Download or read book Laboratory Studies of Till Deformation with Implications for the Motion and Sediment Transport of the Lake Michigan Lobe written by Jason Fleming Thomason and published by . This book was released on 2006 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glacier motion and sediment transport are attributed commonly to pervasive shearing of subglacial till to high strains (the bed-deformation hypothesis). However, the processes that control bed deformation are difficult to observe beneath modern glaciers, and observations of the geologic record have not been sufficient to determine whether tills have been sheared to the high strains required by this hypothesis. The shear strength of the ice-till interface controls whether a glacier slips over its bed or shears it pervasively over much of its thickness. When clasts gripped by basal ice plow through the bed, the ice-till interface is weakened. Results of experiments using a ring-shear device in which hemispheres were pushed through water-saturated till indicate a progressive decrease in resistive force on hemispheres with increasing plowing speed. This effect is due to the generation of high pore-water pressures in front of the hemispheres at fast plowing speeds (e.g. 380 m y−1), which weakens till and reduces resistive forces. These results indicate that increases in glacier sliding speed will reduce resistive forces exerted by till on plowing clasts, which will promote decoupling of the ice from the bed and inhibit pervasive bed deformation. In addition, this positive pore-pressure feedback may constitute a flow instability that promotes fast glacier flow. The ring-shear device was also used to develop criteria at microscopic scales for identifying highly sheared tills. Results of experiments indicate that the alignment (fabric) of elongate, sand-sized particles becomes strong at high strains. Furthermore, microshears become more abundant and align progressively with the shearing direction as strain increases. Magnetic fabrics calibrated to strain in an ancillary ring-shear study and sand-particle fabrics were used to test the till-deformation model as applied to the Batestown advance of the Lake Michigan Lobe. Results indicate that magnetic and sand-particle fabrics are not sufficiently strong to support the bed-deformation model. Furthermore, consistent changes in fabric direction with depth and fabric patterns around cobbles and small boulders indicate that the till likely sheared only in thin zones near the glacier sole during till accretion to the bed from ice. Bed shearing likely contributed only minimally to sediment transport.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 846 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Commencement written by Iowa State University and published by . This book was released on 2006 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial Processes Past and Present written by David M. Mickelson and published by Geological Society of America. This book was released on 1999-01-01 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Glacial Processes Past and Present written by Geological Society of America. Meeting and published by . This book was released on 1999 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measuring and Modeling Time Dependent Soil Behavior written by Thomas C. Sheahan and published by . This book was released on 1996 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of time on the strength and deformation characteristics of various materials can assume importance in a variety of engineering problems. The time dependent mechanical behavior of soil is highly complex and can impact a broad range of applications such as in situ testing, seismic response, landslides, and embankment performance. This volume provides an update on the state of research and practice in the area of soil time effects. Emphasis is placed on laboratory and field developments, modeling time dependent behavior, rate dependence in a variety of soils, from subtropical soils to subglacial till, and on new applications such as soils reinforced with geosynthetics and inclusion dowels. Models are provided that include the influence of soil structure.
Download or read book Trace Elements and Synthetic Organic Compounds in Biota and Streambed Sediment of the Western Lake Michigan Drainages 1992 1995 written by and published by . This book was released on 1997 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Paper written by University of Michigan. Great Lakes Research Division and published by . This book was released on 1960 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Thermal Discharges on the Mass energy Balance of Lake Michigan written by Argonne National Laboratory and published by . This book was released on 1970 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large scale oscillatory motions and seasonal temperature changes in Lake Michigan and Lake Ontario written by C. H. Mortimer and published by . This book was released on 1971 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of Lake Michigan Sediment at the Lincoln Park Gun Club Chicago Illinois written by Bruce J. Yurdin and published by . This book was released on 1993 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Lake Michigan Bottom Sediments written by and published by . This book was released on 1970 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Grain Size Distribution of the Surface Sediments Collected During the Lake Michigan Mass Balance and Environmental Mapping and Assessment Programs written by Brian J. Eadie and published by . This book was released on 1999 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling and Practice of Erosion and Sediment Transport under Change written by Mohamed Meddi and published by MDPI. This book was released on 2019-09-17 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate and anthropogenic changes impact the conditions of erosion and sediment transport in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes in natural areas, as well as in cultivated areas, and, sometimes, in degraded areas and desertified landscapes. These anthropogenized landscapes are more sensitive to erosion. On the other hand, the increase in the number of dams in watersheds traps a great portion of sediment fluxes, which do not reach the sea in the same amount, nor at the same quality, with consequences on coastal geomorphodynamics. This book is dedicated to studies on sediment fluxes from continental areas to coastal areas, as well as observation, modeling, and impact analysis at different scales from watershed slopes to the outputs of large river basins. This book is concentrated on a number of keywords: “erosion” and “sediment transport”, “model” and “practice”, and “change”. The keywords are briefly discussed with respect to the relevant literature. The contributions in this book address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.
Download or read book Sediment Quality Evaluation in the Lower Fox River and Southern Green Bay of Lake Michigan written by Daniel J. Call and published by . This book was released on 1991 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Thermal Effects in Southwestern Lake Michigan January 1970 April 1971 written by Industrial Bio-Test Laboratories and published by . This book was released on 1972 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
