Giant Desiccation Polygons of Great Basin Playas

Giant Desiccation Polygons of Great Basin Playas

Author: James T.. Neal

Publisher:

Published: 1965

Total Pages: 0

ISBN-13:

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Giant desiccation fissures observed on 39 playas (dry lakes) in the Great Basin are greater in size and causative rupture stress than are the typical, small, surface mud cracks. Giant open fissures may be a meter wide and more than 5 m deep, whereas the typical shallow mud cracks are a few centimeters wide and about 25 cm and more deep. The fissures form polygonal patterns that range from 15 to 100 m and more across, with intersections predominantly at approximately right angles. The fissures themselves follow sinuous, irregular lines. Thus, the patterns are for the most part 'irregular random orthogonal polygons'. The fissures form on hard, dry, compact playa crusts where desiccation has been rigorous and ground water is fairly deep. The contractive stress producing the fissures results from loss of moisture and appears to develop over a period of several years; however, the rupture probably takes place in minutes. The greatest release of stress frequently appears to occur below the surface. Tectonic forces and basin subsidence may be a factor in fissure formation. Fissures follow a cycle of growth and destruction: fresh, sediment filled, vegetated, and relict fissures comprise the major geomorphic forms. The patterns can be easily identified on airphotos, and can thus, through inference, offer reconnaissance information on the playa environment. (Author).


The Borrego Mountain Earthquake of April 9, 1968

The Borrego Mountain Earthquake of April 9, 1968

Author:

Publisher:

Published: 1972

Total Pages: 226

ISBN-13:

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Additional title page description: Contributions from: California Institute of Technology, Lamont-Doherty Geological Observatory of Columbia University [and] Seismological Field Survey, National Oceanic and Atmospheric Administration.


Encyclopedia of Geomorphology

Encyclopedia of Geomorphology

Author: Andrew Goudie

Publisher: Routledge

Published: 2013-04-15

Total Pages: 2128

ISBN-13: 1134482752

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Geomorphology, the discipline which analyzes the history and nature of the earth's surface, deals with the landforms produced by erosion, weathering, deposition, transport and tectonic processes. In recent decades there have been major developments in the discipline and these are reflected in this major Encyclopedia, the first such reference work in the field to be published for thirty-five years. Encyclopedia of Geomorphology has been produced in association with the International Association of Geomorphologists (IAG) and has a truly global perspective. The entries have been written by an international editorial team of contributors, drawn from over thirty countries, who are all among the leading experts in the discipline. In two lavishly illustrated volumes, Encyclopedia contains nearly 700 alphabetically organized entries to provide a comprehensive guide both to specific landforms and to the major types of geomorphological processes that create them. The Encyclopedia also demonstrates the major developments that have taken place in recent years in our knowledge of tectonic and climatic changes and in the use of new techniques such as modelling, remote sensing and process measurement. Older concepts, however, are not forgotten and provide an historical perspective on the development of ideas. Both accessible and authoritative, Encyclopedia of Geomorphology is destined to become the definitive resource for students, researchers and applied practitioners in the field of geomorphology and the cognate disciplines of geography, earth science, sedimentology and environmental science.