69261 - Structural Geology and Tectonics

Learning outcomes

This course will teach the students how to understand and analyze the tectonic structures at different scales, from hand samples to outcrop and regional scale, in the frame of the diverse geodinamical settings.

Course contents

Introduction                                                                                                                                                                                     Structural Geology and Tectonics: meaning and fields of work. Different scale of observation and methodological approach.

Stress and Strain
Stress and strain, from the point of view of Structural Geology. Stress-strain relationships. Rheology of rocks and factors controlling rocks behaviour. Brittle and ductile deformations.

Tectonic structures
Brittle tectonic structures: types and nomenclature. Mechanics of brittle deformation. Faults and fault mechanics.
Ductile tectonic structures: types and nomenclature. Processes of ductile deformation. Recrystallization and sin-kinematic crystallization. Ductile deformation and metamorphism.
Brittle-ductile transition and related structures. Fault rock evolution in depth: particulate grain flow, cataclastic flow, mylonites, pseudo-tachylites. Fault and earthquakes.
Folds, classification and nomenclature. Folding models and mechanics. Minor structures associated to folds.

Association of tectonic structures
Reverse and thrust faults, thrust sheets and nappes. Duplex. Thrust-related folding. Convergent margins, contractional tectonics. Oceanic crust subduction, accretionary and erosional margins, accretionary wedges, fore-arc and back-arc basins, ophiolitic back-arc, slab retreat, flat subduction. Microcontinents, terranes. Collision and intracontinental deformations, collisional and post-collisional chains. Continental crusts, cratons, sutures, ophiolites. Crustal discordances and tectonic levels; acoustic, magnetic and structural basament and cover. Reflection and refraction seismic investigation.
Nappe paradox and tectonics. Coulomb wedge and critical taper, analogue and digital model of accretionary wedges.
Normal faults. Graben, listric faults. Divergent margins, extensional tectonics. Graben, half-graben, rift zones, oceanic basins and crust, passive continental margins. Pre-sin and post-rift sequences, subsidence. Pure-shear and simple-shear models of continental crust thinning, metamorphic cores.
Transform and strike-slip faults. Transpressional and transtensional systems. Transform and strike-slip margins.
Salt and mud diapirism. Mud volcanoes.

Geological structure of the Planet Earth
Major physical and geochemical discontinuities. Nucleus, mantle, crust. Isostasy. Astenosphere and lithosphere. Earth's magnetic fields, palaeomagnetism. Plate tectonics paradigm. Plates, types of margins, triple junctions, hot spot, mantle plumes. Kinematics of plate motion, convective cells.

Readings/Bibliography

J. Mercier, P. Vergely "Tectonique" Dunod, 1999
P. Karey, F. Vine "Global tectonics" Blackwell, 1996

Teaching methods

Lectures.

Assessment methods

Written exam (4h), Practical text (15'), Oral exam (30').

Teaching tools

Computer aided presentation of slides. Samples will be used to measure kinematic data. 

Office hours

See the website of Corrado Venturini

See the website of Marco Antonellini