
It was a warm and sunny day in Milford Sound as our Cessna taxied to the runway. Literally less than a minute before take off, Jenny, our pilot, notified us that the control tower had just told her that we were to call the Hollyford Track people immediately. In no way could this be a good thing I thought, and I was right. So we de-taxied, found a phone and eventually got a hold of the Hollyford Track office. A miscommunication through no fault of my own found our plans abruptly dashed to bits. It turned out there would be no jetboats running in the valley the next week which meant that once we flew in we would be on our own- a long 3-day hike out with heavy packs (with rocks), instead of the easy 1 day hike out. Not only would we be able to carry less samples out, but we also would not be able to reach the dark side of Lake McKerrow which has not been visited by a geologist in 30 years and was half the point of the trip. All of a sudden this trip was not the luxurious, remote, high-quality fieldwork to low effort trip I had planned, and half of it would now be a tramping trip with heavy packs and uncertain weather. We unfolded the aviation chart on the tail wing of the airplane and debated our options as the good-natured pilot made no attempt to rush us. Stuck in a confusion of disappointment, I hemmed and hawed over the map, trying to make an intelligent decision whether we should call the trip off and try another time, or just go for it.
But first, how we got this far. We already had a fair bit invested in this trip up to this point. Carolyn had flown down from Christchurch and then we drove to Te Anau. We carefully packed 8 days worth of food, and considered the weight-to-value of every object we might bring. Inevitably, heavy things like a rock hammer and a tent had to come. We then set off early on the Milford Road. Leaving our car at Gunn's Camp half way along the Hollyford Road, we were then given a ride by one of the friendly camp hosts to the Milford Road junction, where we hoped for a hitchhike to Milford. As it was a bit after 9 and we had a flight to catch in Milford at 12, we had about 1.5 hours before we had to consider the hitchhike a failure and one of us would have to run the 9 or so kilometers back to the car.
After about 40 minutes or so, my sign finally worked (above) and two German college students swerved to pick us up. Once we were identified as geologists, much of the conversation centered around them soliciting advice on where and how to find gold. These guys definitely had an obsession with finding gold and promised to show us what they had collected so far. When they dropped us off at the airport, they poured the contents of a small pouch into their hands, and I reluctantly told them that all they found were some shiny, but worthless muscovite. After some lounging in the sun waiting for 12 to roll around, we found ourselves sitting in the plane as above.
So in the end a beautiful flight out of Milford was too much to pass up and off we flew. Jenny kindly flew over the Alpine Fault (instead of the usual coast route) where I drooled at the rocks exposed in slips and the impressive geomorphology. I have now flown over or bush-bashed the whole section of the Alpine Fault from Haast to Milford, except for a 10 kilometer stretch between the Pyke and Hollyford! We touched down on the dirt strip at Martins Bay without incident.

Stirling Falls, 151m high

The Alpine Fault goes offshore near the mouth of Milford Sound (red arrow)

