The origin of different kinds of igneous rocks can be understood in terms of their tectonic setting, and by way of the isotope compositions of strontium, neodymium, and lead. This book explains the petrogenesis of igneous rocks as a consequence of tectonic processes resulting from interactions between asthenopheric plumes and the overlying lithospheric mantle. The relevant principles of isotope geochemistry are explained in the first chapter, making it accessible for university students as well as professionals. The relevant isotopic data is presented in diagrammatic form. The book contains more than 400 original drawings.

A manuscript copy, with corrections and editor's notations in red, of the article published in the Philosophical Society of Washington Bulletin, volume 12, 1892.

Hess (geological sciences, Brown U.) explores the complex process of the generation and cooling of those rocks formed by solidification from a molten state, either intrusively, below the earth's crust, or extrusively as lava. Some topics treated are: magmatic differentiation and other processes; nature of silicate melts; island-arc volcanism; continental flood basalts and rifts; lunar petrology; ocean-floor volcanism. An advanced treatment. Annotation copyrighted by Book News, Inc., Portland, OR

Acknowledgements xix pioneering workers on igneous layering in Greenland xx Wbrkshop participants xxii Henning Sfl!rensen, University of Copenhagen, Dermark. Latte Melchior Larsen, Geological SUrvey of Greenland, Copenhagen, Dermark. Abstract 1 1 • Introduction 1 1. 1 The agpaitic rocks of the Ilimaussaq intrusion 3 2. Igneous layering in the Ilimaussaq intrusion 4 3. Mineralogy of the layered kakortokite series 15 4. Chemistry of the layered kakortokite series 19 5. Origin of the kakortokite layering 20 5. 1 Discussion 22 6. Conclusion 25 References 26 2. I. AYERn«;r CCMPl\CTIOO NID PCBJ. "--MN}tATIC ~ IN '!HE KLOKKEN INTRUSIOO 29 Ian Parsons and SUsanne M. Becker, University of Aberdeen, U. K. Abstract 29 1. Introduction 30 2. Age of the intrusion 31 3. General structure and mineral variation 31 vi TABLE OF CONTENTS 3. 1 Nomenclature of rock types 31 3. 2 Bulk chemical and modal variation 36 4. The contacts and wall-rocks 37 4. 1 Guter contact 37 4. 2 The gabbro sheath 37 4. 3 The unlaminated syenite sheath 39 4. 4 The gabbro-syenite transition 41 5. The layered series 43 5. 1 General relationships 43 5. 2 Granular syenites 43 5. 2. 1 Structure and cryptic variation 43 5. 2. 2 Origin of granular layers 46 5. 2. 3 Trace elements and chamber dlinensions 47 5. 3 Laminated syenites 48 5. 3. 1 General features 48 5. 3. 2 Mineral layering 51 5. 3.