1003145 - GEOLOGIA DEI BASAMENTI CON RILEVAMENTO
Expected Learning Outcomes
The metamorphic geology course has the aim to give the main principles of the metamorphic and magmatic processes at the base of the continental crust formation 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.
Course Structure
The course consists of 6 CFU for a total of 42 hours divided into lessons in power-point alternating with practical exercises classroom aided by hand samples and thin sections of metamorphic rocks.
Further 3 CFU for a total of 36 hours are instead provided during a four days geological field-trip on metamorphic terrains prevalently located in north-eastern Sicily and southern Calabria. The students are divided into groups of four or five units. Each group has an area of about five square kilometers accompanied by a silent geological map (i.e. without legend). Students have to specify the themes in the legend producing a series of structural stations where they will take a series of structural measurement opportunely related to the recognized deformational phases.
Required Prerequisites
• Know the classification principles of igneous and metamorphic rocks;
• Know the principles of optical microscopy for the recognition of fundamental minerals;
• Know the theoretical basis of the use of stereographic projections;
• Know the foundations of the current central Mediterranean geological-geodynamic structure.
Attendance of Lessons
Mandatory, according to the rules indicated by the regulations of the CdS. To guarantee equal opportunities and compliance with the University rules, interested students can ask for a personal interview in order to plan any compensatory and/or dispensatory measures, based on the didactic objectives and specific needs.Detailed Course Content
Metamorphic geology: 6 credits (42 hours)
FIRST PART
INTRODUCTION
Principles and purposes of the Metamorphic Geology. Description of the main orogenetic processes. The geothermal gradient and its influence on the genesis of crystalline basements.
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 Polymineralic 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 characterized 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. Recognition and interpretation of metamorphic microstructures.
FOURTH PART
RECONSTRUCTION OF THE BLASTO-DEFORMATIONAL RELATIONSHIPS, THE CONCEPT OF TEXTURAL EQUILIBRIUM, GEOTHERMOBAROMETRY OVERVIEW, P-T-d-t TRAJECTORIES RECONSTRUCTION.
Reconstruction of the blasto-deformational relationships: Chronology of deformational events. Chronology of the blastic events. Chronological relationships between deformation and blastesis also through image analysis techniques (Effective Reactant Volumes (ERV) and Effective Bulk Chemistry (EBC)). Elements of geothermbarbarometry and geochronology: The reconstruction of the P-T-d-t path. Mineralogical renewal during metamorphic processes and the concept of the sequence of paragenesis. Evolution of geothermbarbarometric techniques: thermodynamic databases and calculation of phase diagrams: sections, projections and pseudosections. The reconstruction of the orogenic cycles: thickening and exhumation/denudation processes.
FIFTH PART
WESTERN MEDITERRANEAN GEODYNAMICS FROM THE END OF PALEOZOIC TO THE PLIOCENE-PLEISTOCENE PHASES
The geological-geodynamic evolution of the Calabrian Peloritani Orogen (CPO). The Variscan vs. Alpine orogenic cycle. The role of crustal-scale shear zones in the present-day structure of the CPO. CPO palinspastic reconstructions up to the Oligocene-Miocene transition.
Field-based module: 3 credits (36 hours)
FIELD TECHNIQUES
Field measurements: arrangement of linear and planar elements. Cartographic representation with an 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 deformation 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 Drone-, GIS- and, GPS-based techniques.
TECTONIC ELEMENTS
Tectonostratigraphic setting and tectonic-metamorphic evolution of the Calabrian Peloritani Orogen basement units.Styles of tectonic structures. Type and scale of folding systems. Characterization and classification the brittle deformation 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 the map: the trend of fold axes, foliation planes, and lineation diversified per timing generation and style.
Textbook Information
Books
- Barker J. – Introduction to metamorphic textures and microstructures. (Blackie USA, Chapman & Hall) 1998.
- 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.
- Vernon R. H. – A practical guide to rock microstructure. (Cambridge University Press) 2004. 594 pp. ISBN: 9780521891332
- WINTER (2001) An Introduction to Igneous and Metamorphic Petrology. Prentice Hall.
- Fossen H. – STRUCTURAL GEOLOGY. (Cambridge University Press) 2010. 463 pp. ISBN: 9780521516648
- Handouts and notes distributed in class during the course.
