The Geology of Baxter State Park and Mt. Katahdin

Summary of Bedrock Geology

Three principle types of rocks form the bedrock of Baxter State Park: granite, and volcanic, and sedimentary rocks. Geologic and fossil evidence indicates that the oldest rock in the area is sedimentary; the youngest is the Katahdin granite, and the volcanic rock is intermediate in age. The layered rocks are folded and faulted by compression acting in the earth's crust. The compression occurred before the intrusion of the Katahdin granite.

The distribution of various bedrock types in Baxter State Park is shown on the geologic map (Plate 1A). This geologic map shows only the surface orientation of bedrock; it does not show the structural relations of the various rock types. Detailed mapping of surface structural features of the bedrock yields information which can be used in the construction of a structural geologic cross-section. Such a cross-section is shown as Plate 1C. It shows the underground structural relations of the various rocks in the State Park. The section lies along a line which extends from Grand Lake Matagamon to Baxter Park and along to the southern State Park boundary. Much of the cross-section is highly generalized, but is substantially accurate.

Introduction Bedrock Glacial geology Geologic features Acknowledgments Glossary References Plates

Last updated on January 11, 2008

Contents

The Geology of Baxter State Park and Mt. Katahdin

Summary of Bedrock Geology