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Methods for the study of sedimentary structures
Marine Geology - Elsevier PublishingCompany, Amsterdam- Printed in The Netherlands
Book Reviews Methods for the Study o f Sedimentary Structures. A. H. BOUMA.Wiley-Interscience,
London, 1969, 458 pp., 232 fig., 190 s. The investigator of unconsolidated deposits, hard rock sediments or soils is, whatever the purpose of his study, confronted with two main problems of a practical nature: how to render possible laboratory investigation of the undisturbed field-material and its application for instruction as well as how to accentuate structures, textures and components to allow detailed observation. Arnold H. Bouma, Associate Professor of Geological Oceanography at Texas A. M. University, experienced in the study of ancient as well as recent deposits, has devoted years of labour to assemble the known techniques, which are rather dispersed in literature, their practical application and further refinement and the development of new methods. The results are compiled in this book, which can be considered as both a field- and laboratory manual. Attention is focussed on five subjects of major importance: Sedimentary peels; Impregnation; Radiography; Laboratory instruments; and Sampling devices. An appendix is added, which contains a list of manufacturers of chemical products and their regional representatives. Consultation for application in specific cases of sediment-lithology and sample-condition (e.g., moisture-content) is facilitated by clear key-schemes and an extensive subject-index. In Chapter I (82 pp.) eight types of sedimentary peels of unconsolidated and indurated sediments are discussed, mainly meant for the study of terrigenous sediments, without neglecting calcareous deposits (acetate- and nitrocellulose peels). Under the heading Impregnation (55 pp.) several methods of cementing unconsolidated and poorly consolidated materials, necessary for the preparation of polished surfaces, thin sections and "thick" sections, are treated. Chapter III presents an extensive discussion of the application of radiography in sedimentary geology (105 pp.) amplified with a treatment of radiography on board of oceanographic vessels and several data regarding X-ray films and processing liquids in the appendix. Comparison of normal photographs and Xradiographs of samples clearly shows the possibilities and limitations of this method. After a discussion of a number of techniques of a divergent nature (among which staining, mainly for mineralogical purposes, and infrared photography seem to be the most important) some laboratory instruments are treated (18 pp.): vacuum-impregnation apparatus, cutting machines, polishing belt and grinding apparatus. Chapter VI presents a survey of sampling-methods and devices for sedimentological (pedological) and oceanographical purposes (76 pp.). Marine Geol., 9 (1970) 295-300
296
ROOK REVIEWS
The treatment of the different subjects is clear and to the point. Quality of the numerous photographs and figures is generally good. This book is evidently a valuable manual of techniques for sedimentologists, pedologists and oceanographers, which may be of occasional use to paleontologists, mineralogists and archeologists. J. A. BROEKMAN(Utrecht)
Geophysical Investigations of The Netherlands Leeward Antilles. R. A. LAGAAY. North-Holland, Amsterdam, 1969, 86 pp., Dft. 12.00.--. The islands of Aruba, Curacao, and Bonaire (The Netherlands Leeward Antilles) form the westernmost end of the chain of coastal islands bordering the northern margin of South America. New gravity and magnetic data from the islands and from two north-south traverses of H. Neth. M. S. "Snellius" have been obtained and gravity and magnetic anomaly maps and profiles for each of the three islands and for the general region are presented. These data, together with a review of the results of older geophysical, geological, and bathymetric investigations, provide the basis for the author's interpretation of regional crustal structure. During Cretaceous and Early Tertiary time, a trough existed at the site of the islands in which a thick sequence of sediments and submarine volcanics was deposited. The area was highly mobile in the Late Cretaceous and Early Tertiary. Uplift and denudation occurred prior to deposition of Upper Eocene strata. Development of deep-sea basins may have started in Late Eocene time but there is little indication of Neogene tectonism, only a gradual relative rising of the islands which has continued into Quaternary time. The general gravity picture is of a series of more or less continuous elongate east-southeast-west-northwest trending anomalies, roughly paralleling this part of the continental margin of northern South America. Gravity values rise northward from the Venezuelan shore to the strong positive trend on which lie The Netherlands Leeward Islands. Strong local gravity and magnetic anomalies on this trend are believed to reflect near-surface volcanics. Northward from Bonaire and Curacao, there is a broad gravity negative zone within which a "low" axis coincides roughly with the Los Roques bathymetric depression followed by a "high" axis along the so-called "Curacao Ridge"; another "low" axis lies just north of the "Curacao Ridge". Gravity values then rise gently but persistently toward the ocean deep of the Venezuelan Basin. Gravity trends show a general relation to bottom topography but locally cut across topographic features. Magnetic trends in general parallel those shown by gravity. The author's interpretation of the region in the light of the combined
