Missinaibi Formation

The Missinaibi Formation is a Late Pleistocene nonglacial sedimentary deposit in the Hudson Bay Lowlands of northern Ontario, within Missinaibi Provincial Park. Unusual in a region largely shaped by glaciation, it has been important for understanding past climate and the advance and retreat of ice across northern Ontario. Identified by geologists in the late 19th century, the formation preserves sediments and fossils, including fish, beaver, and mastodon remains, from the Sangamonian interglacial, a warmer period before the last major glaciation. In 1958, surveyors for Algoma Ore Properties also identified two iron ore deposits there with an airborne magnetometer and staked mining claims.

Ontario · Canada