Granite Foundations

Granite Foundations. Acadia National Park. , Rounded mountains, a deep lake, and sheer cliffs reveal this valley’s icy past. But long before glaciers sculpted Acadia’s surface, the granite foundation was forged deep in the Earth. Over 500 million years ago, colliding continents created a mass of hot magma, or molten rock, far below the Earth’s surface. It cooled and crystallized, creating the strong, beautiful Cadillac granite, admired for its distinctive pink, gray, and black minerals. Hundreds of millions of years of erosion, including a final polish by mile-thick glaciers, gradually shaped the resistant granite into the landscape you enjoy today., Glacial Erratics , See the large boulder in the lake to your left? Like Bubble Rock (photo at left), it is a glacial erratic: a rock carried here by ice from a different location. Both boulders are made of Lucerne granite, glacially transported more than 30 miles from the northwest. Compare the Lucerne and Cadillac granites for differences in color and crystal size., Moraine , As the glaciers melted, they left a mound of rock, gravel, and sand here., Look for glacial evidence as you travel about the park. Notice the north-south alignments of ridges, valleys, elongated lakes, and coves created by rivers of ice. Watch for rocks that glaciers scattered erratically across the landscape.