This was the most productive and enjoyable PhD fieldwork I have done to date. Uncharacteristically good weather, a keen field assistant and longer days allowed me to get to some hard to reach places. Some days we didn't return to camp until 9PM. I managed to answer some questions I had, create many new ones, and find some great outcrops. I am now fully willing to argue I have the most complete and important section through the Alpine Fault! I have much to think about and to plan for the next round of fieldwork, whenever that may be.
I managed to go canyoning, rappelling and even caving in the name of science! Needless to say I am really starting to get into my fieldwork. It's hard work and I can go an entire day of bashing through thick bush without seeing a rock, but overall the persistence has paid off.
Several long days were spent bashing through wet bush to get to Livingstone Fault Zone outcrops. We revisited a previously described outcrop which is the best section through the fault I have seen yet. It's a very tricky place to reach with waterfalls above and below where the fault crosses the creek and steep unstable slopes everywhere else.
All photos of me in this post by Ryan Weidert.
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| Steeper than it looks! |
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| Abseiling a waterfall |
On a bright, sunny day we stretched into wetsuits and descended Monkey Puzzle Gorge, which was one of the most enjoyable days of fieldwork I have ever done. Once we swam the first stretch at the start, we were committed to go out the bottom no matter what we encountered downstream. The entire day was spent swimming, floating, wading, and jumping our way downstream, examining the rocks and taking samples and measurements where necessary. Steep inescapable walls, thick vegetation and deep blue green pools framed a very beautiful and very tropical scene. There was only one section of the gorge which caused terror- we found ourselves at the lip of a 10m waterfall with white frothy rapids and room-sized boulders as far as we could see. This we bypassed with some difficulty by traversing the bush on river left. Imagine room-sized boulders covered in thick moss and ferns with the 5m deep gaps between them covered in unsupportive moss. We took it slow and tested every step before our full weight was applied. The rest of the canyon was a breeze.
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| Greenland Group gneiss |
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| Trying to get a GPS fix in the middle of the river |
Ryan cleared some rather large river boulders at the Martyr River Alpine Fault outcrop with the result that we had several square meters of important footwall outcrop. There is now only a 2m section missing where the fault has thrust over river cobbles to an uncertain depth. We also cleaned an exposure at a Martyr tributary which perfectly exposes the fault core- my missing 2m of section at the other exposure! I won't describe further here but it is all very interesting!
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| Jackson Bay, southernmost settlement on the West Coast |
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| The Cray Pot, only restaurant in field area |
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| Jackson River Road, only road access to field area |
Eying a gap of several days of good weather we then flew into the Jerry River, a place only briefly examined by geologists before because of its remoteness. The Jerry had completely different rock types than I have seen in the Jackson (or anywhere else for that matter) and I couldn't help but laugh and scratch my head every time I saw something new. Entire hillsides of fresh outcrop were mapped, measured and sampled. In a few days we managed to cover quite a bit of ground! Sadly, I collected few samples that aren't held together by glue or aluminum foil which means painstaking preparation later. It is clear the Alpine Fault is a very different beast here than it is to the north. We were picked up just before being completely socked in by low clouds and had to fly the long way out the coast. Had the helicopter arrived any later, we probably would have been sitting out a nasty storm in the tent for a couple more days.
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| Nice outcrop! (note fault at center) |
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| Waiting for our ride |
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| Escaping before the storm |
One day was spent looking for, and exploring, Serendipity Cave. I found the main entrance to Serendipity by crawling into a small hole which intersected the proper entrance. Amazingly, this is not the first time I have found a known cave entrance from the inside by exploring an unmapped hole! There was a lot more cave than I anticipated and it had a main passage with quite comfortable dimensions. One side chamber was absolutely choked with stalactites and flowstone. I checked about a dozen leads, most of which kept going and all of which were virgin passage. The whole time I was giddy that there are caves in my field area. There is still much to explore! My hope is to find a clever way to use the cave to determine an uplift rate for the region west of the Alpine Fault and possibly a record of tilting.
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| Fieldwork! |
The last day we went for a sunset walk along a beautiful West Coast beach near Cole Creek and ended up pitching tents on it.
After caving at the top of the South Island we returned to backpack into the Cascade River to check out the area near Woodhen Creek for a few days. Some good discoveries were made, but a good amount of time was also spent wondering aimlessly through the bush. You can't always have outcrop where you want it.
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| Woodhen Pond (an Alpine Fault sag pond) |
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| Navigating the swamps |
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| Theta Tarn |
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| Cascade River |
Hopefully next up, some rafting and more rappelling to get to those hard to reach outcrops. Rest assured, there is still a seemingly endless list of things to still check out in future fieldwork.
A huge thanks to Ryan Weidert for being my devoted field assistant. He did a superb job of "improving" outcrops, taking photos, observing, blazing trails, carrying stuff, using his height to get better GPS reception, occasionally being a ladder, battling sandflies, testing rotten logs and swamp squishiness, controlling weather, and rationing sweets.
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