1. Lisbeth Louderback ESS 433
Flute/Drumlin Formation: A Review of Boulton (1976) and Shaw and Sharpe (1987)
Lisbeth Louderback
ESS 433

2. Outline Purpose of research papers Boulton (1976)
Provide evidence for flute/drumlin formation and processes
Boulton (1976)
Flute formation
Shaw and Sharpe (1987)
Drumlin formation
Concluding remarks and discussion

3. Boulton (1976)
Studied modern glacially fluted surfaces in Spitsbergen, Iceland, Norway, and the Alps.
Flutes originate from rigid obstructions
Flutes form when till is intruded into tunnels which open up in the lee of obstacles

4. Boulton (1976) Here is a boulder that is transported in a glacier
Slows down by ploughing into the till
Which develops this wedge on its lee side
The till is traced into a flute

5. Boulton (1976)
A relationship exists between flute height and height of initiating obstruction

6. Boulton (1976) Further evidence for origin of glacial fluting Tunnels
Patterns of strain and deformation within fluted sediments
Two major fold sets
Axis parallel to flow
Axis transverse to flow
Tunnels – reconstruct the original form of the flute (like here). The tunnel here intercepted this flute which collapsed into the tunnel
Arrow shows direction of ice flow. There are two sets of folds – one with an axis parallel to ice movement indicates phase of flute formation. The second is transverse to ice movement.

7. Boulton (1976)
Flutes are not depositional or erosional features, rather they are formed from post-depositional deformation of pre-existing materials.

8. Shaw and Sharpe (1987)
Subglacial meltwater is responsible for both erosional and depositional drumlin formation.
Small-scale features
Intermediate-scale features
Drumlins

9. Shaw and Sharpe (1987) Small-scale features Rat tails
Rat tails are small ridges occurring on the lee side of an obstacle. These features are produced by water in the absence of ice
Flow

10. Shaw and Sharpe (1987) Intermediate-scale features Flow
The intermediate features are identical in form, surface texture, and their relationship to obstacles. It shows that these were also produced by subglacial meltwater.
Erosional marks in limestone in Wilton Creek, southeastern Ontario
Flow

11. Shaw and Sharpe (1987) Drumlins
Drumlins in Canada. These show all the morphological characteristics of the smaller scale forms, remnant

12. Concluding Remarks Boulton (1976) Shaw and Sharpe (1987)
Flutes (‘drumlins’) are formed by ice deformation processes
Shaw and Sharpe (1987)
Drumlins are formed by meltwater features

13. Concluding remarks Are drumlins and flutes the same feature in nature?
Boulton (1976) definition of flutes:
‘long, parallel-sided ridges on deformable subglacial surfaces’
Shaw and Sharpe (1987) definition of drumlin:
‘remnant ridges resulting from erosion of the glacial substrate by sub-glacial meltwater sheets’

14. Discussion Source of subglacial meltwater ?
Does origination of sediment (e.g. till in ice sheet environment vs. till in valley glaciers) have an effect on the formation of drumlinoid features?
Coarse lags?
What are other possibilities of drumlin formation?
Floods generated by uplift?