Download or read book Sediment Textures and Internal Structures written by Robert Cornelius Roush and published by . This book was released on 1970 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of sedimentary structures and sediment texture of beach and continental shelf sediments provides a basis for the interpretation of the recent history of sedimentation on the Oregon continental shelf. The texture of various sediment types suggests that coastal rivers supply a considerable quantity of very fine sand in addition to modern mud to the continental shelf. Relict sediments remain uncovered on areas of the shelf not under the influence of major river runoff and are mixed or covered by modern mud and very fine sand where rivers influence shelf sedimentation. Primary sedimentary structures show that sands ranging from very fine to medium in mean grain size are capable of being moved at shelf water depths from at least 38 to 88 meters. No net transport of sand, however, can be determined from these structures. Organic structures apparently are controlled by water depth and/or grain size and sediment type which determine faunal composition and concentration. At mid-shelf depths fine sand cores are characterized by shell fragments, worm tubes, and worm trails. Beyond 100 meters water depth worm tubes were not found, but worm trails become abundant, and large burrows appear in the sediment.
Download or read book Sedimentary Texture written by David William Allen and published by . This book was released on 1970 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The processes responsible for transporting and depositing thick sections of coarse-grained terrigenous clastics on the abyssal floor and for forming associated sedimentary structures are still conjectural. Many workers attribute coarse deep-sea sediments and their probable lithified equivalent, the graywackes of flysch deposits to some type of density movement. Deductions concerning the processes operating in a density flow generally are made from flume studies--in which an artificial situation may develop, or from lithified units--where the magnitude of post-depositional change is unknown. Both approaches contribute to our knowledge, but the unconsolidated elastics themselves should contain a unique key to understanding the dynamics of abyssal sedimentation. To test this theory, divisions of parallel lamination, found in deep-sea sand and silt, were selected for analysis. Since individual laminae closely approach discrete populations of particles assembled under contrasting conditions, their use carries environmental sampling to its practical limits. Northeast Pacific sediments of late Pleistocene and Holocene age, from deep-sea channel and abyssal plain environments, and representing two or three provenances were studied. A total of 115 light-colored and 84 dark-colored laminae were sampled from eight sequences at five locations. Samples averaged about 0.8 gram and were quantitatively processed using quarter-phi calibrated sieves and decantation techniques. Statistical evaluation of the procedure shows better than 95 percent sample recovery, and indicates that textural variance between laminae is significantly greater than within-sample variance. The classic concept of density transport--that coarsest material is carried by the nose of the current, and that clastic size grades tail-ward and upward in a uniformly decreasing manner--is not substantiated by moment measures, sand-silt-clay percentages or factor analysis of grain-size distributions, at least during deposition of the coarse division of parallel lamination. Coarse abyssal lamination develops within a narrow range of current velocity, the limits of which are defined texturally. Absolute velocity values for these limits can only be related, at the present time, to the few flume or in situ bottom current measurements available. Texture indicates that while the total amount of sand carried in suspension varies, lamination does not begin to form until a current is essentially depleted of all material coarser than fine sand--establishing an upper competency limit. At that time, coarse suspended material is distributed throughout the flow mostly in large eddies or vortices whose velocities are estimated on the order of about one meter/sec. Mean current velocity must be sufficient to maintain a dispersed traction carpet without deformation of bedform into ripples. This is postulated at about 50 cm/sec. A current model, based on textural evidence, is proposed to account for lamination. It is suggested that the critical stage in the formation of coarse abyssal lamination occurs while sediment is being dragged along the bottom as bedload. The flowing clastic traction carpet acquires kinetic energy as the current bypasses material lost from suspension. In turn, this energy results in grain shear. When the concentration of granular material in traction is large, it dissipates the energy of bottom shear mostly in collision contacts between gliding grains. The dispersive stresses developed tend to maintain grain separation and prevent settling. Eventually, turbulence in seawater entrapped between grains is suppressed and the net path of grans impelled by repeated collisions becomes quasi-laminar. Within this quasi-laminar traction system, dispersive pressure causes some migration of finer sizes toward the base of the carpet and a concentration of coarser grains in the upper bedload. As new material is introduced in large quantities from suspension, the zone of internal shear--the base of the moving carpet--is displaced progressively upward. As it passes, sediment compacts to a fraction of its dispersed thickness and a population of grains with a slightly finer size distribution than the carpet load comes to rest. This is buried by new deposition and a densely-packed, dark layer continues to accrete upward as long as a moving traction carpet is sustained and a dense rain of clastics is contributed from suspension. When a sand-laden eddy impinges on the bottom, it releases its coarsest load into traction and the dark layer then accreting increases significantly in grains larger than 44 microns. Any eddy, whether laden or not, on striking bottom adds to, or deducts its velocity from the velocity of the traction carpet and either increases or decreases bottom shear. Additional impulse given to tractive shear by eddies merely results in more effective size sorting. However, an eddy whose velocity of rotation is opposed to current movement may reduce shear below the critical necessary to maintain a thick carpet by dispersive pressure, The dispersed carpet collapses and instantaneously ceases moving. This less-densely packed layer has a slightly higher sand content than the accreted material below. When partially dried or weathered, alternate layers exhibit different moisture retention properties--the less-porous, accreted layers appearing dark and the more loosely packed layers appearing light.
Download or read book Sedimentologic Architecture of the Shoreface Prism Relationship to Profile Dynamics and Relevance to Engineering Concerns written by Robert K. Schwartz and published by . This book was released on 1997 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sedimentary Structures written by John Collinson and published by Liverpool University Press. This book was released on 2019-03-01 with total page 697 pages. Available in PDF, EPUB and Kindle. Book excerpt: Completely revised new edition, in colour for the first time, of an established textbook in sedimentology.
