Interpreting of glaical deposits

Question 1

What properties would you expect of a till:

Answer 1

• Poor sorting, heterogenous and mixed
• Matrix often consisting of clay, sometimes sand
  -Colour can be brown, grey or reddish
• Matrix-supported
  -Angular clasts

Question 2

Types of tills:

Answer 2

Lodgement till:
-Dense, strong fabric clasts, matrix-supported, clast angularity

Ablation till:
-Looser than lodgement, rounded due to post- depositional meltwater transport, more sorting

Deformation till:
- Intense deformation w. sheared and folded structures
- Clasts may align in orientation of deformation, streaked fine material

Melt-Out till:
Formed from in situ melting of stagnant ice, poor compaction and more stratified, clast orientation can be random due to lack of directional flow.

Question 3

Methods for Studying Glacial Till

Answer 3

• Sedimentological Analysis: Grain size distribution, sorting, & sedimentary structures
• Micromorphology: Thin sections to study the fabric and structure of till
• Geochemical
• Paleomagnetic Analysis
• Isotopic Analysis
• Remote Sensing and GIS: