Kahurangi National Park, at 452,000 ha, is the second largest park in New Zealand. Located in the northwestern corner of the South Island many of the features seen in Kahurangi National Park are unique to New Zealand. Those who make the effort to explore the hinterland are provided with a wonderful treasure trove of surprises.
Its natural features, ecological value and tramping possibilities are unparalleled. Kahurangi National Park offers seclusion and rugged grandeur in imposing mountain ranges, rolling tussock lands, unspoiled forest valleys and coastline.
The geology of the Kahurangi National Park, although complex, is reasonably well understood. The oldest rocks date from 350-550 million years ago and in the Cobb valley contain the oldest fossils found anywhere in New Zealand.
Old sedimentary rocks such as the karst/limestone of Mt Arthur and Mt Owen are riddled with caves.
A variety of minerals including asbestos, gold and magnesium are known from the region. Many of the geological features link the area with the ancient southern super continent of Gondwana which broke up 80 million years ago.
The landscape is diverse extending from the sea coast to 1,875 metres.
While many elements of older landscapes still exist, the processes that carve and shape the land have been busy. Active fault systems dissect the region, rivers have carved spectacular gorges and in the limestone regions flow through water worn caves.
At higher altitudes frost weathering has shattered rocks sending shingle screes down to the river valleys. Some of Kahurangi National Parks picturesque features like the Matiri Plateau, Mt Owen, Oparara Arch and the rugged Heaphy coastline feature regularly in scenic books and calendars.
Kahurangi is New Zealand's most geologically complex area. Over millions of years, water has slowly dissolved much of the limestone that Mount Owen and Mount Arthur are mainly composed of producing a vast underground drainage network, and resulting in the largest cave system in New Zealand.
Sink holes, pot holes, deep fissures, fluted marble outcrops and magnificent rock formations, form an almost moonscape environment. These mountains, thus, contain the finest examples of karst (limestone) in the Southern Hemisphere.