About to land at Martins Bay at the mouth of the Hollyford Valley
To our surprise, Martins Bay was actually rather civilized with a half-dozen small buildings and rock-lined gravel paths. We tore our packs apart on the lawn and pooled excess food and the tent, which were not needed with our new itinerary. As we did this we were greeted by several of the guides, explaining our predicament to one especially sympathetic guide who turned out to be the jetboat driver! Our hero Shaun said that it would be no trouble to give us a lift across the lake as he had errands to run and crew to shuttle up and down the valley. We then repacked the tent and excess food. Through incredible good fortune, it sounded like our original itinerary was going to work out!
We hiked off to Hokuri Hut along a pleasantly varied trail through the bush and along the shore of Lake McKerrow. I was so happy to be exactly where I was. It was a warm and humid day so a brisk swim in the lake was enjoyed despite a full force of sandflies.
The next morning we were promptly picked up on the beach below Hokuri Hut. A speedy 5 minute jetboat ride later we stepped off on the far shore and watched the jetboat fade from view and sound. At this point I realized I left my field pouch with notebook and compass on the jetboat- it was the first of several tragic mistakes I would make that day, but at least it was not terminal as Carolyn had a backup compass and notebook I could use. We set up our tent, then headed up the unnamed creek into the unknown. The creek quickly steepened and as the rock size increased, so did the slipperiness. Before long there was outcrop to record, which led to the next logical question: where is the fault!? The rocks were very deceptive and troubling (as usual in my field area). Slowly and hesitantly we began to make sense of them, realizing the published map was wrong and that the story was quite a bit more complicated than originally thought. As has happened so many times before, the key outcrops were found furthest from camp at the end of the day. After an initial period of overwhelment, I furiously ran around photographing, measuring and sampling everything I could, before our long, rough walk back down to camp. I had a grand and very memorable fire of driftwood on the lake edge. I was filled with that great feeling of isolation and adventure as whisps of clouds hung half high on the mountains and sunset gave way to night.
The following day we split up to maximize our coverage before an early afternoon pickup back to Hokuri Hut. I explored a couple impressively-waterfalled side creeks with great outcrop until I was convinced it would continue the same. I then bouldered my way up the main creek until I decided the prospects of outcrop were grim. On the way down I wandered through the bush and stumbled on the fault trace. We were then ferried back to Hokuri Hut, with not quite enough time left in the day to do more fieldwork, so we had a good discussion of what we had seen so far instead.

Rocks are larger and slipperier than they appear!

Back to the "civilized" side of the lake
While based in the luxury of Hokuri Hut, we had another day and a half of frantic geologizing. I was able to follow the fault trace for over a kilometer through the bush before eventually losing it. Generally speaking, there were good deer trails, but several places required extensive "swimming" through the lush vegetation. Because of a light drizzle for a half day, the bush was soaking wet. I ran up a creek as far as I could get in an hour, eventually finding the fault trace, but alas, no rocks. Our scouting complete, we returned to the best outcrops of the fault zone where we spent the remainder of the day and a half sampling, measuring and noting like mad. Here we both were presented with an entirely different view of the Alpine Fault. A 10m wide fault core with bizarrely plastic blue clay gouge and abundant serpentine was unlike anything we had seen before. Under the right conditions, serpentine is a very slippery mineral with a low coefficient of friction and so the fault here is likely to have very different mechanical properties to further north. The samples we collected could end up being very exciting with further study.
When the time came we packed up our depressingly (literally) heavy packs and glided off on a thoroughly enjoyable jetboat ride across Lake McKerrow, and up the Hollyford River to the confluence with the Pyke River.

Basecamp

The daily bath (some days with less sandflies than others, but always quick!)

Bush swimming

Alpine Fault core- about 10m wide zone of squishy clay and serpentine!

The daily commute (Alpine Fault goes through low saddle in distance)
Carrying full packs, we both donned ipods to help ease our burden (although the spectacular views of the river and the Darrans helped). We both went at our own pace: me faster until inevitably stopping to take photos, Carolyn much steadier. To her credit, her pack was about the same weight as mine. We stayed the night at Hidden Falls Hut which sits in a scenic clearing with far-reaching views. Day 6 we continued our hike out, arriving at the trailhead just as a car pulled up. We were immediately greeted and two sentences later we were asked if we needed a ride. We did not even have to ask! This saved us having to run the 8km to the car. What incredible luck!
I now have a fresh view of the Alpine Fault and hopefully some samples that will reveal an interesting story. In all, it was some of the more pleasant fieldwork I have ever done and I did not want it to end. We arrived just as a storm cleared and left just before the next one came. We had only a half day of light rain and drizzle and the sandflies were almost always manageable. So many things threatened to go wrong, but in the end it all worked out wonderfully.

Going up the Hollyford River in style
A huge thanks to all those that made it happen: the 2 gold-fevered German tourists whose names I cannot remember, Jennie Rolston of Fly Fiordland, National Geographic for $ and Neil and Daniella for the hitch. Special thanks to Reid and Lyn at Gunn's Camp and to Shaun Bilham and the rest of the good folks at Hollyford Track. Thanks to Carolyn.