- Email: [email protected]
Volcanoes of the Antarctic Plate and Southern Oceans
368
ises the Subcommission's classifications of the carbonatites, charnockitic rocks, lamprophyric rocks, melilitic rocks, plutonic rocks (common), pyroclastic rocks, and volcanic rocks (common), but it also challenges one with the question of whether there are simple natural relationships linking the various groups of igneous rocks. Although the Subcommission has attempted to separate classification from petrogenetic theory, the writer intuitively believes that a comprehensive classification should provide insights into the relationships between the various rock groups, and also draw attention to the minor anomalies that are likely to exist between different classifications devised at different times for different purposes. In the QAPF classification of volcanic rocks, for example, the basalts are not separated from the andesites or basaltic ande-
sites. According to the wall-chart if they are to be separated one has to use another diagram which employs a value of 50% SiO2 to separate the basalts from the andesites. In the a'AS diagram a more realistic value of 52% SiO2 is used in the separation of the basalts from the basaltic andesites. The valuable work of the Subcommission is not yet finished. This is clearly acknowledged by the present chairperson of the Subcommission in his Preface to the book (p.x.). He sees the future work of the Subcommission as "keeping the systematics up-to-date and internationally relevant", and also in reexamining the nomenclature of some specialised areas of igneous petrology, such as the potassic rocks and the basaltic rocks. ERIC MIDDLEMOST (Sydney, NSW)
Volcanoes of the Antarctic Plate and Southern Oceans, edited by W.E. LeMasurier and J.W. Thomson, volume 48, Antarctic Research Series, American Geophysical Union, 487 pp. (ISBN 0-87590-172-7, US $55.00, AGU members US
$38.50). This volume is a comprehensive guide to our state of knowledge of late Cenozoic volcanism on and around the Antarctic plate. Much of the book concerns West Antarctica, one of the great continental rift-related alkaline volcanic regions of the world. Also included are descriptions of the subantarctic oceanic islands of both the Antarctic and Pacific plates. Only the volcanoes of the South Sandwich and South Shetland Islands, which are related to subduction processes, are not representative of intraplate or hot-spot magmatism. The publication is the culmination of an International Association of Volcanology and Chemistry of the Earth's Interior project to update and greatly expand the 1960 Catalogue of Active Volcanoes of Antarctica. Information has been contributed by 38 authors from the U.S., The U.K., New Zealand, Australia, South Africa, Germany and France. Major contributions have been made by P.E. Baker, P.R. Kyle, W.E. LeMasurier, J.L. Smellie and J.W.
Thomson. For descriptive purposes the region has been divided into seven provinces: the McMurdo volcanics of the western Ross Sea; Marie Byrd Land; Alexander Island, Palmer Land and Ellsworth Land; Graham Land and the South Shetland Islands; the South Sandwich Islands; oceanic islands of the Antarctic Plate (including Bouvetoya, Marion and Kerguelen); subantarctic islands of the Pacific Plate (including Auckland, Campbell and Macquarie). A short overview of the volcanology and tectonic relationships within the region as a whole is given by W.E. LeMasurier, and brief summaries for each of the seven provinces are included. The main body of the volume comprises descriptions of individual volcanoes using a format modelled on the Catalogue of the Active Volcanoes of the World and including volcanological, petrological, chronological, structural and historical data. Many contributions are original and contain unpublished
369
data, particularly geological maps and chemical analyses. There is inevitably an unevenness in the amount of information presented for each volcano. For example, descriptions of the two most studied volcanoes in Antarctica, the active volcanoes of Deception Island in the South Shetlands and Mount Erebus on Ross Island, cite more than 40 references each, reflecting the fact that observations of these two volcanoes have been made over a period approaching 150 years. By contrast, the huge 1800 km 3 volcano Mount Siple in remote Marie Byrd Land received its first visit by geologists in 1984. In its coverage of the Cenozoic volcanoes of the Campbell Plateau, the volume under review overlaps the recently published Intraplate Volcanism in Eastern Australia and New Zealand (Johnson et al., 1989). These two books are rather different in style and content. Both contain a wealth of detailed volcanological information and together cover a significant portion of the southern hemisphere. Researchers interested in intraplate
volcanism should have both books on their shelves. Mature syntheses and overall petrogenetic geophysical and tectonic models which are presented for Australian and New Zealand examples are lacking in the Antarctic volume. This is an observation not a criticism and simply reflects the essentially reconnaissance nature of most of the work to date on Antarctic volcanoes and our poor knowledge of the Antarctic lithosphere. The publication of Volcanoes of the Antarctic Plate and Southern Oceans is therefore particularly welcome because it will be a major stimulus for future more intensive scientific investigations in the region. References Johnson, R.W., Knutson, J. and Taylor, S.R. (Editors), 1989. Intraplate Volcanism in Eastern Australia and New Zealand. Cambridge University Press, Cambridge, 408 pp. S.D. WEAVER ( Christchurch, New Zealand)
