Southern Alberta and Saskatchewan contain a variety of interesting geological features. Known as an erosional plateau. The Cypress Hills were not glaciated as the surrounding areas were. Some rock layers exist in the Cypress Hills where in other places they have been eroded away. From about 44 to 35 million years ago, some coarse gravels were deposited by rivers, forming a protective layer over the existing sediments. The Cypress Hills are a drainage divide – a landform around which rivers flow.
The Bearpaw Formation exists at the base of the Cypress Hills. The Eastend, Whitemud, Battle, Frenchman and Ravenscrag formations lie on top of this. For a period of time around 66 million years ago, deposition stopped and some rock was eroded. The top layer of coarse gravel called the Cypress Hills formation. The gravel came from rivers which eroded rock from the newly formed Rocky Mountains.
Red Rock Coulee is a small area about 40 kilometers south of Medicine Hat. It is notable for its sandstone concretions – rounded boulders that formed from sand, calcite and iron oxide which can be up to 2.5 meters in diameter. The minerals were deposited in layers on a nucleus of shells, leaves or bones.
The Foremost – Cypress Hills area has some notable glacial features, including moraines and drumlins. Some major glacial features exist along Frenchman Valley near the Alberta-Saskatchewan border. Known as moraine plateaus, they are elevated patches of land with flat tops which may be circular or irregular in shape. They are composed mostly of glacial till. Most of the plateaus are 400 to 800 meters in diameter.
Studies suggest that moraine plateaus form on land that was poorly drained and had unmoving glacier ice. The currently accepted idea is that moraine plateaus formed in openings in stagnant ice, and this was caused by blocked meltwater drainage as well as a large supply of debris.
A megablock is a large mass of material that has been fixed in place by a glacier. Most of the megablocks discovered in the world are made of bedrock, but some are made of glacial till. A megablock exists about 9 kilometers from Bow Island, on the east bank of the South Saskatchewan River.
A moraine at Green Lake, near the Cypress Hills, marks the furthest extent of glaciers. Silts from glacial lakes were deposited in a basin known as Glacial Lake Downie. The uppermost layer of these sediments has been radiometrically dated at about 13,500 years. The Elk Valley was deglaciated more than 12,200 years ago.. After glaciation, alluvium formed surfaces along the main valleys, between 11,000 and 10,000 years ago.
Read more… about extra-terrestrial rocks in the SEAWA region.