cee 437 lecture 2 earth materials i earth structure and minerals
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CEE 437 Lecture 2 Earth Materials I Earth Structure and Minerals. Thomas Doe. Outline. Global tectonic setting Rock cycle Rock forming minerals Paper 1. Global Structure. Based mainly on seismic information and meteorite compositions - PowerPoint PPT PresentationTRANSCRIPT
CEE 437 Lecture CEE 437 Lecture 22
Earth Materials IEarth Materials IEarth Structure Earth Structure
and Mineralsand MineralsThomas DoeThomas Doe
OutlineOutline Global tectonic settingGlobal tectonic setting Rock cycleRock cycle Rock forming mineralsRock forming minerals Paper 1Paper 1
Global StructureGlobal Structure Based mainly on seismic information Based mainly on seismic information
and meteorite compositionsand meteorite compositions Crust ~25-75 km depending varying Crust ~25-75 km depending varying
under continents and oceansunder continents and oceans
Velocity Variation with Velocity Variation with DepthDepth
Global StructureGlobal Structure
Development of Plate Development of Plate TectonicsTectonics
Evidence from ocean floor Evidence from ocean floor magnetism and agesmagnetism and ages
Evidence from seismicityEvidence from seismicity Evidence from cross-continent Evidence from cross-continent
correlations of rockscorrelations of rocks
Global SeismicityGlobal Seismicity
Benioff ZoneBenioff Zone
Seafloor Spreading — Seafloor Spreading — Sediment AgesSediment Ages
Sea-floor SpreadingSea-floor Spreading Mantle convection drivenMantle convection driven
Evolution of Spreading Evolution of Spreading Sea Floor — Atlantic Sea Floor — Atlantic
AnalogAnalog
Convergent MarginsConvergent Margins Ocean to ContinentOcean to Continent Continent to ContinentContinent to Continent
Convergent Margin - Convergent Margin - Continental Continental
Subduction Zone – Subduction Zone – Island ArcIsland Arc
Evolution of Continents Evolution of Continents — North American — North American
CratonCraton
North American North American AccretionAccretion
Rock CycleRock Cycle
Metamorphic Rocks
Sedimentary Rocks
Igneous Rocks
Sediments
Lithification
Magma
Weathering, Erosion
Burial, metamorphism, recrystallization
Melting
Crystallization at depth or extrusion at surface
Burial, metamorphism, recrystallization
Mineral DifferentiationMineral Differentiation Plate tectonics and Igneous ProcessesPlate tectonics and Igneous Processes
selective melting, selective recrystallizationselective melting, selective recrystallization differentiation by densitydifferentiation by density
Weathering and ErosionWeathering and Erosion Selective weatheringSelective weathering Concentration of quartz (pure Si0Concentration of quartz (pure Si022)) Conversion of alumino-silicates to claysConversion of alumino-silicates to clays Concentration of soluble residues in seawaterConcentration of soluble residues in seawater
DepositionDeposition Courser materials near sediment sourceCourser materials near sediment source Finer materials far from sediment sourceFiner materials far from sediment source Redeposition of salts and solutes by evaporative Redeposition of salts and solutes by evaporative
(Na,KCl; CaSO(Na,KCl; CaSO44) or biological processes (CaCO) or biological processes (CaCO3,; 3,; ) )
Differentiation of Crustal Differentiation of Crustal CompositionComposition
Weathering differentiating towards higher Silica
Preferential melting of high-silica materials
Concentration of C, Ca, Na, K in sea and air
Original basaltic composition of crust
Carbonate concentrated by organic processes
Bowen Reaction SeriesBowen Reaction Series
How to get many different rocks How to get many different rocks from one melt composition?from one melt composition?
