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Sediment Diagenesis
292
Sediment Diagenesis. A Parker and B.W. Sellwood (Editors). NATO Advanced Study Institute Series C, Vol. 115, Reidel, Dordrecht, 1983. Published in cooperation with NATO Scientific Affairs Division, 427 pp., ISBN 90-277-1677-3 (hardback) £stg 35.50; (paperback) £stg 16.50. This volume consists of eight chapters whose contents were keynote addresses given to the NATO Advanced Study Institute held in the University of Reading, U.K., July 12-25, 1981. The major themes were the aspects of deposition and burial of carbonate and terrigenous clastic sediments. T. Elliot overviews facies sequences and sand bodies of clastic depositional environments emphasising that environment is the major factor determining types of diagenesis in sand bodies. Discussions are curtailed and, since sand bodies of only selected depositional environments are treated, controversial issues tend to be avoided. G.V. Chilingarian provides an excellent overview of aspects of compactional diagenesis. He offers a clear definition of diagenesis and emphasizes the importance of compaction in the diagenetic process. The effect of compaction on sediments is expressed within the framework of physico-chemical changes in sediments, sedimentary rocks, and their pore-fluids. The discussions are perceptive and supported by very good illustrations. K. Bjorlykke deals with diagenesis of sandstones in a physico-chemical framework. Discussions of diagenetic processes are made in relation to porosity, reaction between pore-water and minerals, burial, and in relation to basin types and plate-tectonic setting. This appears to be a poorly organized chapter in which the discussions are too sketchy in some sections. For example, the application of stable isotopes of O, C and S are very useful in the study of sandstone diagenesis particularly in back tracking the origin of cements. Bj~rlykke gives very little information about them. B. Velde offers an excellent exposition of methods of study of clay mineral assemblages in peletic aluminous sedimentary rocks. His approach is strongly thermodynamic and kinetic. Application of electron microprobe for identification of clay mineral assemblages is strongly emphasized. The relationship between claymineral assemblages and their chemistry is well demonstrated. The chapter is authoritative and well written. H. Fuchtbaner discusses sandstone diagenesis relating sandstone cement-types to depositional environments, diagenetic texture and time sequences in cementation, and composition of detrital minerals in sandstones with their diagenesis. Finally the diagenetic criteria in sandstones are attributed to the depositional environments. This chapter is well organized and the discussions are precise with heavy emphasis on marine sandstones, but only briefly on their nonmarine counterparts. Although the author states that diagenesis depends on interaction between pore-fluids and rock framework, he did not use much chemistry to explain the phenomena. It would
293 have been better if the author would give some insight into the application of stable isotopes of O, C and S in sandstones determining the origin of cements as well as for interpretation of depositional environment. N.P. James presents a good synthesis on the spectrum of depositional systems of carbonate rocks. Starting with a demonstration of the distinction between carbonate and terrigenous clastic sediments, the author gives a brief summary of the components of carbonate rocks, discusses their classification and follows this with a lengthy description and discussion of the various depositional systems. Platform carbonates are heavily emphasized; his descriptions of reef-carbonates are excellent. R.G.C. Bathurst deals with the diagenesis of carbonate sediments. His chapter is well organized and well written with penetrating discussions, but his treatment is restricted to early diagenesis in marine carbonate sediments; nonmarine carbonates are ignored. Differences between meteoric and the marine diagenesis of marine carbonate sediments from the standpoint of texture, mineralogy and chemistry are clearly presented. In the section on "mechanical compaction" (p. 363), Bathurst presents only the problem of marked differences in response of carbonate sediments to compaction so that fossil shells in carbonate rocks show effects of compaction by natural phenomena, whereas they are unaffected in carbonate sediments subjected to mechanical stress in the laboratory. Bathurst ascribes this difference to cementation at shallow depth developing rigidity before significant mechanical compaction could occur. Partial dissolution a n d / o r recrystallization of aragonite to calcite could, however, create zones of weakness within fossil shells facilitating their breakage under stress; Recent shells are fresh and can withstand mechanical stress applied in laboratory compaction experiments. In fact not all fossil shells are necessarily found to be broken in all carbonate rocks. H.R. Wanless discusses burial diagenesis in limestones pointing out controversial issues. His section on dolomitization is sketchy. A major limitation of the book is that it deals only with the diagenesis of marine sediments; its summaries lack the strict systematic organization of a textbook resulting in repetition and a fair amount of overlap between chapters. The book concentrates on diagenesis of sands, clays and carbonates, and provides chapters on the depositional models for sandstones and carbonates but no chapter on the depositional models for clays or argillaceous sediments. Sadly, there are numerous printing errors throughout the book. I recommend the volume as entertaining reading for all sedimentologists. Sedimentologists in the petroleum industries will probably find it especially interesting and useful. The book, however, is not sufficiently elaborate and systematic to serve as a text for a University course, especially when compared with G. Larsen and G.V. Chilingar's "Diagenesis in Sediments and Sedimentary Rocks". The price is reasonable. I highly recommend it as an important reference. R. AHMAD(North Ryde,N.S.W.)
