Change search
ReferencesLink to record
Permanent link

Direct link
Subglacial processes and the geomorphological impact of cold-based ice sheets
Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology. (paleoglaciologi/paleoglaciology)
2007 (English)Conference paper (Other academic)
Abstract [en]

A continuously growing body of literature describes "relict" landforms, such as tors,

blockfields and patterned ground, in areas formerly glaciated by ice sheets. In almost

all cases where former ice cover can be convincingly demonstrated or safely

assumed, this surprising preservation of often small-scale and fragile landforms is

ascribed to frozen-bed conditions sustained throughout the last glacial event. During

the last decade, the antiquity of many of these landforms has been demonstrated

through cosmogenic dating, and the overriding by an ice sheet (as opposed to preservation

on nunataks) demonstrated by cosmogenic dating of "young" erratics on the

landforms. Based on these observations, a widely held view is that cold-based ice

cover essentially preserves any pre-existing landform, and that the erosion potential of

cold-based ice is zero or minimal. However, contradictory glaciological field evidence

exists from cold-based valley glaciers, where significant basal sliding, and/or deformation

in sandy-silty substrata has been observed. Sliding and deformation are processes

intrinsically linked to change of preexisting morphology and landform production. At

face value, these two sets of observations are therefore contradictory.

We here review the glaciological context of the different data sets that have a bearing

on the issue of landform production under cold-based parts of ice sheets, paying

particular attention to factors such as ice thickness, type of substratum, position along

flowline, temperature and probable thermal history. It is found that no significant contradiction

exists between the two sets of observations because of important differences

in the glaciological context. In addition, we describe a datset that allows a closer anlysis

of a "minimal disturbance" case where a relict surface on a formerly frozen-bed

upland in Sweden is of such a layout and degree of preservation that it allows identification

of horisontal change (transport) rates on the order of 1m/1000yrs with minimal

vertical changes. Based on the observations and considerations above, a scheme for

more detailed classification of "relict" landforms and surfaces is presented, with the

aim that it shall be useful in an inversion context, i.e. for deducing probable formative

glaciological conditions and evolution from preserved landform assemblages.

Place, publisher, year, edition, pages
URN: urn:nbn:se:su:diva-21127OAI: diva2:187653
Available from: 2007-12-05 Created: 2007-12-05Bibliographically approved

Open Access in DiVA

No full text

Other links

Search in DiVA

By author/editor
Kleman, Johan
By organisation
Department of Physical Geography and Quaternary Geology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 11 hits
ReferencesLink to record
Permanent link

Direct link