Earth-Environment

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

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

Hourly volume:

CM : 30  

TD : 30   

TP: 12

That is to say a student face-to-face volume of 72 hours. That is to say 48 blocks of 1.5 hours of teaching (20 blocks of lectures, 20 blocks of lectures and 8 blocks of practical work)

The module is organized in the form of a short introductory lecture to the module followed by the following three thematic blocks which follow one another in the module schedule:

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

The main objectives of the Earth & Environment module are:

1. to provide knowledge and skills at the end of the Bachelor's degree on the couplings between the different components of the Earth system, focusing on the solid earth and hydrosphere envelopes, and to a lesser extent on the atmosphere and biosphere;
2. to illustrate how certain terrestrial processes and their couplings are able to control our immediate environment for good or bad, to help us in our daily life or on the contrary to threaten us, in particular during natural disasters and under the effect of natural hazards;
3. to provide basic skills (initiation) on the sciences that allow to apprehend the danger that the earth system can represent for man and his immediate environment. This knowledge is called risk science, or more formally cindynics.

In order to be better anchored in reality and to facilitate connections and exchanges between the various disciplines covered in the module, the Earth & Environment sessions alternate between, on the one hand, the presentation of concepts and methods and, on the other hand, applications that are systematically concentrated on a territory where all of the subjects mentioned are perfectly expressed: Iceland. On this territory, the applications will take the form of simple calculations, exploration of time series, use of numerical tools and critical analysis of physical and chemical data, maps, and/or historical documents.

Notions of geosciences and oceanography at the L2 level, allowing to support the teachings of this module on some general knowledge.

Recommended prerequisites:

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

The control of knowledge is done in continuous control.

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

For block 3, the evaluation is carried out in the form of a small booklet combining the realization of small calculations on the risks, and the treatment of a precise question in relation to the topics of block 3. 

Blocks 2 and 3 allow you to work on the skills of preparing an oral (assessment of block 2) and preparing a written (assessment of block 3).

The 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 two objectives: (i) to provide an overview of what will be covered in the module, and to present in detail the characteristics of Iceland and (ii) to provide the vocabulary of risk sciences necessary throughout the teaching of this module (and allowing students to better appropriate what is seen in the course with a view to reusing this content in risk-oriented approaches).

Session 1 [1.5h; FB]: The concept of complex coupling (history, formulation in physics and natural sciences, etc). How the couplings between the different components of the Earth system influence man and the biosphere. The session shows the consequences of some of these couplings on our daily life, on resources, on our security, on the evolutionary perspectives of Man in the terrestrial environment. The session does not specifically evoke the couplings specific to geoscience, but is mainly interested in the concept of coupling and its different declinations (threshold, feedback, runaway, sensitive chaos, asymptotic behavior,...). 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 different coupled processes that will be discussed in the course.

Session 3 [1.5h; FB]: Notions of cindynics (risk theory), presentation of the concepts of hazard, hazards, severity, probability of occurrence and return period, resilience, vulnerability, resistance, protection, prevention, risks, issues, Farmer's diagram and the methods implemented for the calculation of natural hazards. The course clearly echoes the highly interdisciplinary nature of these approaches and the need to consider the 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 of classroom time (14 blocks of 1.5 h)

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 internal structure of the Earth and deep 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 of the High Pressure laboratory + TD and TP of modeling of melting and crystallization processes from 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 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 of minerals and rocks) while making the link between the different internal and external envelopes.

We will discuss the carbon cycle and the processes of decarbonation and hydration at subduction zones, the processes of metasomatism in the mantle, and we will review the chemical transfers of carbon and sulfur between the asthenosphere, lithosphere, hydrosphere and atmosphere.

TD and TP: Modeling of deep processes (recycling, metasomatism, melting...) from trace element and isotope concentrations in magmas + Studies of hydration and dehydration processes in mantle rocks from thin section observations (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

This section is intended to relate deep processes to supergene processes - We will relate deep processes to the diversity of rocks at the surface and also discuss the processes that cause high concentrations of rare elements and metals in rocks. We will see how rocks at the surface concentrate rare elements and metals to reach concentrations of economic interest. The approach combines geochemical tracings and experimental petrology at low pressure and low temperature to understand the enrichment processes. Finally, we will see by which processes heat transfers 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 of classroom time (16 blocks of 1.5 h)

Sessions 1 & 2 (RC; 1.5 CM + 4.5 TD): Impact of external forcing and climate on the dynamics of the Solid Earth = 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 a surface load by isostasy or flexure) and a practical part (exercises on "typical" cases, e.g., 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 motions + eustasy) at global and regional scales in relation to climate change. A lecture part on the case study of a subsiding delta (Mississippi, Nile, Rhone), 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 will extend these aspects to the effect of volcanoes on the climate (3h) by making a link with the coupling issues with the hydrosphere and atmosphere. The teaching will also include a part on the coupling between internal and surface processes (e.g. plume/Iceland) based on remote sensing (InSAR/GPS) (6h).

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

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

Two sessions -- one preparatory and one follow-up (1.5 CM + 1.5 TD) -- are devoted to the writing of a micro-dissertation (4 pages): choice of the theme treated in 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): Marine weather forcings and marine and coastal hazards. The course shows how marine weather forcing (waves, wind, atmospheric pressure, temperature gradient including internal, which is relevant on Iceland) control coastal hydrodynamics and thus potentially marine weather 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 (weather-sea risk). Quantification of forcings and calculation of their impact on the coast. Calculation of quantities specific to weather-marine risks (severity, return period, probability of occurrence, calculation of a form of vulnerability). Application to the case of the meteorological-marine hazard on Iceland (Exercise).

Sessions 5 & 6 (FB; 1.5 CM + 1.5 TD): The course introduces the couplings dominated by ocean and atmosphere dynamics and their morphological implications on the littoral zone and the continent. Concepts discussed in the course are for example: (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, ripples, cuttlefish, tides). The course then develops 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 area and Iceland.

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

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

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