Trough mouth fans are fans at the mouth of transverse troughs/channels
on glaciated continental shelves. On the northwest European glaciated
continental margin, eight trough mouth fans, varying in size between
2700 and 215,000 km(2), have been identified. The trough mouth fans ar
e depocentres dominated by debris flows accumulated in front of ice st
reams draining the former large northwest European ice sheets. The deb
ris flow units are separated by hemipelagic interglacial/interstadial
sediments. It is inferred that the number of debris-flow units record
the number of shelfbreak-positions of the ice sheet margins: the numbe
r found varies between three in the south and eight in the north. Typi
cal trough mouth fans and related debris-flow units seem to have been
formed later than the early mid-Pleistocene, thus the north European i
ce sheets did not form ice streams extending to the shelfbreak in any
appreciable length before the mid-Pleistocene. Besides being loci for
sediment deposition, the trough mouth fans were also the main sites of
fresh water supply to the ocean (in the form of icebergs) during the
mid/late Pleistocene ice ages. Copyright (C) 1997 published by Elsevie
r Science Ltd.