Download Petrología de rocas ígneas y

COURSE INFORMATION
NAME OF THE SUBJECT:
Petrology of igneous and metamorphic rocks
Code number: 757609217
Degree in Geology
Academic Year: 2016-2017
Foundational/Elective/Compulsory course. 3rd year
Second semester: 4 1/2 hours a week, 2 days a week
6 credits
TEACHING STAFF
Prof.: Antonio Castro Dorado
Department: Geology
Office: EX. P3. N2. 01
Phone: +34 959 219828
E-mail: [email protected]
Office hours:
First Semester: 9.00-14.00 and 17.00-20.00
Second Semester: 9.00-14.00 and 17.00-20.00
PROGRAMME
1. DESCRIPTION
Rocks form most of our planet, they form the continents where life was developed on
Earth since the last 3000 millions years. The history of the Earth is written in the
rocks in such a way that the study of rocks allows us to reconstruct the complex
processes involved in mountain building, volcanism, new crust generation, mantle
dynamics, etc. Consequently, Petrology of Igneous and Metamorphic Rocks is a
fundamental subject for undergraduate students in Geology. Understanding the
rocks, their origin, composition, classification, etc. are the essential basis to set a
fundamental background for other geological subjects.
The distinction between igneous and metamorphic rocks is conceptually clear.
However, the recognition of particular rocks as igneous or metamorphic is not always
straightforward. Many metamorphic rocks have an ultimate igneous origin and the
igneous past can be, and must be, recognized. Consequently, clear and
unambiguous definitions of concepts and terms must be provided to students. On the
other hand, rocks are complex in terms of mineralogy, structures and field relations.
Thus, the application of rigorous criteria for rock classification must be applied. These
are being revised periodically by international, UNESCO-rooted, expert committees,
the Sub-commission for the Classification of the Igneous Rocks and the Subcommission for the study of Metamorphic rocks; both part of the IUGS (International
Union of Geosciences).
Many basic principles are common for igneous and metamorphic petrology. However,
the methodology of study of natural rocks differs significantly from one group to the
other. Thus, the subject is configured in a first block of lessons about the
1
Campus El Carmen
Avda. 3 de marzo, s/n
21007 Huelva
Tel.: (+34) 959 21 94 94
[email protected]
Fax: (+34) 959 21 93 59
www.uhu.es/sric
fundamental common principles, and particular lessons treating igneous and
metamorphic rocks separately.
The subject is conceived in a double sense, conceptual and practical. Lessons are
accompanied with practical sessions. A large part of the practical sessions will
consist of microscopic studies of rocks representing case-studies of classical
petrologic problems.
2. PREREQUISITES
The study of rocks requires a solid conceptual basis on thermodynamics and reaction
kinetics and crystallization processes. Most igneous and metamorphic rocks are
essentially formed by a reduced group of silicate minerals, with subordinate
phosphates and oxides as accessory minerals. The identification of these minerals is
fundamental to study rocks. Furthermore, rocks form part of large-scale complexes
such as mountain chains, the ocean floor, volcanic islands, etc. Thus, the geological
setting of igneous and metamorphic rocks constitutes the basis of any petrologic
study. In summary, students following this subject must have basic knowledge of the
following matters:
Chemical thermodynamics
Mineralogy of silicate minerals
Tectonics and General Geology
3. OBJECTIVES/LEARNING OUTCOMES
-
A general purpose of this subject is to educate students to think and speak in the
scientific way of petrologists. To accomplish this general objective, the following partial
objectives and outcomes proposed are:
1. To provide students with the basic knowledge on the physico-chemical processes
that lead to the generation of varied rock types in the igneous and metamorphic
environments.
2. To provide students with the skills to recognize rocks and to identify processes
involved in their generation.
3. The acquisition of a petrological “language” based on concepts and terminologies
applied to the study of rocks.
4. To gain new intuition on physical processes related to the generation of igneous and
metamorphic rocks
5. To handle petrological data commonly used in petrological modeling of rock and
magma generation.
6. To recognize the rocks in their tectonic environments by projecting rock data into
large-scale geodynamic processes.
4. TEACHING METHODOLOGY
Lectures and practical sessions will be combined in most of the teaching units listed
in the next section.
Lectures will tend to provoke the active participation of students. To motivate
interaction during lectures, the students will be asked to answer critical questions to
follow the explanations. Visual projections will be used for illustrative purposes of
geological examples, avoiding excessive lettering. The use of classical blackboard is
2
Campus El Carmen
Avda. 3 de marzo, s/n
21007 Huelva
Tel.: (+34) 959 21 94 94
[email protected]
Fax: (+34) 959 21 93 59
www.uhu.es/sric
considered essential to help during lectures. The students will be supplied with a
handout to follow particular parts of lectures.
Lectures will be combined with joint seminars in reduced groups and practical
sessions.
Practical sessions are focused on petrographic examinations with the optical
microscope of rocks from classical associations. Because Petrography is included in
another subject (Petrografía) in the Huelva graduate catalog for Geology, the
programmed sessions in this subject will be focused on particular processes that
have been previously introduced in the lectures.
A reduce but intensive field work of two or three sessions is also included as a part of
the practical sessions.
5. CONTENTS
1. Lectures:
Lectures are organized in three thematic blocks and fourteen lessons. The summarized
content of these lessons are as follows:
Thematic block one: General Principles of Igneous and Metamorphic Petrology
L1: Scope of Petrology
Rocks as material and abstract substances. Petrology and thermodynamics.