Differentiation by selective Differentiation by selective crystallization and removal from crystallization and removal from systemsystem
Bowen’s Reaction SeriesBowen’s Reaction Series
Crustal CompositionCrustal Composition Main Elemental GroupsMain Elemental Groups
SilicaSilica AluminumAluminum Ferro-MagnesianFerro-Magnesian Ca, Na, KCa, Na, K
Elemental FatesElemental Fates Silicon tends to concentrate in crust Silicon tends to concentrate in crust
— quartz is very long lived— quartz is very long lived Aluminum — transforms from Aluminum — transforms from
feldspars to claysfeldspars to clays Mica — transform to clays Mica — transform to clays Fe-Mg-Ca-Na-K concentrate in some Fe-Mg-Ca-Na-K concentrate in some
clays and micas, concentrate in clays and micas, concentrate in oceans in biosphereoceans in biosphere
Differentiation in Differentiation in Crystallization Versus Crystallization Versus
Differentiation in Differentiation in WeatheringWeathering
Olivine
Pyroxene
Amphibole
Biotite
Muscovite
Quartz
Ca,Mg Feldspars
K-Feldspars
High Temperature, Low Silica, Hi Fe Mg
Low Temperature,
High Silica, Low Fe Mg
Fast Weathering
Slow Weathering
Sedimentary Sedimentary DifferentiationDifferentiation
Sorting by Deposition MediumSorting by Deposition Medium Sorting by EnergySorting by Energy
Mineral DefinitionMineral Definition Naturally occurring material with Naturally occurring material with
unique combination of chemical unique combination of chemical composition and crystalline composition and crystalline structurestructure
Natural non-minerals — glasses, Natural non-minerals — glasses, coal, amorphous silicacoal, amorphous silica
Pseudomorphs: diamond:graphitePseudomorphs: diamond:graphite
Galena, PbS Graphite, C
Crystalline Structure of Crystalline Structure of CalciteCalcite
Crystalline Symmetry Crystalline Symmetry GroupsGroups
Isomorphic Crystal Forms, Isomorphic Crystal Forms, Cubic SystemCubic System
Physical PropertiesPhysical Properties Density (Gravity)Density (Gravity) Electrical Conductivity (Resisitivity)Electrical Conductivity (Resisitivity) Thermal ExpansionThermal Expansion StrengthStrength Elasticity (Mechanical properties, Elasticity (Mechanical properties,
Seismic/Acoustic VelocitySeismic/Acoustic Velocity Rheology (Plasticity,Viscosity)Rheology (Plasticity,Viscosity)
Properties and Mineral Properties and Mineral SymmetrySymmetry
Tensor Properties of Tensor Properties of CrystalsCrystals
Cubic Group
Lower Symmetry Groups
General Form for Heat Flow (for example)
Discussion: How to Rock Discussion: How to Rock Properties Relate to Properties Relate to Mineral StructureMineral Structure
How will anisotropy vary with How will anisotropy vary with crystal symmetry class?crystal symmetry class? Rock Salt versus Quartz?Rock Salt versus Quartz?
How will aggregates of minerals How will aggregates of minerals (with same mineral behave?(with same mineral behave? Cubic versus non cubicCubic versus non cubic Rock fabricRock fabric Material property contrastsMaterial property contrasts
Rock Forming MineralsRock Forming Minerals Composition of CrustComposition of Crust
Dominantly O, Si, Fe, Mg, Ca, Na, KDominantly O, Si, Fe, Mg, Ca, Na, K Near surface importance of bio-Near surface importance of bio-
processesprocesses Silicates from inorganic processesSilicates from inorganic processes Carbonates mainly from shell-forming Carbonates mainly from shell-forming
organismsorganisms
Crustal CompositionCrustal Composition Main Elemental GroupsMain Elemental Groups
SilicaSilica AluminumAluminum Ferro-MagnesianFerro-Magnesian Ca, Na, KCa, Na, K
Major Silicate GroupsMajor Silicate Groups Silicon TetrahedronSilicon Tetrahedron
separate tetrahedra — olivineseparate tetrahedra — olivine single chains — pyroxenesingle chains — pyroxene double chains — amphiboledouble chains — amphibole sheet silicates — micas and clayssheet silicates — micas and clays framework silicates — feldspars (with Al framework silicates — feldspars (with Al
substitution), quartz as pure silicasubstitution), quartz as pure silica
Silica TetrahedronSilica Tetrahedron
Forms of SilicatesForms of Silicates
Deformation Deformation MechanismsMechanisms
Effects on Physical Effects on Physical PropertiesProperties
AnisotropyAnisotropy Properties differ by directionProperties differ by direction
HeterogeneityHeterogeneity Properties vary by locationProperties vary by location
Mineral properties may have strong Mineral properties may have strong anisotropy when crystals are alignedanisotropy when crystals are aligned
