Bradwell et al., 2009 Flashcards
What does Bradwell et al., 2009 do?
Use sea-bed imagery and bathymetric data to determine the timing, extent, flow configuration and decay mechanism of the last British Ice Sheet.
What does the model allow for?
a viable pattern of ice-sheet disintegration to be proposed for the first time using echosounder data reveals striking geomorphic evidence – in the form of tunnel valleys and moraines – relating to the former British and Fennoscandian Ice Sheets.
What goes to suggest that at its maximum extent a grounded ice sheet flowed from SE to NW across the northern North Sea Basin, terminating at the continental-shelf edge?
The pattern of tunnel valleys in the northern North Sea Basin and the presence of large moraines on the West Shetland Shelf, coupled with stratigraphic evidence from the Witch Ground Basin.
This period of maximum confluent glaciation (c. 30–25 ka BP) was followed by what?
a remarkable period of large-scale ice-sheet re-organisation.
What does their evidence suggest happened when sea levels rose?
- A large marine embayment opened in the northern North Sea Basin, as far south as the Witch Ground Basin, forcing the two ice sheets to decouple rapidly along a north–south axis east of Shetland.
- As a result, both ice sheets rapidly adjusted to new quasi-stable margin positions forming a second distinct set of moraines.
Final-stage deglaciation was marked by what?
Near-shore ice streaming and increasing topographic control on ice-flow direction.
Retreat of the British Ice Sheet continued until c. 16 ka BP when, following the North Atlantic iceberg-discharge event (Heinrich-1), ice was situated at the present-day coastline in NW Scotland.
