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The worm turns

By Kelly Foss

What can a worm tell you about where to find oil? Quite a bit if you are a member of MUN’s Ichnology Research Group (www.ichnology.ca).

Working with Dr. Duncan McIlroy, a professor in the Department of Earth Sciences, postdoctoral fellow Liam Herringshaw has been studying the burrowing habits of worms, shrimp, snails and clams and how their actions influence their environment.

With a lab full of “the oddest aquariums in the world,” Dr. Herringshaw has been watching these animals to determine what similar creatures may have done millions of years ago.

“Burrows can have a large impact on the properties of sediments,” he explained. “By understanding burrow systems, we can start to get a better idea of where fluids will travel once that sediment has turned into rock. If you project that out on a reservoir scale, information like that is quite important for oil companies who want to know where hydrocarbons are going to go.”

Dr. Herringshaw recently presented his work at the International Paleontological Congress in London, U.K. A paleontological conference might seem an odd place to talk about research involving living animals, but understanding ancient behaviour is impossible without studying what’s going on at the present day.

Dr. Herringshaw presented the techniques the group is using to visualize the structures and sedimentary impact of burrows, both modern and ancient.
These range from putting aquarium tanks through a CT scanner to see what burrows living animals have made in the sediments, to serially destroying large blocks of burrowed rock using high-tech grinding equipment.

“We grind away the rock in very tiny increments and every time we take off a layer, we take a high resolution photograph,” he explained. “Later we can reconstruct the burrow in 3D, showing in amazing detail the impact it has had on the sediment. Destruction of the rock may seem excessive, but you can’t otherwise get the detail we need, even with high resolution scanning techniques. However, we wouldn’t do it to a rare sample.

“It’s all very experimental and no one has ever done it before, but it’s yielding some very impressive results,” he explained. “People have serially ground up fossils, but not burrows, and the idea is that, by destroying one, it will help us understand lots of others.”

At the same conference, Dr. Herringshaw also gave a talk looking at the Cambrian Explosion through the eyes of burrowing animals, using the Precambrian-Cambrian rocks of Fortune Head on the Burin Peninsula. The rocks there are the global standard for strata of that age, and preserve a changing suite of burrow types.

“Although we’ve got clear examples of ecosystem engineering in the modern day, going back in time it’s much harder to pin it down on a particular individual organism, so it might be more of a cumulative effect. By comparing what living animals are doing now with the different burrows that were preserved from these early parts of Earth history we can maybe start to unravel the way in which marine ecosystems evolved.”
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