Glaciers scoured the Fiordland landscape for tens of thousands of years, carving the fiords, lakes and deep U-shaped valleys so typical of the area.

Geology

Fiordland contains some of the oldest rocks in New Zealand, predominantly hard crystalline metamorphic rocks like gneiss and schist, and igneous rocks like granite. Lying close to the alpine fault where two plates of the Earth’s crust meet, the area has been folded, faulted, uplifted and submerged many times.

Periods of submersion under the sea-bed have created areas of sandstone, mudstone, and limestone seen today at Te Ana-au Caves and on the Hump Ridge.

Shaped by glaciers

Over the last 2 million years glaciers have at times covered the area, gouging into the rock and creating U-shaped valleys, many of which are now lakes or fiords.

Today hundreds of lakes dot the landscape, among them Lake Hauroko, the deepest in New Zealand at 462 metres. Fourteen fiords, some stretching up to 40 kilometres inland, extend from Milford Sound/Piopiotahi in the north to Preservation Inlet in the south.