Structural geology

This course presents the fundamentals of structural geology at the undergraduate level. The course will focus on the analysis of various objects and deformation processes present at all levels of the Earth's crust. Rock deformation will be studied using field examples (photos and geological maps), samples, thin sections, and experiments. The main points covered will be the analysis of deformation processes (brittle and ductile), as well as associated structural features. The interpretation of these structures will be addressed in terms of tectonic regimes. Techniques for structural measurements and stereographic projections of features encountered in the field will be taught. Structural analysis will range from small scale using a microscope to large scale using^1:50,000 geological maps and satellite photos of deformed areas.

Hourly volumes:

• CM: 6 hours
• Tutorial: 6 hours
• Practical work: 6 hours

This course aims to provide students with fundamental concepts in structural geology, practical skills, and mastery of tools for acquiring, processing, and interpreting field data. Students will understand how to approach the analysis of naturally deformed objects at all scales and how to characterize a deformation regime based on natural field data.

• HAT102T Geology
• HAV213T Evolution of the Earth and Regional Geological History

Recommended prerequisites:

• HAT202T Experimentation and Earth Dynamics

100% Continuous assessment: 5 grades from lectures, tutorials, and practicals.

Brief description of the concepts covered in CM:

• Stereographic projection techniques: theory, notation systems, transfer techniques: examples of planes and lines.
• Analysis and interpretation of tectonic objects and processes (part 1): brittle deformation
• Analysis and interpretation of tectonic objects and processes (part 2): ductile deformation
• The micro-mechanisms of deformation: cataclastic creep, dynamic recrystallization, and diffusion. Shear criteria.

Brief description of tutorial sessions and number of hours associated with each session

• Stereo reports 1/2: objects and axes of principal stresses - Brittle deformation: stylolites, tension cracks, faults, and striations. Tilting (rotation) of layers. Links with the tectonic regime. 1.5 hours.
• 2/2 stereo reports: objects and axes of main deformation - Ductile deformation: schistosity and lineation; superposition and crenulation; folds, axes, and axial planes; tilting of flanks around the fold axis. 1.5 hours.
• Geological map of Lavelanet or Mas-d'Azil: cross-section based on map extracts. 3 hours.

Brief description of practical sessions and number of hours associated with each session

• Measuring plans on campus, positioning and transferring data onto a map; first use of a compass and clinometer. 1.5 hours (Homework => Stereographic projections).
• Micro-optics: 4 thin sections of deformed rocks to observe (3 granites: deformation at BT, MT, and HT, + 1 mica schist) => annotated drawings of two thin sections, + explanations. 1.5 hours.
• Geological maps of Ornans or Pontarlier: structural diagram and cross-section. 3 hours.

No land

• Understanding the mechanisms of crustal rock deformation at all depths.
• Knowing how to recognize, analyze, and interpret a geological structure in the field, on a map, or under a microscope.
• Know how to measure structural objects in 3D and master stereographic projection techniques (conversion to 2D).
• Mastering the techniques of reading and analyzing geological maps.