There are legends about the scattered islands of the Chuuk lagoon being created by the pounding tail of an angry crocodile, and others about sea gods stealing pieces of land and depositing them in random places. But I am going to skip over those stories for now and give you a short summary of the geological history of the Chuuk lagoon.
Millions of years ago a boiling soup of molten rock swirled and surged in a circular fury. The fiery broth was sealed with a cover of hardened rock that stretched for miles. As the scorching stone slime pushed against its rocky lid, the seemingly impenetrable shield began to split. It began to pull apart and became weakened at a thin spot near the top. A crack splintered through the rock and the magma quickly squirted its way in to fill the gaps. The force of the rising fire was too much for the crumbling rock and it finally snapped off a small piece of its crust.
The melted igneous rock made its long journey to the surface, but was greeted with a watery bath. On top of the crusty lid was the largest body of water on the planet. Now the bubbling magma and massive ocean were locked into an epic battle for survival. The incipient volcano was relentless in its efforts. A gigantic pool of compressed magma at the center of the earth was exerting an immense outward force that was pushing the steaming liquid upwards. But as soon as it would peak out of the hole, the cold waters would squelch its fire and turn the magma into solid rock. The water was winning the battle, but it would lose the war. The causalities on the volcanoes side (rocks) were ironically working for its advantage. It grew wider and taller on top of the bodies of its dead comrades (rocks).
The once tiny crack was forming into a sloping mound that was growing minute by minute. After ages of fighting between fire and water, the volcano finally built a base large enough to pop its scalding bald head out of the ocean. Eons pass and the volcano continues to spew out lava to expand its territory. The peak of the underwater volcano now forms a legitimate island in the middle of the once empty ocean. This volcanic island of ancient Chuuk has a diameter of almost 40 miles and lush vegetation soon sprouts in its fertile soil helped along by an endless cycle of rain and sunshine.
Beneath the surface, the once prominent crack seals itself off and stops letting magma squirt up its spire. The big island is proud of his victory against the elements and stands majestically above the blue waters of the Pacific. But the island still has another challenge ahead of him, one that he will not win. He had conquered the wetness of the ocean, but Mother Nature has a varied toolbox full of weapons to destroy an island. Pounding rain, zipping wind, and slapping waves begin to stab their steely knives into the flesh of the tropical island. Little by little, their slow but consistent efforts start to wear away at the land. The shoreline sinks away and the hillsides crumble down. It appears as if the island is sinking!
But all is not lost for the future of this isolated mountain of rock. The subterranean volcano has one more trick up its sleeve. Around the base of the island, coral gardens grow in the warm shallow waters. These rocklike animals expand quickly as their polyps multiply in the nutrient rich conditions. The coral reefs don’t just attract fish and an abundance of sea life; they also leave behind a gift for the island when they die. Their skeletons pile up and form organic graveyards. These piles of coral bones grow steadily below water at the same time the central island is being worn down by erosion. Eventually the coral builds enough of a base to break the surface of the water. These become low-lying coral atolls. Together they form a ring around the circumference of the main island and act as a barrier shield from the oncoming waves and currents.
PAUSE. This is the Chuuk Lagoon today. The sad remnants of the big island are now all that can be seen in the center. Eleven former mountaintops stick their chins out of the water and struggle for survival. A broken ring of coral atolls surrounds the central islands and encircles them in a protective fortress. If you were standing on the ocean floor and looking at Chuuk from a side view, it would like a tall plateau with a jagged edge of coral and some pimples on its face.
As the life cycle of our lagoon continues, the high central islands will continue to decline into oblivion. Parem and Fono will drown in the turquoise waters and someday even the mighty peaks of Tol and Tonoas will fade into their watery graves. The middle of the lagoon will be an empty lake, but the shoreline of the lake will expand. The coral reef will continue its growth and possibly connect into an enclosed circle. The atolls will never gain substantial altitude, but will survive until sea levels change or erosion takes its toll. Depending on how extreme your views are about climate change, you might think this will happen in 5 years or 5 million.
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