Terre-Environnement

The Earth system is often described as an association of superimposed envelopes, from the central seed to the most discrete zones at the edge of the vacuum of space. It can also be thought of as a system where rocks, water, air and life cohabit. The Earth system is first and foremost a whole, whose components are largely interconnected on all scales of time and space.

The Earth-Environment module is part of the exploration of couplings between the main components of the Earth system: solid earth, hydrosphere, atmosphere and biosphere. It aims to describe and explain some of the most striking interactions, and to show the extent to which these complex processes and couplings control our entire environment, right down to our daily lives, our safety (natural hazards and disasters) and the prospects for human survival on Earth.

Hourly volume :

CM: 30  

TD : 30   

TP: 12

i.e. 72 hours of classroom teaching. 48 blocks of 1.5 hours each (20 blocks of lectures, 20 blocks of lectures on practical subjects and 8 blocks of practical work).

The module is organized in the form of a short introduction to the module, followed by three thematic blocks which follow one another in the module's timetable:

1. Internal earth
2. Outer earth and geological hazards
3. Outer earth, hydrosphere and risks

The main objectives of the Earth & Environment module are to:

1. provide end-of-bachelor's degree-level knowledge and skills in coupling the various components of the Earth system, with a particular focus on the solid earth and hydrosphere envelopes, and to a lesser extent on the atmosphere and biosphere;
2. illustrate how certain terrestrial processes and their couplings are capable of controlling our immediate environment for good or ill, helping us in our daily lives or, on the contrary, threatening us, particularly during natural disasters and under the effect of natural hazards;
3. provide basic skills (initiation) in the sciences that enable us to understand the danger that the earth system can represent for man and his immediate environment. This knowledge is known as risk science, or more formally as cindynics.

In order to be more firmly rooted in reality, and to facilitate comparisons and exchanges between the various disciplines covered in the module, the Earth & Environment sessions alternate between the presentation of concepts and methods, on the one hand, and applications systematically focused on a territory where all the subjects covered are perfectly expressed: Iceland. On this territory, applications will take the form of carrying out simple calculations, exploring time series, using digital tools and critically analyzing physical and chemical data, maps and/or historical documents.

L2-level notions of geosciences and oceanography, to support the teaching of this module with some general knowledge.

Recommended prerequisites:

Preliminary reading of general documentation on climate evolution, ocean dynamics, the concept of waves, geodynamics, earthquakes, volcanoes, etc...

Assessment is based on continuous assessment.

For Block 1, assessment will be based on continuous assessment of the concepts and methods covered in class, and graded practical and practical work.

For Block 3, assessment is carried out in the form of a small booklet combining the performance of small calculations on risks, and the treatment of a precise question in relation to the themes of Block 3. 

Blocks 2 and 3 enable you to work on your oral preparation skills (Block 2 assessment) and written preparation skills (Block 3 assessment).

Speakers are indicated by their initials ( Frédéric Bouchette = FB; Cécilia Cadiot = CC; B. Gibert = BG; Mathieu Ferry = MF; Fleurice Parat = FP)

Introduction to the Earth & Environment module

The introduction has 2 objectives: (i) to give an overview of what will be covered in the module, and to present in detail the characteristics of Iceland, and (ii) to provide the risk science vocabulary needed throughout the module's teaching (and enabling students to better appropriate what is seen in class with a view to reusing this content in risk-oriented approaches).

Session 1 [1.5h; FB]: The notion of complex coupling (history, formulation in physics and natural sciences, etc.). How couplings between the various components of the Earth system influence mankind and the biosphere. The session shows the consequences of some of these couplings on our daily lives, on resources, on our safety, and on the prospects for human evolution in the Earth's environment. The session does not deal specifically with couplings specific to geoscience, but focuses on the concept of coupling and its various variations (threshold, feedback, runaway, sensitive chaos, asymptotic behavior, etc.). This is an introductory session.

