Inaccessible Earth: Integrated View of Its Structure and Composition Book

This is the second edition of a treatment of the origin, structure and internal composition of the Earth, synthesizing the geological, chemical and physical knowledge bearing on the Earth's inaccessible interior. It seeks answers to questions about the Earth's origin, evolution and dynamics, producing an integrated account of these subjects suitable for students and teachers in the earth sciences. Why do we think that the centre of the Earth is a nickel-iron alloy; or that the crust evolves by processes at subduction zones and by vertical plumes rising through the mantle; or that the Earth's magnetic field is generated by some form of convection in the molten outer core? The evidence comes from many disciplines ranging from geology to nuclear physics, but the contributions of geophysics and geochemistry are particularly important and have been given equal weight, while mathematics has been kept to a minimum. The text traces the evolution of the earth's layered structure and explains how its density at depth is deduced from seismic and gravitational data. Density is the prime constraint on chemical composition which is deduced also by reference to new theories of stellar evolution and planetary accretion, combined with evidence from the solar system and meteorites. With this information as background, the second half of the text goes on to describe the probable composition and physical state of the present-day core, mantle and crust. In the second edition, more emphasis is placed on the effects of heat and gravity on dynamic processes at all levels in the Earth. Effects such as stresses in tectonic plates, mantle convection and the geomagnetic dynamo are re-examined in the light of improved understanding. Finally, geological evidence is used to construct a model for the evolutionary history of the Earth's continental crust.Read More