METAMORPHIC GEOLOGY WITH FIELD INVESTIGATIONS

GEO/07 - 9 CFU - 2° Semester

Teaching Staff

GAETANO ORTOLANO
Email: ortolano@unict.it
Office: Palazzo Ramondetta/Corso Italia,57 - 95129 - Catania
Phone: 0957195754
Office Hours: Mart: 10:00-11:00; Giov: 10:00-11:00


Learning Objectives

The metamorphic geology course have the aim to give tha main principles of the metamorphic and magmatic processes at the base of the continental crust formationin in the different geological and geodynamic context. To this aim the student at the end of the course will be able to:

a) understand the basic principles of the solid state rheology as well as the elastic and mechanical properties of the main rock types;

b) describe and classify the different types of deformation structures, reconstructing the setting and the space-time evolution;

c) collect, process, mapping disaggregated structural data, identifying the style and reconstructing the space-time evolution;

d) read and interpret geological maps in the crystalline basement areas;

e) reconstruct the deformation- blastesis relationships occurred during the tectono-metamorphic evolution of metamorphic units;

f) determine, with the integration of opportune geotermobarometric techniques, the changes of pressure and temperature registered by the basement rocks, reconstructing the P-T trajectories;

g) contextualize within the Paleozoic-Oligocene Mediterranean geodynamics the kinematic of the Calabro-Peloritani microplates.



Detailed Course Content

Metamorphic geology: 6 credits (36 hours)

FIRST PART

INTRODUCTION

Description of the main orogenic processes. The geothermal gradient and its influence on the genesis of crystalline basements. Petrogenesis of metamorphic rocks: types of metamorphism, their areal extent and regional significance, concepts of metamorphic facies, metamorphic zone and mineral index.

SECOND PART

MECHANICAL PROPERTIES OF ROCKS

Principles of rheology of the solid state: Analysis of stress and strain. History of the strain: total strain, incremental strain, progressive deformation. Coaxial and non-coaxial deformation. The rheological behaviour of minerals and rocks: Inter and intracrystalline deformation mechanisms; Strain control factors in mono- and Poly-mineralic rocks. Recovery process. The main flow laws in the solid state rheology. Inter-and intra-crystalline deformational mechanisms. Mineral Preferred Orientation: Shape and Lattice Preferred Orientation and their interrelationships.

THIRD PART

MESO-MICROSTRUCTURAL INVESTIGATIONS AND STRUCTURAL DATA REPRESENTATION

Foliations and lineations. Description and classification of the folds. Theoretical models of folding. Distribution of strain in the folds. Examples of representation of structural elements through stereographic projections. Concepts of symmetry of structural data set. Rotation and statistical processing of structural data. Dispersion of the structural elements. Geometry and structural types of interference. Methods of structural analysis in areas chracterized by poly-deformational evolution. Definition of shear zone. Classification of fault rocks and their location in different crustal levels. The kinematic indicators. Microstructural analysis of cataclastic and mylonitic rocks. The pseudotachylite.‚Äč Recognition and interpretation of metamorphic microstructures.

FOURTH PART

PHASE EQUILIBRIA, GEOTHERMOBAROMETRY AND RECONSTRUCTION OF PT PATH

Phase mineralogical transformation during metamorphic processes. Phase diagrams and chemography. Petrogenetic grid and isochemical sections. Conventional geothermobarometry. The evolution of geothermobaromerical techniques: thermodynamic databases and the calculation of pseudosections. The reconstruction of orogenic cycles: investigation of exhumation/denudation process.

FIFTH PART

GRANITE GEOLOGY

Geometry of intrusions and controlling factors. Mapping of granite plutons and batholiths. Extraction, ascent and emplacement of granitoid magmas. Timescales and mechanisms of batholith construction.

Field-based module: 3 credits (36 hours)

FIELD TECHNIQUES

Field measurements: arrangement of linear and planar elements. Cartographic representation with encoded symbology. Stations measurement and processing of structural data. Reconstruction of space-time deformation events. Time-related distinction of structural symbols on thematic maps. Textural and structural characterization of deformative structures. Recognition of mesoscopic paragenetic assemblage in basement rocks. Penetrativity and pervasiveness of deformation structures. Genetics setting of deformation structures. Detection and interpolation of the boundaries between the units. Examples of graphic reconstruction of the limits and the limits on the validity of interpolation. Detection and characterization of the boundaries between plutonic rocks and metamorphic rocks. Elements of geothematic cartography assisted by GIS-, GPS-based techniques.

 

ELEMENTS OF TECTONICS

Tectonostratigraphc setting and tectono-metamorphic evolution of the Calabrian Peloritani Orogen basement units.Styles of tectonic structures. Type and scale of folding systems. Characterization and classification the brittle deformative structures. Influence of brittle tectonic systems (faults and thrust) on the location of the continuity of the basement Units. Relationships between types and timing of emplacement of plutonic bodies within metamorphic units. Reconstruction of structural developments on map: the trend of fold axes, foliation planes, and lineation diversified per timing generation and style. Late-Palaezoic to Oligocene-Miocene geodynamics of the Calabrian-Peloritani Orogen within the western Mediterranean realm.



Textbook Information

Books

  1. Barker J. – Introduction to metamorphic textures and microstructures. (Blackie USA, Chapman & Hall) 1998.
  2. Passchier C. W. & Trouw R. A. J. – Microtectonics. (2nd ed. xvi + 366 pp. + CD-ROM. Berlin, Heidelberg, New York: Springer-Verlag). ISBN 3 540 64003 7.
  3. Vernon R. H. – A practical guide to rock microstructure. (Cambridge University Press) 2004. 594 pp. ISBN: 9780521891332
  4. WINTER (2001) An Introduction to Igneous and Metamorphic Petrology. Prentice Hall.
  5. Fossen H. – STRUCTURAL GEOLOGY. (Cambridge University Press) 2010. 463 pp. ISBN: 9780521516648
  6. Handouts and notes distributed in class during the course

Web Sites

  1. http://jm-derochette.be/metamorphic_rocks.htm
  2. http://www.uwgb.edu/dutchs/EarthSC202Slides/struslid.htm
  3. http://virtualexplorer.com.au/special/meansvolume/contribs/heilbronner/text/00/0000.html
  4. http://www3.uakron.edu/geology/mcconnell/structGeo/syllabus/week15.htm#readings14



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