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Serpentine and its vegetation: A multidisciplinary approach
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authors did not seem to have marine minerals specifically in mind when they wrote it, as multichannel seismic and marine gravity, for example, have little or no application in marine minerals exploration. Chapter 5, which is entitled marine geochemical exploration methods, simply describes seawater and seafloor sampling devices and the chemical techniques used to analyse the samples that they obtain. Geochemical exploration in the sense understood by exploration geochemists is only briefly mentioned. Chapter 6 is one of the few chapters that does draw most of its material from actual marine mineral exploration programmes and deals with the statistical analysis of marine minerals data as and aid to exploration for and assessment of the deposits. The penultimate chapter is perhaps the most useful in the book in that it describes actual marine mineral exploration programmes in an authoritative manner. The application of techniques which should have been described in more detail in earlier chapters are detailed here. The final chapter, like Chapter 3, seems rather out of place, dealing as it does with law rather than minerals, but provides a useful review of the current situation in regard to the Law of the Sea. In my view, any marine mineral exploration effort should be soundly based on scientific principles, as derived from oceanographic research. It will simply not be possible to explore the whole ocean floor for minerals using the empirical techniques described in most of this book in anything like a reasonable time. Deductive exploration techniques are essential, and these are based on oceanographic science providing a knowledge of how and why the minerals vary as they do. In other words, science and exploration cannot reasonably be separated in the search for marine minerals. D.S. CRONAN (London, U.K.)
Serpentine and its Vegetation: A Multidisciplinary Approach, by R.R. Brooks. Dioscorides Press, Portland, Oregon, 1987, 454 pp., US$39.95. In 1972, R.R. Brooks wrote the first book outside of the Soviet Union that dealt with biogeochemical prospecting for minerals. His new text is another "first" in that a quantitatively small, yet economically valuable, body of rocks has been isolated for detailed examination of the chemistry and ecology which give rise to specific floral communities. Subsequent discussion relates the significance of these communities to the presence of mineralization. From a geological standpoint, the title of the book is rather a misnomer. It covers not only serpentine, but ultramaflc rocks in general. Brooks points out (p. 5 ) that "botanists (always refer) to ultramafic floras as 'serpentine floras', whether the soils are derived from serpentinized rocks or not". Since the declared aim of this comprehensive text is to reach a wide spectrum of scientists
333 and laymen, Brooks has adopted this common usage as the book's title. It is important that the geologist or geochemist, who seeks to find what biogeochemical aspects of ultramafic rocks may assist in the discovery of valuable commodities, is made aware of this difference in terminology. "Serpentine Floras" is in two parts. The first 118 pages is entitled "Serpentine Ecology" which includes a summary of the nature, occurrence, and composition of ultramafic rocks, before launching into a discussion of the formation of serpentine soils. A chapter on "The Serpentine Factor" gives a fascinating chemical insight into the complex reasons for the general infertility of serpentine soils, examining in some detail the effects of high levels of nickel, cobalt, chromium and magnesium on the development of the flora and floral assemblages. The ensuing chapter on agricultural aspects includes a short section on revegetating serpentinitic mine dumps and tailings. Even some animals, it appears from chapter 7, are restricted to ultramafic bodies. For example, some butterflies preferentially feed on species endemic to ultramafic substrates, and therefore their presence is indicative of this rock group. The last two chapters in part one deal at length with the hyperaccumulation of nickel by a large number of species, and the vegetative cover of kimberlites and carbonatites. Although there are many studies that have investigated nickel accumulation in plants (and in fact probably more is known about the behaviour of nickel than other trace metals in vegetation), it is sobering to note Brooks' comment that a great deal of research still remains to be done - - clearly the controls on metal distributions in and among plants is an open area for research. Part two comprises nearly 300 pages in which the serpentine vegetation of the world is divided into appropriate geographical regions for description and discussion. Each chapter summarizes briefly the geology of the area under consideration, provides a map of the occurrence of ultramafic bodies, and proceeds to outline the floral characteristics of the region as a whole and provides details of most major occurrences. Following each descriptive portion there is a section entitled "biogeochemical studies" which gives information on the relative value of common species to assist in the discovery of minerals. Unfortunately for the mineral explorationist, most of the biogeochemical sections are rather short, but this is more a reflection of the relatively small amount of information available in the world literature, rather than a deficiency on the part of the author. A useful glossary of terms is appended to the book, plus an extensive botanical index. Brooks' style is rather informal which, coupled with many snippets of amusing and intriguing information, makes the book of potentially dry subject matter most interesting to read. The non-botanist will find detailed information difficult to appreciate, since latin names for plants are used throughout, only rarely citing any the common names which would be more readily understood by most explorationists. The uninitiated will need a botanical encyclopedia at hand!
