Part I - Introduction
A moraine is a glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas
acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have fallen off the valley walls
as a result of frost wedging or landslide.
Moraines may be composed of debris ranging in size from silt-sized glacial flour to large boulders. The debris is typically sub-angular to rounded in shape.
Moraines may be on the glacier’s surface or deposited as piles or sheets of debris where the glacier has melted. Moraines may also occur when glacier- or iceberg-transported
rocks fall into a body of water as the ice melts.
Terminal moraines, are ridges of debris deposited at the end of the glacier. They reflect the shape of the glacier's terminus. Glaciers act like a conveyor belt, carrying debris
from the top of the glacier to the bottom where it deposits it in end moraines. End moraine size and shape is determined by whether the glacier is advancing, receding or at
equilibrium. The longer the terminus of the glacier stays in one place the more debris will accumulate in the moraine.
There are two types of end moraines; terminal and recessional. Terminal moraines mark the maximum advance of the glacier. Recessional moraines are small ridges left
as a glacier pauses during its retreat.
The Oak Ridges Moraine is the best example of a Terminal Moraine in S. Ontario with huge benefits to the inhabitants..
Click for Part II => Genesis of the Oak Ridges Moraine