Structural geology

This course introduces the fundamentals of structural geology at the undergraduate level. The teaching will focus on the analysis of the different objects and deformation processes present at all levels of the earth's crust. The deformation of rocks will be studied from field examples (photos and geological maps), samples, thin sections and experiments. The major points presented will be the analysis of the deformation processes (brittle and ductile), as well as the associated structural objects. The interpretation of these structures will be discussed in terms of tectonic regimes. Techniques for structural measurements and stereographic projections of objects encountered in the field will be taught. The structural analysis will be done from the small scale with the microscope, to the large scale via the study of geological maps ^1/50000th and satellite photos in deformed domains.

Hourly volumes:

• CM : 6h
• TD : 6h
• TP : 6h

This course aims to provide the student with fundamental notions in structural geology, practical know-how and the mastery of tools for the acquisition, processing and interpretation of field data. The student will understand how to approach the analysis of naturally deformed objects at all scales, and how to characterize a deformation regime from natural field data.

• HAT102T Geology
• HAV213T Earth evolution and regional geological history

Recommended prerequisites:

• HAT202T Experimentation and Earth Dynamics

100% Continuous assessment: 5 grades of CM, TD and TP.

Synthetic description of the concepts covered in CM:

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

Synthetic description of the TD sessions and number of hours associated with each session

• Stereo reports 1/2: objects and axes of principal stresses - Brittle deformation: styloliths, tension cracks, faults and striations. Tilting (rotation) of layers. Links with the tectonic regime. 1h30.
• Stereo reports 2/2 : objects and axes of the main deformation - Ductile deformation : schistosity and lineation ; superposition and crenulation ; folds, axes and axial planes ; flank unturning around the fold axis. 1h30.
• Geological map of Lavelanet or Mas-d'Azil: section from map extracts. 3h.

Synthetic description of the practical sessions and number of hours associated with each session

• Measurements of plans on campus, positioning and transfer of data to map; 1st use of compass and clinometer. 1h30 (Homework => Stereographic projections).
• Micro-optics: 4 thin slides of deformed rocks to observe (3 granites: deformation at BT, MT and HT, + 1 micaschist) => annotated drawings of two thin slides, + explanations. 1h30.
• Geological maps of Ornans or Pontarlier: structural diagram and section. 3h.

No land

• Understand the mechanisms of crustal rock deformation at all depths.
• Know 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 the techniques of stereographic projections (transition to 2D).
• Master the techniques of reading and analyzing geological maps.