ises the Subcommission's classifications of the carbonatites, charnockitic rocks, lamprophyric rocks, melilitic rocks, plutonic rocks (common), pyroclastic rocks, and volcanic rocks (common), but it also challenges one with the question of whether there are simple natural relationships linking the various groups of igneous rocks. Although the Subcommission has attempted to separate classification from petrogenetic theory, the writer intuitively believes that a comprehensive classification should provide insights into the relationships between the various rock groups, and also draw attention to the minor anomalies that are likely to exist between different classifications devised at different times for different purposes. In the QAPF classification of volcanic rocks, for example, the basalts are not separated from the andesites or basaltic ande-
sites. According to the wall-chart if they are to be separated one has to use another diagram which employs a value of 50% SiO2 to separate the basalts from the andesites. In the a'AS diagram a more realistic value of 52% SiO2 is used in the separation of the basalts from the basaltic andesites. The valuable work of the Subcommission is not yet finished. This is clearly acknowledged by the present chairperson of the Subcommission in his Preface to the book (p.x.). He sees the future work of the Subcommission as "keeping the systematics up-to-date and internationally relevant", and also in reexamining the nomenclature of some specialised areas of igneous petrology, such as the potassic rocks and the basaltic rocks. ERIC MIDDLEMOST (Sydney, NSW)
Volcanoes of the Antarctic Plate and Southern Oceans, edited by W.E. LeMasurier and J.W. Thomson, volume 48, Antarctic Research Series, American Geophysical Union, 487 pp. (ISBN 0-87590-172-7, US $55.00, AGU members US
$38.50). This volume is a comprehensive guide to our state of knowledge of late Cenozoic volcanism on and around the Antarctic plate. Much of the book concerns West Antarctica, one of the great continental rift-related alkaline volcanic regions of the world. Also included are descriptions of the subantarctic oceanic islands of both the Antarctic and Pacific plates. Only the volcanoes of the South Sandwich and South Shetland Islands, which are related to subduction processes, are not representative of intraplate or hot-spot magmatism. The publication is the culmination of an International Association of Volcanology and Chemistry of the Earth's Interior project to update and greatly expand the 1960 Catalogue of Active Volcanoes of Antarctica. Information has been contributed by 38 authors from the U.S., The U.K., New Zealand, Australia, South Africa, Germany and France. Major contributions have been made by P.E. Baker, P.R. Kyle, W.E. LeMasurier, J.L. Smellie and J.W.
Thomson. For descriptive purposes the region has been divided into seven provinces: the McMurdo volcanics of the western Ross Sea; Marie Byrd Land; Alexander Island, Palmer Land and Ellsworth Land; Graham Land and the South Shetland Islands; the South Sandwich Islands; oceanic islands of the Antarctic Plate (including Bouvetoya, Marion and Kerguelen); subantarctic islands of the Pacific Plate (including Auckland, Campbell and Macquarie). A short overview of the volcanology and tectonic relationships within the region as a whole is given by W.E. LeMasurier, and brief summaries for each of the seven provinces are included. The main body of the volume comprises descriptions of individual volcanoes using a format modelled on the Catalogue of the Active Volcanoes of the World and including volcanological, petrological, chronological, structural and historical data. Many contributions are original and contain unpublished
369
data, particularly geological maps and chemical analyses. There is inevitably an unevenness in the amount of information presented for each volcano. For example, descriptions of the two most studied volcanoes in Antarctica, the active volcanoes of Deception Island in the South Shetlands and Mount Erebus on Ross Island, cite more than 40 references each, reflecting the fact that observations of these two volcanoes have been made over a period approaching 150 years. By contrast, the huge 1800 km 3 volcano Mount Siple in remote Marie Byrd Land received its first visit by geologists in 1984. In its coverage of the Cenozoic volcanoes of the Campbell Plateau, the volume under review overlaps the recently published Intraplate Volcanism in Eastern Australia and New Zealand (Johnson et al., 1989). These two books are rather different in style and content. Both contain a wealth of detailed volcanological information and together cover a significant portion of the southern hemisphere. Researchers interested in intraplate
volcanism should have both books on their shelves. Mature syntheses and overall petrogenetic geophysical and tectonic models which are presented for Australian and New Zealand examples are lacking in the Antarctic volume. This is an observation not a criticism and simply reflects the essentially reconnaissance nature of most of the work to date on Antarctic volcanoes and our poor knowledge of the Antarctic lithosphere. The publication of Volcanoes of the Antarctic Plate and Southern Oceans is therefore particularly welcome because it will be a major stimulus for future more intensive scientific investigations in the region. References Johnson, R.W., Knutson, J. and Taylor, S.R. (Editors), 1989. Intraplate Volcanism in Eastern Australia and New Zealand. Cambridge University Press, Cambridge, 408 pp. S.D. WEAVER ( Christchurch, New Zealand)