Transcript Chapter 1: Philosophy and Fundamental Concepts

Chapter 1: Philosophy and
Fundamental Concepts
geology
science
study of the earth
physical - how the earth works
historical - what the earth was like in
the past
environment
total set of circumstances that
surround an individual or
community
all physical conditions
social and cultural conditions
environmental geology
applied geology
interactions between humans and
the earth
environmental geology – areas of focus
earth materials
resources - in and out of place
effects on human health
natural hazards
landscape and environmental analysis
hydrologic processes
resources
pollution
geologic processes
analysis of global change
geologic time
fundamental concepts:
population growth
number one environmental problem
exponential
growth rate
doubling time
D=70/G
figures p 10
tables p 11 & 12
carrying capacity
fundamental concepts:
sustainability
environmental objective
Environmental crisis
deforestation w/soil erosion, water pollution, air
pollution
geologic resource mining
development of ground and surface water resources
what can the earth support for the long
haul
growth (?)
economy
Fund. concepts: systems & change
system concepts
open vs closed
changes
• input-output analysis - fig p 17
• average residence time - fig p 19
• rates
feedback
• positive - can cause runaway increase
• negative - self-stopping
response to disturbance
• disturbance
• complex response
• thresholds
earth system science
Fund. concepts: systems & change
uniformitarianism/actualism
the present is the key to the past
thePAST is the key to the future
Fund. concepts: systems & change
earth systems
all closed (mostly)
• exceptions: energy, meteoric additons
all linked
driven by energy
four systems
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atmosphere
hydrosphere
biosphere
lithosphere
Fund. concepts: some earth processes
are hazardous to humans
assessment
perception
accommodation
avoid
plan for
fundamental concepts: scientific
knowledge & values
science
objective examination
How does science work?
• “method”
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observation & data collection
hypothesis
testing & data collection
revision/refinement
publication/review
• problems
– historical aspect
– multiple inputs and outputs
– complex response
Environmental Ethics
morals - right vs. wrong
values
intrinsic/inherent
instrumental
moral status
agents
subjects
neither
Scientific values
obligations to future generations
effects of land use are cumulative
importance of aesthetic
considerations
Ethical viewpoints
Universalist
fundamental principles: unchanging, eternal,
universal
modernists: develop universal laws through
science
Utilitarian
the greatest good, for the greatest number of
people
environmentalists added: for the longest time
Types of Environmentalism
pragmatic resource conservation
protect, develop, and use
utilitarian conservation
US Forest Service
moral and aesthetic nature preservation
nature for nature’s sake
altruistic preservation
US Park Service
modern environmentalism
concern for effects of pollution
research, activism, focus on local issues
US EPA
global environmentalism
concern for global changes
climate, extinctions, population, pollution
international treaties
Environmental Justice
environmental health as it relates to:
race
social standing
wealth
clean environment is a civil right
examples
environmental racism
toxic colonialism
Economics
the study of the production, distribution,
and consumption of capital
capital - any form of wealth available for
use in the production of more wealth
uses
assess relative values of goods and actions
choose between competing options: cost-benefits
analysis
supply and demand
supply: quantity of product available at a
given price
demand: amount consumers will buy at a
given price
the development cycle
as supply decreases, cost increases and:
use declines
money for research & development increases
more natural resources become economic
efficiency of use increases
substitution of/replacement with another
resource
Common property
usually owned by all
may encourage poor use
open, unregulated access
benefits of use are focused
costs are widely distributed
must be carefully managed
privatization
Political decision making
policy made via a political process
two models
“power politics”
“rational choice”
Government actions
Legislative
laws
funding
Executive
rules
enforcement
Judicial
interpretation
enforcement
Laws
NEPA 1969
Clean Air Act 1970, 77, 90
Clean Water Act 1972, 77, 96
Endangered Species Act 1973
TSCA 1976
RCRA 1976, 84
CERCLA 1980
SARA 1994
Chapter 3: Minerals &
Rocks
Atoms & Elements
definitions
atom: smallest part of a chemical element
that can take part in a chemical reaction or
combine with another element
element: chemical substance composed of
identical atoms that may not be separated
into different substances by ordinary
chemical means
parts of an atom
proton
+ charge
atomic weight = 1
neutron
0 charge
atomic weight = 1
electron
- charge
atomic weight = 0
Atoms & Elements
terms
atomic number = # of protons
mass number = # of protons + # of
neutrons
• isotope - variations due to # of neutrons
ionic charge = # protons - # of
electrons
Chemical bonding
electron shells are most stable when full
or empty
types
ionic bond – electrons exchanged
Van der Waals bond - ionic attraction of sheets
or chains
covalent bond – shared electrons
metallic bond - electrons are shared by all atoms
most minerals have several types of
bonds
Minerals
naturally occurring , solid,
crystalline, known physical &
