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JOURNAL OF PETROLOGY VOLUME 50 NUMBER 1 PAGES 195^196 2009 doi:10.1093/petrology/egn080 Book Review Carbonatite occurrences of the world: map and database, by A. R. Woolley and B. A. Kjarsgaard. Geological Survey of Canada, Open File 5796; 28 pages, 1 sheet, 1 CD ROM. $18.45 in Canada; $24 for other countries. Free download http://ess.nrcan.gc.ca/esic/ geoscan-e.php Labour of love For those of us who do not have the genes needed for sorting, cataloguing, and pigeon-holing, we need those who do. This open-file report (5796) from the Geological Survey of Canada entitled Carbonatite occurrences of the world: map and database includes a CD brimming, perhaps overflowing, with information about carbonatites. Woolley started listing alkaline rocks and carbonatites along with their ages, spatial distribution, and associated rocks types in his volume on the carbonatites of North and South America that appeared in 1987. Since then, other volumes have appeared with Woolley acting as the main driving force. These volumes catalogued and described carbonatites from Africa, and the former USSR, including details of location, associated rock types, tectonic setting and ages. This GSC open file consists of Word, Excel and pdf files that include: (1) a master file containing brief descriptions of 527 carbonatite occurrences; (2) a list of references; (3) an introduction along with several maps; (4) an index list of all localities; (5) a reference file listing those carbonatites associated with economic deposits. The five Excel files list: (1) all known carbonatites; (2) carbonatite occurrences of economic interest; (3) extrusive carbonatites including mantle debris contained within them; (4) silicate rock associations; (5) an index list of all localities. Maps include a world geological map with all occurrences noted (in both hard copy as well as digital format), and 21 maps contained in the introductory document, most available in digital form. In the early days, carbonatites were difficult to recognize but now, particularly with airborne geophysics, many more have been identified and this open file documents 527 occurrences. No doubt more will be found. Based on this recent compilation, Africa still manages to hold the record (35%), and Asia contains 30% (Russia has been included in Asia). We already knew that carbonatites are found on all continents and that most occur in stable cratonic areas, but now we have substantial confirmation that this is indeed the case. The introductory document reviews the different carbonatite^silicate rock associations (now listed as eight), age groupings (11 in all) and carbonatites of economic interest, and contains 22 figures (all but one are maps) showing the localities of carbonatites. Whether all of the 21 maps are needed is a moot point. Figure 8 includes a map of ‘kimberlite^carbonatite association’ and only five occurrences are documented, and in Fig. 4 showing the ‘basanite^carbonatite’ association only three are shown. In the introductory text, the authors have managed, for the most part, to avoid many of the minefields associated with carbonatite research, but they do venture into distinguishing carbohydrothermal from magmatic carbonatites, an excursion no doubt of interest to many Russian geologists. A neophyte might ask for the definition of a carbohydrothermal carbonatite, how such rocks differ from magmatic carbonatites, and the criteria used to recognize them. In addition, the introduction tends to be somewhat choppy and partly muddied by diversions into discussions that are of interest only to those involved with carbonatite research. It perhaps would have been better to leave the introduction as simply an account of the database, how it is organized and what the highlights are. The authors have wisely avoided any ‘in depth’ discussion in interpreting the findings that emerged from their compilation. They draw attention to some interesting features, especially the association of carbonatites with a relatively wide range of rock types (including kimberlites), and the division of carbonatites into 11 age groupings using data of variable quality. Compiling the ages, 264 in all, and then dividing them into 11 distinct groups implies some significance to the temporal evolution of carbonatite magmatism, and implies events of global significance. A more detailed discussion of the criteria used to establish the groupings and the range for each particular group would have been useful. This compilation will undoubtedly settle some questions and it appears that the authors already have a paper in press that will answer some of these. Questions that immediately spring to mind are: how many carbonatites of the 527 are spatially associated with silicate rocks, at least at their present erosion level? How many are dolomitic carbonatites? How many are contained within Archean cratons? How many are associated with rifts? Why do some carbonatites of the same age occur over extensive areas of the Earth’s crust, such as those in the Kola Peninsula? ß The Author 2009. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@ oxfordjournals.org JOURNAL OF PETROLOGY VOLUME 50 How useful is this compilation? Clearly, it is packed with information but accessibility is not easy. I was forced into the introduction and then I had to dig myself out to download other files. Unfortunately, there is no direct access from the main menu into each file. This was something of a nuisance. Who will benefit from this package? Certainly the mining community as well as national and state surveys will find it useful, not only for providing relatively detailed information about each complex, but also for assessing carbonatite exploration programmes. Additional ages, especially high-quality, U^Pb zircon dates will, no doubt, help resolve whether there are distinct, worldwide events capable of generating carbonatitic melts, and how many of the silicate rocks are coeval with their spatially associated carbonatites. It will take some years before we get this sorted out but now at least we have a framework. This compilation is a good start. NUMBER 1 JANUARY 2009 It would be easy, but unfair, to be picky about a detailed compilation such as this. However, if I were to have one single criticism about this compilation it would be that it is not easy to navigate. Given the considerable amount of time that has been spent on the compilation, some additional work to help make the open file more user-friendly, more accessible, and better linked would have helped a great deal. However, this compilation represents a contribution that will be invaluable to anyone interested in carbonatites, and the world map that outlines the global distribution of carbonatites is especially useful. Advance Access Publication January 21, 2009 Keith Bell Ottawa 196