What is the structure of the earth’s crust in the regions to which most of the lakes of North

What is the structure of the earth’s crust in the regions to which most of the lakes of North America are confined? What is the origin of these lakes?

The largest, most visible and important lakes in North America are the Great Lakes, located near the border between the United States and Canada. The natural system, in addition to the five largest lakes, includes smaller lakes, different in area and depth, rivers and islands. In this area lies the southern boundary of the Canadian Shield – a folded basement of the Precambrian period, and even further south is a platform plate with sedimentary rocks formed during the Paleozoic and Mesozoic. This area has been subjected to glaciation many times, due to the movements of the glaciers, characteristic landforms have formed. The Great Lakes were formed in tectonic depressions, then their shape changed under the influence of the glacier, therefore, by origin, the Great Lakes are classified as glacial-tectonic.

To the north, there are large lakes of glacial origin: Big Slave and Big Medvezhye, Winnipeg and many others, smaller.

In addition to these, in different parts of North America there are many lakes of other origin.