by Jeffrey A. Karson and Robert J. Wysocki Friday, August 17, 2012
Picture this: You’re walking across the tree-lined quad of Syracuse University, amid brick and stone buildings, when you happen upon a crowd of people. Crowds on the quad aren’t unusual, but this crowd is unusually diverse — students, professors and even parents with kids. You move a little closer and smell something odd: a blend of sulfur and marshmallows. Then you see it — molten lava pouring down the slope of a parking lot.
This is our brainchild, the Syracuse University (SU) Lava Project — a unique mix of science, art and education that we developed to investigate the physical properties, aesthetics and educational opportunities of creating basaltic lava flows in a controlled— albeit outdoor — laboratory environment.
Chunks of basaltic rock, similar to that found on the seafloor and in Hawaii and Iceland, are melted and poured to produce natural-scale lava flows up to a few meters long. In addition to facilitating scientific experiments that engage faculty and students at SU and volcanologists from other institutions, the project also supports artistic creations and engages the public, providing formal and informal educational opportunities.
In between experiments, we occasionally let kids roast hot dogs and marshmallows over the hot lava. But the main goal of the project is to study basaltic lava.
Basaltic lava flows — including the frequent and very visible eruptions in Hawaii, Iceland and Italy — constitute the most common and voluminous volcanic outpourings on Earth and the terrestrial planets. Basaltic lavas also dominate Large Igneous Provinces in the oceans and on the continents, such as the Columbia River Basalt Group, which covers parts of five Western states, and the Siberian Traps, which likely contributed to the Permian-Triassic extinction 252 million years ago.
Over geologic time, the most voluminous volcanic eruptions occur out of sight along mid-ocean ridge systems as the seafloor is continuously repaved with basaltic lava. Despite the significance of basaltic flows, many questions remain regarding the behavior of the lava.
Part of the reason that the understanding of basaltic lava flows remains so limited is that active lava flows are seldom witnessed up close; they tend to be inaccessible and erupt without much warning. Plus, flowing lava as a general rule can be dangerous. For volcanologists, these unscheduled and uncontrolled “experiments” provide an important observational database, but only within the limits of nature’s whims. Thus, it is difficult to constrain the key parameters that influence the behavior of lava — everything from composition (especially silica content), dissolved volatiles and crystallinity, to temperature, flow rate, slope and what material the lava flows over.
Geologists turn to features like the overall shapes and surface textures of lava flows to interpret how lava behaves. Based on Hawaiian lava flows, the terms a’a and pahoehoe have been widely used to describe jagged, blocky lava and smooth, lobate to sheet-like lava flows, respectively. Scientists also employ numerical models and analog experiments (using wax or syrup, for example) to provide a framework for understanding the behavior of basaltic lava flows.
Previous attempts have been made to melt basaltic rock and pour lava under controlled conditions in order to better understand the influence of the natural parameters. In one early experiment, for example, famed geologist James Hall used a blacksmith’s forge to melt basalt to make small lava flows in the 1700s. Since that time, most scientific investigations have used only very small amounts of lava (a few ounces) to measure various properties. But applying the results on such tiny samples to natural-scale lava flows is a challenge, to say the least.
Pouring lava for artistic and scientific projects is an opportunity to bridge the gaps between natural lava flows, experiments on tiny drips of lava, analog models and theory.
We start with commercially available crushed basalt gravel from the Mid-Continent Rift in northwestern Wisconsin. This material is 1.1 billion years old and originated from lava flows similar to those of the modern seafloor, the East African Rift, Iceland or Hawaii. We load the crushed basalt into a natural gas-fueled, tilt furnace — originally designed for pouring molten metals — that is heated to 1,200 degrees Celsius. The bathtub-sized crucible can hold up to 800 pounds of molten basalt. The lava is heated for several hours to produce a homogeneous, convecting magma. After the lava is poured, it can often be collected, “recycled” and poured again.
Our first experiments were in mid-January 2010 with relatively small lava flows. During these initial trials, we refined the melting and pouring process and conducted basic tests involving flows consisting of a few tens of pounds of lava poured manually from a moveable crucible. As word of the project spread, SU classes, student groups, and crowds of interested visitors began to show up for these events.
