How Was Milford Sound Formed?

Milford Sound GeologyLike many areas of the world, Milford Sound is a geological wonder. Much of the earth emerged before its European discovery, following tectonic activity that caused the ground to rise from the ocean beneath. Today, visitors to the area like to know how Milford Sound was formed, so they can marvel further at each of its beautiful bends and curves.

How Milford Sound was Formed from the Geological Landscape

It all started 400 million years ago. At this point, Milford Sound’s world-famous mountains were under the sea, and its floors were yet to be walked by human feet. In fact, the planet lacked diversity to the extent that animals were relatively indistinct; a far cry from the creatures Darwin would later document.

As the world’s continents began to shuffle around each other to form the unmistakable outlines we see on maps today, tectonic activity was stirring in the Milford Sound area. As two plates began to rub together, the rocks beneath splintered and shifted, protruding through the waters to form the mountains that tower over New Zealand’s Fiordlands.

Milford Sound’s Sinking Mountains

Millions of years passed with these towering mountains protruding above the ocean floor, with just a little greenery tumbling down their sides. Then, they began to move downwards, causing dirt and sediment to rise. Suddenly Milford Sound had flat lands, the type of lands that man could later walk on.

Thousands of years contributed to the initial squelch of mud and sand turning into limestone. Around 2-million years ago, yet more tectonic activity forced a little of the earth’s crust upwards, giving birth to a layer of limestone and sandstone that would eventually form the rugged dips and craters of Milford Sound.

Milford Sound During the Ice Age

During the most recent ice age, the volcanic sediment that came to characterize Milford Sound gave way to sharp glaciers. Ice firmly embedded itself from the mountaintops down to the valleys, and although it would later melt, the stamp it left on Milford Sound formed much of its mysterious character.

As glaciers began to run from the peaks of the mountains down to the coast, they formed the crevices that are known today as the Fiords. Towering chunks of rocks were shifted from one side to another, and when the time came for the ice to melt 10,000 years ago, they were displaced further. Groaning under the ache of each other, these rocks deposited into the small hills that visitors see when they drive along Eglington Valley.

The shaping of Milford Sound is not over yet. As the world around it continues to evolve, so does the way it looks. What all this diverse activity has left the world with is a varied collection of rocks. Most notably, there is the greenstone, which has a heartbreaking Maori story behind it. Legend has it that Tama-Ahua was deserted by his three wives, and so he went to the area to look for them. When he got there, one of his wives had been turned into greenstone. Crying tears of despair, he left white tracks along the stone, to protect his lost wife forever.

Milford Sound’s geographic and mythical origins hold equal beauty. For visitors, the area’s landscape tells its own story, allowing them to soak it in as they observe the beauty while walking or resting on a cruise deck.

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