It is a truth universally acknowledged that geologists have cake on a Friday. Nobody knows why. Nobody knows when it started. Nobody knows who started it (except me, because it was me). But in the whole endless (6 month) history of cake Friday (Kuchenfreitag) it has NEVER taken place next to a major plate boundary. Today, today was that day.
Amidst torrentially light rain and wind we ventured along a never-before-travelled gravel track and bashed through Helen-sized shrubs (Helen is about 1.57m, apparently) to visit a huge (New Zealand huge, not Australia huge) cliff face exposing the boundary between the Pacific plate and the Indo-Australian plate, the Alpine Fault.
Where these ‘plates’; huge chunks of rock floating around on the outside of the earth, meet, they can collide into one another, slide past one another, or one can slip under the other. At least, this is what we learnt at school. In New Zealand it seems the geology, like pronunciation of vowel sounds, is not so simple. The locality (pointless geology word for place) we visited today shows the two plates slipping past one another, giving us huge earthquakes such as the tragic 2011 Christchurch disaster, but also colliding with one another leading to the Southern Alps popping up along the spine of South Island. To make matters more complicated, if we follow the same plate boundary either north or south we find plates slipping underneath one another (subduction zones) leading to volcanism and confusion. We saw only a tiny part of this large boundary, and each ate only a tiny part of a large cake, but seeing two worlds collide in front of us was an awesome experience.