Fieldwork in the land of ice and fire

At the end of July Dr Katie Street and myself went back into the field to collect a new selection of samples from Iceland. This mostly involved driving through different regions of Iceland in a 4×4 truck to sample from different volcanic eruptions in the Eastern Volcanic Zone and the Reykjanes Penninsula. This was my second time going out for fieldwork in my PhD (see what we got up to last year).

The Goal:

glassy rim

Figure 1: Pillow lava with glassy rim containing olivine and plagioclase

Katie and I both work with sub-glacial erupted glassy rims from pillow lavas. These are formed from volcanic eruptions which take place beneath an ice cap. When the lava comes into contact with the cold ice it is cooled so rapidly that it forms basaltic glass around the edge, with pillow lavas forming inside. This rapid cooling means that volatile elements are less affected by degassing in the glass rim than the rest of the rock. Katie works on noble gases and I work on halogens, both volatile elements, which is why we samples these glasses.

Getting about:

Iceland’s interior roads are typically gravel tracks making a 4×4 vehicle essential. In addition to driving on uneven surfaces drivers often have to travel through streams or small rivers:

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Figure 2 – Driving through a river to get to samples

Driving in Iceland makes for some cinematic views, be it driving through lava fields, past glaciers or the famous beauty spots which attract many tourists to the country.

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Figure 3 – Skogafoss waterfall, a popular tourist spot on the south coast of Iceland

Accommodation:

As our fieldwork involves a lot of sample collection we are always on the move, rarely staying in the same place for more than a night and sometimes heading out to relatively remote locations. Thankfully camping is popular in Iceland with many locals exploring the country in the summer, meaning there are lots of campsites for us to stay at. Sometimes there is the extra luxury of a hut where we can cook indoors. It takes a bit of time to get use to sleeping in almost 24hr daylight but it gives us lots of time to enjoy the views.

The country’s volcanic setting can also be useful during camping as lava flows can provide a welcomed wind break:

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Figure 4 – Camping beside an old lava flow

These picturesque lava flows also have a special place in Icelandic folklore. The mossy rocks you can see in the picture are known as ‘elf hills’ and are the home of the Icelandic elves – the Huldufólk (hidden people). The magic beings are thought to be mostly unseen, living lives like us, but may come out on New Year’s Eve and Midsummer’s Night. It is important to respect them and their homes as they can cause you harm if you disturb them. Roads have been diverted in the past to protect elf communities.

Back in the lab:

Now we are back in Manchester we will be working to analyse our new samples. The samples are crushed and glass chips are separated for Katie to analyse their noble gas content in a mass spectrometer in one our labs. I will separate the crystals in the glass samples and look for melt inclusions inside them. These are tiny droplets of melt which become trapped inside the crystal as it grows in the magma. They are very useful as they trap bits of the magma as it evolves and mixes with different sources. Therefore I can look at multiple mantle sources which have been trapped by the crystals and get more information about the magmatic systems of Iceland than the final lava that erupts could give. Using an electron microprobe and secondary ion mass spectrometer (SIMS) I will analyse the chemical composition of the melt inclusion, focusing on the halogen content.

melt inclusion

Figure 5 – a melt inclusion with an olivine crystal

Iceland is a great place to work as a geologist. With so much volcanic activity and it’s unique setting on top of the Mid-Atlantic Ridge and a mantle plume it remains a popular location for volcanologist and geochemists to work in a ‘natural laboratory’. I hope to get out and explore the country more and continue working its exciting geology, Iceland is certainly one of my favourite places in the world.

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Figure 6 – Columnar basalt

Takk fyrir að lesa! (Thanks for reading!)

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