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The Carswell structure uranium deposits, Saskatchewan
406 what out of date. The volume merits serious consideration for the personal bookshelves of industry and other geologists concerned with ores in sedimentary rocks, but the price, U.S. $61.50, will send those with a more casual interest to institutional libraries. R.I. THORPE (Ottawa, Ont.)
High Heat Production ( H H P ) Granites, Hydrothermal Circulation and Ore Genesis. C. Halls (Editor). Institution of Mining and Metallurgy, vii + 593 pp., £stg. 30.00. This book is an outgrowth of IGCP project 26 ("Mineralization Associated with Acid Magmatism") and the product of a conference held in Cornwall, England in September, 1985. The volume is a compendium of 40 articles, and understandably, has a heavy emphasis on the Cornubian batholith: 12 articles are directly concerned with southwestern England and four others are at least partly dedicated to the Cornish granites. There are, however, examples from throughout the world such that the book has a broad geographic base, and although there is a preponderance of Hercynian/Variscan /Acadian examples, ages from Archean through Tertiary are represented. The articles are well written, and Christopher Halls has done an excellent job of editing. Most of the articles are thoroughly referenced and provide valuable source materials for information on specific deposits and/or mechanisms of ore deposition. A large amount of new data is presented. For example, nearly half of the articles present trace-element data for High Heat Production ( H H P ) granites, and several papers present new major-element analyses. The subject matter of the articles covers a broad spectrum of investigations from results of laboratory experiments at hydrothermal conditions to detailed petrography and/or geology of specific ore deposits. Four articles report results of fluid inclusion studies, a few papers discuss results of stable or tracer isotope anal-
yses, and a couple of papers examine heat flow and geologic parameters that may control hydrothermal systems. Many of the papers are authored by well-known authorities, and most of the reports represent state-of-the-art research. The book leaves the reader with the impression that H H P granites are only associated with deposits of tin or tungsten. Although elevated contents of uranium and thorium seem to be characteristic, uraniferous granites, such as the uranium-producing granites of France, are not represented among the examples. A few articles, most notably those about granites of the A r a b i a n - N u b i a n Shield, report elevated values for rare-earth elements, niobium, tantalum, and certain chalcophile elements. However, the authors of these articles note that at least the Nigerian examples seem to be anomalous when compared to other H H P granites. Several of the articles comment on the question of protoliths for H H P granites as well as other factors that may control the origin of these unique and economically important granites. There is a fairly strong concensus among those who contributed to the book (especially the British) that H H P granites have a genetic tie to the mantle, but opinions range from melting of crustal sediments to partial melting of anomalous mantle. In spite of the wealth of data presented in the book, this and other controversial issues are left to future research. J.S. STUCKLESS (Denver, Colo.)
The CarsweU Structure Uranium Deposits, Saskatchewan. R. Laine, D. Alonzo and M. Svab (Editors). Geological Association of Canada, Special Paper 29, 1985, vi + 230 pp., Can $35.00 ( m e m b e r s ) , Can $42.00 (non-members) (cloth). This study of the magnificently complicated Carswell structure and its uranium deposits contains 18 papers in the writing of which 26 authors participated. Eight authors took part
407 in the writing of two papers, the remaining 18 in one. Only four papers had one author, two had seven, six had three and one had four. Thus, the project was truly a cooperative effort, and this intermixing of' authors has produced a valuable contribution to the geologic history of a fascinating district, even though every paper does not agree with every other one. Probably the best place to begin the use of this Volume is the "R~sum~" of the first paper - - Geology and Mineralization in the Carswell Structure- A General A p p r o a c h - - which is, for some reason, about 3.5 times as long as its English equivalent (and much more informative). The R~sum~ reads (in translation) as follows. "The Carswell circular structure, situated in the west of' the Athabasca plateau in the north of the province of Saskatchewan, is composed of a ring, comparable to those of the Western Craton, and of an overlying annular ring of sedimentary rocks belonging to the Athabasca group. The actual structure, the origin of which endogene (cryptoexplosion) or exogene (meteoric impact) - - is not clear, was formed in the Ordovician. The metamorphic ring is made up of two assemblages: (1) the Earl River complex which could represent an ancient volcano-sedimentary series, beginning with komatiites and being ended by an Archean or Aphebian arkosic or silicic series that has been metamorphosed to quartz-feldspathic gneiss or amphibolites and (2) the Peter River gneiss, an ancient sedimentary series, probably originally shale, of Aphebian age that has been convetted to an aluminous gneiss. These two assemblages have undergone a subcatatonal gneiss (granulite facies) during the ancient Hudsonian orogeny, before being remetamorphosed in the course of the recent Hudonian phases (amphibolite facies in consequence of N E - S W tangential tectonics)." "The overlying Helikian is composed of a basal silicic volcano-sedimentary series, residual paleo-Helikian and of the classic series of the Athabasca group, completed in the Car-
-
swell sector by the Douglas and Carswell formations." "The Grenville orogeny is marked by the intrusion of diabases to the south of the circular Carswell structure. The Carswell 'event' disorganized the structures and caused a more than 1000-m uplift of the basement that cut the Athabascan formations with the accompaniment of the emplacement of the sub-volcanic (Cluff) breccia facies." "The principal uranium deposits are distributed in the southern part of the metamorphic ring, perhaps in the basement, perhaps at the contact with the sandstone basement but always near the Athabasca sandstone. All of the 'uranium' mineralizations are situated in strongly altered tectonic zones." "Several episodes of mineralization have been recognized: (1) a Hudsonian episode of uraninite-monzonite (1800 Ma); (2) a major episode contemporaneous with the other (uranium) ore bodies of the Athabasca plateau (1050 Ma) which produced an uraninite-polymetallic S e - T e assemblage; (3) a distinct remobilization of the preceding (2) mineralization (900 Ma) which created an assemblage of quartz, uraninite, and sulfides; and (4) a characteristic episode of hematite-pitchblende ( 380 Ma) found mainly in the Athabascan sandstones." "The 'D' ore body is located at the sandstonebasement discordance going back to the Carswell event on the south border south of the weathered metamorphosed ring. The major part of the very rich mineralization accompanies the argillaceous cement of a zone of spheroidal weathering, the zone of lens-shaped tectonic effects developed in the Athabasca sandstone following the recurrence of a zone of Hudsonian mylonitization. Two uraniferous assemblages have been identified: (1) an uraninite-polymetallic (Mo, Cu, Pb, Co, Ni) assemblage, (2) uraninite and simple (Cu, Pb) sulfides. The emplacement was preceded by a long magnesian-argillaceous hydrothermal alteration."
408 "The Dominique-Peter deposit is situated about 1.5 km to the NW of the 'D' ore body and was developed entirely in the metamorphosed basement. The location of the mineralization is preferentially controlled by the limit of the Peter River gneiss series and by the Earl River complex." " T h e mineralization fills two fracture systems, the dips of which are contrary to that of the mylonite; some of these fractures are oriented N-S and have a dip of 50 ~W, others strike N60 E and dip NW. The later faults strike N NE and N 2 0 E; they cut the earlier faults but are no~ mineralized. A fragment of sandstone and of weathered metamorphosed basement have been discovered in the Dominique zone; it emphasizes the proximity to the pre-Athabascan discordance. The parageneses (assemblages) observed in ore body 'D' also are present in the Dominique-Peter." " T h e Claude ore body, to the N W of Dominique-Peter, also is situated in the Peter River aluminous gneiss. The uranium mineralization is controlled by an E - W mylonitic zone where a zone of spheroidal weathering has been developed; this zone separates the altered gneiss to the north from the sound gneiss to the south. The late N20 ~E faults give the form of the lett e ~ J ' to the mineralized envelope." "The OP and N ore bodies are both in the basement, near to the discordance. The OP is made up of three N-S, subvertically dipping structures in the midst of Peter aluminous gneiss; these lie immediately north of ore body 'D'. N ore body is developed essentially in the altered quartzo-feldspathic facies of the Earl River complex overthrust on the Pearl River gneiss. The mineralization there is controlled perhaps by the zone of weathering, perhaps by a vertical N 4 0 : E vein." The Carswell structure is located about 60 km south of Lake Athabasca and 25 miles east of the Alberta-Saskatchewan border. This rudely circular structure occurs in the Western Craton in the Churchill geologic province along the southwestern edge of the Canadian Shield.
