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Sedimentology and origin of deposits from a small ice‐dammed lake, Leirbreen, Norway
Author(s) -
DONNELLY ROBERT,
HARRIS CHARLES
Publication year - 1989
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1989.tb02087.x
Subject(s) - geology , varve , shelf ice , sedimentology , facies , geomorphology , meltwater , sedimentary rock , crevasse , sedimentary structures , fluvial , shore , sediment , paleontology , glacier , ice stream , structural basin , oceanography , cryosphere , sea ice
This paper describes recent proglacial lacustrine sediments exposed by the drainage of a small (probably never more than 0·03 km 2 ) ice‐dammed lake basin at Leirbreen, central Jotunheimen, Norway. The dominant facies include ripple‐laminated, massive and horizontally‐stratified sands, massive and horizontally‐laminated silts, and irregularly‐laminated fine sands and silts. The major control on lake circulation and the nature and distribution of these facies was an underflow driven by a subglacial meltwater stream which formed the major lake input. Although much of the sedimentary sequence indicates a pulsatory input, the proximal character of this small lake prevented the development of classic varved silts. Compressional deformation of shoreline sediments was due to winter lake ice push. Other deformational processes included the grounding of icebergs, water escape and syn‐sedimentary downslope collapse. Observations from an adjacent small ice‐marginal lake at Leirbreen provide support for several of the inferences drawn from the sediments of the former ice‐dammed lake.