Methods in the study of rocks. Geochemical and geophysical connections.
L2: The structure of the Earth
The mantle: its composition and thermal regime. The continental crust: its structure,
age and composition. The oceanic crust. Heat flow and thermal regime of the
lithosphere.
Thematic block two: Igneous Rocks
L3: Magmas and magmatic rocks
Physical properties of magmas. Crystallization of magmatic rocks. Nucleation and
growth of crystals. Volatile solubility. Viscosity and flow of magma. Magma chambers
and eruption of magma. Shape of plutonic bodies.
L4: Phase diagrams in igneous petrology
Two component systems. Systems with solid solutions. Systems with peritectic
reactions. Ideal systems for basalts and rhyolites
L5: Basalts and the origin of basaltic magmas
Natural occurrence of basalts. The Bowen’s concept of differentiation series. The
Yoder-Tilley basalt tetrahedron. The source of basalt magmas. Differentiation of
basaltic magmas. Liquid lines of descent for basaltic magmas.
L6: Andesites and arc magmatism
Natural occurrence of andesites and related arc magmas. Magmatic series: the
Peacock index. Origin of andesites. Source components in arc settings.
L7: Granite batholiths and the origin of the continental crust
3
Campus El Carmen
Avda. 3 de marzo, s/n
21007 Huelva
Tel.: (+34) 959 21 94 94
[email protected]
Fax: (+34) 959 21 93 59
www.uhu.es/sric
Rock associations in batholiths. Emplacement mechanisms of plutons and batholiths.
Cordilleran and intra-plate batholiths. Granite types. Crustal recycling and granite
magma generation.
L8: Archaean and Proterozoic igneous rocks.
Igneous rocks of the Archaean cratons. TTG complexes and the origin of protocontinents. Proterozoic igneous rocks: massif-type anorthosites and related rocks.
Thematic block three: Metamorphic Rocks
L9: Metamorphism and metamorphic rocks
General principles and definitions. The limits of metamorphism. Metamorphic grade
and metamorphic facies.
L10: Metamorphic mineral assemblages
Equilibrium and compatibility diagrams. Petrogenetic grids.
L11: Compositional series
Pelites and greywackes. Metabasites and calc-silicate rocks. Metamorphism of
ultramafic rocks.
L12: Rocks derived from ultrametamorphism and anatexis in the crust
Migmatites. Metamorphic reactions leading to melt generation. Congruent and
incongruent melting. Peritectic mineral phases and restites.
L13: Microstructures of metamorphic rocks
Porphyroblast matrix relations and tectonic implications. Intra-crystalline deformation
and flow. Deformation mechanisms. Development of foliations in metamorphic rocks.
Mylonites and cataclasites.
L14: Geothermometry and geobarometry
General principles. Solid solutions. Solvus thermometry. Pseudosections.
2. Practical sessions
2.1 Petrological modeling (sessions in reduced groups)
- The use of classification diagrams and series characterization in igneous rocks
- The use of thermodynamic modeling using the software MELTS
- Geochemical modeling of igneous processes by using major and trace elements
- Identification of magmatic series. Geochemical discriminant diagrams
- Algebraic handling of the compositional space in metamorphic systems
- Making compatibility diagrams and identification of equilibrium assemblages
2.2 Microscopic and textural analyses:
- Examination of igneous textures and textural modifications in igneous rocks
- Examination of textures and rock types resulting of crystallization/differentiation
processes
- Identification of equilibrium and disequilibrium textures in metamorphic rocks by
application of interfacial free-energy principles and dihedral angles.
- Porphyroblast-matrix relations and identification of tectonic processes by means of
textural analysis
4
Campus El Carmen
Avda. 3 de marzo, s/n
21007 Huelva
Tel.: (+34) 959 21 94 94
[email protected]
Fax: (+34) 959 21 93 59
www.uhu.es/sric
6. BIBLIOGRAPHY
Bucher, K., Grapes, R., 2011, Petrogenesis of Metamorphic Rocks, Springer-Verlag Berlin
Heidelberg
Castro Dorado, A. 2015. Petrografía de Rocas Ígneas y Metamórficas. Paraninfo. Madrid.
MacKenzie, W.S., Guilford, C., Yardley, B.W.D., 1990, Atlas of metamorphic rocks and their
textures. Longman.
Maaløe S. 1985. Principles of Igneous Petrology. Springer-Verlag. Berlin.
Philpotts, A.R., Ague, J.J. 2009. Principles of Igneous and Metamorphic Rocks. Cambridge
University Press.
Spear, F.S., 1993, Metamorphic phase equilibria and pressure-temperature-time paths. Min.
Soc. Am. Monographs.
Winter, J., 2001, An Introduction to igneous and metamorphic petrology.Prentice-Hall.
Yardley, B.W.D., 1989, An introduction to metamorphic petrology. Longman.
7. ASSESSMENT
Assessment will be based on the following parts:
1. Written exam on fundamental concepts of igneous and metamorphic petrology.
2. Petrographic study of selected rocks in thin sections
3. Continuous assessment according to participation in seminars (reduced groups) and
practical sessions
The relative charges of these parts in the final assessment are: 1: 50%; 2: 20%; 3: 30%
Antonio Castro
Professor of Petrology and Geochemistry
5
Campus El Carmen
Avda. 3 de marzo, s/n
21007 Huelva
Tel.: (+34) 959 21 94 94
[email protected]
Fax: (+34) 959 21 93 59
www.uhu.es/sric