Transcript Origins and Formation of deGeer Moraines

Origins and Formation of deGeer
Moraines
Erica Doody
What is a deGeer
moraine?
Small moraine ridges that
occur in clusters parallel to
each other
Usually found in coastal
marine settings
First identified by Gerard
deGeer
Previously known annual
moraines or washboard
moraines
Two popular hypotheses that explain
their origins
Subglacial
• Crevasse opens up parallel
to the margin of the glacier
• Sediments fill in the
opening and are left behind
as the glacier retreats
Marginal
• Moraines are formed at the
grounding line of the glacier
• Sediments pile up through
calving and
pushing/overriding by the
glacier
Subglacial crevasse formation
Grounding line formation
Deglaciation
Closer spaced moraines
indicate a quickly receding
glacier
Curved moraines indicate that
frontal ice lobes were
retreating
Straight moraines indicated a
more stable ice margin was
retreating
References Cited
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Beaudry, L.M. & Prichonnet, G., 1999: Late Glacial De Geer moraines with glaciofluvial sediment in
the Chapais area, Quebec (Canada). Boreas, v. 20, p. 377-394.
Blake, K.P., 2000: Common origin for De Geer moraines of variable composition in Raudvassdalen,
northern Norway. Journal Of Quaternary Science, v. 15, p. 633-644.
Borgstrom, I., 1979: De Geer moraines in a Swedish mountain area? Geografiska Annaler. Series A,
Physical Geography, v. 61, p. 35-42.
Golledge, N.R. and Phillips, E., 2008: Sedimentology and architecture of De Geer moraines in
Western Scottish Highlands, and implications for grounding-line glacier dynamics. Sedimentary
Geology, v. 208, p. 1-14.
Hoppe, G., 1959: Glacial morphology and inland ice recession in northern Sweden. Geografiska
annaler, v. 41(1), p. 93.
Lajeunesse, P., 2008: Early Holocene deglaciation of the eastern coast of Hudson Bay.
Geomorphology, v. 99, p. 341-352.
Larsen, E. O. Longva, and B.A. Follestad, 1991: Formation of De Geer moraines and implications for
deglaciation dynamics. Journal of Quaternary Science, v. 6, p. 263-277.
Linden, M. and Moller, P., 2005: Marginal formation of De Geer moraines and their implications to
the dynamics of grounding-line recession. Journal Of Quarternary Science, v. 20(2), p. 113-133.
Lundqvist, J., 2000: Palaeoseismicity and De Geer moraines. Quaternary International, v. 68, p. 175186.
Zilliacus, H., 1989: Genesis of De Geer moraines in Finland. Sedimentary Geology, v. 62, p. 309-317.