Book contents
- Frontmatter
- Contents
- Preface and Philosophy
- Abbreviations and acronyms
- Part I Planetary perspective
- Part II Earth: the dynamic planet
- Part III Radial and lateral structure
- Part IV Sampling the Earth
- Chapter 12 Statistics and other damned lies
- Chapter 13 Making an Earth
- Chapter 14 Magmas: windows into the mantle
- Chapter 15 The hard rock cafe
- Chapter 16 Noble gas isotopes
- Chapter 17 The other isotopes
- Part V Mineral physics
- Part VI Origin and evolution of the layers and blobs
- Part VII Energetics
- References and notes
- Appendix
- Index
Chapter 14 - Magmas: windows into the mantle
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface and Philosophy
- Abbreviations and acronyms
- Part I Planetary perspective
- Part II Earth: the dynamic planet
- Part III Radial and lateral structure
- Part IV Sampling the Earth
- Chapter 12 Statistics and other damned lies
- Chapter 13 Making an Earth
- Chapter 14 Magmas: windows into the mantle
- Chapter 15 The hard rock cafe
- Chapter 16 Noble gas isotopes
- Chapter 17 The other isotopes
- Part V Mineral physics
- Part VI Origin and evolution of the layers and blobs
- Part VII Energetics
- References and notes
- Appendix
- Index
Summary
If our eye could penetrate the Earth and see its interior from pole to pole, from where we stand to the antipodes, we would glimpse with horror a mass terrifying riddled with fissures and caverns
Tellus Theoria Sacra (1694), Thomas BurnetVarious kinds of magmas, ranging from mido-cean-ridge basalts (MORB) to kimberlite (KIMB) emerge from the mantle. Material is also recycled into the mantle; sediments, oceanic crust, delaminated continental crust, water and peridotite. Parts of the mantle are inaccessible to direct sampling and we can only infer their compositions by subtracting off the sampled components from what is thought to be the original composition. There is no assurance that we are currently receiving samples from all parts of the Earth, although this is the hope of many geochemists. There is reason to believe that the chemical stratification of the mantle is irreversible, and that there exist hidden ‘reservoirs’ (a bad term for a permanent repository). Nevertheless, the accretional stratification of the Earth may have placed most of the low-melting point lithophile elements within reach. In fact, one can construct a plausible compositional model for the mantle by isolating the dense refractory depleted products of differentiation in the deep mantle. This would make the Mg, Si and Fe contents of the mantle uncertain but these can be constrained by geophysics, mineral physics and cosmology.
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- New Theory of the Earth , pp. 168 - 188Publisher: Cambridge University PressPrint publication year: 2007