A comparison of the styles of deformation associated with two recent push moraines,South Van Keulenfjorden,Svalbard |
| |
| Authors: | Jane K Hart Robert J Watts |
| |
| Abstract: | In this paper, two push moraine systems associated with two small subpolar glaciers, Finsterwalderbreen and Penckbreen, were investigated. This study showed that at these glaciers the push moraines were formed in association with surges, which produced a different style of moraine depending on the rheology of the deformed material and the glacial history. The moraines are similar in that they are formed by folded outwash sediments and contain little till. However, the forms of these moraines are very different. The Penckbreen moraine is composed of a lower shallow marine sand, silt and clay, and an upper fluvial sand and gravel. Deformation at this site led to the formation of large anticlines in the silts and clays, with disharmonic smaller folds and thrusts in the upper gravels, above a detachment surface between the fine-grained and overlying coarse-grained lithologies. This deformation decreases towards the foreland, with marine and fluvial sediments responding differently because of their different rheological properties. This moraine was formed during one surge event which occured during the early 19th century. In contrast, the Finsterwalderbreen moraine is composed of outwash sand and gravel, and was formed as the result of a series of surge events. These advances all reached a similar limit and occurred at regular intervals. © 1997 John Wiley & Sons, Ltd. |
| |
| Keywords: | proglacial deformation Spitsbergen surging glaciers neoglacial fluctuations |
|
|
