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Side‐scan targets in Lake Superior—evidence for bedforms and sediment transport
Author(s) -
FLOOD ROGER D.,
JOHNSON THOMAS C.
Publication year - 1984
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.1365-3091.1984.tb00862.x
Subject(s) - geology , bedform , shore , turbidity current , geomorphology , sedimentary rock , sedimentary structures , facies , benthic zone , clastic rock , sediment transport , peninsula , glacial period , sediment , oceanography , ripple marks , storm , paleontology , structural basin , sedimentary depositional environment , archaeology , history , physics , ripple , voltage , quantum mechanics
A high‐resolution side‐scan sonar survey of the lake bed off the Keweenaw Peninsula, Lake Superior, demonstrates that bottom currents are affecting lake bed morphology at depths up to 240 m. Numerous lineations which run parallel to the shore appear to be sand ribbons. A field of sedimentary furrows which occurs in one area demonstrates the long‐term directional stability of the near‐bottom flow. Large (100–300 m in diameter, 2–5 m deep), unusual ring‐like or arcuate depressions are common throughout the western half of Lake Superior. These rings themselves do not appear to have been formed by bottom currents, but may have developed as water was released by the rapid compaction of glacial sediments which underlie the lake bed. Off the Keweenaw Peninsula the forms of the rings have been modified by bottom currents. The bottom currents which have modified the lake bed are probably generated when storms cross the lake at times when it is poorly stratified.