Alkaline Rocks Kimberlites And Carbonatites Geochemistry And Genesis

This proceedings book represents a collection of conference papers examining the fundamental problems of deep magmatism.Enriched mantle reservoirs can be the source of the most massive apatite and rare metal deposits. Additionally, this book also presents some of the characteristics of kimberlites' composition from the deep Yubileinaya pipe and the mineralogical features of the Nakyn kimberlite field (Yakutia) and the crystallochemical features of rare and complex silicates from charoite rocks of the deep Murunskii massif in South Africa and the comendites of Mongolia.

This study documents alkaline rock occurrences in British Columbia; describes their petrography, geochemistry, economic geology, and field relationships; and determines the timing and tectonic controls of emplacement, providing a basis for future, detailed studies. Work was begun in 1984 and included field mapping during the summers of 1984, 1985, and 1986. All the carbonatite-syenite localities (with the exception of the Wicheeda Lake and Mount Bisson showings) and a large number of the diatreme breccias were mapped and sampled.

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.

Petrology and Genesis of Igneous Rocks comprises of two parts - the first part (Chapters 1 to 8) deals with constituent minerals, texture, thermodynamic principles, phase relations in natural rock systems and causes of diversity in a single petrographic province. Petrology of the crust, mantle and core, the convective cycle patterns in the mantle and their relation to magma genesis and physicochemical properties of magma are also discussed in this part. Use of Isotope geology in determination of age and degree of magma mixing is included towards the end of the first part. The second part (Chapters 9-13) describes individual rock types, from various countries including their geochemistry, petrology and genesis.

Phoscorites are dark, often very handsome, sometimes economically valuable, magnetite-apatite-silicate rocks, almost always associated with carbonatite. They are key to understanding the longstanding question of how carbonate and carbonate-bearing magmas rise to the crust and the Earths surface. Despite this, they have been given little attention; a search on geological literature databases will produce thousands of references to carbonatite (up to 4125 on Georef) but not more than thirty references to phoscorite. This book goes some way to redress this balance. Over recent years many European and North American scientists have studied Kola rocks in collaboration with Russian colleagues. The idea for this book came from one such project funded by the European organisation, INTAS (Grant No 97-0722). The Kola Peninsula is one of the outstanding areas in the World for the concentration and economic importance of alkaline rocks. However, Russian work on the Kola complexes is still relatively unknown and a particular aim of this book, as well as presenting current research, is to make this knowledge accessible to English language readers. A large exploration programme on Kola alkaline rocks was active from 1950 to 1990 and involved teams of geologists who studied many kilometres of drill core and carried out detailed mineralogical and petrological studies.