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GEOL 302 - Petrology

photo - rock

PETROLOGY 302, SPRING 2003

Instructor: Dr. Jodie L. Hayob Office Phone: 654 -1425
Assoc. Professor of Geology (voice mail)

Office: 439 Jepson Science Center Home Phone: 371-0281
(no calls after 9 p.m. please)

Office Hours: M,W 9:30 - 10:45 a.m. e-mail: jhayob (on campus) or
(or by appt./ T, R 9:30 - 10:45 a.m. jhayob@umw.edu
walk-in anytime)

Course Objectives: In Petrology 302 you will utilize skills learned in Mineralogy 301 to identify minerals and thus classify rocks in hand sample and thin section. However, we will emphasize the genesis of igneous and metamorphic rocks, their distribution and significance (i.e., what do these rocks tell us about the geologic processes that shape our Earth).

Prerequisite(s): Geology 301. College chemistry (CHEM 111 and 112) is strongly recommended as a pre-requisite or co-requisite.

Lecture: MWF 11 - 11:50 Room 409 Jepson Center
Labs: M 1 - 3:50 Rooms 405/409 Jepson Center

Field Trip: Sun. 3/23 or 3/30 (9 ~ 4) Smithsonian Museum of Natural History
(excl. labs)

Text(s): Blatt, H and Tracy, RJ (1996) Petrology: Igneous, Sedimentary and
Metamorphic. 2nd edition, W.H. Freeman and Co. Publ.
MacKenzie, WS and Adams, AE (1994) A Color Atlas of Rocks and
Minerals in Thin Section. Wiley Publ. Co.

Grading Policy: Lecture: 3 Midterms 15 % each
(60 % total) Final (cum; Fri. 5/2, 12-2:30) 15 %

Lab: 4 Homework + 6 Quizzes 30 % total (equal wt.)
(40 % total) Final Exams 10 % total
scheduled individually

(Mid-semester: Satisfactory ? 73 % overall; due March 6th)

Labs are mandatory.
Grading is on a 'straight' scale (i.e., 70-72 = C-, 73-76 = C, 77-79 = C+).
Please call in advance if an unforeseen illness causes you to miss an EXAM or LAB.

Honor Pledge: "I pledge that I have neither given nor received unauthorized help on this work".

PETROLOGY 302 - LECTURE GUIDELINE

Final Exam: Friday, May 2 (12 p.m. – 2:30 p.m.)

Week Date Topic(s) Chapter(s)

IGNEOUS PROCESSES

1 1-15 Course Intro., Review of Gross Earth Structure; Distr. of Pressure (P) w/in Earth I:1-4; 1:7-13; 7:137-140
1-17 Earth's Internal Heat: geothermal gradients and heat flow in the lithosphere 7:140-149

2 1-20 Earth's Internal Heat: sources of heat within our Earth; the steady-state geotherm 7:140-149
1-22 Physical Properties of Magma: magmatic temperatures, densities 3:61-63
1-24 magmatic viscosities 3:61-63

3 1-27 Separation of Magma (dihedral angle) 7:147-149
1-29 ~ Adiabatic (~ no loss of heat) Mechanisms for Intrusion of Magma:
buoyant rise 1:20-22
1-31 volume expansion “ ”

4 2-3 vesiculation, tectonic pressure “ ”
2-5 ~ Non-Adiabatic Mechanism for Intrusion of Magma: diapiric rise ----
2-7 Rates of Magma Intrusion: Newtonian, Bingham and turbulent magmas ----

5 2-10 Rates of Magma Intrusion: Newtonian, Bingham and turbulent magmas ----
2-12 Cooling of Magma: conduction, convection, advection, radiation ----
2-14 EXAM #1 ----

Structures (& Chemistry) of Extrusive Igneous Bodies: 1:22-30
6 2-17 fissure/plateau/flood basalts (CFB's) “ ”
2-19 central volcanoes “ ”
2-21 pyroclastic deposits “ ”

Structures (& Chemistry) of Intrusive Igneous Bodies: 1:13-22
7 2-24 concordance vs. discordance, tabular bodies (veins, dikes, ring dikes and sills) “ ”
2-26 “ ” “ ”
2-28 diatremes, laccoliths “ ”

8 3-3 lopoliths and layered intrusions (Bushveld, Skaergaard, Stillwater) 1:13-20
2-5 stocks and batholiths 1:13-20; 5:113-116
3-7 “ ” “ ”

9 3/10 – 3/14 SPRING BREAK ----

Mantle Melting, Processes of Differentiation & Modification of Magma Compositions:
10 3-17 origin of basalts (melting in the mantle), fractional crystallization 5:110-113
3-19 fractional crystallization, layered mafic complexes (lopoliths) 6:119-136
3-21 assimilation, magma mixing 6:119-136

METAMORPHIC PROCESSES

11 3-24 EXAM #2 ----
3-26 Introduction: definition, agents of metamorphism, P-T limits, types
and scales of metamorphism, historical background (important scholars) 18:353-357
3-28 Overview of Textures and Structures of metamorphic rocks 18:357-364

12 3-31 Characteristics and Classification (types) of metamorphic rocks 18:364-373
4-2 Concepts of metamorphic Grade, Index Minerals, zones/Isograds in terranes 19:375-377
4-4 Metamorphic Facies and Facies Series 19:377-381

13 4-7 P-T-t Models for metamorphism, Metamorphic Field Gradients, and P-T-t paths 19:381-393
4-9 P-T-t paths 19:381-393
4-11 Components, phases, assemblages; concept of Equilibrium; application of equilibrium
to metamorphic rocks; metamorphic reactions and the Phase Rule 20:395-402

14 4-14 “ ”, Petrogenetic Grids 20:395-402
4-16 Graphical representation of assemblages and reactions (ACF, A'KF, AFM Diagrams) 20:402-410
4-18 “ ” 20:402-410

15 4-21 Environmental Controls on metamorphic Reactions; Reaction Mechanisms 21:411-419
4-23 Types of Re

PETROLOGY 302 - LABORATORY GUIDELINE

[Note: Chapters are from Blatt & Tracy unless an 'MA' is indicated for MacKenzie & Adams.]

