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Course Coordinator Dr. Martin Klausen (021 808 3825)
  klausen@sun.ac.za
Lecturers Dr. Martin Klausen
Course Structure 3 lectures and one 3-hr practical per week plus field excursions
Course Timetable Lectures: Mon 12midday; Wed 8am; Fri 9am: Practical: Wed 2-5pm, Thur 2-5pm
Language Specification E
Course Pass Prerequisite Geology 224, 244, 254; Chemistry 124, 144
Course Corequisite None
 
 
Igneous rocks are rocks that initially crystallized from a magma (= silicate melt + crystals + gases). Magmas form (by melting of a source rock); migrate and ascent towards the surface; evolve (by fractional crystallization, mixing, etc.); emplace, either at the surface (volcanoes) or at depth (plutons); and cool down and crystallize.
This course examines
(1) most important types of igneous rock types (basaltic, gabbroic, ultramafic, andesite-dacite-rhyolites, granitic and alkaline rocks); (2) the tools that geologists use to study igneous rocks (thin-section petrography, major and trace element geochemistry and experimental petrology – phase diagrams); (3) the processes, from partial melting of source rocks, through diversification of primary melts (e.g., fractional crystallization, mixing, etc.), to final cooling and crystallization, that lead to the formation of volcanic, intrusive/cumulative igneous rocks; (4) most important associations of igneous rocks (oceanic islands, continental flood basalts, ophiolites and oceanic crust, layered intrusions, island and continental arcs as well as in orogenies, continental rifts), including more unusual igneous rock types from the Archaean.
The curriculum provides a broad and comprehensive knowledge base, but the course also emphasises the scientific approach, whereby field relationships, petrographies and compositions of igneous rocks are first described and processes are deduced from such facts. The student will as far as possible practise his/her skills at reporting such observations, descriptions and interpretations of natural objects both orally and in writing.
A five day Geology 374 Field Skills trip will be held during the April break to examine and map field relationships amongst gabbros, diorites, granites and possible ignimbrites across the West Coast (mostly on Cape Columbine). This independently marked Field Skills report forms the basis for two subsequent practicals on (1) thin section petrography, and (2) bulk rock geochemistry, of samples collected from this study area, compared to available data on other igneous rocks from this approximately 520-560 Ma old Cape Granite Suite.


 
  • (1) Understand the tools used to study igneous rocks;
  • (2) Understand the processes leading to the formation, evolution and emplacement of magmas;
  • (3) Obtain general knowledge on the main groups of igneous rocks;
  • (4) Develop an ability to describe and interpret igneous rocks, and present observations and interpretations in a scientific, structured way.
 

Students should have the following skills at the end of the course
  • General knowledge on the main groups of igneous rocks, their origins and models of formation;
  • Understanding of the main processes that lead to the formation, evolution and emplacement of magmas and accumulating crystals;
  • Understanding of the tools used to study igneous rocks (field observations, optical mineralogy, geochemistry, physical and chemical phase diagrams);
  • Ability to describe igneous rocks at all scales (from outcrop to geochemical analysis) and to provide at least some elements of interpretation, using basic tools and concepts;
  • Ability to present the above as a structured, rigorous scientific text, or orally, where factual evidence clearly support interpretations.
In addition to the reference books used for Geology 224 and 254 (that remain useful!), students should use the following book, that is the most recent and applicable for Geol314:
Gill, Robin. Igneous Rocks and Processes. Wiley-Blackwell, 2010.

Lectures and pracs attempt to follow this textbook as stringently as possible and thereby becomes much of the course curriculum that you will be examined in. Lecture and prac slides will be available on SunLearner soon AFTER these have been presented in class. Lecture and prac slides from previous years are also available.


 
 

My best advice is that every student, as aminimum, reads relevant sections of Gill (2010) BEFORE every lecture and prac. The better prepared you are the more you get out of my classes. Students are also encouraged to consult different text books (e.g., Winter, J.D. An introduction to igneous and metamorphic petrology. Prentice Hall, 2010), web sites, as well as read journal articles. Multiple choice tests will as far as possible be made available every week(end) for the student to test his/her progress, just as excercises and questions are provided at the end of Gill’s (2010) chapters as well as supplementary question material from Winter (2010). After being prepared, practise is important since it makes you perfect.

 
The final course mark is calculated from the course mark (40%) and the exam mark (60%). Normal university rules apply for rounding, second exams, etc.
 
Allowing for some changes during the course, the class mark will most likely be composed of:
  1. Mid-semester test on the first half of Gill (2010); i.e., chapters 1-5. A one-hour test is scheduled for the end of March (date to be specified), either during a lecture period or outside teaching hours. It will be held under similar conditions (closed-book) as the final exam, and will include similar questions. The test is 20% of the course mark.
  2. Continuous assessments to be handed in at the end of every prac, marked and returned on the following Friday or Monday lecture. Each prac is weighted 5% of the course mark.
  3. End-semester test on the second half of Gill (2010), excluding the last chapter on alkaline rocks (i.e., chapters 6-8) A one-hour test is scheduled for the end of the semester (date to be specified), either during a lecture period or outside teaching hours. It will be in the same conditions (closed-book) as the final exam, and will include similar questions. The test is 20% of the course mark.
The final exam is 3 hours long. It is an closed-book exam, based mostly on acquired skills and memorized knowledge. Partly modified photos, graphs, maps, etc., from Gill (2010) and elsewhere might be included in the paper’s short essay to bullet point questions (typically several shorter questions within each of four topical questions). Examples of Geol314 exam questions from previous years are available on SunLearner, but note that the closed-book format based on Gill (2010) only started in 2014 (thus, older open-book exam papers were based on Winter (2010).