A compass-spinning geologic inheritance
Deep beneath the tundra and ice of the Canadian Arctic Archipelago lies the source of its deep magnetic strangeness. The region is built upon the Canadian Shield, the ancient core of the North American continent, with some of its rocks dating back more than three billion years. These are the eroded roots of primordial mountains that once stood up to 12,000 meters tall. This foundation of ancient crust is not uniform; it is a mix of different rock types, each with its own magnetic signature.
The most significant contributor to the magnetic chaos is a massive geological event known as the Franklin Large Igneous Province. Around 720 to 718 million years ago, a colossal outpouring of magma covered over 1.1 million square kilometers of the Arctic. This event created extensive layers of iron-rich basaltic rock, both as surface lava flows and as intrusions called dikes and sills that sliced through the older crust. The iron-bearing minerals in these volcanic rocks act like tiny magnets, creating powerful local magnetic fields that distort the Earth's main magnetic field. Flying an aircraft with a magnetometer over this region reveals a dramatic area of intense magnetic highs (often shown as red) and lows (blue), which directly map the hidden geology below.
The pole's long arctic movement
This highly variable magnetic crust had a deep effect on the North Magnetic Pole, the point on the Earth's surface where the magnetic field points directly downward. For centuries, the pole meandered slowly through the islands of Nunavut. James Clark Ross first located it on the Boothia Peninsula in 1831. Subsequent surveys by Canadian scientists found it at Allen Lake on Prince of Wales Island in 1947 and tracked its slow drift. This wandering was not a smooth journey; the pole makes a daily elliptical wobble up to 80 kilometers across due to charged particles from the sun.
In the 1990s, the pole's movement began to accelerate dramatically, increasing from a crawl to a sprint of about 55 kilometers per year. This acceleration is driven by changes deep within the planet's liquid iron outer core, specifically a tug-of-war between two large blobs of magnetic flux under Canada and Siberia. The Siberian blob has been strengthening while the Canadian one has weakened, pulling the pole out of the archipelago and across the Arctic Ocean. By the year 2000, it had moved offshore from Canadian territory entirely. This rapid shift forces constant updates to the World Magnetic Model, which is used for navigation in the high Arctic for everything from ships to military operations.