Synthesis of deep-sea drilling results in the Indian ocean. Elsevier oceanography series, 21

306 C.C. van der Borch (Editor), 1978.Synthesis of Deep-Sea Drilling Results in the Indian Ocean. Elsevier Oceanography Series, 21. Elsevier, Amsterdam, 175 pp., Dfl. 90.00, U.S. $ 37.50. The seven papers on Indian Ocean geology have been bound into this slim, handsome and well-edited volume are substantial, although one might argue with the claim made in the title that the collection constitutes a synthesis. There is, however, a serious attempt to synthesize large amounts of information in several of the papers, Topics addressed are biostratigraphy, hiatus stratigraphy, sea-floor spreading history, subsidence history of drill sites, sedimentation history and CCD fluctuation, volcanism on Ninetyeast Ridge, basement rock petroIogy and origin of Nineweast Ridge, and evolution of Upper Oligocene and Neogene benthic foraminifera, McGowran compares oceanic and continental events of the Early Tertiary,stressing the isochronous nature of platewide (and even global) stratigraphic change. One striking feature of the record is widespread deep-ocean hiatus formation, as at the Paleocene--Eocene boundary. McGowran lists an impressive number of tectonic and climatic events associated with this boundary, in support of his argument of stratigraphic interconnections. He makes a strong case for a record punctuated by global happenings. Clearly, some intensive thought must now be given to the mechanisms providing stratigraphic linkage. Changes in the chemistry and circulation of the ocean, associated with transgression and regression and with varying access to semi-enclosed basins, should play an important role in controlling patterns of sedimentation and evolution, Kidd and Davies, in their survey of sedimentation history, likewise present evidence for supraregional stratigraphy. They invoke the presumed onset of large-scale production of Antarctic bottom water at the beginning of the Oligocene, to explain widespread hiatuses in the Early Oligocene. Where then is the sediment thus eroded? And why does all this 'copious', 'aggressive' bottom water allow the CCD to take a drastic drop from the Eocene to the Oligocene? Elsewhere, Davies and colleagues

have suggested low input rates of sediment from dry continents to explain tow sedimentation rates in the Oligocene. This seems to make more sense than the erosion-bybottom water idea. Besides the nature of the stratigraphic record, the makeup of Ninetyeast Ridge is a central theme of the collection. Reddy and co-workers, and Thompson and colleagues present a large body of petrologic and geochemical data bearing on the origin of this enigmatic feature. A wide range of differentiation is indicated. According to Thompson et al., results are compattible with the interpretation of the Ridge as a hot spot trace. The last paper, by Boltovskoy on deepsea benthic foraminifera, with excellent reproduction of extensive illustrations, is a wellcome addition to the small pool of relevant information. Everyone concerned with deep-sea geology will want to have access to this volume and will need one or several of the articles for reference. W.H. Berger, La Jolla, Calif.

PETROLOGY W.G. Ernst, 1976. Petrologic Phase Equilibria. Freeman and Co., Reading, 333 pp., £ 15.60. The text is intended for senior undergraduate and beginning graduate students and stresses the application of experiments and classical thermodynamics to igneous and metamorphic petrology. A skeleton outline of thermodynamics, which leaves more subtle concepts for later development, helps maintain the reader's interest, but basic fundamentals are spread through the text and are not readily accessible. Calculations and interpretations of phase diagrams give the reader an appreciation for the author's methods, but problems would allow an instructor to show the multiplicity of solutions to a problem. Chapter one gives a brief review of deftnitions and elementary thermodynamics. Fugacity, activity, partial molal quantities and standard states are covered in rudimentary fashion, making introduction of the geologically inescapable concept of solu-