Minerals and Rocks

The objective of this course unit is to introduce the concepts and tools needed to observe and describe igneous and metamorphic rocks, to understand their origin, and to appreciate their importance within the geosciences.

The course will begin with an introduction to the concepts of mineralogy (crystallography, crystal chemistry) and the tools needed to identify the minerals that make up igneous and metamorphic rocks, both on a macroscopic and microscopic scale.

The various types of igneous and metamorphic rocks will then be discussed and placed within the geodynamic contexts in which they formed.

Two field trips in the Montpellier region will be offered to illustrate and supplement the course material: the first field trip will focus on volcanism in the Hérault Valley (from Agde to Salagou), and the second will explore magmatic and metamorphic features in the Cévennes.

Be able to identify the main minerals in igneous and metamorphic rocks, understand the conditions under which they form, identify the main igneous and metamorphic rocks, and understand the conditions under which they form.

Basic knowledge of chemistry: the periodic table of elements and the physical and chemical properties of chemical elements. Basic concepts of mineralogy and crystallography (definition of a mineral, what it is composed of, the properties used to identify it, and recognition of common minerals).

Continuous, comprehensive assessment. Students will be evaluated throughout the semester based on three assessments designed to evaluate their practical and theoretical knowledge gained in lectures, lab sessions, and fieldwork:

- a test on mineralogy, accounting for 40% of the final grade,

- a test on magmatism, accounting for 30% of the final grade

- a test on metamorphism, accounting for 30% of the final grade.

• Brief description of the concepts covered in fourth grade:

4th Grade: Mineralogy. Basics of crystal chemistry: How is a crystal formed? From the properties of the elements to the formation of a silicate (Pauling’s rules).

5th Grade: Mineralogy: Systematics of Silicates. Introduction to the major groups of silicates, with a focus on several silicates that illustrate the role of atomic-scale structure in determining physical and chemical properties.

CM3: Magmatic Petrology: Classification of igneous rocks, structure and nature of the mantle, processes of partial melting and fractional crystallization.

CM4: Magmatic Petrology: Physical Properties of Magmas, Dynamics and Eruptive Styles, Magmas in Their Geodynamic Context.

CM5: Metamorphic Petrology

CM6: Metamorphic Petrology

• Summary description of the lab sessions and the number of hours associated with each session

Lab 1: Mineralogy. Review of the physical properties of minerals that enable their identification. Macroscopic identification of silicates (quartz, micas, amphibole, pyroxenes, garnets, olivine, metamorphic silicates)

Lab 2: Macroscopic identification of silicates. Study of the atomic structures of several silicates to illustrate the course (quartz, olivine, micas).

Lab 3: Introduction to the Optical Microscope: Use with Unanalyzed Polarized Light.

Lab 4: Introduction to the Optical Microscope: Use with Analyzed Polarized Light.

TP5: Macroscopic and Microscopic Identification of Volcanic Rocks.

TP6: Macroscopic and Microscopic Identification of Plutonic Rocks.

TP7: Macroscopic and Microscopic Identification of MP/MT Metamorphic Rocks.

TP8: Macroscopic and Microscopic Identification of HP/HT Metamorphic Rocks.

• Description of the topics/hands-on activities covered during your field trip(s) and details on the destinations/sites

Field Trip 1: Volcanism in the Lower Hérault Valley: the Baumes Volcano, the Lézignan-la-Cèbe lava flows, the Cap d’Agde Volcano, and La Conque Beach. The purpose of this field trip is to illustrate the basaltic volcanism that prevailed during the Quaternary period in the lower Hérault Valley. The goal is to highlight, through field observation of exposed volcanic structures, different eruptive styles (phreatomagmatism, Strombolian activity, and lava flow structuring). It also aims to explore the origin of the magmas through observation of the exposed rocks.

Field Trip 2: Metamorphism in the Cévennes: Arres, Col de la Barrière, Dourbies.

The main objective of this field trip will be to identify the metamorphic rocks and structures outcropping in the Cévennes (green schists, metamorphic dolomites, cordierite and andalusite schists) and to reconstruct the history of the formation of these metamorphic rocks. A 2-kilometer-long section will be surveyed between the Col de Rhodes and Dourbies to characterize the metamorphism associated with the emplacement of the Saint-Guiral-Liron granitic pluton.

• Be able to identify, at the macroscopic level, the main minerals found in igneous and metamorphic rocks
• Understand the basic principles of how a polarizing optical microscope works and know how to use it to identify common minerals under polarized and polarized-analyzed light.
• Be able to identify the major types of igneous and metamorphic rocks and associate them with geological contexts.
• How to Read a Geological Map
• How to Interpret a Landscape and Create a Drawing of an Outcrop