O'Cofaigh 2012 (11) Flashcards
During full glacial periods, ice sheets advance across continental shelves adjacent to terrestrial landmasses, often to the shelf edge, and deliver what?
Icebergs, meltwater and sediment to the deep ocean.
Much of this sediment delivery was associated with ice streams.
What are ice streams?
Ice streams are fast-flowing features that can be several hundred kilometres in length and can flow at speeds of several hundred to several thousand metres per year.
Why are ice streams important?
They are important because they are responsible for most of the drainage from the large polar ice sheets both today and during past glaciations, and hence impact directly on ocean circulation and, through this, climate.
What is iceberg rafting?
Iceberg rafting refers to the transport by icebergs of glacial debris into the ocean.
The melting of icebergs through time results in the delivery of this debris to the seafloor as…
‘IRD’. It is the principal mechanism by which glacial sediment is delivered to the deep ocean basins beyond the continental shelf edge.
What are moraines?
Moraines are sedimentary ridges orientated parallel to the former ice-sheet edge and mark the maximum ice-sheet extent or successive positions of the ice-sheet margin during deglaciation.
Submarine features formed transverse to ice-sheet flow provide information about what?
The position of the ice-sheet margin or grounding line in time and space.
The formation of these landforms typically requires ice-marginal or grounding-line stabilization so that sediment build-up can take place, and dated cores from these features allow a chronology of ice-sheet retreat to be established.
