The Tablelands in Gros Morne National Park, Newfoundland, are one of two sites on earth where mantle rock lies exposed on the surface and is readily accessible to visitors. This rock, called peridotite, was forced to the surface in a tectonic event approximately 500 million years ago, and it has weathered into rich orange color as a result of the oxidation (rusting) of the iron in it. The earth's mantle, which makes up approximately 84% of the planet by volume, lies underneath the crust at least 5 to 50 kilometers below the surface and has an average thickness of nearly 2,900 kilometers.
Stepping onto mantle rock gives hikers an opportunity to ponder the ancient history of this planet we enjoy on our adventures. The viscous nature of the mantle, swirling slowly on a geologic time scale, is what causes the drifting of the continental plates and the formation of the mountains we climb and hike in. The iron that gives the weathered peridotite its rusty color has also enabled the planet to become magnetized, powering our compasses that we rely on for navigation. And the volcanism caused by the agitation of the mantle through the eons has released the vapors that now make up the atmosphere we fly through and the oceans we sail on. Reflecting on the connections between our adventures and the natural history of our planet is worth a day at this beautiful location in western Newfoundland.
The Tablelands are accessed via NL-431 from Bonne Bay. If you are staying in Norris Point for a Gros Morne adventure, you can take a fun ferry across the bay and catch a local taxi to the trailhead at the Tablelands. Consider budgeting an hour or two each in Norris Point and Bonne Bay, where charming shops and restaurants are kept by delightful Newfies eager to share their slice of heaven with visitors.