334 The text is accompanied by an abundance of tables, simple maps, plant drawings and sketches, and both colour and black and white photographs of characteristic flora and general views. The reference lists that appear after each chapter are exhaustive, leading the interested reader to appropriate texts for more detailed information. 'Serpentine and its Vegetation' is a high quality production for which the author is to be commended for drawing together such diversity of disciplines in such a coherent and entertaining manner. The hardcover volume is extremely well produced and remarkably good value for money. It is a book that will be of value to anyone interested in studying this relatively rare, yet economically important group of rocks. COLINE. DUNN (Ottawa, Canada)
Mineral Deposit Models, by Dennis P. Cox and Donald A. Singer (Editors). Bulletin 1693, U.S. Geological Survey, Washington, DC, USA, 1986, 379 pp., $19.00. The concept of mineral deposit types or models has flowered in the 1970's and 80's. This book is an ambitious attempt by the U.S. Geological Survey to compile a set of models for use in mineral resource assessment and mineral exploration. A secondary goal is to stimulate discussion and research on genetic and economic aspects of ore types. A mineral deposit model is defined as a set of systematically arranged information describing the essential attributes (properties) of a class of mineral deposits. This effort follows a somewhat less comprehensive effort by the Geological Survey of Canada (Economic Geology Report 36, 1984). The development of the models has necessarily required the classification of known deposits. A combination of descriptive and genetic concepts have been used to distinguish 85 types of deposits, and to summarize a general set of characteristics for each type. The majority of models are for metallic deposits, but a few nonmetals are also included (phosphate, asbestos, diamond, emerald, barite). The classification is admittedly experimental, and will doubtless generate some controversy. The first level of subdivision is geologic-tectonic environment (igneous, sedimentary, regional metamorphic, surficial), followed by lithologic, geologic and metal-mineral associations within each environment. Most of the commonly accepted ore types, such as porphyry Cu, sandstone U, and hot-spring Au-Ag, are represented, along with some types new to the writer (Limassol Forest Co-Ni, Sado epithermal vein). However, no class appears to include the Sudbury deposit, despite 6 models for Cu-Ni sulfides with mafic-ultramafic rocks. Also, Kennecott, Alaska, and Redstone, NWT, are included with Keweenaw, Michigan and others in the Basaltic Copper
authors did not seem to have marine minerals specifically in mind when they wrote it, as multichannel seismic and marine gravity, for example, have little or no application in marine minerals exploration. Chapter 5, which is entitled marine geochemical exploration methods, simply describes seawater and seafloor sampling devices and the chemical techniques used to analyse the samples that they obtain. Geochemical exploration in the sense understood by exploration geochemists is only briefly mentioned. Chapter 6 is one of the few chapters that does draw most of its material from actual marine mineral exploration programmes and deals with the statistical analysis of marine minerals data as and aid to exploration for and assessment of the deposits. The penultimate chapter is perhaps the most useful in the book in that it describes actual marine mineral exploration programmes in an authoritative manner. The application of techniques which should have been described in more detail in earlier chapters are detailed here. The final chapter, like Chapter 3, seems rather out of place, dealing as it does with law rather than minerals, but provides a useful review of the current situation in regard to the Law of the Sea. In my view, any marine mineral exploration effort should be soundly based on scientific principles, as derived from oceanographic research. It will simply not be possible to explore the whole ocean floor for minerals using the empirical techniques described in most of this book in anything like a reasonable time. Deductive exploration techniques are essential, and these are based on oceanographic science providing a knowledge of how and why the minerals vary as they do. In other words, science and exploration cannot reasonably be separated in the search for marine minerals. D.S. CRONAN (London, U.K.)