With this much information readily at hand, the study of' the individual papers is rendered much more satisfactory as each can the more easily be put into is proper geological and ore development context. The titles of' these papers, in addition to the one mentioned at the beginning of' this review, are: Clay mineral stratigraphy of the Athabasca Group: Correlation inside and outside the ('/arswell structure; Geochronology of the Carswell area northern Saskatchewan; K Ar dating of different rock types from the Cliff' I,ake uranium ore deposits; Petrographic and chemical variations within the Carswell structure metamorphic core and their implications with respect to uranium mineralization; Petrogra phy and geochemistry of the Earl River complex, Carswell structure - - a possible Proterozoic komatiitic succession: The study of the basal Athabasca succession in the D, E, I,, F, and S areas of' the Carswell structure; The Carswell formation, northern Saskatchewan: stratigraphy, sedimentology, and structure: Mineralogy and metallogeny of the uraniferous occurrences in the Carswell structure: A (sici uranium unconformity deposit: the geological setting of the D orebody ( Saskatchewan, Canada); Mineralogical and structural aspects of the Dominique-Peter uranium deposit: (?hemistry of uranium minerals in deposits and showings of' the Carswell structure: Geochemistry and glacial geolo~, - - Application to exploration in the Carswell structure; Case histories of the Radon Tube Sampler in the Carswell structure; Geophysical mapping of gneiss domes in the Carswell structure and their relationship to uranium mineralization: the origin of the Carswell circular structure: Conclusion: lhe Carswell uranium deposits - - an example of not s~ unique unconformity related uranium mineralization. It is impossible in the space available even to summarize each of these papers. As Slama and Artru point out in their Forword, the main uranium occurrences are clustered near the southern edge of the basement core, an area where
409 the structure is at its most complex, and where the relationship between mineralization and the geological aspects of the basement and its sedimentary cover would be most difficult of interpretation. The necessary vital clues to solving these stratigraphic and structural puzzles appear to have been derived from the results of the 1980 high-sensitivity airborne magnetic survey. This lead to the assumption t h a t the basement was not completely broken up and that it. still retained the structure existing prior to the Carswell event. The interpretations so drawn were soon confirmed, largely through their leading to the finding of the Dominique-Peter ore body. The ()re was found at the stratigraphic contact between the aluminous gneiss and the flanks of the magnetic quartzose-feldspathic gneiss domes. The drilling t h a t fbllowed the location of this target further aided the problem of geologic interpretation by showing the role of the mylonitic zones and the faulting t h a t occurred after the mylonitization in supplying the major structural controls t h a t provided a home fbr the uranium mineralization. The one structural problem left unsolved is: was the Carswell ring produced by a meteoric impact or resulted from some other cryptoexplosive phenomenon? The reader of this volume should not immediately turn to paper 17 - - The origin of the Carswell circular structure - - but should read those t h a t precede it, so that he too will be, to some extent, prepared to make a decision as to which concept he considers to he the correct one or does he come to a third conclusion instead? As the Editors of this volume point out, the majority of the papers in the volume were written by geologists whose first language was not English. Had this not been indicated in their Preface, it is to be doubted if the student would have reached this conclusion by him- or herself. The Authors, Editors, and Referees should take great pride in having contributed to this outstanding volume. The 1:50,000 map of the Bedrock Geology of
the Carswell Structure t h a t accompanies the Volume is a great aid to understanding the geology so well described in the text. ,I.D. RIDGE Gainesville,Fla.)
Empirical Metallogeny. Depositional Environments, LithoIogic Associations and Metallic Ores. Vol. I: Phanerozoic Enc, ironments, Associations and Deposits, Part A and B. P. Laznicka. (Developments in Economic Geology, 19) Elsevier, Amsterdam, 1985, xxxvi+1758 pp., US $ 176.00/Dfl. 455.00 (hardback, in 2 parts ). This is what I thought not to be possible any more: a book by one single author covering all types of ore deposits, of which these enormous two parts only constitute the first volume covering Phanerozoic (Cambrian to Recent) deposits and their environments. "A second, companion volume will cover metallic ores of Precambrian age and unusual associations of all ages, and will contain search tables covering both volumes" (p.xxvii). A tremendous amount of work has been done by P. Laznicka to compile this "large body of information on Phanerozoic metallic ore deposits" throughout