Heterogeneity may have strong mechanical Heterogeneity may have strong mechanical effects when different minerals have effects when different minerals have different deformation propertiesdifferent deformation properties
Minerals versus RocksMinerals versus Rocks Minerals ElementsMinerals Elements
Anisotropy from crystal Anisotropy from crystal structurestructure
Elastic PropertiesElastic Properties Thermal PropertiesThermal Properties Optical PropertiesOptical Properties
DeformationDeformation Shear transformationsShear transformations DislocationsDislocations
Rock ElementsRock Elements IntragranularIntragranular
Anisotropy from fabricAnisotropy from fabric Crystal anisotropy if Crystal anisotropy if
preferred orientationpreferred orientation Anisotropy from bedding, Anisotropy from bedding,
foliation, flow structuresfoliation, flow structures IntergranularIntergranular
CementsCements MicrocracksMicrocracks
HeterogeneityHeterogeneity Mineral compositionMineral composition Other segregration Other segregration
processesprocesses
Clay MineralsClay Minerals Extremely Important Mineral GroupExtremely Important Mineral Group
SealsSeals StabilityStability Pore pressurePore pressure Chemical interactionChemical interaction SwellingSwelling SlakingSlaking
Confusion as both “Size” and Confusion as both “Size” and “Mineral” Classification“Mineral” Classification
Clay SourcesClay Sources WeatheringWeathering Hydrothermal AlterationHydrothermal Alteration DepositionDeposition Clay TransformationsClay Transformations
Feldspar Feldspar Illite Illite Ferro-Magnesian Ferro-Magnesian Chlorite Chlorite Volcanics (alkaline conditions) Volcanics (alkaline conditions) Smectite Smectite Volcanics (acidic conditions) Volcanics (acidic conditions) Kaolinite Kaolinite
Bentonite: plastic, highly swellingBentonite: plastic, highly swelling
Clay UnitsClay Units
From West, Geology Applied to Engineering, Prentice Hall, 1995)
Two and Three-Layer Clay Two and Three-Layer Clay StructureStructure
From West, Geology Applied to Engineering, Prentice Hall, 1995)
Mixed Layer ClaysMixed Layer Clays
From West, Geology Applied to Engineering, Prentice Hall, 1995)
TopicsTopics Mineral DefinitionMineral Definition Rock Forming MineralsRock Forming Minerals Physical Proprieties of MineralsPhysical Proprieties of Minerals Mineral IdentificationMineral Identification Mineral LabMineral Lab
Clay Viewed from Clay Viewed from Electron MicroscopeElectron Microscope
Mineral IdentificationMineral Identification DensityDensity HardnessHardness Color, luster (metallic, non-metalic, Color, luster (metallic, non-metalic,
semi-metallic)semi-metallic) Crystalline habitCrystalline habit CleavageCleavage Optical microscopyOptical microscopy Mineral chemistry, x-ray diffractionMineral chemistry, x-ray diffraction
Hardness ScaleHardness Scale
X-Ray DiffractionX-Ray Diffraction
spacing lattice,angle incidence,wavelength,sin2
dd
Bragg’s Law
Weathering FatesWeathering Fates Feldspars to clays (clays, shales)Feldspars to clays (clays, shales) Quartz endures (siltstones, sandstones)Quartz endures (siltstones, sandstones) Calcium recirculated into carbonate Calcium recirculated into carbonate
minerals by organic processes minerals by organic processes (limestones)(limestones)
Consequence:Consequence: Over time, evolution of less dense more Over time, evolution of less dense more
silicic continental crustsilicic continental crust
Engineering ImplicationsEngineering Implications ““Style” of geology and geo-engineering Style” of geology and geo-engineering
problems varies with plate tectonic settingproblems varies with plate tectonic setting Faulting, and structural complexityFaulting, and structural complexity
Maturity of materials varies with plate Maturity of materials varies with plate tectonics settingtectonics setting Higher degree of more stable materials from Higher degree of more stable materials from
sorting by weatheringsorting by weathering Geohazards vary with plate tectonic Geohazards vary with plate tectonic
settingsetting
Paper and Paper TopicsPaper and Paper Topics Paper I TopicsPaper I Topics Columbia River Basalts – Origin, Columbia River Basalts – Origin,
Structure, Hydrologic and Structure, Hydrologic and Engineering PropertiesEngineering Properties
Geology and Engineering Geology of Geology and Engineering Geology of the Snoqualmie Pass Quadranglethe Snoqualmie Pass Quadrangle
Clay Minerals – Origin, Crystal Clay Minerals – Origin, Crystal Structure, Engineering PropertiesStructure, Engineering Properties
