My geoscience journey - Hilde Koch

I’ve been passionate about Geoscience and have had a special interest in volcanoes for 15 years. Four years ago, I was very lucky to start a PhD position that involves volcanology. My PhD research project deals with the correlation of ash beds; ash that erupted from volcanoes and settled down (geologists call this being deposited) in thick sheets that formed rocks. The ash beds I study were deposited in the Irish Midlands by volcanoes 350 Million years ago. But so far it is unknown, if there were several eruptions from different volcanoes, or if there was only one big eruption. Luckily, these ash beds have a specific geochemical pattern, comparable to your own personal fingerprint. Correlation of ash beds means to link ash layers with the same fingerprint as they most likely stem from the same volcanic eruption. Volcanic ashes also contain distinct minerals, which are called apatite and zircon. Apatite can be also used to characterise unique layers, whereas zircons yield very precise eruption ages. Both of these tiny minerals help me to correlate the ash beds that are older than the dinosaurs!

Geoscientists observe currently active and dormant volcanoes (we call these modern analogues of past volcanoes) to figure out how ash layers were deposited in the past. Studying modern analogues to make assumptions on past processes is one of the principles applied in geology, which is also called uniformitarianism. Thus, as a geologist, you will spend a lot of time in the field, investigating current processes and apply them to the past. This has allowed me to visit lots of fantastic places, like Mount Etna in Sicily and Cotopaxi in Ecuador!

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