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