Lecture Outlines
These lecture outlines should help you understand
the content of the course. However, they are NOT intended to
replace lectures! You are expected to attend all lectures and labs for this
course. There will be material presented in lectures that is not found in
these outlines, and yes, all material covered in lectures will be examinable.
PETROLOGY
Course introduction
handouts: lecture schedule, lab schedule
- EOSC 324 is for MINE students, General Science students,
plus students from other Faculties who are interested and have the co-requisites.
It is not for credit for students in the Earth and Ocean Sciences department.
- Course covers an introduction to mineralogy and petrology
- mineralogy, crystal chemistry
- igneous rocks
- sedimentary rocks
- metamorphic rocks
- Because of the MINE students in the class, the course will
cover examples related to mineral deposits and emphasize how concepts learned
in study of mineralogy and petrology are useful for working in mines and mineral
deposits.
- By the end of the course you will learn how to:
- identify major rock-forming minerals.
- key out unknown minerals.
- identify igneous/sedimentary/metamorphic rocks.
- understand the processes of formation of these in a plate
tectonic context, and
- understand why major rock types form in a specific
geologic environment.
- Use your knowledge of minerals and rocks to solve forensic
puzzles.
Text: Perkins. D, 2002, Mineralogy 2/e,
Prentice Hall.
plus
supplementary
reading on reserve in Main Library
Reading: please do reading in advance of every lecture!
Labs: hands-on identification of common rocks and minerals
- weekly labs are due at the beginning of the next lab
- 1st year geol. lab kit required; buy from Pacific Museum
of hte Earth shop prior to first lab
- Note that both Labs 0 and 1 will be worked on during the
first lab session
- Labs will be graded with a check, check plus, or check minus,
and lab grades will be used only if your final grade for course is borderline.
Grading Scheme
Exam Policy
back to top
MINERALOGY
Physical properties of minerals
no handouts
- Definitions to know: mineral, mineraloid, crystal
- Pacific Museum of the Earth - mineral properties exercise
- optional Introductory video- "Rocks and Minerals",
on minerals and rocks and their uses
PHYSICAL PROPERTIES
- Properties dependent on internal structure
- crystal form, crystal habit
- cleavage
- fracture
- hardness - Mohs scale
- specific gravity
- Properties dependent on interaction with light
- color
- streak
- luster
- Others: useful for specific minerals
- magnetism
- taste
- feel (e.g. soapy)
- reaction to HCl "acid test"
- sticks to tongue (?!)
back to top
Crystals, symmetry, crystal
systems, crystal forms
handout: common crystal forms
- Definitions to know: crystal, euhedral, subhedral, anhedral
- envision 2-D order of atoms in a crystal structure, easily
extended to 3-D
- repeated patterns form symmetrical crystals
-crystals have a 3-D internal order of atoms
in crystal structure; this order is repeated in space and we see symmetry
(repeated) patterns in crystals
Symmetry Elements- 3 basic types
- center (C)
- axis (A)
- plane, mirror plane (M)
-crystals can have combinations
of symmetry elements
There are 32 possible combinations called 32 crystal classes.
These yield 6 crystal systems. KNOW THESE!
- ISOMETRIC
- TETRAGONAL
- HEXAGONAL
- ORTHORHOMBIC
- MONOCLINIC
- TRICLINIC
Law of Constancy of Interfacial Angles, Steno, 1669
back to top
Chemical composition of Earth;
common minerals and mineral groups
handouts: chemical composition of Earth, geochemical classifications
- Definition to know: rock forming minerals, accessory minerals,
ore minerals
- Earth layers: crust, mantle, core (refer to handout)
- different elements are concentrated at different depths,
so mineralogy varies with depth
-important- 8 elements make up most of the crust
- O, Si most abundant - hence silicate minerals abundant
-note: sulfides "ore minerals" in short supply!
-thus, abundance of minerals dependent on chemical composition, P (pressure),
and T (temperature).
