The eruption of deep-seated xenoliths in basaltic, alnoitic, kimberlitic, etc volcanoes provides the geologist with an important direct means of examining the fragments of the earth's mantle and lower crust.

courses more petrogenesis-orientated are im My main objective in writing this book has been to mediately confronted with a basic problem; the review the processes involved in present-day mag ma generation and their relationship to global average student does not have a strong enough tectonic processes. Clearly, these are fundamental background in geochemistry to understand the to our understanding of the petrogenesis of ancient finer points of most of the relevant publications in volcanic and plutonic sequences, the original tec scientific journals. It is virtually impossible to fmd tonic setting of which may have been obscured by suitable reading material for such students, as most subsequent deformation and metamorphism. authors of igneous petrology textbooks have de Until fairly recently, undergraduate courses in liberately steered clear of potentially controversial igneous petrology tended to follow rather classical petrogenetic models. Even the most recent texts lines, based on the classification of igneous rocks, place very little emphasis on the geochemistry of descriptive petrography, volcanic landforms, types magmas erupted in different tectonic settings, of igneous intrusions and regional petrology . despite extensive discussions of the processes re However, the geologist of the late 1980s requires, in sponsible for the chemical diversity of magmas.

Fluid-aided mass transfer and subsequent mineral re-equilibration are the two defining features of metasomatism and must be present in order for metamorphism to occur. Coupled with igneous and tectonic processes, metasomatism has played a major role in the formation of the Earth’s continental and oceanic crust and lithospheric mantle as well as in their evolution and subsequent stabilization. Metasomatic processes can include ore mineralization, metasomatically induced alteration of oceanic lithosphere, mass transport in and alteration of subducted oceanic crust and overlying mantle wedge, which has subsequent implications regarding mass transport, fluid flow, and volatile storage in the lithospheric mantle overall, as well as both regional and localized crustal metamorphism. Metasomatic alteration of accessory minerals such as zircon or monazite can allow for the dating of metasomatic events as well as give additional information regarding the chemistry of the fluids responsible. Lastly present day movement of fluids in both the lithospheric mantle and deep to mid crust can be observed utilizing geophysical resources such as electrical resistivity and seismic data. Such observations help to further clarify the picture of actual metasomatic processes as inferred from basic petrographic, mineralogical, and geochemical data. The goal of this volume is to bring together a diverse group of geologists, each of whose specialities and long range experience regarding one or more aspects of metasomatism during geologic processes, should allow them to contribute to a series of review chapters, which outline the basis of our current understanding of how metasomatism influences and helps to control both the evolution and stability of the crust and lithospheric mantle.

Earth as an Evolving Planetary System, Second Edition, explores key topics and questions relating to the evolution of the Earth's crust and mantle over the last four billion years. This updated edition features exciting new information on Earth and planetary evolution and examines how all subsystems in our planet—crust, mantle, core, atmosphere, oceans and life—have worked together and changed over time. It synthesizes data from the fields of oceanography, geophysics, planetology, and geochemistry to address Earth's evolution. This volume consists of 10 chapters, including two new ones that deal with the Supercontinent Cycle and on Great Events in Earth history. There are also new and updated sections on Earth's thermal history, planetary volcanism, planetary crusts, the onset of plate tectonics, changing composition of the oceans and atmosphere, and paleoclimatic regimes. In addition, the book now includes new tomographic data tracking plume tails into the deep mantle. This book is intended for advanced undergraduate and graduate students in Earth, Atmospheric, and Planetary Sciences, with a basic knowledge of geology, biology, chemistry, and physics. It also may serve as a reference tool for structural geologists and professionals in related disciplines who want to look at the Earth in a broader perspective. - Kent Condie's corresponding interactive CD, Plate Tectonics and How the Earth Works, can be purchased from Tasa Graphic Arts here: http://www.tasagraphicarts.com/progptearth.html - Two new chapters on the Supercontinent Cycle and on Great Events in Earth history - New and updated sections on Earth's thermal history, planetary volcanism, planetary crusts, the onset of plate tectonics, changing composition of the oceans and atmosphere, and paleoclimatic regimes - Also new in this Second Edition: the lower mantle and the role of the post-perovskite transition, the role of water in the mantle, new tomographic data tracking plume tails into the deep mantle, Euxinia in Proterozoic oceans, The Hadean, A crustal age gap at 2.4-2.2 Ga, and continental growth