Structure and Dynamics of the Earth's Interior 2 E-Book

Sylvie Demouchy

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Serie: ISTE Invoiced
• Sprache: Englisch

Seitenzahl: 505

Veröffentlichungsjahr: 2025

Beschreibung

The interior of our planet is one of the last 'terra incognita'. Its chemical composition and onion-like structure of solid rocks and rare minerals make it a fascinating object. It is primarily its dynamic that makes Earth such a singular object in the solar system, with perennial, active plate tectonics for several billion years.

While its dynamic is obvious on the surface (earthquakes, volcanic eruptions, mid-oceanic rifts), the very nature of the Earth's mantle – beneath the crust and in contact with the core – has not revealed all of its secrets.

Structure and Dynamics of the Earth's Interior 2 recalls the fundamental principles of several key physicochemical properties of the materials which make up the Earth's mantle. This book then describes the latest technological advances used at high pressures and temperatures to reproduce the extreme conditions of the Earth's mantle in the laboratory. It also presents the latest and most significant scientific results.

Leseprobe

SCIENCES

Geoscience, Field Director – Yves Lagabrielle

Earth’s Interior, Subject Head – Nathalie Bolfan-Casanova

Structure and Dynamics of the Earth’s Interior 2

Composition and Structure of the Earth’s Mantle

Coordinated by

Sylvie Demouchy

Nathalie Bolfan-Casanova

First published 2025 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

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© ISTE Ltd 2025The rights of Sylvie Demouchy and Nathalie Bolfan-Casanova to be identified as the authors of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.

Library of Congress Control Number: 2024950231

British Library Cataloguing-in-Publication DataA CIP record for this book is available from the British LibraryISBN 978-1-78945-166-5

ERC code:PE10 Earth System Science PE10_5 Geology, tectonics, volcanology PE10_7 Physics of earth’s interior, seismology, volcanology

Foreword

Michel GRÉGOIRE

GET, Université Toulouse III, France

The Earth’s mantle, which lies between the Earth’s crust and the planetary core, largely dominates the volume (83%) and mass (66%) of our planet. It extends from 2,900 km to a depth of 5–10 km beneath the oceans, and from 2,900 km to a depth of 30–50 km beneath the continents. It is subdivided into a lower mantle and an upper mantle. Its immense thermal inertia controls the slow cooling of the planet and, through the convection process that drives it, has maintained plate tectonics for at least 2 billion years, if not more. Contrary to popular belief, which sometimes still persists, the Earth’s mantle is solid and magma production takes place only very locally, in zones of partial melting corresponding essentially to oceanic ridges, subduction zones and hot spots or mantle plumes.

The Earth’s mantle, by virtue of the considerable volume of rock it represents, but also by virtue of its major role in the sensu lato geological history of our planet, has been the subject of numerous studies over the last century. It is the focus of attention of many Earth-science disciplines: petrology, mineralogy, geochemistry, petrophysics, geophysics, structural geology, experimentation and modeling. The history of the mantle has been highly complex since the Archean period, due in particular to the evolution over time of convection processes, linked in particular to the progressive cooling of our planet’s interior, the appearance and differences in time and space of recycling processes of the crust in the mantle (subduction and delamination). Another aspect is the existence and variation in the activity of mantle plumes, some of which are rooted in complex and still largely enigmatic zones close to the mantle-core interface (D″ layer). Our knowledge of the evolution and functioning of the Earth’s mantle remains incomplete, even today, and generates much debate in the scientific communities concerned. To explain this state of our knowledge, we need to remember that it was only some 60 years ago that most of the mantle was no longer seen as a static object but rather as an object behaving like a viscous fluid that flows slowly, dragging tectonic plates along its surface, plates that combine the Earth’s crust and the lithospheric part of the mantle. In fact, it was not until the late 1960s that bathymetric and magnetic surveys of the ocean floor made it possible to establish plate tectonics, the driving force behind continental drift.

Another difficulty is that the mantle rarely appears on the surface of the globe: it is mainly found in mountain ranges, at the bottom of the oceans and in the form of fragments (xenoliths) torn off at depth by certain magmas and rapidly brought to the surface by the eruption of these magmas. Moreover, these mantle rocks very rarely come from depths greater than 200 km. The only other natural samples to reach the surface are very small minerals (periclase, ringwoodite, etc.) embedded in diamonds and brought up from the localized transition zone between the lower and upper mantle. In any case, studies of these natural samples are providing essential constraints on our understanding of the Earth’s mantle. However, alternative approaches enabling a more global vision and understanding are becoming increasingly essential. In this context, the geochemical approach, which some refer to as chemical geodynamics, based solely on the isotopic characteristics of lavas of mantle origin observed at the earth’s surface, in particular basalts from oceanic rifts (mid-ocean ridge basalt (MORB)) and oceanic islands (ocean island basalt (OIB)) or continental volcanoes has made it possible to define major geochemical reservoirs in the earth’s mantle. This approach now appears very schematic, given the complexity of the Earth’s mantle and associated mantle processes. It does, however, provide important information when the results are integrated with those of other approaches.

Geophysical and experimental approaches, along with modeling and tomography, form the core of this book. They are the other main and complementary approaches to understanding and constraining the complex history of the Earth’s mantle, at scales ranging from the crystal scale to the global scale. The results of these experimental and geophysical studies, when integrated with those of studies on natural samples, both directly from the mantle and from MORBs and OIBs, currently allow the best advances in our understanding of the Earth’s mantle, from its formation to the present day, and the processes that have affected it and continue to affect it.

Ultimately, it is the combination of these different approaches that will, as I believe, lead to major advances in our understanding in the near future. Over the last few decades, this understanding has also extended to other bodies in the Solar System (mantle of telluric planets, asteroids and meteorites), some of whose mineralogical constituents are, for the most part, similar to those of the Earth’s mantle.