Ground moraine
A ground moraine is a glacial landfill landscape that arises under glaciers or under inland ice . It is part of the glacial series . The typical sediment of the ground moraine is the glacial till , the glacier was deposited.
Deposits
Glaciers carry large amounts of moraine material in the form of gravel , sand , silt and clay with. This is deposited on the ground unsorted and appears when the ice melts. Depending on its carbonate content , the result of sedimentation is referred to as boulder clay or boulder clay . Even very large boulders ( debris / blocks ) could be transported over very long distances by the advancing glaciers during the various ice advances. Particularly large stones that are scattered in the otherwise flat undulating landscape are called boulders .
Surface shape
The typical ground moraine has a flat undulating surface with relatively small differences in height. In general, the ground moraines of the old moraine country are even more poor in relief than those of the young moraine country . But there are also extremely flat (e.g. the Kulmerland in Poland) or very hilly (e.g. north of Chorin / Brandenburg ) ground moraine areas. Typical of the ground moraines of the young moraine landscape are still numerous closed hollow forms, the soils .
Because of the mostly fertile soils that arise from boulder clay, ground moraines in Central Europe are mainly used as arable land today.
Other forms that are often found in ground moraine landscapes are drumlins , glacial channels and oser .
distribution
Ground moraine landscapes are very widespread in northern Germany and in the Alpine foothills . They were formed during the repeated glaciations in the Ice Age . The ground moraines are located in the Alpine foothills in the wide glacier tongue basins and are often framed by the terminal moraines . In northern Germany they occupy very large areas north of the terminal moraine ranges.
Use of the terms ground moraine and glacial till
In the specialist literature it has become customary to refer the term ground moraine only to the form of the landscape that arises under the glacier ice. The material ( sediment ) itself on the other hand, which is deposited under the glacier is as boulder clay or Till designated.
See also
literature
- Jan A. Piotrowski: What is a till? In: The Geosciences. Vol. 10, No. 4, 1992, ISSN 0933-0704 , pp. 100-108, doi : 10.2312 / geoscientific . 1992.10.100 .
- Sven Lukas: Moraine or Till? A suggestion for the description, interpretation and naming of glacial sediments. In: Journal of Glacier Science and Glacial Geology. Vol. 39, 2003/2004, ISSN 0044-2836 , pp. 141-159.