Open AccessSedimentary features of a Weichselian glaciolacustrine delta
Author(s) -
CLEMMENSEN LARS B.,
HOUMARKNIELSEN MICHAEL
Publication year - 1981
Publication title -
boreas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.95
H-Index - 74
eISSN - 1502-3885
pISSN - 0300-9483
DOI - 10.1111/j.1502-3885.1981.tb00484.x
Subject(s) - geology , geomorphology , silt , delta , bedding , sedimentary structures , sedimentary rock , cobble , lamination , paleontology , sedimentary depositional environment , structural basin , ecology , chemistry , organic chemistry , layer (electronics) , aerospace engineering , habitat , horticulture , engineering , biology
Inclined beds of sand, granules, pebbles and cobbles resembling a glacio‐tectonically tilted sequence were shown by sedimentological studies to constitute the 10–12 m thick foreset beds of a glaciolacustrine Gilbert‐type delta in Kyndby, North Sjælland, Denmark. The foreset beds are slightly curved, dip 10–28d̀ SE, and display a bundlewise structure with alternating coarse‐grained cobble‐rich and fine‐grained sandy units. The occurrence of ascending megaripple cross‐bedding and climbing ripple cross‐lamination in the sandy foresets can be ascribed to strong backflow currents formed by the lee‐side vortice. The foreset beds are underlain by flat‐lying fine‐grained sand, silt and clay (bottomset beds), and are overlain transitionally or erosively by 2–3 m of flat‐lying sand, pebbles and cobbles (topset beds). In the transition zone between foreset beds and topset beds, various delta distributary channel units occur. The delta probably formed in a partly ice‐dammed lake in connection with the general retreat of a Weichselian advance from the north (‘Norwegian ice’)