chemical properties
building blocks of rocks
over 2000 identified - few common
common mineral groups
silicates (98% of crust by weight)
quartz
feldspar - most common
mica
ferromagnesian
clay (weathering product of other silicates)
oxides - hematite, bauxite, magnetite
carbonates - calcite
sulfides - pyrite, often in coal - acid
runoff
native elements - gold, silver, copper,
diamonds
Rocks
aggregates of minerals
rock texture - size, shape,
arrangement of grains
Igneous rock
from solidification of molten rock
intrusive vs. extrusive
composition
mafic
intermediate
felsic
Igneous activity – molten rock
formation
temp up
pressure down
addition of water
rises due to lower density
differentiation
crystal fractionation - enriched in remaining
elements & volatiles
Incorporation
Igneous rock - intrusive
magma
texture
cool slowly
coarse grain:phaneritic, pegmatitic, porphyritic
bodies
batholith
pluton
laccoliths
dikes and sills
hydrothermal deposits
rocks: granite, diorite, gabbro, peridotite
Igneous rocks - extrusive
lava
volcanoes
texture
cool quickly
fine: aphanitic, glassy, pyroclastic,
porphyritic
rocks
rhyolite, andesite, basalt
obsidian
tuff, volc breccia, bentonite
Igneous rocks – env. properties
source of economic minerals
economic rocks
intrusive
strong
resistant to weathering
resistant to fluid flow
extrusive
may be weak
more susceptible to weathering
less resistant to fluid flow
Sedimentary rocks - formation
weathering
physical
chemical
erosion & transportation
deposition - accumulation of sediments
environment of deposition
sedimentary basins
transgression & regression
sorting of sediments
rounding of clasts
burial & lithification
Sedimentary rocks - types
clastic - detrital
gravel, sand, silt, clay
non-clastic - chemical & biological
limestone/dolostone - biological or chemical
chert - biological (or post dep chem)
evaporites - chemical(gypsum, rock salt)
coal - biological
Sedimentary rocks – env. properties
source of economic minerals
economic rocks
strength varies with
sediment type
cementation
bedding plane weaknesses
fluid flow varies with
sediment type
cementation
dissolution (esp. limestone)
expansive clays
Metamorphic rocks - formation
Previously existing rock
altered by
heat
• contact
• hydrothermal
pressure - fault zone
heat & pressure
• regional
• impact
foliated vs non-foliated: alignment of
platy or linear minerals due to pressure
Metamorphic rock
types
foliated: slate-phyllite-schist-gneiss
non-foliated
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marble
quartzite
hornfels
anthracite
grade
type of foliation
size of mineral crystals
index minerals
Metamorphic rock – env. properties
source of economic minerals
economic rocks
strength varies with
foliation
degree of metamorphism
type of rock
fluid flow is usually slow
the rock cycle
shows how rocks form and how
they relate to each other
each rock type can be transformed
into one of the others
Rock strength and deformation
stress
compression
extension
shear
strain
elastic - earthquakes
plastic - folds
brittle
• joints
• faults
Strength of Earth materials
response based on
rock type
time
rock features/orientation
• stratification
• foliation
• intrusions
structures
folds
fractures
joints
faults
Stratigraphy
correlation
unconformities
rock laws
cross cutting relationships
original horizontality
superposition
mapping
formations
structures
orientation of layers
allows planning
Earth’s Interior
evidence
seismology
samples
• volcanoes
• drilling
• meteors
gravity
magnetics
Earth layers - core
Fe & Ni
107 g/cm3
inner core - solid
outer core - liquid
convects
source of magnetic field
Earth layers - mantle
ultramafic
45 g/cm3
lower mantle - plastic solid
asthenosphere - partially molten
upper mantle (lower lithosphere –
rigid)
Earth layers - crust
rigid
ocean
5 km thick
mafic
28-30 g/cm3
continental
20-35 km thick
intermediate to felsic
27-28 g/cm3
Plate Tectonics
overall effects
surface topography
• continents
• oceans
geologic hazards - esp volcanoes and
EQs
resource locations
climate
Plate Tectonics
Lithosperic plates
rigid upper mantle & crust
appx 100 km thick
move
• horizontal - 2-15cm/yr
• vertical - isostacy
Plate Tectonics:
divergent boundaries
plates pull apart
ocean basins form
topographic features
rift valley (normal faulting)
mid-ocean ridge
geologic activity
shallow EQ’s
igneous activity - mafic & ultramafic
history - age of the sea floor - fig p 51
Plate Tectonics: convergent
boundaries (cont.-ocean or ocean-ocean)
subduction - ocean lithosphere is
overrun
topographic features
mountain ranges
volcanic
faulted
ocean trench
faults (reverse & thrust)
Plate Tectonics: convergent
boundaries (cont.-ocean or ocean-ocean)
geologic effects
shallow and deep EQ’s
igneous activity - intermediate & felsic
regional metamorphism (in long belts)
ophiolites
accreted terranes (west coast of North America)
Japan, Andes Mtns., Cascade Mtns., New
Zealand, Philippines, Aleutian Islands,
Caribbean Islands
Plate Tectonics: convergent
boundaries (cont.-cont.)
topographic features
large mountains
faults
geologic effects
shallow EQs
Himalayas
Plate Tectonics: transform
boundaries
topographic features
complex faulting
small mountains
geologic effects
shallow EQ’s
California, Turkey
Plate Tectonics: hot spots
not a boundary
topographic features
volcanic chain (one or two active
volcanoes at end of chain)
geologic effects
isolated igneous activity
Hawaii, Yellowstone
Plate tectonics and
environmental geology
resource zones
oil
gas
minerals
hazard zones
earthquakes
volcanoes
landscapes
climate