2017/2018

2019/2020

DM270

GEO/03 (STRUCTURAL GEOLOGY)

DEPARTMENT OF EARTH AND ENVIRONMENTAL SCIENCES

GEOLOGICAL SCIENCES

PERCORSO COMUNE

3°

1st semester (01/10/2019 - 15/01/2020)

12

114 lesson hours

Italian

WRITTEN AND ORAL TEST

SENO SILVIO (titolare) - 9 ECTS
MAINO MATTEO - 3 ECTS

Students must hold basic knowledge of mathematic, physic, sedimentology, petrography, physical geography and cartography .

The course deals with the mechanisms and processes driving the rock deformation, throughout presentation and discussion of the following points:
1. Relationships among force, stress, strain
2. Tectonic structures from micro to regional scale
3. From deformation structure to deformation mechanism
4. Mathematical and graphical representation and elaboration of tectonic structures and deformation mechanisms
5. Interpretation of geological maps in deformed terranes; processing of maps and geological sections

Lectures. Significance and topics of tectonics. Strain: Displacement, extension, 2D-strain, pure shear, simple shear, strain and geological structures. Progressive deformation: en echelon set of veins (tension gashes), sintaxial and antitaxial growing fibres, pressure shadows. Measuring the strain. Heterogeneous strain, 3D-strain. Folds: terminology, elements of fold style, anatomy, morphology. Structures associated with folding and their use. The concepts of vergence and polyphase folding. Folding mechanism. Foliations: classification, development mechanisms, use, relationships with other structures, folding and cleavage, superimposed foliations. Lineations: structural and mineralogical lineations, relationship with other structures. Faults: classification on the basis of the relative displacement. Slip on the fault plane and layers offset: possible differences. Stress: definition and representation. Mohr circle. Relationships between stress and faults: the Anderson model. Outline of regional fault systems and related structures: Horst and Graben, half-Graben, domino-style structures, nappes and thrusts, growing faults; transfer-faults, flower structures, pull-apart basins. Shear zones: geometry, sheat folds, conjugate shear zones, kinematic indicators, kinematics.
Practicals. Analysis of deformed rock samples. Stereonet plot of structural data (planes, lines, intersections). Analysis of geological map. Geological sections. Measurements of displacement (heave, throw, dip separation). Fold analysis from map. Field survey of tectonic structures.

The course is divided in two blocks: i) structural geology and ii) a laboratory course of structural and cartographic analysis
Frontal lessons offer theoretical basics on deformation structures and deformation mechanisms. The laboratories supply analysis of deformed samples, geological maps and sections.
Two field trips in highly deformed regions of the Alps or Apennines complete the program. Students are accompanied to observe deformation and tectonic structures. They must also work alone in producing report of the results deriving from mapping and structural analysis of a small area.

Haakon Fossen, Structural Geology, 2010, Cambridge University Press, ISBN: 978-0-521-51664-8

Robert J. Twiss, Eldridge M. Moores, Structural Geology, 2006, W H Freeman & Co (Sd), ISBN: 978-0716749516

The exam is divided in two parts:
1. A written test on both theoretical and practical arguments. About 20 questions in 1.15 h. This test corresponds to the 75% of the final grade. Textbooks, laptops, phones, or other electronic devices are forbidden. Only a calculator and one A4 sheet of paper with personal notes are allowed.
2. A practical test of a geological section. This must be completed in 2 h and corresponds to the 25% of the final grade. Textbooks, laptops, phones, or other electronic devices are forbidden. Only a calculator and drawing instruments are allowed.

The exam is passed when the student riches 18/30 in both tests. If one of the two parts has an insufficient evaluation (<18/30), both tests (1 and 2) must be repeated in a next session.
Both tests take place on the same day in about 3.15 h of total time.