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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
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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 • 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” • 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
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 • 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