Petrology of the Ocean Floor

Petrology of the Ocean Floor

Journal of Volcanology and Geothermal Research, Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands 343 Book Reviews Petrology...

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Journal of Volcanology and Geothermal Research, Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

343

Book Reviews Petrology o f the Ocean Floor. Roger H~kinian. Elsevier Oceanographic Series, 33. Elsevier, Amsterdam, 1982. XIV + 393 pp. Dfl. 200.00/U.S. $93.00.

Most of this book comprises a detailed description of the volcanic rocks of the ocean floor. It does not include descriptions of sedimentary materials; but it does contain a particularly valuable chapter on the metamorphic changes that are often f o u n d in the igneous rocks of the accessible oceanic crust. The reviewer was particularly interested in the concept of the "brownstone facies" (pp. 273-273), and the search for phases and textures that characterize the transition from weathering to low-grade metamorphism in basaltic materials. Submarine hydrothermal deposits are also discussed; and an a t t e m p t is made to establish criteria for recognizing these deposits when they are encountered in core samples. Most of the book is an excellent systematic review of the igneous rocks f o u n d associated with, (a) oceanic ridges and rises, (b) aseismic ridge, (c) thrust-faulted regions of the ocean floor, (d) ocean basins, (e) seamounts, (f) oceanic trenches, and (g) oceanic fracture zones. This work is particularly valuable in t h a t it gives comprehensive descriptions of those few areas of the ocean floor (such as, the FAMOUS area of the Mid-Atlantic ridge near 26°N, and the RITA area of the East Pacific rise near 21°N) that have been examined in detail by submersibles and other underwater vehicles. Petrologists will find this book useful because it contains large numbers of petrographic descriptions, and chemical analyses of rocks and the minerals they contain. The work also contains m a n y photomicrographs which are labelled microphotographs, seafloor photographs, and bathymetric charts t h a t enable one to visualize the many different submarine landforms described in the text. The text does, however, contain a number of typographical errors; such as, glameroporphyritic for glomeroporphyritic (p. 79), Se for Sr (p. 153), phonalite for phonolite (p. 181), Ny for Hy (p. 198), expulsed for expelled (p. 326) and scarpments for escarpments (p. 351). Whereas the basaltic rocks are classified in great detail, the other igneous rocks are classified in a vague manner; for example, the term granitic is used to describe all the rocks t h a t are more silicic than basalts and andesites and contain more than 60% SiO2 (p. 43), and the "alkali-rich volcanics" are described as consisting of alkali basalts, mugearites and trachytes, and there is no mention of hawiites or benmoreites (pp. 45-46). The book ends with a long and useful list of references. A notable omission from this list is the Basaltic Volcanism Study Project (1981) book on "Basaltic Volcanism on the Terrestrial Planets". E.A.K. MIDDLEMOST (Sydney, Australia)