Marine Geol., 9 (1970) 295-300
Book Reviews Methods for the Study o f Sedimentary Structures. A. H. BOUMA.Wiley-Interscience,
London, 1969, 458 pp., 232 fig., 190 s. The investigator of unconsolidated deposits, hard rock sediments or soils is, whatever the purpose of his study, confronted with two main problems of a practical nature: how to render possible laboratory investigation of the undisturbed field-material and its application for instruction as well as how to accentuate structures, textures and components to allow detailed observation. Arnold H. Bouma, Associate Professor of Geological Oceanography at Texas A. M. University, experienced in the study of ancient as well as recent deposits, has devoted years of labour to assemble the known techniques, which are rather dispersed in literature, their practical application and further refinement and the development of new methods. The results are compiled in this book, which can be considered as both a field- and laboratory manual. Attention is focussed on five subjects of major importance: Sedimentary peels; Impregnation; Radiography; Laboratory instruments; and Sampling devices. An appendix is added, which contains a list of manufacturers of chemical products and their regional representatives. Consultation for application in specific cases of sediment-lithology and sample-condition (e.g., moisture-content) is facilitated by clear key-schemes and an extensive subject-index. In Chapter I (82 pp.) eight types of sedimentary peels of unconsolidated and indurated sediments are discussed, mainly meant for the study of terrigenous sediments, without neglecting calcareous deposits (acetate- and nitrocellulose peels). Under the heading Impregnation (55 pp.) several methods of cementing unconsolidated and poorly consolidated materials, necessary for the preparation of polished surfaces, thin sections and "thick" sections, are treated. Chapter III presents an extensive discussion of the application of radiography in sedimentary geology (105 pp.) amplified with a treatment of radiography on board of oceanographic vessels and several data regarding X-ray films and processing liquids in the appendix. Comparison of normal photographs and Xradiographs of samples clearly shows the possibilities and limitations of this method. After a discussion of a number of techniques of a divergent nature (among which staining, mainly for mineralogical purposes, and infrared photography seem to be the most important) some laboratory instruments are treated (18 pp.): vacuum-impregnation apparatus, cutting machines, polishing belt and grinding apparatus. Chapter VI presents a survey of sampling-methods and devices for sedimentological (pedological) and oceanographical purposes (76 pp.). Marine Geol., 9 (1970) 295-300
296
ROOK REVIEWS
The treatment of the different subjects is clear and to the point. Quality of the numerous photographs and figures is generally good. This book is evidently a valuable manual of techniques for sedimentologists, pedologists and oceanographers, which may be of occasional use to paleontologists, mineralogists and archeologists. J. A. BROEKMAN(Utrecht)
Geophysical Investigations of The Netherlands Leeward Antilles. R. A. LAGAAY. North-Holland, Amsterdam, 1969, 86 pp., Dft. 12.00.--. The islands of Aruba, Curacao, and Bonaire (The Netherlands Leeward Antilles) form the westernmost end of the chain of coastal islands bordering the northern margin of South America. New gravity and magnetic data from the islands and from two north-south traverses of H. Neth. M. S. "Snellius" have been obtained and gravity and magnetic anomaly maps and profiles for each of the three islands and for the general region are presented. These data, together with a review of the results of older geophysical, geological, and bathymetric investigations, provide the basis for the author's interpretation of regional crustal structure. During Cretaceous and Early Tertiary time, a trough existed at the site of the islands in which a thick sequence of sediments and submarine volcanics was deposited. The area was highly mobile in the Late Cretaceous and Early Tertiary. Uplift and denudation occurred prior to deposition of Upper Eocene strata. Development of deep-sea basins may have started in Late Eocene time but there is little indication of Neogene tectonism, only a gradual relative rising of the islands which has continued into Quaternary time. The general gravity picture is of a series of more or less continuous elongate east-southeast-west-northwest trending anomalies, roughly paralleling this part of the continental margin of northern South America. Gravity values rise northward from the Venezuelan shore to the strong positive trend on which lie The Netherlands Leeward Islands. Strong local gravity and magnetic anomalies on this trend are believed to reflect near-surface volcanics. Northward from Bonaire and Curacao, there is a broad gravity negative zone within which a "low" axis coincides roughly with the Los Roques bathymetric depression followed by a "high" axis along the so-called "Curacao Ridge"; another "low" axis lies just north of the "Curacao Ridge". Gravity values then rise gently but persistently toward the ocean deep of the Venezuelan Basin. Gravity trends show a general relation to bottom topography but locally cut across topographic features. Magnetic trends in general parallel those shown by gravity. The author's interpretation of the region in the light of the combined
Marine Geol., 9 (1970) 295-300