Rock Pride E-Newsletter

CORE OF THE MATTER: Levi Markwood, a Slippery Rock University geology major from Sandy Lake, collects core samples of rock outside Thunder Bay, Ontario. He extracted the samples for a student-faculty research project on continental rifting (Photo by Michael Zieg, associate professor of geography, geology and the environment).

Geology majors earn honors
for rifting research in Canada

SLIPPERY ROCK, Pa. - Geologists who want to learn more about how continents moved in the past drill a steel cylinder into the ground and examine the extracted material, like pushing a straw into a cake. Two Slippery Rock University geology majors have been honored for their award-winning geology research with Michael Zieg, SRU associate professor of geology, which focused on continental movement, called "rifting," in Ontario, Canada.

Students collected core samples of rock from the Nipigon sill - a sheet of solidified molten rock - and examined crystals in the igneous rocks to determine how they cooled 1.1 billion years ago. Understanding the cooling process sheds light on the geologic processes involved with the movement of continents, the students said.

"This has been a valuable experience because it has opened my eyes to a field of science that I knew very little about a year ago," said Andrew Ryan, a geology major from Slippery Rock. "It has enabled me to develop my research skills so that I may continue to produce more accurate and meaningful results during my future research-related endeavors."

Ryan presented his research at the 56th Annual Institute on Lake Superior Geology conference in International Falls, Minn. He won the Best Student Poster Presentation Award. Levi Markwood, a geology major from Sandy Lake, won Best Student Paper at the Pittsburgh Geological Society conference for his abstract on rifting.

"Presenting is a great way to get out and network with professionals in my field," Markwood said. "It also provides the opportunity to get feedback from those people, often providing insight on how to make a project better."

The Nipigon sill, located on the northern shore of Lake Superior, is part of the Midcontinent Rift system extending from Kansas into Canada. Geologists say the sill was formed when North America began to split apart 1.1 billion years ago, but the rifting process was aborted before the split was complete. Students studied two different sills and found visible evidence of the rifting process.

They used microscopes in the Advanced Technology Science Hall to study crystals in the rocks they brought back from Canada to learn more about the cooling process. As magna cools, minerals crystallize. The slower it cools, the more time crystals have to grow larger, so studying crystals provide a window into the cooling process, said Markwood. Students concluded that the smaller intrusion cooled in a week, and the larger one over thousands of years.

"The initial goal of this research project was to determine the mineralogy and overall chemical composition of the Nipigon sill rock and use the information to determine the process of magna injection, cooling and crystallization," Ryan said. "The department of geography, geology and the environment has sections of the 266-meter thick core sample. From these sections, we prepared about 30 microscope slides and examined the sill's mineralogy."

Their other conclusion is that the larger sill was emplaced by a series of magna injections. "Additionally, we are confident that we possess core samples containing a silicic segregation vein about 220 meters above the base of the sill," he said. "We plan to conduct an in-depth examination of this segregation vein this year so that we may determine the manner of movement and course of the magna from which it formed."

Zieg said it's difficult to determine why the rifting aborted, but his students learned a lot about the process that takes place during rifting. "It doesn't necessary sound exciting to the public, but for a geologist, pining down exactly how these big magna bodies form is pretty exciting," he said. "It's particularly neat that you can take tiny crystals and use that to tell the history of the crust when it split apart a billion years ago."

Both students aspire to careers in science. Ryan said he wants to study planetary science and obtain a doctorate so that he can continue his research, "Hopefully with future robotic or manned missions to the planets and moons in our solar system. I choose not to set the sky as my limit."

Markwood said he wants to find a job in the mineral exploration industry. He spent a month in Minnesota last summer completing a field camp that focused on geophysical data collection and interpretation.

Zieg said the Canadian fieldwork helped them develop as scholars.

"I kind of stepped back. I let them take the samples and let them decide where they're going to get rocks to try to characterize the process so that they got to see what it's like to design a geologic investigation. They prepared the samples and they analyzed the samples and interpreted the results, so they went through the whole process."

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