Physics of the Earth and Planetary Interiors, 9 (1974) 161 - 164 © North-Holland Publishing Company, Amsterdam - Printed in The Netherlands
Proceedings o f the Fourth Lunar Science Conference, Houston, Texas. W.A. Gose. Pergamon Press, Oxford, 1973, £40.00. The great days of manned landings on the Moon are over, the intense excitement of examining the first rocks from the Moon is a thing of the past and the expectant air with which we arrived for the first lunar science conference is a memory, but the scientific achievement becomes more impressive. Perhaps the papers contained in these three beautifully, speedily and efficiently produced volumes are a high water mark. Just as great art has been said to be great emotion recollected in tranquillity, so many of these papers achieve new insight into the Moon because the right interval has now elapsed since the first results so that investigators are making mature judgements. Nevertheless their imaginations still remain stretched to see in a few samples the key to the major problems of the Moon's origin and evolution. Few geologists, astronomers or physicists would not gain a broadened view of their own fields by delving almost at random in these volumes, representative of all scientific disciplines and many countries. The first volume on mineralogy and petrology opens with a discussion of the geology of the Apollo 16 site, the papers describing results mainly on Apollo 15 and 16 rocks. Tantalisingly incomplete maps of the Moon's radioactivity, magnetism and figure from the orbiters are included - until there is a lunar polar orbiter this data will remain largely uninterpretable. The orbital photographs stimulate impressive use of geological reasoning by Mattingly and E1-Baz on the highlands and many impressive papers on the mode of origin of the lava flows in the mare, for instance by Schaber and by Bryan. There are many papers on the complex shock history of the material of the lunar regolith. Volume 2 on the chemistry and on isotopic analysis is full of important data. Excellent and accurate data are now available on ages of the lunar rocks and
the history of the main events on the lunar surface seems likely to be reliable. The Moon originated 4,600 m.y. ago. About 2 0 0 - 3 0 0 m.y. later an anorthositic shell formed by differentiation largely covering the surface. Just before 4,000 m.y. ago the last huge impacts formed first the irregular mare and then the circular mare. Filling of these basins with lava from the then lunar asthenosphere took place between 3,900 m.y. and 3,200 m.y. ago. Similarly the broad elemental abundances of the Moon rocks seem now unlikely to be seriously changed; the depletion of volatile elements being relatively easy to understand but the greater deficiency of the siderphile elements with respect to cosmic abundances, seems puzzling. Surely it is a key to lunar origin but we don't know which door it opens. Volume 3 deals with physical properties. There are many papers on the unexpected physical discoveries of the Apollo project; mascons, moonquakes and magnetism. The cause of each still remains a matter of hot debate. The editors and press are to be congratulated on what I think can be safely described as the publication which makes the greatest contribution yet to our knowledge of a body external to the earth. S.K. RUNCORN (Newcastle upon Tyne.)
The Structure o f the Earth's Crust, S. MueUer (Editor). Elsevier, Amsterdam, 1974, 392pp., 193 ill., 11 tables, Dr. 100.--. Developments in Geotectonics, 8.
This volume is a collection of 33 papers which were given at an International Upper Mantle Project Symposium on 'Crustal Structure Based on Seismic Data' held in Moscow, 30-31 July 1971, just before the 15th General Assembly of the International Union of Geodesy and Geophysics. It is a reprint in hardback form of Volume 20 of the journal Tectonophysics.