- crust and mantle dominated by silicates
- Common minerals (called rock forming minerals or
RFM) are mostly silicates
-accessory minerals: always present but in small amounts
-ore minerals: mostly sulfides, oxides; rare to be concentrated
- Minerals are classified by anionic groups - unmistakable
family resemblances
- slides of minerals
back to top
Crystal chemistry: the
atom, bond types
handouts: tables and figures
-
Definitions to know: atom, atomic number (Z), isotopes,
ion, bond (4 types)
-
Crystal chemistry: relationship of internal structure and
chemical composition of minerals to their physical properties
-basic chemistry:
-
common ions of the elements (refer to handout)
-
Bond: electrical force that attracts atoms or ions together;
it determines physical and chemical properties
-types
- Ionic
- Covalent
- Metallic
- Van der Waals
Summary
- minerals can have more than one bond type
- strong directional properties in minerals are a result of
different bonds in different directions
- the hybrid bond Si-O is common in minerals and is strong
- bond types determine physical and chemical properties
back to top
Bonding in minerals: packing
and coordination, introduction to common mineral structures
handouts: Pauling's Rules, figures
- Definitions to know: Pauling's Rules, Principle of Parsimony,
coordination number
- Pauling's Rules (1 through 5)
- Packing of spheres is governed by electrical neutrality
and geometric fit in minimum energy (E) state
- interstices between anions mostly turn out to be either
4-fold (tetrahedral sites) or 6-fold (octahedral
sites)
- General silicate structures
back to top
Silicate structures
handout: silicate structures
- Definitions to know: isostructural minerals
- Silicate structures:
- neso-silicates
- soro-silicates
- cyclo-silicates
- ino-silicates
- phyllo-silicates
- tekto-silicates
back to top
Isostructural minerals, polymorphs,
solid solution, exsolution
handouts: P-T phase diagram
- Definitions to know: isostructural minerals, polymorphs,
solid solution, exsolution
- Polymorphism occurs in 3 ways:
- reconstruction
- displacement
- reordering
- 3 types of solid solution:
- substitution
- interstitial
- omission (defect)
- Exsolution: general process described
- Samples to examine
back to top
Rock forming minerals I. &
II.
handouts: RFM outline, feldspar triangle/plagioclase loop,
table of common characteristics of magmas
- Rock Forming Minerals:
- common in igneous rocks
- silica minerals
- feldspars
- pyroxenes
- amphiboles
- olivine
- mica's (biotite, muscovite)
-common in sedimentary or metamorphic rocks
- carbonates (calcite-aragonite, dolomite)
- clays (kaolinite, montmorillonite, etc.)
-metamorphic minerals
- garnet
- Al silicate polymorphs (kyanite, andalusite, sillimanite)
- staurolite
- epidote group
Samples to examine
back to top
Ore minerals; associated gangue
minerals
handouts: sulfide ore deposits, 2 diagrams
- Economically important (non-silicate) minerals: sulfides,
sulfates, carbonates, oxides, hydroxides
- Types of deposits:
- Volcanogenic massive sulfide deposits
- Porphyry copper deposits
- Supergene sulfide deposits
- Problems associated with mining massive sulfide deposits
- Cool samples to check out!
back to top
PETROLOGY
Petrology and
plate tectonics
handout: igneous magma type classification scheme
-
Comments on naming igneous rocks (IUGS
scheme, chemical classification schemes, field scheme)
-
Review of material covered so far
that is relevant to studying PETROLOGY
-
chemical composition of crust,
upper mantle
-
mineralogy of crust, upper mantle
-
IUGS classification schemes for
igneous rocks (lab)
- Petrology in a plate tectonic context: -> specific rock
associations correlate with particular plate tectonic settings
- Optional video from The Earth Explored series "Plate
Tectonics: A Revolution in the Earth Sciences"
- Specific igneous rock associations:
- Constructive plate margins (divergent margins)(mostly
mid-ocean ridges)
- Destructive plate margins (convergent margins)
- Intraplate settings, "hot spot" related
back to top
Igneous processes: mafic magma
genesis (2 lectures)
NOTE: igneous lectures have been condensed
to 4-5 total, so not all of the following will be discussed.
handouts: several diagrams and figures
- Definitions to know: geothermal gradient (geotherm), solidus,
liquidus, low velocity zone (LVZ)
- Introduction to igneous processes:
- magma genesis, transportation, crystallization, emplacement,
differentiation
- Mantle petrology and structure
- How water gets into the mantle:
- hydrous minerals left over from Earth's origin
- reintroduction by subduction processes
- Partial melting of mantle is a function of P (pressure),
T (temperature), X (composition)
- Dry vs. wet peridotite phase diagrams indicate partial melting
of wet peridotite at 100-375km produces mafic magma.