Course Planning
| Subjects | Text References | |
| 1 | Descrizione dei principali processi orogenetici | Barker J., Fossen H.; Dispense |
| 2 | Il gradiente geotermico e la sua influenza sulla genesi dei basamenti cristallini. | Barker J., Fossen H.; Dispense |
| 3 | Principi di reologia dello stato solido: Analisi dello stress e dello strain. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 4 | Storia dello strain: Strain coassiali e non coassiali. strain totale, strain incrementale, deformazione progressiva. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 5 | Il comportamento reologico di minerali e rocce: Meccanismi deformativi inter- ed intra-cristallini | Passchier C. W. & Trouw R. A. J.; Dispense |
| 6 | Fattori di controllo dello strain in rocce monomineraliche e polimineraliche. I processi di recovery. | Passchier C. W. & Trouw R. A. J.; Dispense |
| 7 | Le principali leggi di flusso nella reologia dei corpi solidi. | Dispense |
| 8 | Foliazioni e lineazioni. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 9 | Descrizione e classificazione delle pieghe. | Dispense |
| 10 | Modelli teorici di piegamento. | Dispense |
| 11 | Distribuzione dello strain nelle pieghe. | Dispense |
| 12 | Geometria e tipi di interferenza strutturale. | Dispense |
| 13 | Metodi di analisi strutturale in aree polideformate: Reticolo di Wulff; reticolo di Schmidt. Proiezione di un piano, proiezione di una linea. Esempi di calcolo di elementi geometrici. | Dispense |
| 14 | Elaborazione statistica dei dati attraverso l’ausilio di software. | Dispense ed esercitazioni in aula informatica |
| 15 | Ricostruzione dei rapporti blasto-deformazionali: Cronologia degli eventi deformativi. Cronologia degli eventi blastici. Relazioni cronologiche fra deformazione e blastesi. | Dispense; Vernon R.H.; Winter |
| 16 | Classificazione delle rocce di faglia e loro collocazione nei vari livelli crostali. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 17 | Gli indicatori cinematici. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 18 | Caratteri microstrutturali delle cataclasiti e delle miloniti. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 19 | Le pseudotachiliti. | Passchier C. W. & Trouw R. A. J.; Fossen H.; Dispense |
| 20 | Riconoscimento ed interpretazione delle microstrutture metamorfiche. | Dispense; Vernon R.H.; Winter |
| 21 | Misure sul terreno: giacitura degli elementi planari e lineari. | Attività di terreno |
| 22 | Rappresentazione cartografica con simbologia codificata. | Attività di terreno ed in aula informatica |
| 23 | Stazioni di misura ed elaborazione dei dati strutturali. | Attività di terreno ed in aula informatica |
| 24 | Ricostruzione spazio-temporale degli eventi deformativi. Distinzione delle simbologie strutturali su base tempo-relativa. | Attività di terreno |
| 25 | Caratterizzazione tessiturale e strutturale delle strutture deformative. | Attività di terreno |
| 26 | Riconoscimento mesoscopico delle associazioni paragenetiche in rocce di basamento. | Attività di terreno |
| 27 | Penetratività e pervasività delle strutture deformative. | Attività di terreno |
| 28 | Ambientazione genetica delle strutture deformative. | Attività di terreno |
| 29 | Individuazione ed interpolazione dei limiti tra le unità. | Attività di terreno |
| 30 | Riconoscimento e caratterizzazione dei limiti tra rocce plutoniche e rocce metamorfiche. | Attività di terreno |
| 31 | L’assetto tettonostratigrafico e l'evoluzione tettono-metamorfica delle unità di basamento nell'Orogene Calabro-Peloritanio. | Dispense |
| 32 | Strutture e stili tettonici. | Attività di terreno |
| 33 | Tipologia e scala dei sistemi plicativi. | Attività di terreno |
| 34 | Influenza dei sistemi tettonici fragili (faglie e thrust) sulla dislocazione della continuità delle unità di basamento. | Attività di terreno |
| 35 | Rapporti tra tipologie e tempi di messa in posto di unità plutoniche ed unità metamorfiche incassanti. | Attività di terreno |
| 36 | Ricostruzione degli andamenti strutturali su carta: trend degli assi di piega, dei piani di foliazione e delle principali strutture lineari diversificati per generazione. | Attività di terreno ed in aula informatica |
| 37 | Caratterizzazione e classificazione dei sistemi deformativi fragili. | Attività di terreno |
| 38 | Ricostruzione dell'evoluzione geologico-geodinamica dell'Orogene Calabro-Peloritano nel Mediterraneo centrale dalla fine del Paeozoico all'Oligo-Miocene. | Dispense |
Learning Assessment
Learning Assessment Procedures
The final evaluation relating to the course of Metamorphic Geology provides the possibility (optional) to carry out an ongoing test on the principles of solid-state rheology during the course. At the end of the course, the assessment of the ongoing test will be integrated with the production of an end-of-course work group, normally developed in groups of four or five students, relating to the statistical processing of structural measurements taken autonomously during the field-related surveys in Samo or Palmi (RC) or Scifì (ME), contextualized within the central Mediterranean geological-geodynamic framework from the Palaeozoic to the Oligo-Miocene passage.
This work can be presented either in paper form or with the aid of a power-point presentation.
During and at the end of the presentation of the paper, the teacher will ask the students a whole series of basic theoretical notions, among those dealt with during the course.
The final grade will include a balanced synthesis between the judgment of the synthesis and expository skills demonstrated and the degree of maturity in understanding the theoretical notions underlying the course.
Versione in italiano