Premium
Sieve deposition by debris flow on a permeable substrate, Leirdalen, Norway
Author(s) -
Shakesby Richard A.,
Matthews John A.
Publication year - 2002
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.390
Subject(s) - debris , debris flow , geology , deposition (geology) , drainage , substrate (aquarium) , channel (broadcasting) , mudflow , sieve (category theory) , geomorphology , sediment , oceanography , ecology , mathematics , engineering , combinatorics , electrical engineering , biology
The characteristics of two recent ( AD 1994) debris flows in upper Leirdalen, Jotunheimen, Norway, suggest deposition controlled by fluid loss into the underlying, highly permeable, coarse talus. The evidence comprises: (1) drainage holes (sieveholes) up to 44 cm wide and 125 cm deep in the debris‐flow channel floors, which remained open throughout the debris‐flow event; (2) marked channel narrowing, with reduced cross‐sectional areas and termination of the debris flows in flat‐topped, clast‐dominated lobes within a relatively short distance after crossing the junction between impermeable and permeable substrate; (3) the presence of fines deposited in the sieveholes demonstrating the passage of transported matrix; and (4) the absence of substantial lateral drainage through (or dissection of) the levées or the terminal lobes. The term ‘sieve deposition’ is considered particularly well suited to this process involving drainage through the substrate, which is likely to be most effective where debris flows traverse coarse talus either for the first time or only infrequently. Copyright © 2002 John Wiley & Sons, Ltd.