Kōrero: Geology – overview

Much of New Zealand’s mountainous spine is underlain by the rocks grouped together as Torlesse greywacke. This exposure on the side of Wakefield Ridge in Aoraki/Mount Cook National Park consists of thick beds of greywacke (light grey) with thinner layers of hardened mudstone known as argillite (black). When deposited the rocks were horizontal, but they were later deformed and uplifted so that they are now almost vertical.