about :30 years ("since my student days in the 1950's"). "The work is based on the literature, consulted in the original in over thirty languages, and on field work, and it treats locality examples in some one hundred and fifty countries and regions, many of them checked in the field" (p.xxvii). One more quotation from the Preface (p.xxix): "Intended initially as a 'DC 9'-size modern substitute of the Lindgren (1933) book, a 'DC 3' of economic geologic literature in terms of versatility, the book turned into a 'Boeing 747'. Whereas, however, in the Lindgren's days the geological literature of the world amounted to some 50,000 items, the count is now some 1.5 to 2 million. This provides some justification of' the book size". Peter Laznicka theretbre is an expert who has seen much more than most of us. His descrip-
High Heat Production ( H H P ) Granites, Hydrothermal Circulation and Ore Genesis. C. Halls (Editor). Institution of Mining and Metallurgy, vii + 593 pp., £stg. 30.00. This book is an outgrowth of IGCP project 26 ("Mineralization Associated with Acid Magmatism") and the product of a conference held in Cornwall, England in September, 1985. The volume is a compendium of 40 articles, and understandably, has a heavy emphasis on the Cornubian batholith: 12 articles are directly concerned with southwestern England and four others are at least partly dedicated to the Cornish granites. There are, however, examples from throughout the world such that the book has a broad geographic base, and although there is a preponderance of Hercynian/Variscan /Acadian examples, ages from Archean through Tertiary are represented. The articles are well written, and Christopher Halls has done an excellent job of editing. Most of the articles are thoroughly referenced and provide valuable source materials for information on specific deposits and/or mechanisms of ore deposition. A large amount of new data is presented. For example, nearly half of the articles present trace-element data for High Heat Production ( H H P ) granites, and several papers present new major-element analyses. The subject matter of the articles covers a broad spectrum of investigations from results of laboratory experiments at hydrothermal conditions to detailed petrography and/or geology of specific ore deposits. Four articles report results of fluid inclusion studies, a few papers discuss results of stable or tracer isotope anal-
yses, and a couple of papers examine heat flow and geologic parameters that may control hydrothermal systems. Many of the papers are authored by well-known authorities, and most of the reports represent state-of-the-art research. The book leaves the reader with the impression that H H P granites are only associated with deposits of tin or tungsten. Although elevated contents of uranium and thorium seem to be characteristic, uraniferous granites, such as the uranium-producing granites of France, are not represented among the examples. A few articles, most notably those about granites of the A r a b i a n - N u b i a n Shield, report elevated values for rare-earth elements, niobium, tantalum, and certain chalcophile elements. However, the authors of these articles note that at least the Nigerian examples seem to be anomalous when compared to other H H P granites. Several of the articles comment on the question of protoliths for H H P granites as well as other factors that may control the origin of these unique and economically important granites. There is a fairly strong concensus among those who contributed to the book (especially the British) that H H P granites have a genetic tie to the mantle, but opinions range from melting of crustal sediments to partial melting of anomalous mantle. In spite of the wealth of data presented in the book, this and other controversial issues are left to future research. J.S. STUCKLESS (Denver, Colo.)
The CarsweU Structure Uranium Deposits, Saskatchewan. R. Laine, D. Alonzo and M. Svab (Editors). Geological Association of Canada, Special Paper 29, 1985, vi + 230 pp., Can $35.00 ( m e m b e r s ) , Can $42.00 (non-members) (cloth). This study of the magnificently complicated Carswell structure and its uranium deposits contains 18 papers in the writing of which 26 authors participated. Eight authors took part
407 in the writing of two papers, the remaining 18 in one. Only four papers had one author, two had seven, six had three and one had four. Thus, the project was truly a cooperative effort, and this intermixing of' authors has produced a valuable contribution to the geologic history of a fascinating district, even though every paper does not agree with every other one. Probably the best place to begin the use of this Volume is the "R~sum~" of the first paper - - Geology and Mineralization in the Carswell Structure- A General A p p r o a c h - - which is, for some reason, about 3.5 times as long as its English equivalent (and much more informative). The R~sum~ reads (in translation) as follows. "The Carswell circular structure, situated in the west of' the Athabasca plateau in the north of the province of