6 Pages, 1.5 space, plus figures, 6 Pages, 1.5 space, plus figures, include references.include references.
Undergrad PresentationsUndergrad Presentations 1. Geologic History of Columbia Plateau1. Geologic History of Columbia Plateau 2. Geologic History of Olympic Peninsula2. Geologic History of Olympic Peninsula 3. Coal Mines of Newcastle, Washington3. Coal Mines of Newcastle, Washington 4. Geological Issue Effecting Construction I-5 through Seattle4. Geological Issue Effecting Construction I-5 through Seattle 5. The Seattle Fault5. The Seattle Fault 6. Foundations on Peat6. Foundations on Peat 7. Rock Slope Stability Problems in I-907. Rock Slope Stability Problems in I-90 8. Fracture Image Logging Technologies8. Fracture Image Logging Technologies 9. Tunneling for Sound Transit9. Tunneling for Sound Transit 10. Engineering Properties of Organic Soils in the Puget Sound 10. Engineering Properties of Organic Soils in the Puget Sound
AreaArea 11. Engineering Properties of Glacial Soils in the Puget Sound 11. Engineering Properties of Glacial Soils in the Puget Sound
Area 12. Solute Transport in Fractured Rock 13. Economic Area 12. Solute Transport in Fractured Rock 13. Economic Minerals of Washington State 14. Quarry Mines of Puget SoundMinerals of Washington State 14. Quarry Mines of Puget Sound
15. Failure of Malpassat Dam15. Failure of Malpassat Dam 16. Rock Tunnel Failures in the Alps16. Rock Tunnel Failures in the Alps 17. Seattle Watershed Geology17. Seattle Watershed Geology
Grad RequirementsGrad Requirements Add Goodman – Engineer as Artist Add Goodman – Engineer as Artist
(unless discuss with us otherwise)(unless discuss with us otherwise)
Paper and Paper TopicsPaper and Paper Topics Paper I TopicsPaper I Topics Columbia River Basalts – Origin, Columbia River Basalts – Origin,
Structure, Hydrologic and Structure, Hydrologic and Engineering PropertiesEngineering Properties
Geology and Engineering Geology of Geology and Engineering Geology of the Snoqualmie Pass Quadranglethe Snoqualmie Pass Quadrangle
Clay Minerals – Origin, Crystal Clay Minerals – Origin, Crystal Structure, Engineering PropertiesStructure, Engineering Properties
6 Pages, 1.5 space, plus figures, 6 Pages, 1.5 space, plus figures, include references.include references.
CEE 437 Syllabus, Rev.2006-10-3
Week Day Date Lecturer Quiz Paper LectureStudy Guide
Textbook -West
1 Thu 28-Sep Doe Overview: Earth as an Engineering Material Ch. 1
2 Tue 3-Oct DoePlate tectonics, rock cycle, mineral introduction Ch 1
2 Thu 5-Oct Doe Minerals Continued, Clays, Minerals Lab Ch 2
3 Tue 10-Oct Doe x Igneous and Metamorphic Rocks3 Thu 12-Oct Doe Sedimentary Rocks, Rock Lab Ch 3, 5
4 Tue 17-Oct DoeGeologic Time; Structural Geology I Ch 9, 10
4 Thu 19-Oct Doe xStructural Geology II Field Trip Overview, Geologic Maps Ch. 10
5 Tue 24-Oct Dershowitz Rock Mass Classification Ch 10
5 Thu 26-Oct WestGeologic Aspects of Seismic Events Ch 18
Field Trip - Cascades Geology
Field Trip - Cascades Geology
1
2
Sun 29-Oct x
Sun 22-Oct x