Lecture 12 - Glacial Landsystems

Question 1

Evans (2003)

Answer 1

whole book on G land systems

Question 2

Benn and Lukas (2006)

Answer 2

explicitly linking process to form, landsystem models developed in modern environments provide good tools for reconstruction of the past environment from sedimentological and geomorphological record

some landform characteristics may originate from more than one processes so a particular depositional model may fit the data but may not be the correct on

problems with the uniformitarian approach of linking process form relationships to inform on past environments - inaccessible modern glacial environments therefore few linking genetic processes to forms that can be observed in the geological record, or some ancient glacigenic sequences may not have modern analogues - equifinality of landscapes

despite limitations, modern process studies frequently provide the best source of insight into the earths glacial record as long as they’re applied flexibly with due attention to issue of scales

modern analogues should only be invoked with multiple lines of evidence
- surface morphology alone is a poor guide

Question 3

Benn and Lukas (2006) hummocky moraine

Answer 3

Hummocky moraine = distinctive landform association consisting of numerous sharp crested moraine mounds and ridge fragments, seen in many valley floors of Upland Britain

studies show they represent ice-contact fans formed at active, oscillating margins, effected by varying degrees of ice push and subglacial deformation

no sedimentary data suggesting thrusting

Question 4

Benn and Lukas (2006) NW scotland

Answer 4

YD landsystems in NW scotland

• Hummocky moraine have close but no exact modern analogues: may reflect the distinctive Western Scotland climate during YDm high activity type (warm and heavy snow) and a lot of subG debris
• many elements of the YD glacial land system in the study area have modern analouges, the particular combination of observed characteristic is not represented in any of the examined examples, therefore although modern observations can serve to guide interpretation of ancient examples, they should not be regarded as rigid templates