Saskatchewan, is composed of a ring, comparable to those of the Western Craton, and of an overlying annular ring of sedimentary rocks belonging to the Athabasca group. The actual structure, the origin of which endogene (cryptoexplosion) or exogene (meteoric impact) - - is not clear, was formed in the Ordovician. The metamorphic ring is made up of two assemblages: (1) the Earl River complex which could represent an ancient volcano-sedimentary series, beginning with komatiites and being ended by an Archean or Aphebian arkosic or silicic series that has been metamorphosed to quartz-feldspathic gneiss or amphibolites and (2) the Peter River gneiss, an ancient sedimentary series, probably originally shale, of Aphebian age that has been convetted to an aluminous gneiss. These two assemblages have undergone a subcatatonal gneiss (granulite facies) during the ancient Hudsonian orogeny, before being remetamorphosed in the course of the recent Hudonian phases (amphibolite facies in consequence of N E - S W tangential tectonics)." "The overlying Helikian is composed of a basal silicic volcano-sedimentary series, residual paleo-Helikian and of the classic series of the Athabasca group, completed in the Car-
-
swell sector by the Douglas and Carswell formations." "The Grenville orogeny is marked by the intrusion of diabases to the south of the circular Carswell structure. The Carswell 'event' disorganized the structures and caused a more than 1000-m uplift of the basement that cut the Athabascan formations with the accompaniment of the emplacement of the sub-volcanic (Cluff) breccia facies." "The principal uranium deposits are distributed in the southern part of the metamorphic ring, perhaps in the basement, perhaps at the contact with the sandstone basement but always near the Athabasca sandstone. All of the 'uranium' mineralizations are situated in strongly altered tectonic zones." "Several episodes of mineralization have been recognized: (1) a Hudsonian episode of uraninite-monzonite (1800 Ma); (2) a major episode contemporaneous with the other (uranium) ore bodies of the Athabasca plateau (1050 Ma) which produced an uraninite-polymetallic S e - T e assemblage; (3) a distinct remobilization of the preceding (2) mineralization (900 Ma) which created an assemblage of quartz, uraninite, and sulfides; and (4) a characteristic episode of hematite-pitchblende ( 380 Ma) found mainly in the Athabascan sandstones." "The 'D' ore body is located at the sandstonebasement discordance going back to the Carswell event on the south border south of the weathered metamorphosed ring. The major part of the very rich mineralization accompanies the argillaceous cement of a zone of spheroidal weathering, the zone of lens-shaped tectonic effects developed in the Athabasca sandstone following the recurrence of a zone of Hudsonian mylonitization. Two uraniferous assemblages have been identified: (1) an uraninite-polymetallic (Mo, Cu, Pb, Co, Ni) assemblage, (2) uraninite and simple (Cu, Pb) sulfides. The emplacement was preceded by a long magnesian-argillaceous hydrothermal alteration."
408 "The Dominique-Peter deposit is situated about 1.5 km to the NW of the 'D' ore body and was developed entirely in the metamorphosed basement. The location of the mineralization is preferentially controlled by the limit of the Peter River gneiss series and by the Earl River complex." " T h e mineralization fills two fracture systems, the dips of which are contrary to that of the mylonite; some of these fractures are oriented N-S and have a dip of 50 ~W, others strike N60 E and dip NW. The later faults strike N NE and N 2 0 E; they cut the earlier faults but are no~ mineralized. A fragment of sandstone and of weathered metamorphosed basement have been discovered in the Dominique zone; it emphasizes the proximity to the pre-Athabascan discordance. The parageneses (assemblages) observed in ore body 'D' also are present in the Dominique-Peter." " T h e Claude ore body, to the N W of Dominique-Peter, also is situated in the Peter River aluminous gneiss. The uranium mineralization is controlled by an E - W mylonitic zone where a zone of spheroidal weathering has been developed; this zone separates the altered gneiss to the north from the sound gneiss to the south. The late N20 ~E faults give the form of the lett e ~ J ' to the mineralized envelope." "The OP and N ore bodies are both in the basement, near to the discordance. The OP is made up of three N-S, subvertically dipping structures in the midst of Peter aluminous gneiss; these lie immediately north of ore body 'D'. N ore body is developed essentially in the altered quartzo-feldspathic facies of the Earl River complex overthrust on the Pearl River gneiss. The mineralization there is controlled perhaps by the zone of weathering, perhaps by a vertical N 4 0 : E vein." The Carswell structure is located about 60 km south of Lake Athabasca and 25 miles east of the Alberta-Saskatchewan border. This rudely circular structure occurs in the Western Craton in the Churchill geologic province along the southwestern edge of the Canadian Shield.
