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Transcript of Chapter 1: Philosophy and Fundamental Concepts geology science study of the earth physical - how the...
Chapter 1: Philosophy and Fundamental Concepts
geology
sciencestudy of the earth
physical - how the earth workshistorical - what the earth was like in the past
environment
total set of circumstances that surround an individual or communityall physical conditionssocial and cultural conditions
environmental geology
applied geologyinteractions between humans and the earth
environmental geology – areas of focusearth materials
resources - in and out of placeeffects on human health
natural hazardslandscape and environmental analysishydrologic processes
resourcespollution
geologic processesanalysis of global change
geologic time
fundamental concepts: population growth
number one environmental problemexponential
growth ratedoubling timeD=70/G
figures p 10tables p 11 & 12carrying capacity
fundamental concepts: sustainability
environmental objectiveEnvironmental crisis
deforestation w/soil erosion, water pollution, air pollutiongeologic resource miningdevelopment of ground and surface water resources
what can the earth support for the long haul
growth (?)economy
Fund. concepts: systems & changesystem concepts
open vs closedchanges• 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/actualismthe present is the key to the pastthePAST is the key to the future
Fund. concepts: systems & change
earth systemsall closed (mostly)• exceptions: energy, meteoric additons
all linkeddriven by energyfour systems• atmosphere• hydrosphere• biosphere• lithosphere
Fund. concepts: some earth processes are hazardous to humans
assessmentperceptionaccommodation
avoidplan for
fundamental concepts: scientific knowledge & values
scienceobjective examinationHow does science work?• “method”
– 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
valuesintrinsic/inherent
instrumental
moral statusagents
subjects
neither
Scientific values
obligations to future generations
effects of land use are cumulative
importance of aesthetic considerations
Ethical viewpointsUniversalist
fundamental principles: unchanging, eternal, universalmodernists: develop universal laws through science
Utilitarianthe greatest good, for the greatest number of peopleenvironmentalists added: for the longest time
Types of Environmentalismpragmatic resource conservation
protect, develop, and useutilitarian conservationUS Forest Service
moral and aesthetic nature preservationnature for nature’s sakealtruistic preservationUS Park Service
modern environmentalismconcern for effects of pollutionresearch, activism, focus on local issuesUS EPA
global environmentalismconcern for global changesclimate, extinctions, population, pollutioninternational treaties
Environmental Justiceenvironmental health as it relates to:
race
social standing
wealth
clean environment is a civil right
examplesenvironmental racism
toxic colonialism
Economicsthe study of the production, distribution, and consumption of capital
capital - any form of wealth available for use in the production of more wealth
usesassess relative values of goods and actions
choose between competing options: cost-benefits analysis
supply and demandsupply: quantity of product available at a given price
demand: amount consumers will buy at a given price
the development cycleas 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 useopen, 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 actionsLegislative
laws
funding
Executiverules
enforcement
Judicialinterpretation
enforcement
LawsNEPA 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
definitionsatom: smallest part of a chemical element that can take part in a chemical reaction or combine with another elementelement: chemical substance composed of identical atoms that may not be separated into different substances by ordinary chemical means
parts of an atom
proton+ chargeatomic weight = 1
neutron0 chargeatomic weight = 1
electron- chargeatomic weight = 0
Atoms & Elements
termsatomic number = # of protonsmass 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 emptytypes
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 propertiesbuilding blocks of rocksover 2000 identified - few common
common mineral groupssilicates (98% of crust by weight)
quartzfeldspar - most commonmicaferromagnesianclay (weathering product of other silicates)
oxides - hematite, bauxite, magnetitecarbonates - calcitesulfides - pyrite, often in coal - acid runoffnative elements - gold, silver, copper, diamonds
Rocks
aggregates of mineralsrock texture - size, shape, arrangement of grains