By late spring 2010, with financial support from the SU administration, we had acquired the much larger furnace we use today. The first flow of about 200 pounds of lava took place in May 2010. Since that time, the volumes of lava poured have risen steadily to more than 800 pounds and the experiments entered a new phase, producing a wide range of flow morphologies and other features that closely mimic those found in nature and at a scale comparable to natural lava flows. More recently we began using a coke-fired furnace capable of creating a nearly continuous flow, limited only by the starting material available. Although lava is created for some industrial applications, to our knowledge, experiments on this scale are not being done at any other research facility.
One of the main factors controlling the behavior of lava is its composition, particularly the amount of silica it contains. To eliminate composition as a variable, we have used a single lava type in our experiments (so far) — the Wisconsin basalt. This material is well characterized from previous geological studies, relatively uniform in composition and texture, and only moderately altered, despite its age. In the future we expect to pour more silica-rich basaltic andesites, typical of subduction zones; very magnesium-rich komatiite, similar to lavas that erupted early in Earth’s history; and carbonatites, exotic carbonate lavas.
To date, more than 50 lava flow experiments with more than 100 individual flows have been conducted and have given us stunning results (see story below ).
Engaging students is a large part of our project, as nothing compares to experiencing a real lava flow. We have many opportunities to interact with students before, during and after our lava pours, which stimulate the imagination and trigger many scientific questions. Large poster panels with pictures and diagrams show natural lava flows on land, the seafloor and other planets and provide context; the posters also provide opportunities to point out interesting features and hazards as they form in the lava.
Some of the topics that we have discussed during our lava pour events include: crystalline versus glassy material; nucleation and growth of crystals; solid versus liquid states of matter; viscosity and its relation to temperature; cooling of materials; convection versus conduction; rheology; and heat capacity. Students can also view videos of previous pours or do a wide range of classroom experiments with analog materials to enhance the experience. Some of the most interesting activities occur when students propose their own experiments, usually as “what happens if …” questions. Often, we can address their curiosity right away by arranging to run their experiments “on the fly.”
There is a significant body of literature in education that emphasizes the importance of active or hands-on learning and its impact relative to reading or lecture presentations. Our experiments with student participation provide us with an opportunity to study the relative effectiveness of verbal descriptions, still images, videos and actual in-person experiences on student learning and engagement.
Beyond the science and education, the aesthetic qualities of molten and solidified lava provide an added dimension to the project, with the potential to excite and inspire a remarkably wide range of spectators. The spectators commonly include clusters of children, college students, artists, reporters and scientists — groups that do not commonly intersect. Kids roast hot dogs and marshmallows over the stationary lava as it cools, learning about cooling and solidification of natural materials in the process. Adults learn how scientific investigations are carried out and how both systematic studies and serendipity can play a role in transforming academic investigations into applied results.
There is an inherent beauty to the lava as it flows and solidifies. The lava experiments permit sculpture students to create works of art by pouring lava into molds and onto a variety of surfaces. One of our (Wysocki’s) major goals of the program is to create large-scale, geomorphically accurate, lava flow fields, tens of meters across. From a practical standpoint, we hope to be able to create lava flow structures that can be preserved for display in schools and museums. We can apply what we learn of lava behavior in our experiments to develop improved methods for creating both display works and works of art. For example, in some recent pours, we have found that inserting metal rods into the flow helps reduce uneven cooling and contraction that leads to thermal cracking. This will allow for more robust pieces to be produced for display purposes. On all scales, the art and science in the project contribute to one another.
Although textbook images, videos and the Internet provide one kind of experience, there is nothing quite like seeing a molten mass of incandescent, orange basalt, heated to more than 1,200 degrees Celsius, as it flows and forms complex shapes and patterns. Souvenir pieces of lava are available to everyone and serve as lasting reminders of the notion that mixing science, art and education can lead to glowing results. For students, teachers and the general public who cannot go to see a natural lava flow, we are bringing the volcano to them.
Beware though: This unforgettable experience may leave you with a case of “red-rock fever,” an intense fascination with molten lava.
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