Midwest US: local anomalies make us one of the only “cold

spots” on earth

NOAA:

National

Oceanic and

Atmospheric

Administration

Big cliché #1

All geologic resources are finite

mined

Once it‟s gone, it‟s gone

Long before that, it‟s scarce

Big cliché #2

If it isnt grown, it must be ______

Water as a resource

Our supply

Groundwater sources and uses

Regional supply and demand

Solutions

Fresh water on earth:

a very small

percentage of total

• Polar ice

• Groundwater

• Surface water –

a distant third

water is a resource: it is important for domestic use,

agriculture, and industry

Water is a finite resource

Just like most other geologic resources

Water is a regionally renewable resource – but not always locally!

Geology affects the quality and quality of water in a region

{ closed system }

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

Sick of this yet?

Groundwater will slowly

flow or stay

underground for up to

millions of years

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!

Recharge can take place over large timescales

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Aquifer rocks may compact after ground water is withdrawn, leading to subsidence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

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

• 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

A geopolitical issue - global water usage

Mali, Afghanistan, Somalia, Nigeria, DR Congo

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 strategiesBuild artificial recharge basinsRetention strategies

Soil as a resource

Soils defined – characteristics

Soil formation process, weathering, erosion

Minnesota soil issues

Soil solutions

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

Soil is produced by weathering - chemical, physical, biological

Climate, topography, source composition, and time are factors

Erosion is the physical removal & transport

of weathered material

…creates and destroys the raw materials for soil

Erosion >>>formation

Calcium Carbonate and some

silicates dissolve in water

Organic acids and acid rain from

sulfates break down minerals

Biological activity - roots &

burrowers – aids weathering

Soil blanket shows zones of different colors, chemical compositions, & properties

Topsoil [„E Horizon‟] rooted and organicA Horizon - exposed to heavy leachingB Horizon - accumulation / deposition + leachingC Horizon - Very coarsely broken-up bedrockR horizon: bedrock material

Most soils are defined

by the combination of

their profiles M

inera

l

org

anic

Climate x usage x populationImpacts 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

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

Nearly all solutions involve keeping the soil unharmed and in placeProtect the soil from fast moving wind

Plant wind breaks perpendicular to windProtect the soil from fast moving water

Reduce the slope so runoff is slowed

Terrace and contour farmingEncourage the growth of rooty plants

Mineral resource basics

Demand and dependence

Occurrence on the earth

Costs and steps in recovery

Distribution and resource

bottlenecks

Case studies in mineral resources

Aluminum & Iron – appliances and vehicles

„rare earth‟ metals - semiconductorsGems, gold, and silver – jewelryLead, zinc, metal coatingsCopper for many electrical uses

„if it isn‟t grown, it must be mined‟

Sedimentary,

igneous and

metamorphic

sources

Minerals and rocks are classic

nonrenewable resources; supply is

finite, demand is growing

Igneous Rocks and Magmatic Deposits

PegmatiteHydrothermal Ores

VeinsRelationship to Plate MarginsSedimentary Deposits

Banded iron formation

EvaporiteMetamorphic RocksSecondary deposits such asgold „placer‟ concentrations

Many different kinds of geologic features can host mineral resources

Prime locations for mineral resources are sites of current or

past active geology– especially at plate boundaries

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!

Mining includes major costs associated with each step: Exploration Extraction

Production Mitigation

Extraction costsminingseparation or concentration

Production coststransportpurification

Environmental costsAt every step of this process, toxic

chemicals, energy and water intensive processes, and harmful byproducts are common

Example - copper miningsulfide ore extraction: leach H2S, metals Processing – lots of water, acid smoke & steam

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 !

Lithium is used in LOTS of our

favorite toys: electronics and

batteries, esp rechargeable

Bolivia: 50% of reserves

Neodymium, a rare earrth metal with

interesting properties, used in

magnets motors

China: 95% reserves, export freeze

Phosphorus, fertilizer

prices rising ~50% per year

>50% Morocco

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

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

amounts

Annual

values

Lifetime

values