Just Me and the Big Dude

Toward the beginning of my PhD I won a scholarship from an organization that gives grants to students doing research in the Taranaki region, and as part of the bargain I agreed to come down to New Plymouth in early December to give a public lecture at the Puke Ariki, the city’s big cultural and natural history museum. I decided that while I was down there already I’d take the opportunity to do one last batch of fieldwork before the end of the year.

My co-supervisor at Victoria University of Wellington drove up and met me in Oakura (a small town in the northwest part of the peninsula), and we planned a couple days of exploring and sample collection.

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Protip: When possible, do fieldwork with your supervisor(s). They tend to pay for cushier lodging and tastier food than when you do it yourself. 😉

I’ve already told you about looking for stratigraphic sections and learning to tell apart the different types of deposits that I look at during my fieldwork. And about mapping those deposits in different places. Naturally, the next step is to actually take samples of those different deposits to take back to the lab for testing.

I had already done a good bit of sample collection on the last trip (the one forever lost to the annals of my dead hard drive), but there was plenty more to do in the same (and new) places, so off we went back into the park, up the Puniho track, and into Maero Stream.

We started by climbing up toward the “type section” I’ve already told you about, but this time we decided to push on a bit farther and see what lays higher up the stream. The first thing we noticed on the way up was a really red outcrop, different from anything we’d seen so far. Farther on up we also found a potential good spot to get into and out of the riverbed, which might be good to know about for future trips. It would be very convenient to be able to follow the easy track much further along rather than having to climb up the rocky stream bed.

We stopped at the red unit again on the way down to take some samples. What does that mean, exactly? Well, basically, there’s a few different types.

  1. Matrix and clast samples: Basically, I just scoop a bunch of stuff that I think is well representative of the outcrop into a sandwich baggie. The matrix is the sandy stuff in between the clasts (the pebble to boulder rocks contained in the matrix).
  2. Oriented core: We use a drill (I’ll show more later) to take a little cylinder, roughly the diameter of a quarter (NZ/Euro 50c coin) and around 4-8 cm (2-4 in) deep.
  3. Oriented hand sample: When we can’t drill a hole in the field, instead we just take the rock home instead so we can drill a hole in it back in the lab.
  4. Charcoal: For radiocarbon dating you need stuff with lots of carbon. One thing with lots of carbon are burnt bits of trees, leaves, and twigs.

So notice I used the word “oriented” a few times in the sample names. That’s because for paleomagnetism direction is everything. Later in the lab we’ll be trying to figure out the direction of earth’s ancient magnetic field. But to do that, we need a reference point for the direction of the rock when it was deposited. So we spend a lot of time recording with compasses and marking the rocks with sharpies so we’ll be able to test accurately later on.

Another question you may have is “what if you don’t find any big enough rocks to take as oriented hand samples?” It’s a good question, and this time out we got to test another sampling method, where we hammered a little plastic box into the fine grained material and took an orientation of it (see picture above) in order to get a sample. It will be interesting to see if it works. We also found some little charcoal bits for the first time, which should be helpful.

After some pretty lousy weather on the first day, we got much better conditions on day two. Here, we found some good outcrops right along the road to ample, which meant we could test out our drill. Vroom vroom!

We only tested a couple times, but we drilled two useful cores. Funny thing was, the drill was tough to get started…but then once it got going we couldn’t get it to shut off! A Hanukkah miracle! Eventually we just had to remove all the fuel and let it run itself down.

After finishing fieldwork on the second day, my supervisor took off for home, and I went to do the actual purpose of my trip–the talk at the museum. Basically, I got to do my proposal defense, but slightly longer and for a broader audience. It was quite fun, a good chance to get to talk to people in the area and get their perspectives on the volcano. And of course a great chance to screen Geology: The Movie (provided here for your education and entertainment just in case you haven’t seen it or want to watch again).

When I finished with that, it was time to celebrate. Fancy dinner? Chill on the beach? Nah, how about we climb a volcano instead?

I took a drive around the northeast side of the volcano to a place where you can actually drive a decent ways into the park to the North Egmont Visitor Centre. As I got closer I willed the small bits of clouds that remained in the sky to drift away. “Show yourself, you majestic fucker!” And show himself he did.

From the visitor centre I started off on the summit track. While my field area is on the western side of the volcano, this is probably the easiest route to the top, and I imagine this is the way we go when we get around to doing fieldwork at the summit. For this trip, I wasn’t intending to go all the way up and back, that takes a full day. I just wanted some quality time with just me and Taranaki and to see how far I could get in an hour or so.

The track (as far as I took it) is well paved and easy to follow–that’s not to say it isn’t quite steep and strenuous all the same. And that’s the easy part! I got pretty high up, almost to the bottom of the volcano itself, but it’s quite the climb to get to the top. Still a bit too much snow to do it at the moment, as well, but hopefully I’ll get back there in January or February when things are clearer.

That just left me with a little more fieldwork to do on the final day before driving home, as well as one important pit stop on the way home.

With that, I’m done with fieldwork for the year. After wrapping things up at the office, I’m off on a holiday visit from my parents and a whirlwind tour around both the North and South Islands.