Download or read book Dynamics of Recent Carbonate Sedimentation and Ecology written by Conrad D. Gebelein and published by Brill Archive. This book was released on 1977 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tidal Signatures in Modern and Ancient Sediments written by B. W. Flemming and published by John Wiley & Sons. This book was released on 2009-04-01 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: This IAS Special Publication contains 23 papers presented at the 3rd International Research Symposium on Modern and Ancient Clastic Tidal Deposits. This symposium series has an enviable international reputation for its quality, and so the contributions represent the latest developments in the field. The conference was preceded and followed by a number of field trips to some of the most prominent tidal flat and barrier island systems of continental Europe, and these have been written up as overview papers that summarize the current state of knowledge about these various tidal regions. The latest research results from this very specialized field. If you are a member of the International Association of Sedimentologists, for purchasing details, please see: http://www.iasnet.org/publications/details.asp?code=SP24
Download or read book Dynamics of Recent Carbonate Sedimentation and Ecology Cape Sable Florida written by Conrad D. Gebelein and published by BRILL. This book was released on 2023-06-26 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NOAA Technical Memorandum EDS ESIC written by United States. National Oceanic and Atmospheric Administration and published by . This book was released on 1972 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NOAA Technical Memorandum EDS ESIC written by Environmental Science Information Center and published by . This book was released on 1972 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sea Grant Publications Index 1968 71 written by and published by . This book was released on 1972 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Depositional Sedimentary Environments written by H.-E. Reineck and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been written with the aim of compiling from modern environments information that can be useful in the reconstruction of ancient environments. It is intended for all those interested in recognizing depositional environments. The study of sediments includes investigations of various aspects of sediments. This needs a study by standard methods. Methods of study have not been included, as many textbooks exist on the subject. However, the importance of various results obtained from such investigations has been discussed, as far as these results can be helpful in environ mental reconstruction. Special attention is given to information that has accumulated during the last decades on the mode of genesis of various sedimentary features and their distribution in present-day environments. As far as possible, existing terminology has been used. How ever, in several cases new simple groupings and classifications have been proposed. In making classification, generally, the form and shape of the features have been considered, so that they can be applied easily to ancient sediments. At the same time, the genesis of such features has been noted, and genetic names and their characteristics have been given for detailed work. The subject is so vast that several primary sedimentary features that have no direct bearing on environmental interpretation have been omitted. The subject is vast, and numerous publications are available.
Download or read book Sedimentary structures their character and physical basis Volume 1 written by and published by Elsevier. This book was released on 1982-01-01 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sedimentary structures, their character and physical basis Volume 1
Download or read book Sedimentary Basins written by Gerhard Einsele and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 795 pages. Available in PDF, EPUB and Kindle. Book excerpt: This completely revised and enlarged second edition provides an up-to-date overview of all major topics in sedimentary geology. It is unique in its quantitative approach to denudation-accumulation systems and basin fillings, including dynamic aspects. The relationship between tectonism and basin evolution as well as the concepts of sequence cycle and event stratigraphy in various depositional environments are extensively discussed. Numerous, often composite figures, a well-structured text, brief summaries in boxes, and several examples from all continents make the book an invaluable source of information for students, researchers and professors in academia as well as for professionals in the oil industry.
Download or read book A Colour Illustrated Guide to Sedimentary Textures written by C. Prasada Rao and published by . This book was released on 1997 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Research Fiscal Year 1968 written by National Council on Marine Resources and Engineering Development (U.S.) and published by . This book was released on 1969 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glaciers and Glaciation 2nd edition written by Douglas Benn and published by Routledge. This book was released on 2014-02-04 with total page 1864 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glaciers and Glaciation is the classic textbook for all students of glaciation. Stimulating and accessible, it has established a reputation as a comprehensive and essential resource. In this new edition, the text, references and illustrations have been thoroughly updated to give today's reader an up-to-the minute overview of the nature, origin and behaviour of glaciers and the geological and geomorphological evidence for their past history on earth. The first part of the book investigates the processes involved in forming glacier ice, the nature of glacier-climate relationships, the mechanisms of glacier flow and the interactions of glaciers with other natural systems such as rivers, lakes and oceans. In the second part, the emphasis moves to landforms and sediment, the interpretation of the earth's glacial legacy and the reconstruction of glacial depositional environments and palaeoglaciology.
Download or read book Sandstone Depositional Models for Exploration for Fossil Fuels written by G. Devries Klein and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this monograph is to provide participants in my various short courses with a brief statement of the material I cover in my lectures. In addition, key illustrations are reproduced for guidance. A brief bibliography of reference material is appended to each chapter. The bibliographic material includes those references that I consider critical to my remarks. No claim is made of topical or bibliographic completeness. This monograph also is intended as a brief summary of depositional processes, Holocene sediments, ancient counterparts of depositional environments, and examples of oil- and gas-bearing stratigraphic traps in five depositional environments. This summary is intended to complement lecture and reading courses dealing with sedimentology, depositional systems, sedimentary facies, sedimentary environments, sandstone diagenesis, and sedimentary modelling as a predictive tool for exploration. The student is cautioned, however, that this monograph is merely an introduction and summary overview of the subject. More complete treatments appear in standard textbooks. Sedimentology has changed and advanced over the past twenty-five years, in part because the American oil industry needed to make predictions about the occurrence of the harder-to-find stratigraphic traps. In addition, the development of plate-tectonic theory, and supportive data from the Deep Sea Drilling Project, have caused sedimentology to change from an essentially descriptive science to a mature, predictive science. The 1960s and 1970s in particular witnessed an explosion of new insights and understanding of how sediments are deposited, and how sedimentary rocks are formed.
