Leaving the comfort of our heated rooms, we prepared for a day full of roadside adventures by packing our lunch, putting on our layers, and praying it wouldn’t rain. Between us two blog writers, today we wore 18 articles of clothing; not including hats and gloves! Gone are the days of simply walking out the door and into the van. Instead, we made the treacherous trek down a precipitous slope of boulders before snuggling into the van.
Our first stop for the day was a (you guessed it) roadside outcrop, off of Highway 47, north of Mt. Ruapehu. Donned with our essential hi-vis gear, we were able to diagnose ignimbrites from Taupo and a lahar and volcanic deposit that came from Mt. Ruapehu. The Taupo eruption left 7 layers of pumice. Some layers were very fine grained, while others had pieces of pumice up to 15cm. These large pieces were found in pockets rather than continuous layers. These layers sat on top of the darker Mt. Ruapehu deposit indicating the Taupo eruption was more recent. We learned about lahars, or large mud slides accompanying eruptions. In this particular instance, the Mt. Ruapehu lahar was strong enough to carry large boulders up to ~2 meters long.
After the outcrop, we fortuitously stumbled upon a quaint trailer park with a view like no other. Complete with a rusted trampoline and a friendly nearby horse, the park provided a wonderful view of Lake Rotoaira. By the end of lunch even the coldest of us hiding in the car was physically and spiritually warmed by the panoramic view, abundant sunshine, and ubiquitous PB&Js.
A short hour-long drive brought us to the other side of Mt. Ruapehu. After walking ten minutes through gentle streams and squishy surfaces, we arrived to a minute but geologically intriguing canyon.
Even after 45 minutes of close observations, the group was stumped on how this canyon came to be. In the end, the angularity of the scoria and andesitic rock coupled with the curtain-like draping of the layers across the surface led to the conclusion that it was a sequence of fall deposits from Mt. Ruapehu, just a few kilometers away. However, large chunks of pumice in nearby neat piles held another mystery. Our confusion subsided as we determined the deposit originated from a pyroclastic flow travelling all the way from Taupo (35 km away!!), weathering away in all but a few spots leaving select clusters of pumice-rich ignimbrite deposits.
The rest of the afternoon was spent doing an intriguing activity. Our task was to log the orientation of charcoal logs found in the area in order to determine the direction of pyroclastic flow. In pairs, we measured the orientation of many charcoal logs, burned by the Taupo flow deposit. In total, we measured over 360 fallen trees. We took this data back to our cozy ski lodge residence before charting Rose plots (radial histograms) as pairs, and then as a group. It was interesting to see that not only was there a strong mode in a South-South-West direction, but also there was a surprising perpendicular secondary mode as well, indicative that logs given enough momentum may have also rolled perpendicularly due to the pyroclastic flow.
We travelled to the Skotel for a pizza and pasta dinner before settling in for a restful night in preparation for another full day tomorrow!
Overall, we survived our first day on the frigid volcano and learned a mountain of new information! Even in the cold, geology rocks.
Jag & Mel
Our first stop for the day was a (you guessed it) roadside outcrop, off of Highway 47, north of Mt. Ruapehu. Donned with our essential hi-vis gear, we were able to diagnose ignimbrites from Taupo and a lahar and volcanic deposit that came from Mt. Ruapehu. The Taupo eruption left 7 layers of pumice. Some layers were very fine grained, while others had pieces of pumice up to 15cm. These large pieces were found in pockets rather than continuous layers. These layers sat on top of the darker Mt. Ruapehu deposit indicating the Taupo eruption was more recent. We learned about lahars, or large mud slides accompanying eruptions. In this particular instance, the Mt. Ruapehu lahar was strong enough to carry large boulders up to ~2 meters long.
After the outcrop, we fortuitously stumbled upon a quaint trailer park with a view like no other. Complete with a rusted trampoline and a friendly nearby horse, the park provided a wonderful view of Lake Rotoaira. By the end of lunch even the coldest of us hiding in the car was physically and spiritually warmed by the panoramic view, abundant sunshine, and ubiquitous PB&Js.
A short hour-long drive brought us to the other side of Mt. Ruapehu. After walking ten minutes through gentle streams and squishy surfaces, we arrived to a minute but geologically intriguing canyon.
Even after 45 minutes of close observations, the group was stumped on how this canyon came to be. In the end, the angularity of the scoria and andesitic rock coupled with the curtain-like draping of the layers across the surface led to the conclusion that it was a sequence of fall deposits from Mt. Ruapehu, just a few kilometers away. However, large chunks of pumice in nearby neat piles held another mystery. Our confusion subsided as we determined the deposit originated from a pyroclastic flow travelling all the way from Taupo (35 km away!!), weathering away in all but a few spots leaving select clusters of pumice-rich ignimbrite deposits.
The rest of the afternoon was spent doing an intriguing activity. Our task was to log the orientation of charcoal logs found in the area in order to determine the direction of pyroclastic flow. In pairs, we measured the orientation of many charcoal logs, burned by the Taupo flow deposit. In total, we measured over 360 fallen trees. We took this data back to our cozy ski lodge residence before charting Rose plots (radial histograms) as pairs, and then as a group. It was interesting to see that not only was there a strong mode in a South-South-West direction, but also there was a surprising perpendicular secondary mode as well, indicative that logs given enough momentum may have also rolled perpendicularly due to the pyroclastic flow.
We travelled to the Skotel for a pizza and pasta dinner before settling in for a restful night in preparation for another full day tomorrow!
Overall, we survived our first day on the frigid volcano and learned a mountain of new information! Even in the cold, geology rocks.
Jag & Mel
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