Session 2 [1.5h CM, FP]: Introduction to the study of couplings within the Earth system, at different time and space scales. Presentation of the physical, mechanical and chemical characteristics of the various coupled processes covered in the course.

Session 3 [1.5h; FB]: Notions of cindynics (risk theory), presentation of the notions of danger, hazards, severity, probability of occurrence and return period, resilience, vulnerability, resistance, protection, prevention, risks, stakes, Farmer's diagram and the methods used to calculate natural hazards. The course clearly echoes the highly interdisciplinary nature of these approaches and the need to consider couplings within the earth system in this work.

Block 1: Deep couplings and their relationship with other components of the Earth system

Content: 7.5 CM; 10.5 TD; 3 TP = 21 h face-to-face (14 blocks of 1.5h FdS)

Sessions 1 & 2 & 3 (FP; 3 CM + 3 TD + 1.5 TP) - Internal structure of the Earth - Differentiation of the Earth.

Introduction to experimental petrology (tools, concepts) to understand the Earth's internal structure and deep-sea processes. Notion of phase change and phase equilibrium, mineralogy and physical properties (PREM model, Birch experiment), link between internal structure and geodynamics (density, moment of inertia, convection...).

TD/TP: Visit to the High Pressure Laboratory + TD and TP on modeling melting and crystallization processes using simple phase equilibrium diagrams and observations of thin sections of mantle and magmatic rocks.

Sessions 4 & 5 (FP; 1.5 CM + 3 TD + 1.5 TP) Geochemical tracing of deep-sea processes

Notion of recycling, mass balance and geochemical cycle by coupling petrogeochemical approaches at different scales (study of trace elements, radiogenic and stable isotopes and volatile elements in minerals and rocks) while linking the different internal and external envelopes.

In particular, we'll be looking at the carbon cycle and the processes of decarbonation and hydration at subduction zones, the processes of mantle metasomatism, and we'll be taking stock of the chemical transfers of carbon and sulfur between the asthenosphere, lithosphere, hydrosphere and atmosphere.

TD and TP: Modeling of deep processes (recycling, metasomatism, melting, etc.) based on trace element and isotope concentrations in magmas + Studies of hydration and dehydration processes in mantle rocks based on observations of thin sections (peridotites, serpentinites) and thermodynamic models.

Sessions 6 & 7 & 8 (FP: 1.5 CM + 1.5 TD ; BG; 1.5 CM + 3 TD) Mineral resources and geothermal energy

The aim of this section is to make the link between deep processes and supergene processes - We will make the link between deep processes and the diversity of rocks on the surface, and will also look at the processes behind the high concentrations of rare elements and metals in rocks. We'll see how rocks at the surface concentrate rare elements and metals to concentrations of economic interest. The approach combines geochemical tracing and experimental petrology at low pressure and low temperature to understand enrichment processes. Finally, we will examine how heat transfer from the depths of the Earth to the surface can lead to the concentration of geothermal resources.

Block 2: Solid Earth - Hydrosphere - Climate couplings

Content: 7.5 CM; 13.5 TD; 3 TP = 24 h face-to-face (16 FdS blocks of 1.5h each)

Sessions 1 & 2 (RC; 1.5 CM + 4.5 TD): Impact of external forcings and climate on Solid Earth dynamics = Effects of glacial, hydrological and erosion-sedimentation cycles on lithospheric deformation, seismic and volcanic activity. These two sessions mix a lecture part (physical geodynamics, response to surface loading by isostasy or flexure) and a practical part (exercises on "typical" cases, e.g. the effect of glacier melting on the activity of a volcano in Iceland).

Session 3 (RC; 1.5 CM + 1.5 TD): Solid Earth-Sea Level Interactions. A lecture on relative sea level (= vertical movements + eustasy) at global and regional scales in relation to climate change. A TD section on a case study of a subsiding delta (Mississippi, Nile, Rhône), potentially with tide gauge time series analysis.

