The shelf break marks a distinct change
in the slope of the sea floor from the flat continental shelf to the steep sea floor of
the continental slope.
The shelf break is typically located at a water depth of 130
meters, which coincides with the position of shoreline 18,000 years ago during height of
last ice age.
Massive continental glaciers have grown or retreated with
each change in global climate over the last 3-5 million years (especially last 2 million
years), the so-called ice ages. The large volume of water locked in massive continental
glaciers during cold periods of earth history has been removed from the ocean, thus
resulting in a fall in the position of sea level worldwide.
Conversely, retreating or melting continental glaciers
produces a rise in global sea level.