Knife Lake Series

The Knife Lake Series is a division of Precambrian rocks found in northern Minnesota and Ontario, dating back to approximately 2.6 billion years ago. These rocks are primarily sedimentary and have undergone metamorphic alteration. The Knife Lake Series may be equivalent to the Seine Series, which is also a Precambrian rock division in the same region. The Seine Series begins with a conglomerate containing large granite boulders, suggesting a significant period of erosion that exposed the granitic cores of ancient mountains. Intrusions within the Seine Series have been dated to about 1.1 billion years old.12