Have a good end of the year everyone, see you in 2016!

Fantastic Volcanoes and Where to Find Them, Part 2

I hope you like maps.

The week after my return to Ruapehu was an exciting milestone in my PhD. It was the first time going to see the volcano that I’ll be doing the vast majority of my work on. We’d had to cancel trips already, but a small window of good weather had opened up at the end of the first week of June, and we decided to take advantage.

As I mentioned previously, the days are short right now so if you don’t start early it’s hard to get much done while it’s still light enough to see the outcrops you’re looking for. And with the Taranaki region a 4-5 hour drive from Auckland (about halfway between Auckland and the bottom of the North Island), it would be hard to get there and get field work done on the same day. We remedied this by leaving at 4am (uffa!), meaning we still had a full day to check stuff out after we arrived.

Since we were in a hurry to get down to the volcano (and it was dark for a lot of the trip), I didn’t get to take any pictures of the countryside, but it’s really pretty, and I’ll go back sometime just to look around at a more relaxed pace. Once we got close, sort of as you come around the turn onto the Taranaki Peninsula, we could see Mt. Taranaki off in the distance across the water. I was told this is pretty lucky–many people don’t get any good views of the mountain on their first trip there, especially this time of year. It was quite a nice view. I didn’t take a picture. Then we went closer so I could formally introduce myself (How do you formally meet a volcano? Maybe just find a cool looking outcrop and high-five it? I think I will do that next time I meet one.).

Now, according to Maori legend Taranaki was a great being that was brave enough to fight Tongariro (one of the NZ’s other major volcanoes) over the island’s one female volcano, Pihanga, in a great battle. When the battle ended, Pihanga chose Tongariro, so Taranaki moved far away to where it is today (which explains why it off by itself far from the North Island’s other volcanoes). This story is important because it will help you understand just how terrifyingly intimidating our group was when I tell you that as soon as we got closer, Taranaki hid in a cloud and didn’t come out for pretty much the entire rest of the trip.

Since we’re on a map binge, here’s one more just to get you acquainted with the landscape surrounding Mt. Taranaki.

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Pretty cool, innit? Mt. Taranaki is located in the center of Egmont National Park (Mt. Egmont is the volcano’s other name), which forms a near-perfect circle of forest surrounding the volcano. The little bit of dark green extending to the northwest is the lineament on which Mt. Taranaki and all the older, extinct volcanoes that were active before Mt. Taranaki formed lie. The forest stops abruptly at the park’s edge, and lots of farmland begins, full of endless green hills and mounds. Due to weather and time constraints, we decided to leave the higher elevation areas of the park for another time. Instead, we took a tour counterclockwise around the more distal parts of the peninsula (starting at New Plymouth), stopping to see interesting things and planning future trips.

Are you ready for some FOOTBAAAALL science?

We started by looking at the oldest known deposit from Mt. Taranaki slightly northeast of New Plymouth, called the Motunui deposit, which is likely over 130,000 years old. It’s what is called a debris avalanche deposit, basically it’s a massive amount of boulders and sand and everything in between that came crashing down the mountain when part of the volcano collapsed. Also, it didn’t contain very much water, it wasn’t a mudslide (remember that, because it’s important).

We made a stop at another beach farther west to look at the Okawa unit, a slightly younger debris avalanche.

After a quick stop in New Plymouth, the region’s (far and away) largest city (~70,000 people) we moved on to the northwestern-most part of the peninsula to see the Sugarloaf Islands. They’re all the remains of the region’s very first volcanic structures from over a million and a half years ago.

Our next point of interest was the Stony River (also called the Hangatahua River), one of the largest rivers running from Mt. Taranaki to the coast where I will be doing much of my mapping and sampling. Unlike volcanic ash and other explosive deposits which are usually very light and can go anywhere (affected by factors like wind direction), lahars (volcanic mudslides) which I study are mostly driven by gravity. This means that they tend to always flow downhill into and through the lowest areas. That’s why riverbeds are generally the best place to study lahar deposits. Some of the hiking in this area required a lot of bushbashing, a down-under term for forcing your way through dense vegetation instead of taking a trail. There’s quite a lot of forest in Taranaki, so I plan on doing a lot of this during my research.

Then…another trip to the beach to check out another huge debris avalanche deposit. The tide was coming in, so we had to move fast!

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The next day we continued our tour, driving all the way around the peninsula along the coast from New Plymouth and back around. We stopped at a bunch more potential research sites (which I’m sure I’ll cover in future posts) and got to check out more of the landscape.

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After all that science, I think you deserve a photo of a volcano.

When we had driven around most of the volcano, we decided to drive up into the national park. Unfortunately, it was still really foggy at this point, so we really didn’t see anything. It was a bit disappointing, and we were about ready to drive home at this point. It was a bummer to not have gotten a close-up view of Mt. Taranaki, when suddenly, he mustered up the courage to show himself!

Good to meet you, sir. We’re going to be seeing a lot of each other for the next few years, so I hope we can be friends!

And then we were on our way back. We’ve already got some good plans for the next trip, so it’s just a matter of finding some good weather that lines up with people’s schedules. Hopefully that happens soon!