Paying the Geologist Tax

When you travel to a volcano with a geologist, there are days that are going to be about rocks. Like, lots of rocks.

(before we get into the day – all the comments for this trip were gummed up in WordPress, I wasn’t trying to censor anyone!)

We planned a shorter day today, both because yesterday was a big hike, and because tomorrow’s hike starts at 3:30 in the morning. We didn’t cut short our “flopping around with coffee in the sunrise” though, nor did we skip a walk to the bakery for pastries. I mean, some things are sacred.

By around 9:30 we hit the road for the eastern side of the island. This is where the most recent eruptions have taken place – as recently as last summer. There’s a lot less development on that side, for obvious reasons. Our goal was to explore the site of the bigger 2007 eruption, which took out the highway and spewed lava down to the sea.

Our hike started out with a mild diversion, looking for a lava tube marked on the map. After slipping and sliding the wrong way, we eventually found the (collapsed) tube, which was somewhat less than spectacular. Then we set out on the real hike!

The trail started with a nicely paved descent, before ending at a sign with a lot of French writing and a picture of a person with a red X. Since we don’t speak French, we walked around the sign and kept going.

Before long, we were on the lava field. And here, we turn the blog over to the rock nerd…

Hi, it’s me. I’m the problem. It’s me.

In my defense, they were some VERY sparkly rocks. Why are they so sparkly you ask? Olivine! The black lava rock formed by the 2007 eruption was a picrite basalt with extremely high olivine content. Olivine is a green mineral which you may know by its gemstone name peridot (hello August babies!). It also happens to be one of my favorite minerals. When minerals grow in a magma they tend to settle out to the bottom of the magma chamber and accumulate. When that magma erupts at a volcano as lava, the resulting rock is full of beautiful green crystals. This particular rock is so high in olivine (over 50%!) that it has a special name – oceanite, which was first described at Reunion in 1923. So yes, there was much oo-ing and ah-ing and many tiny sparkles slipped into my pocket. Ok, back to your regularly scheduled programming.

Way more interesting was the shipwrecked Tresta Star, which is slowly being reclaimed by the sea. The ship made some unreal noises when waves hit it just right. A very large part of me wanted to climb on board, but I chose life. The hike itself was like walking on another planet. A very, very sharp planet. The kind of planet where, if one of you is prone to looking at rocks instead of their feet, they might fall and end up with some nasty cuts. That kind of planet.

The hike ended with a not-really-that-steep ascent back to the car. We drove home, got gas for tomorrow, and set about getting ready to get in the car at 2am for the drive to our hike.