Serpentine and its Vegetation: A Multidisciplinary Approach, by R.R. Brooks. Dioscorides Press, Portland, Oregon, 1987, 454 pp., US$39.95. In 1972, R.R. Brooks wrote the first book outside of the Soviet Union that dealt with biogeochemical prospecting for minerals. His new text is another "first" in that a quantitatively small, yet economically valuable, body of rocks has been isolated for detailed examination of the chemistry and ecology which give rise to specific floral communities. Subsequent discussion relates the significance of these communities to the presence of mineralization. From a geological standpoint, the title of the book is rather a misnomer. It covers not only serpentine, but ultramaflc rocks in general. Brooks points out (p. 5 ) that "botanists (always refer) to ultramafic floras as 'serpentine floras', whether the soils are derived from serpentinized rocks or not". Since the declared aim of this comprehensive text is to reach a wide spectrum of scientists
333 and laymen, Brooks has adopted this common usage as the book's title. It is important that the geologist or geochemist, who seeks to find what biogeochemical aspects of ultramafic rocks may assist in the discovery of valuable commodities, is made aware of this difference in terminology. "Serpentine Floras" is in two parts. The first 118 pages is entitled "Serpentine Ecology" which includes a summary of the nature, occurrence, and composition of ultramafic rocks, before launching into a discussion of the formation of serpentine soils. A chapter on "The Serpentine Factor" gives a fascinating chemical insight into the complex reasons for the general infertility of serpentine soils, examining in some detail the effects of high levels of nickel, cobalt, chromium and magnesium on the development of the flora and floral assemblages. The ensuing chapter on agricultural aspects includes a short section on revegetating serpentinitic mine dumps and tailings. Even some animals, it appears from chapter 7, are restricted to ultramafic bodies. For example, some butterflies preferentially feed on species endemic to ultramafic substrates, and therefore their presence is indicative of this rock group. The last two chapters in part one deal at length with the hyperaccumulation of nickel by a large number of species, and the vegetative cover of kimberlites and carbonatites. Although there are many studies that have investigated nickel accumulation in plants (and in fact probably more is known about the behaviour of nickel than other trace metals in vegetation), it is sobering to note Brooks' comment that a great deal of research still remains to be done - - clearly the controls on metal distributions in and among plants is an open area for research. Part two comprises nearly 300 pages in which the serpentine vegetation of the world is divided into appropriate geographical regions for description and discussion. Each chapter summarizes briefly the geology of the area under consideration, provides a map of the occurrence of ultramafic bodies, and proceeds to outline the floral characteristics of the region as a whole and provides details of most major occurrences. Following each descriptive portion there is a section entitled "biogeochemical studies" which gives information on the relative value of common species to assist in the discovery of minerals. Unfortunately for the mineral explorationist, most of the biogeochemical sections are rather short, but this is more a reflection of the relatively small amount of information available in the world literature, rather than a deficiency on the part of the author. A useful glossary of terms is appended to the book, plus an extensive botanical index. Brooks' style is rather informal which, coupled with many snippets of amusing and intriguing information, makes the book of potentially dry subject matter most interesting to read. The non-botanist will find detailed information difficult to appreciate, since latin names for plants are used throughout, only rarely citing any the common names which would be more readily understood by most explorationists. The uninitiated will need a botanical encyclopedia at hand!
334 The text is accompanied by an abundance of tables, simple maps, plant drawings and sketches, and both colour and black and white photographs of characteristic flora and general views. The reference lists that appear after each chapter are exhaustive, leading the interested reader to appropriate texts for more detailed information. 'Serpentine and its Vegetation' is a high quality production for which the author is to be commended for drawing together such diversity of disciplines in such a coherent and entertaining manner. The hardcover volume is extremely well produced and remarkably good value for money. It is a book that will be of value to anyone interested in studying this relatively rare, yet economically important group of rocks. COLINE. DUNN (Ottawa, Canada)
Mineral Deposit Models, by Dennis P. Cox and Donald A. Singer (Editors). Bulletin 1693, U.S. Geological Survey, Washington, DC, USA, 1986, 379 pp., $19.00. The concept of mineral deposit types or models has flowered in the 1970's and 80's. This book is an ambitious attempt by the U.S. Geological Survey to compile a set of models for use in mineral resource assessment and mineral exploration. A secondary goal is to stimulate discussion and research on genetic and economic aspects of ore types. A mineral deposit model is defined as a set of systematically arranged information describing the essential attributes (properties) of a class of mineral deposits. This effort follows a somewhat less comprehensive effort by the Geological Survey of Canada (Economic Geology Report 36, 1984). The development of the models has necessarily required the classification of known deposits. A combination of descriptive and genetic concepts have been used to distinguish 85 types of deposits, and to summarize a general set of characteristics for each type. The majority of models are for metallic deposits, but a few nonmetals are also included (phosphate, asbestos, diamond, emerald, barite). The classification is admittedly experimental, and will doubtless generate some controversy. The first level of subdivision is geologic-tectonic environment (igneous, sedimentary, regional metamorphic, surficial), followed by lithologic, geologic and metal-mineral associations within each environment. Most of the commonly accepted ore types, such as porphyry Cu, sandstone U, and hot-spring Au-Ag, are represented, along with some types new to the writer (Limassol Forest Co-Ni, Sado epithermal vein). However, no class appears to include the Sudbury deposit, despite 6 models for Cu-Ni sulfides with mafic-ultramafic rocks. Also, Kennecott, Alaska, and Redstone, NWT, are included with Keweenaw, Michigan and others in the Basaltic Copper