SubjectsSubjects(version: 901)
Course, academic year 2022/2023
  
Igneous Processes - MG440P24
Title: Igneous Processes
Czech title: Magmatické procesy
Guaranteed by: Institute of Petrology and Structural Geology (31-440)
Faculty: Faculty of Science
Actual: from 2020
Semester: summer
E-Credits: 4
Examination process: summer s.:combined
Hours per week, examination: summer s.:2/1 C+Ex [hours/week]
Capacity: unlimited
Min. number of students: 3
Virtual mobility / capacity: no
State of the course: taught
Language: English, Czech
Level: specialized
Additional information: https://www.natur.cuni.cz/geologie/petrologie/vyukove-materialy/magmaticke-procesy
Note: enabled for web enrollment
Guarantor: prof. Mgr. Vojtěch Janoušek, Ph.D.
Class: QUICKpress Piston Cylinder Apparatus
Opinion survey results   Examination dates   Schedule   
Annotation -
Last update: doc. RNDr. Petr Jeřábek, Ph.D. (16.01.2018)
The course is taught in English when at least one international student is enrolled. This course is focused on petrological and compositional variability of igneous rocks as well as petrogenetic processes playing role in their origin (partial melting of various source rocks, relations between compositions of the melt and co-existing crystals during melting and crystallisation processes, fractionation and contamination of magmas). Addressed are peculiarities and petrogenetic problems of selected rock types and suites in individual geotectonic settings. Particular emphasis is on practical exercises demonstrating the techniques commonly employed in graphical presentation and interpretation of major- and trace-element whole-rock geochemical data as well as radiogenic isotopic compositions.
Literature -
Last update: prof. Mgr. Vojtěch Janoušek, Ph.D. (10.02.2021)

In the summer term 2020/2021 the course will be taught remotely, using Google Classroom, starting on 15 February.

 

Albaréde, F., 1995. Introduction to Geochemical Modeling. Cambridge University Press, Cambridge.

Dickin, A.P., 2005. Radiogenic Isotope Geology. Cambridge University Press, Cambridge.

Gill, R., 2010. Igneous Rocks and Processes: A Practical Guide. J. Wiley, Chichester.

Janoušek, V., Moyen, J.F., Martin, H., Erban, V. and Farrow, C., 2016. Geochemical Modelling of Igneous Processes - Principles and Recipes in R Language. Bringing the Power of R to a Geochemical Community. Springer-Verlag, Berlin, Heidelberg.

Philpotts, A.R. and Ague, J.J., 2009. Principles of Igneous and Metamorphic Geology. University Press, Cambridge.

Rollinson, H.R., 1993. Using Geochemical Data: Evaluation, Presentation, Interpretation. Longman, London.

Wilson, M., 1989. Igneous Petrogenesis. Unwin Hyman, London.

Winter, J.D., 2001. An Introduction to Igneous and Metamorphic Geology. Prentice Hall, Upper Saddle River, NJ.

Requirements to the exam -
Last update: prof. Mgr. Vojtěch Janoušek, Ph.D. (04.08.2016)

Oral exam. Lectures are available to download at the course web.

Also required are written protocols with solutions of the numerical exercises (including their understanding).

Syllabus -
Last update: prof. Mgr. Vojtěch Janoušek, Ph.D. (03.03.2020)

1.      Physical properties of magma and diversity of the igneous rocks

o   Composition of magma vs. composition of magmatic rock

o   Heat sources for partial melting

o   Physical properties of magmas: temperature, volatiles, density, viscosity

o   Classification of igneous rocks

§  Qualitative parameters:

·        Texture

·        Silica saturation

·        Alumina saturation

§  Quantitative parameters:

·        Silica contents

·        Geochemical data

·        Modal vs. normative composition

·        QAPF (modal) classification

·        TAS (chemical) classification

·        Alkaline, sub-alkaline (series)

·        Subdivision of the subalkaline series to tholeiitic and calc-alkaline suites

·        Alternatives for altered/weathered samples

·        Multicationic parameters, millications

2.      Graphical presentation and recalculation of whole-rock geochemical  data from igneous rocks

o   Software available for Microsoft Windows – state of the art

§  Spreadsheets

§  Dedicated programs (MinPet, IgPet, PetroGraph…)

o   What is R language?

o   Main features of the GCDkit system

o   Graphical presentation of various types of whole-rock geochemical data

§  Classification of elements, major and trace elements

§  Presentation of unidimensional data, including small datasets

§  Two-dimensional data, Harker plots, log–log diagrams etc.