Sessions 4/5/6/7/8 (CC; 4.5 CM; 7.5 TD; 3 TP ) : Volcanic hazards. These sessions will deal with volcanic hazards (6h) and extend these aspects to the effect of volcanoes on climate (3h), with a link to issues of coupling with the hydrosphere and atmosphere. The course will also include a section on internal-surface process coupling (e.g. plume/Iceland) based on remote sensing (InSAR/GPS) (6h).

Block 3: Couplings and risks focused on the hydrosphere and atmosphere

Content: 10.5 CM; 6 TD; 6 TP = 21 face-to-face hours (15 FdS blocks of 1.5h each)

Two sessions -- one preparatory and one follow-up (1.5 CM + 1.5 TD) -- are devoted to writing a micro-dissertation (4 pages): choice of topic from a pre-proposed list, construction of the accompanied plan, definition of the writing strategy (content/form), writing methods.

Sessions 1 & 2 (FB; 1.5 CM + 1.5 TD): Weather-sea forcings and weather-sea and coastal hazards. The course shows how meteo-sea forcings (waves, wind, atmospheric pressure, temperature gradient including internal, which is relevant to Iceland) control coastal hydrodynamics and thus potentially meteo-sea and coastal hazards (submersion, erosion). Principles, examples, case studies on Iceland.

Sessions 3 & 4 (FB; 1.5 CM + 1.5 TD): Impact of storms on the coast (meteo-sea risk). Quantification of forcings and calculation of their impact on the coast. Calculation of quantities specific to weather-sea hazards (severity, return period, probability of occurrence, calculation of a form of vulnerability). Application to the case of marine weather hazards on Iceland (Exercise).

Sessions 5 & 6 (FB; 1.5 CM + 1.5 TD): The course presents the couplings dominated by ocean dynamics and the atmosphere and their morphological implications on the littoral zone and the continent. Concepts covered include: (i) definition of marine weather indices (NAO & co) as markers of climate and large-scale ocean/atmosphere instabilities/couplings, (ii) atmosphere/ocean surface couplings: wave growth, (iii) wave/wave/current couplings and rogue waves, (iv) feedback of terrestrial dynamics on ocean dynamics (tsunamis, edge waves, seiches, tides). The course then goes on to develop scenarios in which perturbations of the weather-sea signal by other components of the earth system (a volcanic explosion, an earthquake, etc.) can totally alter these dynamics. Systematic examples are taken from the North Atlantic and Iceland.

Sessions 7 & 8 (FB; 1.5 CM + 1.5 TP): The double session focuses on quantifying water levels at the coast (a coupled process par excellence) under different trend or catastrophic scenarios: (i) volcanic eruption, (ii) tsunamis, (iii) storms, (iv) rising water levels due to global change (role of ice expansion/ melting, rebound). The session quickly calculates these different situations in terms of run-up (change in water level at the coastline) and water level at rest, based on simple laws. The student is led to compare the orders of magnitude of the energy imposed and the orders of magnitude of the response in terms of hazard. The session revisits the notions of hazard severity and return period seen in session 2, and opens up the analysis of long-term trends. This session echoes the work done in Block 2 on water levels (Block 2, session 3).

Sessions 9 & 10 (1.5 TP + 1.5 TP): Double session of physical experimentation (channel or digital channel). A gravity slide generates a tsunami wave in a wave channel and produces certain morphodynamic effects on the littoral zone after propagation. Study of similarity, qualitative analysis of chained and coupled effects, outline of quantification (run-up, volume displaced, energy mobilized). Allows us to illustrate terrestrial couplings, the role of the hydrosphere in energy transfer, and the final effect on a key territory for man (the coastline), with a view to quantifying the hazard.

Sessions 11 & 12 (1.5 CM + 1.5 TP): More advanced notions of cindynics (on examples taken from the hydrosphere)