Seriously, Science: What lava flows can tell us about Earth’s history

A graphic of a volcano with a green, orange and brown gradient. There is a blue sky behind the volcano and a road at the bottom of the volcano.
Graphic by Catherine Ward

Most people remember creating a paper mache volcano or at least watching one “erupt” when they were younger. This seemingly simple activity shines a light on one of the most exciting and captivating parts of a volcanic eruption: lava.

But outside of elementary school projects, what can lava flows tell us about Earth’s history?

Joe Biasi, a geology graduate student at the California Institute of Technology, says they can tell us quite a lot. Biasi spoke at the geology department colloquium series talk in Pomona College’s Edmunds Hall April 19.

Biasi does research on certain lava flows that primarily exist in Oregon at the Columbia River Flood Basalts. The lava flows there carry information about what the world looked like thousands of years ago.

According to Michigan Tech, lava flows are “high volume eruptions that flood vast areas of the Earth, covering broad regions with flat lying lava surfaces.” These lava flows cover hundreds of square miles and can be extremely destructive to the land surrounding the point of eruption.

One of the most famous flood basalts is the one that Biasi studies. Researchers hypothesize that eruptions this strong do not occur often, but can continue to flow for years when they do.

When these eruptions occur, there is often a large release of gas, which can upset the atmosphere that allows life on Earth to flourish. Noxious gases such as carbon dioxide, sulfur dioxide, and hydrogen fluoride can lower the temperature of the atmosphere, which causes the earth to cool.

Sulfuric gas in particular can be converted into a gas that lingers and ultimately affects the temperature of the earth’s surface, according to Michigan Tech.

Because of the large volume of magma that comes from these eruptions and the gas that is released, these eruptions are linked to nearly every mass extinction that is recorded in Earth’s history. Flows such as the Deccan, Siberian and Newark flood basalts have been linked to mass extinctions, according to The Geological Society.

This is just one of many reasons that these lava flows are so interesting to geologists.

Biasi said there is no real way to know how long the lava flows last for, though it is possible to preserve another part of history within the cooled lava.

He discussed the ways that these cooled flows can preserve the magnetic poles of the Earth during that time in its history. Interestingly, while we may have never thought about north being anywhere but north, Earth’s magnetic poles do in fact change over time.

This can help researchers learn more about what the earth looked like at that time in Earth’s history and, subsequently, learn about future pole deviations. If we know about future deviations, we can learn about movement patterns that may take place and what that means for life on Earth in the future.

Biasi has used this very idea in his own research, where he has dated specific lava flows from the Columbia River Flood Basalt to learn more about how and when there were deviations in the magnetic poles from what we know now.

In the future, his research will include more of this same dating and will hopefully begin to uncover more about when these shifts occurred.

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Caitlyn Fick SC ’19 is TSL’s science columnist. She is a chemistry major who enjoys mountains, trees, water and dogs.

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