§  Three-dimensional data – ternary plots, various 3D projections

§  Spiderplots including their modifications

§  Working with large datasets

§  Looking for anomalies

§  Classification diagrams

§  Geotectonic diagrams

o   Installation of GCDkit and basic operation (practical exercises)

3.      Processes determining/modifying the composition of magmatic rocks

o   Overview of processes affecting the composition of magmatic rocks

o   Partial melting and its causes, segregation of melts, field evidence

o   Differentiation (thermal (Soret) diffusion, thermogravitational diffusion, liquid immiscibility, equilibrium and fractional crystallization, crystal accumulation …) including field and textural evidence

o   Open-system processes (assimilation, AFC, hybridization – magma mixing and mingling)

  1. Using whole-rock major-element data in genetic interpretation of igneous rocks (mass-balance principles)

o   Mass balance during fractional crystallization (direct modelling)

o   The mass-balance equation for partial melting

o   Binary and ternary mixing

o   Generalized mixing of m components: matrix formulation

o   Liquid lines of descent

o   Reverse modelling of fractional crystallization and partial melting by the least-squares method

o   Everything is mixing!

o   Why are major elements alone not enough?

5.      Trace elements: concept of partitioning for “diluted” elements

o   Classification of trace elements according to their geochemical behaviour

o   Subdivision of the trace elements into those “diluted” in major rock-forming minerals and Essential Structural Components  (ESC) forming own accessory phases

o   Henry’s Law

o   Mineral–melt equilibria, distribution coefficients  (KD)

o   Physical factors influencing values of distribution coefficients

o   Compatibility concept

o   Crystallization: fractional (Rayleigh equation) and equilibrium (direct models)

o   Partial melting, fractional and batch, various formulations (direct models)

o   Distinguishing between fractional crystallization and partial melting

o   Reverse modelling of fractional crystallization by the least-squares method

o   Reverse modelling of batch melting

6.      Trace elements forming accessory minerals (Essential Structural Constituents, ESC) and saturation models

o   Saturation concept

o   Behaviour of ESC during fractional crystallization and partial melting

o   Saturation equations for the most important accessories (zircon, apatite, monazite,…), their main parameters and use in thermometry

o   Identifying the petrogenetic role of accessory minerals

o   Studying internal structure of accessory minerals (BSE, CL…)

o   Dealing with accessory minerals in models

o   Saturation calculations in GCDkit

7.      Open-system processes: hybridization, assimilation, AFC

o   Classification of enclaves, MME

o   Interaction of contrasting magmas: magma mingling and mixing

o   Filed evidence for magma mixing

o   Using cathodoluminescence (CL)

o   Microtextural evidence of magma interaction

o   Assimilation and crustal contamination

o   „Deep Crustal Hot Zones“

o   (Binary) mixing – major/trace elements, mixing test

o   Processes determining/modifying the isotopic composition of magmatic rocks (closed- and open-system processes)

o   Radiogenic isotopes– a quick recap:

§  Calculating initial ratio

§  Using Nd isotopes:  including epsilon values and model ages

§  SrNd plugin in GCDkit

o   Binary mixing – single nad two isotopic ratios (direct and reverse modelling)

o   Assimilation and Fractional Crystallization (AFC)

o   Energy-Constrained Assimilation–Fractional Crystallization (EC-AFC)  and similar models

8.      Magmatic crystallization

o   Variability of magmatic textures. Why shall we study crystallization and why do we need kinetics?

o   Thermodynamics of crystallization: equilibrium conditions, crystallization in one- and multicomponent systems, thermodynamic driving force

o   Kinetics: undercooling, nucleation and crystal growth, basic physico-chemical theories

o   Magmatic texture as a record of kinetic processes: Avrami theory, granularity, crystal size distributions  (CSD) and their genesis

o   Magmatic textures as a record of mechanic processes in the magma chamber

o   Lifestyle and crystallization style of magma chambers: solidification fronts, cumulates, geochemical implications

9.      Diversity and petrogenesis of (subalkaline) basaltic rocks

o   Variability and classification of basaltoids

o   Volcanology of basaltic magmas

o   Information on composition of the Earth’s mantle

o   Heterogeneity of the upper mantle

o   Mantle depletion and enrichment processes

o   Mantle metasomatism, crustal contamination of the mantle and UHP metamorphism of crustal protoliths

o   Generation of the basaltic magmas

o   Basalts in various tectonic settings – their occurrence, petrology, geochemistry and genesis

10.      Diversity and petrogenesis of rhyolitic and granitic rocks

o   Volcanology of intermediate–acid magmas

o   Enclaves and roof pendants

o   Genetic classification of granitoid rocks

o   Petrogenetic models for granitoids

o   Granitoids in various tectonic settings – their occurrence, petrology, geochemistry and genesis

11.      Diversity and petrogenesis of alkaline igneous rocks

o   Alkaline (vs. peralkaline) rocks – definition, classification (plutonic vs. volcanic)

o   Tertiary–Quaternary intraplate magmatism in Europe

o   Continental rifts

o   Carbonatites

o   Lamprophyres

o   Ultrapotassic rocks

o   Kimberlites

o   Plutonic equivalents of lamprophyres

o   (Ultra-) K magmatism in the Moldanubian Zone: durbachites and allied rocks

 
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