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Sonographs of the sea floor—a picture atlas
37 external to the plates, summarises the palaeomagnetic evidence. The last two chapters deal with processes at accreting and consuming plate margins respectively. It is a pity that the book has no index, but the ample list of nearly six hundred references more than makes up for this. The book is n o t suitable for the general reader interested in plate tectonics and its general format as a pr@cis of recent literature may make it indigestible to the undergraduate embarking on a career in the earth sciences. But to the scientist already working in the field or the research student who already has a grasp of plate tectonics it will be valuable, both as a guide to work going on in fields adjacent to his own and for its identification of unsolved problems. It is emphasised early in the book that the driving mechanism of plate movement is still poorly understood and little space is devoted to speculation on this subject. However, a warning is sounded against too ready an acceptance of " h o t spots", either as a reference f r a m e against which motion can be observed or as a source of plate movement. There has been such an explosion of literature on plate tectonics over the past few years that writing this book must have been like writing recent history, if not journalism. So much is so new that it is often difficult to see the wood for the trees. And things are still moving fast. Already since the book was completed in June 1972 a number of long standing problems may have fallen into place: transgressions and regressions of the sea have been related to the inflation and deflation of the mid-oceanic ridges that accompany changes in spreading rate; intra-plate earthquakes may be the result of plate deformation caused by movement over a non-spherical earth. In ten years time this book will u n d o u b t e d l y be out of date. For the present it is the most complete and up-to-date available. T. J. G. Francis (Blacknest near Reading)
Sonographs of the Sea F l o o r - A Picture Atlas. R. H. Belderson, N. H. Kenyon, A. H. Stride and A. R. Stubbs. Elsevier, Amsterdam, 1972, 200 pp., Dfl. 80,00. The book contains a brief Introduction, 163 photographs of side scan sonar records, referred to as sonographs and carefully selected from the now extensive library kept at the Institute of Oceanographic Sciences, to cover the Continental Shelf, Slope, Deep-Sea Floor and effects caused by marine life, and the sea itself; a short glossary of technical terms and a comprehensive reference list. In each case the sonographs are accompanied by an explanatory diagram and a brief description which details the width exaggeration by showing the length and width measurements of the sea floor represented by the sonograph and indicates the illumination direction. Although according to the "Preface" this book has been primarily written for the geologist the presentation appears to be more suited to those for w h o m the sea floor holds the fascination of an u n k n o w n world. Certainly
88
the photographs are superb both in clarity and content, so much so that they may give the impression to those unfamiliar with this survey technique that these were the norm, whereas in fact, large areas of the Continental Shelf appear on the records as dull and apparently featureless. The short " I n t r o d u c t i o n " is clear, undemanding and easily followed; but for anyone actually wanting to apply the principles of side scan sonar it must be considered a low key account. With the sudden and recent increase in sonar users this b o o k is timely, for it provides the basic references for this aspect of Marine Survey. For although many of the presented interpretations are to be found in references listed, this is the first comprehensive collection of interpreted records, and thus deserves a place in any reference library. Indeed, the full potential of this technique is y e t to be realised for the problems such as. texture and topography, and the dynamic range limits imposed by the recording paper still constrain the user. This together with a rapidly expanding involvement particularly on the Continental Shelf ensures an excellent future for this technique as it will also be for future editions of this book. M . R . Dobson (Aberystwyth)
ERRATUM J. E. Hawley and R. M. P y t k o w i c z , 1973. I n t e r p r e t a t i o n of p H m e a s u r e m e n t s in c o n c e n t r a t e d e l e c t r o l y t e s o l u t i o n s . Mar. Chem., 1 (3): 2 4 5 - - 2 5 0 . O n p . 2 4 8 , eq.7 s h o u l d r e a d as follows: , KI
=
X[HCO3-7 [CO2"]
=
h a l l [HCO3--] [CO2"]
-
h[H+] [HCO3 ] [CO2"]
,, ~H
=
kK1%'H
On p . 2 4 9 , t h r e e lines b e l o w e q . t 1 t h e e x p r e s s i o n s h o u l d read K'~ = 1 . 1 0 0 " 10 -~'.
Sonographs of the Sea F l o o r - A Picture Atlas. R. H. Belderson, N. H. Kenyon, A. H. Stride and A. R. Stubbs. Elsevier, Amsterdam, 1972, 200 pp., Dfl. 80,00. The book contains a brief Introduction, 163 photographs of side scan sonar records, referred to as sonographs and carefully selected from the now extensive library kept at the Institute of Oceanographic Sciences, to cover the Continental Shelf, Slope, Deep-Sea Floor and effects caused by marine life, and the sea itself; a short glossary of technical terms and a comprehensive reference list. In each case the sonographs are accompanied by an explanatory diagram and a brief description which details the width exaggeration by showing the length and width measurements of the sea floor represented by the sonograph and indicates the illumination direction. Although according to the "Preface" this book has been primarily written for the geologist the presentation appears to be more suited to those for w h o m the sea floor holds the fascination of an u n k n o w n world. Certainly
88
the photographs are superb both in clarity and content, so much so that they may give the impression to those unfamiliar with this survey technique that these were the norm, whereas in fact, large areas of the Continental Shelf appear on the records as dull and apparently featureless. The short " I n t r o d u c t i o n " is clear, undemanding and easily followed; but for anyone actually wanting to apply the principles of side scan sonar it must be considered a low key account. With the sudden and recent increase in sonar users this b o o k is timely, for it provides the basic references for this aspect of Marine Survey. For although many of the presented interpretations are to be found in references listed, this is the first comprehensive collection of interpreted records, and thus deserves a place in any reference library. Indeed, the full potential of this technique is y e t to be realised for the problems such as. texture and topography, and the dynamic range limits imposed by the recording paper still constrain the user. This together with a rapidly expanding involvement particularly on the Continental Shelf ensures an excellent future for this technique as it will also be for future editions of this book. M . R . Dobson (Aberystwyth)
ERRATUM J. E. Hawley and R. M. P y t k o w i c z , 1973. I n t e r p r e t a t i o n of p H m e a s u r e m e n t s in c o n c e n t r a t e d e l e c t r o l y t e s o l u t i o n s . Mar. Chem., 1 (3): 2 4 5 - - 2 5 0 . O n p . 2 4 8 , eq.7 s h o u l d r e a d as follows: , KI
=
X[HCO3-7 [CO2"]
=
h a l l [HCO3--] [CO2"]
-
h[H+] [HCO3 ] [CO2"]
,, ~H
=
kK1%'H
On p . 2 4 9 , t h r e e lines b e l o w e q . t 1 t h e e x p r e s s i o n s h o u l d read K'~ = 1 . 1 0 0 " 10 -~'.