Attendance is mandatory - no makeups will be given without prior approval unless you are ill (please call).

Week Topic(s) Chapter(s)


1 1/15 FIRST WEEK - No Labs (review optics of common minerals from Mineralogy 301). 2
P = ?gh Homework - due 1/20 (assigned in class). (overview/review)


2 1/20 Gibbs' Phase Rule. Phase Diagrams (P-T, T-X): 4:81-89; 5:101-102
P-T Diagrams - solidii and liquidii. Effect of Volatiles on Melting. 20:395-399
T-X Diagrams & Lever Rule - binary systems with no solid solution. Handouts

Phase Diagram Homework - due 1/27. “ ”

3 1/27 T-X Phase Diagrams: binary systems with limited and complete solid solution, 4:89-93
binary systems with intermediate (binary) compounds - congruent and incongruent. 5:102-105

Phase Diagram Homework - due 2/3. Handouts

4 2/3 Classif. of Igneous Rocks – Chemistry (IUGS mode and CIPW norm) & Textures 2; 3
CIPW and Mode Homework - due 2/10. Appendix 1

Crystal growth - textures of igneous rocks. 2; 3

5 2/10 Igneous Rocks of Oceanic Regions (ophiolites, volcanoes) - MORB, OIB 8
(mafic extrusive = tholeitic ± alkaline basalts, mafic and ultramafic intrusives = gabbro,
dunite, harzburgite, wehrlite, troctolite, etc.).

Petrography of Mafic and Ultramafic Igneous Rocks. p. 31-41, 56-59, 67-81 MA

Week Topic(s) Chapter(s)


6 2/17 QUIZ: Igneous Rocks of Oceanic Regions.
Igneous Rocks Associated with Convergent Plate Margins - Island Arc Rocks,
Andean-type Rocks (intermediate to felsic extrusives = andesite to rhyolite;
pyroclastics = tuff, obsidian, pumice 9

Petrography of Intermediate to Felsic Extrusive Igneous Rocks. p. 40-45, 48-59, 82-83,
88-89, 104-105 MA

7 2/24 QUIZ: Igneous Rocks Associated with Convergent Plate Margins (Extrusives).
Igneous Rocks Associated with Convergent Plate Margins - Island Arc Rocks, Andean-type Rocks
intermediate to felsic intrusives = diorite to I/S granite; some mafic rocks =
tholeitic, calc-alkaline or shoshonite (high K) basalts and gabbros). 9

Petrography of Intermediate to Felsic Intrusive Igneous Rocks. p. 40-45, 48-59, 84-87, 90-95 MA

8 3/3 QUIZ: Igneous Rocks Associated with Convergent Plate Margins (Intrusives). -----

FIELD TRIP - Rappahannock River -----

9 3/10 SPRING BREAK - No Lab -----

10 3/17 Igneous Rocks within Continents (excl. meteor-impact rocks): 10
Flood Basalts (rifts) - Deccan Traps, Columbia River, etc.
Layered Mafic Intrusions (Bowen's Series) - Skaergaard, Stillwater, Bushveld.
Alkaline Rocks (localized rift valleys and hotspots) - E. African Rift
(nephelinite, phonolite, alkali basalt, carbonatite, kimberlite, syenite).
Hotspot Trails - Yellowstone Example (rhyolites and basalts).

Hand Samples of Alkaline and Ultra-Alkaline Rocks p. 60-61, 76-77, 96-103 MA


Week Topic(s) Chapter(s)

11 3/24 'Special' Rocks of the Precambrian - greenstone belts, iron formations, 10; 17:339-343;
komatiites, anorthosites.
18:367
Hand Samples p. 148-149, 184-185 MA

12 3/31 QUIZ: Hand Sample Only - Igneous Rocks within Continents (excl. meteor-
impact rocks) and ‘Special' Rocks of the Precambrian.

Hand Sample Classif. of Metamorphic Rocks (textures, structures and mineralogy). 18
Meta-Pelites (non-foliated and foliated) - quartzite, meta-conglomerate, hornfels, skim 23
slate, phyllite, schists, gneisses Handouts

13 4/7 Petrography of Metapelites. 18, 23
Handouts
p. 153-161, 164-167,
170-173, 178-181 MA

14 4/14 QUIZ: Metapelites (hand sample and petrography).

Meta-Igneous Rocks (mafic to ultramafic; non-foliated and foliated) 22
hornfels, greenstone, granulite, eclogite, serpentinite, soapstone,
amphibolite, ‘green' schists Handouts

Petrography of Meta-Igneous Rocks. p. 168-169, 176-177, 182-187 MA

15 4/21 QUIZ: Meta-Igneous Rocks (hand sample and petrography).

Meta-Calcareous Rocks, Mylonites and Cataclasites 24
marble, skarn, graphite, anthracite coal, mylonites, cataclasites.

Petrography of Meta-Calcareous Rocks. p. 19, 162-163, 174-175 MA


16 4/28 LAST WEEK – LAB FINAL -----

actions – discontinuous vs. continuous 21:419-422
4-25 EXAM #3 ----

16 4-28 Types of reactions – solid/solid vs. volatilization (dehydration and decarbonation) 21:422-426