Igneous rock
from solidification of molten rockintrusive vs. extrusivecomposition
maficintermediatefelsic
Igneous activity – molten rock
formationtemp uppressure downaddition of water
rises due to lower densitydifferentiation
crystal fractionation - enriched in remaining elements & volatilesIncorporation
Igneous rock - intrusivemagmatexture
cool slowlycoarse grain:phaneritic, pegmatitic, porphyritic
bodiesbatholithplutonlaccolithsdikes and sillshydrothermal deposits
rocks: granite, diorite, gabbro, peridotite
Igneous rocks - extrusivelavavolcanoestexture
cool quicklyfine: aphanitic, glassy, pyroclastic, porphyritic
rocksrhyolite, andesite, basaltobsidiantuff, volc breccia, bentonite
Igneous rocks – env. propertiessource of economic mineralseconomic rocksintrusive
strongresistant to weatheringresistant to fluid flow
extrusivemay be weakmore susceptible to weatheringless resistant to fluid flow
Sedimentary rocks - formationweathering
physicalchemical
erosion & transportationdeposition - accumulation of sediments
environment of depositionsedimentary basinstransgression & regressionsorting of sedimentsrounding of clasts
burial & lithification
Sedimentary rocks - types
clastic - detritalgravel, sand, silt, clay
non-clastic - chemical & biologicallimestone/dolostone - biological or chemicalchert - biological (or post dep chem)evaporites - chemical(gypsum, rock salt)coal - biological
Sedimentary rocks – env. propertiessource of economic mineralseconomic rocksstrength varies with
sediment typecementationbedding plane weaknesses
fluid flow varies withsediment typecementation
dissolution (esp. limestone)expansive clays
Metamorphic rocks - formationPreviously existing rockaltered by
heat• contact• hydrothermal
pressure - fault zoneheat & pressure• regional• impact
foliated vs non-foliated: alignment of platy or linear minerals due to pressure
Metamorphic rock types
foliated: slate-phyllite-schist-gneissnon-foliated• marble• quartzite• hornfels• anthracite
gradetype of foliationsize of mineral crystalsindex minerals
Metamorphic rock – env. properties
source of economic mineralseconomic rocksstrength varies with
foliationdegree of metamorphismtype of rock
fluid flow is usually slow
the rock cycle
shows how rocks form and how they relate to each othereach rock type can be transformed into one of the others
Rock strength and deformation
stresscompressionextensionshear
strainelastic - earthquakesplastic - foldsbrittle• joints• faults
Strength of Earth materials
response based onrock typetimerock features/orientation•stratification• foliation• intrusions
structures
foldsfractures
jointsfaults
Stratigraphycorrelationunconformitiesrock laws
cross cutting relationshipsoriginal horizontalitysuperposition
mappingformationsstructuresorientation of layersallows planning
Earth’s Interior
evidenceseismologysamples•volcanoes•drilling•meteors
gravitymagnetics
Earth layers - core
Fe & Ni107 g/cm3
inner core - solidouter core - liquid
convectssource of magnetic field
Earth layers - mantle
ultramafic45 g/cm3
lower mantle - plastic solidasthenosphere - partially moltenupper mantle (lower lithosphere – rigid)
Earth layers - crust
rigidocean
5 km thickmafic28-30 g/cm3
continental20-35 km thickintermediate to felsic27-28 g/cm3
Plate Tectonics
overall effectssurface topography•continents•oceans
geologic hazards - esp volcanoes and EQsresource locationsclimate
Plate Tectonics
Lithosperic platesrigid upper mantle & crustappx 100 km thickmove•horizontal - 2-15cm/yr•vertical - isostacy
Plate Tectonics:divergent boundaries
plates pull apartocean basins formtopographic features
rift valley (normal faulting)mid-ocean ridge
geologic activityshallow EQ’signeous 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 overruntopographic features
mountain rangesvolcanicfaultedocean trenchfaults (reverse & thrust)
Plate Tectonics: convergent boundaries (cont.-ocean or ocean-ocean)geologic effects
shallow and deep EQ’signeous activity - intermediate & felsicregional metamorphism (in long belts)ophiolitesaccreted 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 featureslarge mountainsfaults
geologic effectsshallow EQs
Himalayas
Plate Tectonics: transform boundaries
topographic featurescomplex faultingsmall mountains
geologic effectsshallow EQ’s
California, Turkey
Plate Tectonics: hot spots
not a boundarytopographic features
volcanic chain (one or two active volcanoes at end of chain)
geologic effectsisolated igneous activity
Hawaii, Yellowstone
Plate tectonics and environmental geology
resource zonesoilgasminerals
hazard zonesearthquakesvolcanoes
landscapesclimate