Travels: Fiordland Geologizing Feb 17-21

I hardly left Fiordland long enough to get deja vu, yet somehow I managed to make it right back. This time around I was assisting a NASA researcher who is interested in basic (high pH) springs related to ultramafic rocks. These springs, some of which have pH in excess of 11.5, are compelling examples of thresholds required for life and are seen as analogs for life on Mars.

We spent the days helicoptering around fiords, glacial river valleys and jagged cloud-soaked peaks visiting springs and taking water, gas and rock samples. Fortunately, one of the springs visited was in my PhD field area (see photo above right), so I got a sneak peek of what I am in for. There's a reason why this stretch of the Alpine Fault has hardly been looked at; for the most part it is very rough and inaccessible country. There was no complaining on my part that these springs of interest happen to be in one of the most beautiful and remote places in New Zealand. Except in regard to the sandflies...

Sandflies, for the blissfully ignorant, are pure, concentrated evil. In a land where there really is nothing to fear but the weather (no poisonous flora or fauna), these rice grain-sized biting flies are the Achille's heel of New Zealand fieldwork. Ungodly numbers of these flies frequent coastal regions of the West Coast. They swarm in black clouds of thousands and instantly prey on any exposed flesh. Their itchy bites leave welts which can last many weeks. Sandflies seem to be partially immune to the most toxic substances you put on your skin so really the best solution is to be completely covered head to toe. Even if protected, having hundreds of sandflies sitting on your clothes and several thousand swarming around you can be mentally exhausting.

So as I was saying we flew around in helicopters to several different sites and returned each evening to a cozy house at Milford Sound. One of the Milford pilots was a bit of a hotshot which made for some memorable rides- skimming close to steep hillsides, dropping steeply over alpine passes, and fast G-force-inducing sideways turns. It was quite luxurious fieldwork and we were blessed with exceptionally fair weather. The first day we checked out the Anita Bay Ultramafics (one of two ultramafic mylonite occurences in the world!) near Lake Ronald- fantastic rocks but no springs. Days 2 and 3 were spent stranded on a 150m long beach surrounded by cliffs in a fiord called Poison Bay. The name apparently comes from the gaseous seeps we sampled that reek strongly of sulfur. These seeps emit hydrogen and methane gas believed to be a product of active serpentinization at depth! Some researchers have suggested that the serpentinization processes here are partially driven by microbes, which is a pretty cool prospect as well. I got good and wet collecting escaping gas from the intertidal zone, while a pod of Hector's dolphins played offshore. Poison Bay may be the motherlode for sandflies. The next day we flew up the Alpine Fault into the Cascade River region to a beautiful spring with cascading orange-red flowstone terraces for 100m down the hillside. This spring has an impressive pH of 11.6 and extremely high rates of calcite precipitation. We then heli-ed to the Transit River where we refound several previously documented warm sulfurous springs. These springs had abundant white stringers of algae typically found at hot springs. The last day was a freebee as the NASA researcher had to conduct chemistry tests on collected samples so I decided to go for a tramp. I hiked up the Deadman's Track, a brutally steep suggestion of a trail that climbs 1000m in only a few kilometers to the highest and most scenic stretch of the Routeburn Track. Despite low clouds and a light horizontal rain, there were still some good views to be had from Harris Saddle. So in under 4 hours I saw the highlights of what is usually a 3 day tramp. My knees are still wrecked from the decent. In a little over a month I've managed to rack up 13 helicopters flights! I don't know what that says for my carbon footprint...but it has been good fun!