Wednesday, December 30, 2015

Podcast: Lava in the Lab

From prodding streams of lava, to molten rock poured in the lab, to miniature flows made of analogue materials, there are many ways to study this red-hot force of nature. Today’s podcast joins planetary scientist and volcanologist Dr. Elise Rumpf on a deep dive into the physics of lava flows, from the field to the lab.

Because the composition of each individual lava flow depends on what happened to it on its way up to the surface, studying these rocks can tell us what’s going on far below our feet, and the volcanic history of a region can offer clues to the future.  The composition of each lava also influences the flow patterns, textures, and structures that it leaves behind, since viscosity — or the lava’s tendency or resistance to flow — depends strongly on the silica content.  Basaltic lava flows, like those currently active on the Big Island, tend to flow more readily, while andesitic or rhyolitic lavas contain more silica and have a higher viscosity as a result.

Running experiments in the field can be unpredictable, which makes laboratory experiments an attractive option — but how do you bring lava to the lab? It turns out that art has as much to do with it as science, at least for the Syracuse University Lava Project, a collaboration between Assistant Professor of Art Bob Wysocki and Professor of Earth Sciences Jeff Karson.  Lava researchers like travel to Syracuse from across the country to run experiments at the facility, which is capable of handling 800 pounds of lava in a single pour.  You don’t have to melt rocks to study lava in the lab, however.  Analogue materials, such as corn syrup or polyethylene glycol, can go a long way toward revealing how their scaled-up lava counterparts behave under different conditions.  Whether it’s in the field or in the lab, lava is a hot topic, and researchers don’t have to look far for inspiration.  “It's really just exciting to be in the presence of an active lava flow or a recently emplaced lava flow,” says Rumpf, “Just to be able to see new rock being created, or see a piece of land that was never there before...that’s just a really cool concept.”

—Podcast and Post by Meg Rosenburg

1 comment:

  1. Watching rocks cool, sounds like an interesting profession. I think it's cool to look at rocks and I do it as a casual hobby. I have some rock piles around my home. The rocks that catch my eye have been tossed around in a Vermont river for a period of time lasting many many years (I don't actually know). Panning in streams has yielded nearly 50lbs of black sand which is magnetic powder. Put some black sand in a jar with water, apply a magnet to the outside of the jar, and the black sand forms along the magnetic lines of force in a really nice display. A person can use a small bucket to pan black sand from a river or stream, if it can be found in the local area. The technique is similar to using a pan but requires a little more work while shaking it and washing away the over burden. When the bucket with a dirt sample is shaken with the right amount of water for a period of time, to settle apart the aggregate, and carefully the top over burden is washed away, the work leaves the heavier material in the bottom of the bucket along the ridge corner. Since I had a gold pan, I used it to further process the bucket filtrate to filter and separate the black sand. Another easy way to get the back sand is to use a magnet placed into a plastic bag, old tin can, or a jar and then drag the magnet lightly across the dirt of a bucket sample to collect the black sand that sticks to the magnet. Carefully remove the magnet from the plastic bag, or container, so as to release the magnetic dust onto a collecting device. If the activity is done correctly, no dust will collect on the magnet and the dust is filtered into a pile. With the right tools and materials a person can construct an automated way to filter black sand from over burden with a home made sluice or home made blue bowl, or just buy one. A blue bowl can filter different size particles of black sand, fine to course.