With this much information readily at hand, the study of' the individual papers is rendered much more satisfactory as each can the more easily be put into is proper geological and ore development context. The titles of' these papers, in addition to the one mentioned at the beginning of' this review, are: Clay mineral stratigraphy of the Athabasca Group: Correlation inside and outside the ('/arswell structure; Geochronology of the Carswell area northern Saskatchewan; K Ar dating of different rock types from the Cliff' I,ake uranium ore deposits; Petrographic and chemical variations within the Carswell structure metamorphic core and their implications with respect to uranium mineralization; Petrogra phy and geochemistry of the Earl River complex, Carswell structure - - a possible Proterozoic komatiitic succession: The study of the basal Athabasca succession in the D, E, I,, F, and S areas of' the Carswell structure; The Carswell formation, northern Saskatchewan: stratigraphy, sedimentology, and structure: Mineralogy and metallogeny of the uraniferous occurrences in the Carswell structure: A (sici uranium unconformity deposit: the geological setting of the D orebody ( Saskatchewan, Canada); Mineralogical and structural aspects of the Dominique-Peter uranium deposit: (?hemistry of uranium minerals in deposits and showings of' the Carswell structure: Geochemistry and glacial geolo~, - - Application to exploration in the Carswell structure; Case histories of the Radon Tube Sampler in the Carswell structure; Geophysical mapping of gneiss domes in the Carswell structure and their relationship to uranium mineralization: the origin of the Carswell circular structure: Conclusion: lhe Carswell uranium deposits - - an example of not s~ unique unconformity related uranium mineralization. It is impossible in the space available even to summarize each of these papers. As Slama and Artru point out in their Forword, the main uranium occurrences are clustered near the southern edge of the basement core, an area where
409 the structure is at its most complex, and where the relationship between mineralization and the geological aspects of the basement and its sedimentary cover would be most difficult of interpretation. The necessary vital clues to solving these stratigraphic and structural puzzles appear to have been derived from the results of the 1980 high-sensitivity airborne magnetic survey. This lead to the assumption t h a t the basement was not completely broken up and that it. still retained the structure existing prior to the Carswell event. The interpretations so drawn were soon confirmed, largely through their leading to the finding of the Dominique-Peter ore body. The ()re was found at the stratigraphic contact between the aluminous gneiss and the flanks of the magnetic quartzose-feldspathic gneiss domes. The drilling t h a t fbllowed the location of this target further aided the problem of geologic interpretation by showing the role of the mylonitic zones and the faulting t h a t occurred after the mylonitization in supplying the major structural controls t h a t provided a home fbr the uranium mineralization. The one structural problem left unsolved is: was the Carswell ring produced by a meteoric impact or resulted from some other cryptoexplosive phenomenon? The reader of this volume should not immediately turn to paper 17 - - The origin of the Carswell circular structure - - but should read those t h a t precede it, so that he too will be, to some extent, prepared to make a decision as to which concept he considers to he the correct one or does he come to a third conclusion instead? As the Editors of this volume point out, the majority of the papers in the volume were written by geologists whose first language was not English. Had this not been indicated in their Preface, it is to be doubted if the student would have reached this conclusion by him- or herself. The Authors, Editors, and Referees should take great pride in having contributed to this outstanding volume. The 1:50,000 map of the Bedrock Geology of
the Carswell Structure t h a t accompanies the Volume is a great aid to understanding the geology so well described in the text. ,I.D. RIDGE Gainesville,Fla.)
Empirical Metallogeny. Depositional Environments, LithoIogic Associations and Metallic Ores. Vol. I: Phanerozoic Enc, ironments, Associations and Deposits, Part A and B. P. Laznicka. (Developments in Economic Geology, 19) Elsevier, Amsterdam, 1985, xxxvi+1758 pp., US $ 176.00/Dfl. 455.00 (hardback, in 2 parts ). This is what I thought not to be possible any more: a book by one single author covering all types of ore deposits, of which these enormous two parts only constitute the first volume covering Phanerozoic (Cambrian to Recent) deposits and their environments. "A second, companion volume will cover metallic ores of Precambrian age and unusual associations of all ages, and will contain search tables covering both volumes" (p.xxvii). A tremendous amount of work has been done by P. Laznicka to compile this "large body of information on Phanerozoic metallic ore deposits" throughout about :30 years ("since my student days in the 1950's"). "The work is based on the literature, consulted in the original in over thirty languages, and on field work, and it treats locality examples in some one hundred and fifty countries and regions, many of them checked in the field" (p.xxvii). One more quotation from the Preface (p.xxix): "Intended initially as a 'DC 9'-size modern substitute of the Lindgren (1933) book, a 'DC 3' of economic geologic literature in terms of versatility, the book turned into a 'Boeing 747'. Whereas, however, in the Lindgren's days the geological literature of the world amounted to some 50,000 items, the count is now some 1.5 to 2 million. This provides some justification of' the book size". Peter Laznicka theretbre is an expert who has seen much more than most of us. His descrip-