Sediment Diagenesis. A Parker and B.W. Sellwood (Editors). NATO Advanced Study Institute Series C, Vol. 115, Reidel, Dordrecht, 1983. Published in cooperation with NATO Scientific Affairs Division, 427 pp., ISBN 90-277-1677-3 (hardback) £stg 35.50; (paperback) £stg 16.50. This volume consists of eight chapters whose contents were keynote addresses given to the NATO Advanced Study Institute held in the University of Reading, U.K., July 12-25, 1981. The major themes were the aspects of deposition and burial of carbonate and terrigenous clastic sediments. T. Elliot overviews facies sequences and sand bodies of clastic depositional environments emphasising that environment is the major factor determining types of diagenesis in sand bodies. Discussions are curtailed and, since sand bodies of only selected depositional environments are treated, controversial issues tend to be avoided. G.V. Chilingarian provides an excellent overview of aspects of compactional diagenesis. He offers a clear definition of diagenesis and emphasizes the importance of compaction in the diagenetic process. The effect of compaction on sediments is expressed within the framework of physico-chemical changes in sediments, sedimentary rocks, and their pore-fluids. The discussions are perceptive and supported by very good illustrations. K. Bjorlykke deals with diagenesis of sandstones in a physico-chemical framework. Discussions of diagenetic processes are made in relation to porosity, reaction between pore-water and minerals, burial, and in relation to basin types and plate-tectonic setting. This appears to be a poorly organized chapter in which the discussions are too sketchy in some sections. For example, the application of stable isotopes of O, C and S are very useful in the study of sandstone diagenesis particularly in back tracking the origin of cements. Bj~rlykke gives very little information about them. B. Velde offers an excellent exposition of methods of study of clay mineral assemblages in peletic aluminous sedimentary rocks. His approach is strongly thermodynamic and kinetic. Application of electron microprobe for identification of clay mineral assemblages is strongly emphasized. The relationship between claymineral assemblages and their chemistry is well demonstrated. The chapter is authoritative and well written. H. Fuchtbaner discusses sandstone diagenesis relating sandstone cement-types to depositional environments, diagenetic texture and time sequences in cementation, and composition of detrital minerals in sandstones with their diagenesis. Finally the diagenetic criteria in sandstones are attributed to the depositional environments. This chapter is well organized and the discussions are precise with heavy emphasis on marine sandstones, but only briefly on their nonmarine counterparts. Although the author states that diagenesis depends on interaction between pore-fluids and rock framework, he did not use much chemistry to explain the phenomena. It would
293 have been better if the author would give some insight into the application of stable isotopes of O, C and S in sandstones determining the origin of cements as well as for interpretation of depositional environment. N.P. James presents a good synthesis on the spectrum of depositional systems of carbonate rocks. Starting with a demonstration of the distinction between carbonate and terrigenous clastic sediments, the author gives a brief summary of the components of carbonate rocks, discusses their classification and follows this with a lengthy description and discussion of the various depositional systems. Platform carbonates are heavily emphasized; his descriptions of reef-carbonates are excellent. R.G.C. Bathurst deals with the diagenesis of carbonate sediments. His chapter is well organized and well written with penetrating discussions, but his treatment is restricted to early diagenesis in marine carbonate sediments; nonmarine carbonates are ignored. Differences between meteoric and the marine diagenesis of marine carbonate sediments from the standpoint of texture, mineralogy and chemistry are clearly presented. In the section on "mechanical compaction" (p. 363), Bathurst presents only the problem of marked differences in response of carbonate sediments to compaction so that fossil shells in carbonate rocks show effects of compaction by natural phenomena, whereas they are unaffected in carbonate sediments subjected to mechanical stress in the laboratory. Bathurst ascribes this difference to cementation at shallow depth developing rigidity before significant mechanical compaction could occur. Partial dissolution a n d / o r recrystallization of aragonite to calcite could, however, create zones of weakness within fossil shells facilitating their breakage under stress; Recent shells are fresh and can withstand mechanical stress applied in laboratory compaction experiments. In fact not all fossil shells are necessarily found to be broken in all carbonate rocks. H.R. Wanless discusses burial diagenesis in limestones pointing out controversial issues. His section on dolomitization is sketchy. A major limitation of the book is that it deals only with the diagenesis of marine sediments; its summaries lack the strict systematic organization of a textbook resulting in repetition and a fair amount of overlap between chapters. The book concentrates on diagenesis of sands, clays and carbonates, and provides chapters on the depositional models for sandstones and carbonates but no chapter on the depositional models for clays or argillaceous sediments. Sadly, there are numerous printing errors throughout the book. I recommend the volume as entertaining reading for all sedimentologists. Sedimentologists in the petroleum industries will probably find it especially interesting and useful. The book, however, is not sufficiently elaborate and systematic to serve as a text for a University course, especially when compared with G. Larsen and G.V. Chilingar's "Diagenesis in Sediments and Sedimentary Rocks". The price is reasonable. I highly recommend it as an important reference. R. AHMAD(North Ryde,N.S.W.)