Dr. Lloyd in the field

Did you know that we have a volcanologist in our Hun community? 

That’s right. Dr. Alex Lloyd, who is a chemistry teacher here on campus, is also a respected geochemist and volcanologist. In fact, just recently, a research publication which he co-authored was published by Frontiers in Earth Science. 

This publication, titled “Magma Pressure-Temperature-Time Paths During Mafic Explosive Eruptions” answers the grand question of what happens to the temperature of magma as it ascends to the surface. 

Since 2014, nine volcanologists, including Dr. Lloyd have collaborated on collecting samples, taking measurements, analyzing melt inclusions, and gathering research to answer this question. 

Dr. Lloyd’s contribution to the research paper are the samples and measurements of two historic eruptions; the 1974 eruption of Volcán de Fuego in Guatemala and the 1981 eruption of Seguam volcano in Alaska. 

For several years, Dr. Lloyd spent hours at a time in the lab, breaking down the rocks that were gathered from the two eruptions into individual mineral grains to begin studying. Once the samples were finely polished, they were analyzed using laser beam technology to learn the composition of each mineral grain. For this work specifically, Dr. Lloyd focused on the elements magnesium and iron to tell him what he needed to know about the sample.

To begin explaining the research that was conducted for the publication, Dr. Lloyd starts by debunking a common theory. He notes that when magma is at depth, it is around 1800 to 2000 degrees Fahrenheit, and the general assumption is that when the magma ascends towards the surface of the earth, which is much cooler, the temperature should cool down. But, Dr. Lloyd explains that isn’t the case. In fact, the temperature of the magma doesn’t change very much at all. 

And for those who may not understand, Dr. Lloyd breaks it down with a helpful food analogy. 

“It’s like if you roast a turkey and when it’s done you turn the oven off but keep the turkey in the oven, and the turkey stays the same temperature even though the oven is cooling down.” he says. “You would think it would cool down because the surrounding temperature is cooling down. Similarly, when a volcano erupts and magma ascends out of the extremely hot magma chamber to the less hot earth’s surface, you would think it would cool down, but it actually stays the same temperature.” 

Dr. Lloyd explains that although he knew that this was most likely the case, it is not something that is easily measurable to prove accurate. 

“We can’t just go into the magma chamber with a thermometer and have our answers. So in order to answer that question, we need to use these proxies of crystals and melt inclusions in order to look at that. The grand result of this research paper is that there is a new tool that we can use to track magma on its way to the surface.”

As a volcanologist, Dr. Lloyd says that the reason he loves this type of work so much is because it’s a challenge to measure something that is simply unmeasurable.

“As a volcanologist, we are like investigative scientists,” he said. “We aren’t there watching the crime occur, but we go to the crime scene afterwards and we try to piece together what just happened at these unimaginable temperatures deep below the earth’s surface to make this happen.” 

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