Isolated outcrops of rock standing in the ocean are called sea stacks, and they are remnants of rocky headlands that were eroded by wave action. They are indeed ancient – millions and millions of years old. And incredibly resilient. Many stacks were the result of volcanic action, with lava flowing to the sea. Cooling lava became hardened basalt over time. The heavy basalt remained buried under marine sediments for millions of years. As the climate shifted and sea level receded, the rocks were revealed and parts worn away by winds and water. Tidepools at the base of many sea stacks provide habitat for a variety of marine creatures. Soil has settled into crevices of some of the sea stacks, building up a soft layer perfect for nesting puffins, murres and other seabirds.
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