OVERVIEW

The Geodynamics course explores the relationships between causes and effects ruling global tectonics on our planet and the geological structure of other planetary bodies of the Solar System including their internal structure.

AIMS AND CONTENT

LEARNING OUTCOMES

The course provides the fundamentals of plate tectonics and the upper mantle dynamics. We explore the geometry, kinematics and dynamics of the processes involving the Earth's crust / lithosphere in order to quantitatively study and model the relationships between causes (forces and stress) and effects (tectonics) at the various spatial and temporal scales. This knowledge is the basic tool for understanding the past evolution and for modeling the future evolution of the Earth as well as other planetary bodies. Applications include the understanding of the seismo-tectonics of active regions.

AIMS AND LEARNING OUTCOMES

The knowledge acquired during the course will allow students to quantify the geological and geodynamical processes at the various scale in order to be able to evaluate the role of stress/forces and associated deformations (tectonics). The learning outcomes include: the quantification and numerical solution of practical geological problems through the application of the equations presented at the course; the solution of complex problems through the Monte Carlo Method approach; the creation of 2D models of crustal thickening and thinning; the quantification of the state of stress along passive continental margins; the quantification of the role of the oceans in plate tectonics; the modeling of the elastic behavior of the lithosphere in different geodynamical contexts; the understanding of the crustal stress trajectories through the analysis of the lineament domains revealed on synthetic images of planet surfaces.

PREREQUISITES

Basic knowledge in Mathematics, Physics, Earth Physics, Plate Tectonics, Geology, and Structural Geology, acquired during the undergraduate degree courses.

TEACHING METHODS

In agreement with the current legislation on the COVID19 emergency, the teaching will include blended activities in-presence and web conference. Both classes and test exercises are based on multimedia presentations, in-presence and/or web-conference. Attendance to all planned activities is strongly recommended.

Students will prepare reports to be presented to the class on specific geodynamic problems analyzed individually and/or in small teams.

Test exercises will be carried out for evaluating the ongoing assessment of class learning.

Please refer to the specific AulaWeb application for teaching for any updates due to changes in the health and epidemiological situation.

SYLLABUS/CONTENT

Introduction to Geodynamics. Scale and Resolution. “Fundamental” and “negligible” forces. Kinematic and dynamic related forces. The “Chinese box mechanism”. Limits related to volume preservation. Analytical matematical vs fractal models. Dynamic Interaction between lithospere and astenosphere, and between crust and mantle.

Plate tectonics. The interior of the Earth. Active margins kinematics: subduction zones, rifting zones, transform zones. Intraplate strike-slip tectonics. Plate motions. Euler theorem and its limits. Rotations. Paleomagnetic data and magnetic anomalies to reconstruct plate tectonic movements. The Wilson Cycle. Principles of planetary geodynamics.

Body forces and surface forces. Isostasy. Continental buoyancy. Application of isostasy to the different geodynamic environments. Vertical surface forces. Horizontal surface forces. Balancing of horizontal and vertical surface forces. Stress in two dimensions. Stress in three dimensions. Pressures in the Deep Interiors of Planets. Stress measurements. Strain measurements.

Linear elasticity. Uniaxial stress. Uniaxial strain. Plane stress. Plane strain. Pure shear and simple shear. Isotropic stress. 2D flexure of an elastic plate.  Balancing forces and torques. Deflection of a simple elastic plate. Buckling of a Plate under a Horizontal Load. Deformation of Strata Overlying an Igneous Intrusion. Application to the Earth lithosphere. Periodic loading. Stability of the Earth’s Lithosphere Under an End Load. Bending of the Elastic Lithosphere under the Loads of Island. Bending of the Elastic Lithosphere at an Ocean Trench. Flexure and the Structure of Sedimentary Basins

Richiamo del concetto di elasticità lineare. Uniaxial stress. Uniaxial strain. Plane stress. Plane strain. Pure shear and simple shear. Stress isotropico. Flessurazione 2D di una piastra elastica. Bilanciamento di forze e momenti. Bending di una piastra sottoposta a torsione, ad una forza verticale concentrata ad un estremo, a carico omogeneo. Buckling di una piastra sotto l’effetto di un carico orizzontale. Flessione di uno strato di roccia sovrastante un laccolite. Applicazione alla litosfera terrestre. Carico periodico. Stabilità della litosfera terrestre alla compressione laterale. Flessurazione della litosfera sotto il carico di catene di isole vulcaniche. Flessurazione della litosfera in subduzione. Flessurazione della litosfera in bacini sedimentari.

Subcontinental geodynamic study from synthetic scaled images (remotely sensed data, geophysical images). Principles of Remote Sensing. Analysis of digital elevation models (DEM) and satellite images. Manual and automatic analysis of lineament domains. Statistical analysis of lineaments.

RECOMMENDED READING/BIBLIOGRAPHY

- Turcotte, Donald, and Gerald Schubert. Geodynamics. Cambridge University Press, 2014.

-Kearey, Philip, Keith A. Klepeis, and Frederick J. Vine. Global tectonics. John Wiley & Sons, 2009.

- Frisch, Wolfgang, Martin Meschede, and Ronald C. Blakey. Plate tectonics: continental drift and mountain building. Springer Science & Business Media, 2010.

- Turcotte, Donald L. Fractals and chaos in geology and geophysics. Cambridge university press, 1997.

Material presented during the class will be available in aulaweb.

TEACHERS AND EXAM BOARD

Exam Board

PAOLA CIANFARRA (President)

LAURA CRISPINI

FRANCO ELTER (President Substitute)

NICOLA CORRADI (Substitute)

LAURA FEDERICO (Substitute)

DANILO MORELLI (Substitute)

LESSONS

LESSONS START

Please refer to  https://easyacademy.unige.it/portalestudenti/

Class schedule

GEODYNAMICS

EXAMS

EXAM DESCRIPTION

By interview. Please refer to the specific AulaWeb application for teaching for any updates due to changes in the health and epidemiological situation

ASSESSMENT METHODS

Interview on the topics covered during the course.

Exam schedule

FURTHER INFORMATION

Continuous attendance at classes and course activities is strongly recommended.