Sedimentary,
igneous and
metamorphic
sources
Minerals and rocks are classic
nonrenewable resources; supply is
finite, demand is growing

21. Many different kinds of geologic features can host mineral resources
Igneous Rocks and Magmatic Deposits
Pegmatite
Hydrothermal Ores
Veins
Relationship to Plate Margins
Sedimentary Deposits
Banded iron formation
Evaporite
Metamorphic Rocks
Secondary deposits such as
gold „placer‟ concentrations
Prime locations for mineral resources are sites of current or
past active geology– especially at plate boundaries

22. Iron – big impact in World War II, mined out
Later, new technology allowed taconite extraction
Building stone – gneiss, granite – local importance
Clay – specialty uses
Recently, proposed sulfide mining in these areas
Copper, nickel
gold, platinum
- And lots of acids!

23. Mining includes major costs associated with
each step: Exploration  Extraction 
Production  Mitigation
Extraction costs
mining
separation or concentration
Production costs
transport
purification
Environmental costs
At every step of this process, toxic
chemicals, energy and water intensive
processes, and harmful byproducts are
common
Example - copper mining
sulfide ore extraction: leach H2S, metals
Processing – lots of water, acid smoke &
steam

24. Uneven global distribution
spurs tension and trade
Demand fluctuates, grows
Supply can experience
bottlenecks
Current trends:
• Standard of living
increase
• Population increases in
mineral-poor regions
Consumption rates will not likely level off or decline soon !

25. Lithium is used in LOTS of our
favorite toys: electronics and
batteries, esp rechargeable
Bolivia: 50% of reserves
Phosphorus, fertilizer
prices rising ~50% per year
>50% Morocco
Neodymium, a rare earrth metal with
interesting properties, used in
magnets  motors
China: 95% reserves, export freeze

26. Exploration & extraction technology
Some minerals may be substituted by other,
more abundant resources
Plastics replacing automobile parts
Recycling – many metals are successfully
recycled
Measures to reduce demand
must play a greater role in
resource use

27. Annual
values
US: 4.5% of population but consumes many
times the average share of world supply

As more of the world mirrors the US, global
resource use will approach the same
Lifetime
amounts
values
