‘Total’ fabric of some till landforms
作者:
Edward Derbyshire,
Alan McGown,
Amr Radwan,
期刊:
Earth Surface Processes
(WILEY Available online 1976)
卷期:
Volume 1,
issue 1
页码: 17-26
ISSN:0360-1269
年代: 1976
DOI:10.1002/esp.3290010103
出版商: John Wiley&Sons, Ltd
数据来源: WILEY
摘要:
AbstractThe distinction between clast‐dominant, matrix‐dominant and well‐graded tills is important in view of the influence of texture on the definition and function of till fines. Till fabric includes a wide range of features of both primary and secondary origin including folds, thrusts, fissures (the macrofabric), disposition of clasts (the mesofabric) and organization of the matrix (the microfabric). The results of fabric analysis of pebble, granule, sand, silt and clay in small depositional landforms beneath currently‐active glaciers are described. Deformation fabrics are distinguished in freshly deposited end moraines and flutes. The sand‐size material in deformed till may or may not behave in the same way as larger clasts, depending on the degree to which the till is matrix‐dominant. While clasts in saturated subglacial till tend to align themselves sub‐parallel to the depositional surface, the matrix usually retains abundant pore spaces. With slow, unloaded drainage, clast fabrics appear to be little modified. Such material is potentially unstable and any subsequent increase in overburden and hydraulic pressures may cause slope collapse and flowtill development. It is concluded that examination of a wide range of fabric parameters provides a means of distinguishing tills of diverse origins and of assessing their potentia
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