This is a book about the petrology of kimberlites. It is not about upper mantle xenoliths, diamonds, or prospecting for kimberlites. The object of the book is to provide a comprehensive survey and critique of the advances which have been made in kimberlite studies over the last twenty-five years. Kimberlites are rare rock types; however, their relative obscurity is overriden by their economic and petrological importance to a degree which is not shared with the commoner varieties of igneous rocks. Kimberlites are consequently of interest to a diverse group of earth scientists, ranging from isotope g~ochemists concerned with the evolution of the mantle, to volcanologists pondering the origins of diatremes, to exploration geologists seeking new occurrences of the diamondiferous varieties. A common factor essential to all of these activities is a thorough understanding of the characteristics of kimberlites. For the petrologist, kimberlites are exciting and challenging objects for study. Their petrographic diversity, complex mineralogy and geochemistry, and unusual style of intrusion provide endless opportunities for stimulating hypothesis and conjecture concerning their origin and evolution. Kimberlites are a part of a wide spectrum of continental intra-cratonic magmatism. Only by understanding all of the parts of this activity in detail may we make progress in our understanding of the whole.

This remarkable volume presents the first revision to the classification system of diamond-bearing rocks in over eighty years. Presenting the latest mineralogical data, this book offers a detailed description of the mineralogy and geochemistry of kimberlites, orangeites, and lamproites. Several hundred new analyses of minerals in orangeites are included. This volume follows the publication of Kimberlites, by R.H. Mitchell, and Petrology of Lamproites, by R.H. Mitchell and S.C. Bergman, concluding the trilogy.

Volume 1 of this special issue of Lithos, dedicated to Roger Clement, presents papers describing the geology and emplacement of several of the recently discovered kimberlites in northern Canada in which diamond mines are now operating. Other papers are concerned with the petrography, age of emplacement, geochemistry and petrogenesis of kimberlites from Canada and other worldwide localities.

International Kimberlite Conferences (IKCs) are special events that are held across the world once in four to five years. IKC is the confluence platform for academicians, scientists and industrial personnel concerned with diamond exploration and exploitation, petrology, geochemistry, geochronology, geophysics and origin of the primary diamond host rocks and their entrained xenoliths and xenocrysts (including diamond) to get together and deliberate on new advances in research made in the intervening years. Ever since the organization of first IKC in 1973 and its tremendous success, the entire geological world eagerly look forward to subsequent such conferences with great enthusiasm and excitement. The scientific emanations from IKCs continue to make significant impact on our understanding of the composition, nature and evolution of the planet we live on. The previous conferences were held at Cape Town (1973), Santa Fe, New Mexico (1977), Clermont-Ferrand, France, (1982), Perth, Western Australia (1987), Araxa, Brazil (1991), Novosibirsk, Russia (1995), Cape Town (1998), Victoria, Canada (2003) and Frankfurt, Germany (2008). The 10th IKC was held at Bangalore, India between 5th and 11th February 2012. The conference was organized by the Geological Society of India in association with the government organizations, academic institutions and Indian diamond mining companies. About 300 delegates from 36 countries attended the conference and 224 papers were presented. The papers include 78 oral presentations and 146 poster presentations on following topics: Kimberlite geology, origin, evolution and emplacement of kimberlites and related rocks, petrology and geochemistry of metasomatised lithospheric mantle magmas, diamond exploration, cratonic roots, diamonds, diamond mining and sustainable developments and policies and governance of diamond exploration. Pre- and post-conference field trips were organized to (i) the diamond bearing kimberlites of Dharwar Craton in South India, (ii) lamproites of Bundelkhand Craton in northern India and (iii) diamond cutting and polishing industry of Surat, Gujarat in western India. A series of social and cultural programmes depicting cultural diversity of India were organized during the conference. The Kimberlite fraternity enjoyed yet another socially and scientifically successful conference.

Volume 2, dedicated to Barry Hawthorne, presents papers concerned with the genesis of eclogites, the mineralogy of diamond and its inclusions, exploration methods for kimberlite, the geochemistry of the upper mantle and the character of cratons.

Given the established nature of geoscientific knowledge of the Kaapvaal craton compared to the Slave craton, and given the exciting new interdisciplinary results coming from the Kaapvaal Project and from Slave craton studies, scientists working on both cratons were brought together in a workshop to compare and contrast the nature of these two cratons. Of the 54 papers presented at the workshop, 24 are included in this volume. There are clearly major similarities and differences between these two Archean cratons. The crust of both was predominantly formed in the Mesoarchean. Both contain crustal sections consisting of terranes of different ages welded together by Archean accretionary events. Both crustal sections are underlain by lithospheric mantle sections consisting of peridotites that experienced extensive partial melt extraction between 2.9 Ga and 3.2 Ga, but this is where the similarities between the cratons end. One of the most striking differences between the Slave and Kaapvaal cartons is the apparent seismic homogeneity of the Kaapvaal craton's SCLM whereas the Slave craton is seismically layered. The seismic layering in the centre of the craton correlates laterally and with depth with electrical layering and geochemical layering. Taken together, these differences suggest that SCLM formation was different for the two cratons, implying that the search for a single causative formation process is bound to fail. Reprinted from the journal Lithos Volume 71, numbers 2-4.

In this book, the first dedicated entirely to the petrology of lamproites and their relationships to other potassium-rich rocks, the objective of the authors is to provide a comprehensive critical review of the occurrence, mineralogy, geochemistry, and petrogenesis of the clan. Although lamproites represent one of the rarest of all rock types, they are both economically and scientifically important and we believe the time is ripe for a review of the advances made in their petrology over the past two decades. Many of these advances stem from the recognition of diamond-bearing lamproites in Western Australia and the reclassification of several anomalous diamond-bearing kim berlites as lamproites. Consequently lamproites, previously of interest only to a small number of mineralogists specializing in exotica outside the mainstream of igneous petrol ogy, have become prime targets for diamond exploration on a worldwide basis. Contemporaneously with these developments, petrologists realized that lamproites possess isotopic signatures complementary to those of midoceanic ridge basalts, alkali basalts, kimberlites, and other mantle-derived melts. These isotopic studies provided new insights into the long-term development of the mantle by suggesting that the source regions of lamproites were metasomatically enriched in light rare earth and other incompatible elements up to 1-2 Ga prior to the melting events leading to generation of the magma.