- P-T diagrams: binary systems, ternary systems
- Ways to perturb the upper mantle to induce partial melting
- add water
- decrease P
- increase T
back to top
Magmatic crystallization
and emplacement; igneous structures and textures
handouts: King Hill basalt P-T diagram, chemical analyses of
New Georgia lavas
- Review Magmatic Processes:
- magma genesis, transportation, crystallization, emplacement,
differentiation
- Rock classification - e.g. IUGS ->composition and texture
-texture depends on crystallization history
-crystallization at different depths/pressures produces different structures
and textures
- Modal mineralogy vs. normative mineralogy (mode vs. norm);
examples.
- Know the difference between rock structures and rock
textures.
back to top
Formation of intermediate and
silicic magmas by crustal melting and differentiation
handouts: PPT, previous handouts
- Definitions to know: differentiation, stoping, assimilation
- Origin of silicic magmas by crustal melting, use of Ab-Or-Q
ternary diagram
- Review- origin of magmas
- partial melt peridotite in mantle-> mafic magma
- inject mafic magma into average crust and melt the crust->silicic
magma
- processes that form intermediate composition magmas?->differentiation
- Differentiation: processes that change the composition
of a primary (mafic) magma to more silica-rich (intermediate or silicic)
- Differentiation Processes:
- fractional crystallization (e.g. by crystal settling
or by filter pressing)
- wall rock assimilation=crustal contamination
- magma mixing
- disequilibrium phenocryst assemblage
- Differentiation is (mostly) a crustal process
Summary
- igneous rocks and plate tectonics, constructive margin
(rift) vs. destructive margin diagram
- slides
back to top
Sedimentary processes
handouts: sed. depositional environments, diagrams
- Sedimentary petrology-> two major types of rocks: detrital
(clastic), chemical or biochemical precipitates
- How these two types are formed
- In reality, 3 sedimentary rock types dominate: sandstone,
mudstone, and carbonates (limestone, dolostone)
-Know why!
- Sedimentary structures and textures: slides, and samples
to examine
- Importance of sedimentary rock composition and texture:
- reflect source rocks
- reflect processes of erosion and transportation
- reflect physical and chemical conditions during deposition/compaction
- Plate tectonic controls on sedimentation->basin formation
-5 main locations to examine
- oceanic basins
- rifted continental margins
- arc-trench systems
- continent-continent sutures
- intracontinental basins
back to top
Metamorphic processes: grade, facies, zones
(2 lectures)
handouts: P-T meta., regional and contact meta., P-T-t paths,
facies grid
- Definitions to know: metamorphic facies, porphyroblast
- Metamorphism: process of mineralogical and textural change
in a rock, due to it being subjected to P, T, and/or fluid conditions different
than those of origin
- lower limit
- upper limit
- "solid state" changes
- contact vs. regional vs. dynamic
- What are the driving forces for metamorphism?
- Pressure: lithostatic vs. differential
- Temperature: increases due to burial or proximity to
igneous intrusion
- fluid activity
- Examine how P-T conditions vary with time during
metamorphism: P-T-t paths (P-T-time)
- Facies concept (see handouts)
back to top
Regional and contact metamorphism
handout: snowball garnets
- Changes to rocks due to metamorphism(textures and structures)
- types of metamorphism (contact, regional, dynamic) controls
scale or extent
- 'relict' structures and textures may be preserved (bedding
planes, volcanic flows, intrusive contacts)
- Skarns, e.g. of metamorphic mineral deposits
back to top
Metamorphism and
plate tectonics
handouts: diagrams and figures
- Definitions: facies series
- Metamorphism and plate tectonics:
- sea floor settings (constructive margins)
- destructive margin settings
- sea floor metamorphism: greenstone, serpentinite, amphibolite
(common meta. rocks)
- faults, fractures provide pathways for sea water to
circulate
- paired metamorphic belts
- same age, parallel
geothermal gradient varies, hence facies series vary
- Different P-T-t paths for:
- subduction zone proper
- magmatic arc- regional scale
- magmatic arc- contact metamorphism close to intrusions
at shallow crustal depths
back to top
Forensic petrology
- Introduction - how knowledge of rocks and
minerals and their physical properties is used in forensic studies
- Case studies
- Samples to study and cases to solve
back to top