September 11, 2008

College Geoscientists to Present Research

By Jeanine Kendle

WOOSTER -- Three faculty members and two students from The College of Wooster will join more than 10,000 other scientists at the first joint meeting of the Geological Society of America, the Soil Science Society of America, the American Society of Agronomy, the Crop Science Society of America, and the Gulf Coast Association of Geological Societies.

Mark Wilson, the Lewis M. and Marian Senter Nixon Professor of Natural Sciences and Geology; Greg Wiles, associate professor of geology; Meagen Pollock, assistant professor of geology; and Caitlin Fetters and Michael Krivicich, senior geology majors from Westlake and Athens, respectively, will present their recent research at the George R. Brown Convention Center in Houston on Oct. 5-9.

Wilson will make two presentations. The first, titled "The Upper Ordovician of the Cincinnati, Ohio, Region: A Natural Laboratory for Studying the Sedimentological and Biological Effects of Calcite Sea Chemistry," describes the rich paleontological and sedimentological features of this region, which were controlled by unusual seawater chemistry about 450 million years ago.

Wilson and his colleague, Tim Palmer of The Palaeontological Association, show the fossils near Cincinnati can be used to demonstrate early aragonite dissolution and rapid calcite cementation at this time. This is not the case in today's oceans.

Wilson's second presentation, titled "The First Macroborings Known from Quartzite Substrates: Trypanites in Boulders from the Upper Cambrian Deadwood Formation, Black Hills of South Dakota," is the first description of significant bioerosion of this siliceous material, and one of the few examples of bioerosion in the Late Cambrian (about 520 million years ago).

Wilson and his colleagues Markes Johnson of Williams College and Jack Redden of the South Dakota School of Mines and Technology say they aren't sure how the boring took place, but they hypothesize that ancient organisms used a micro-boring technique to exploit surfaces already chemically bioeroded by microorganisms.

Wiles will update his research on climate change when he presents "Alaskan Tidewater Glacier Response to Climate Change during the Medieval Climate Anomaly." Wiles, who was joined by fellow geologists Lawson Daniel of the Cold Regions Research and Engineering Lab, David Barclay of the State University of New York in Cortland, and Thomas Lowell of the University of Cincinnati, will attempt to explain how glaciers continued to expand during a period of warming between 900-1000 AD.

The research team suggests that an increase in sediment flux to the fjords resulted from elevated precipitation in the region that maintained glacier expansion, despite the higher loss in ice mass due to increased summer temperatures. This increase in sedimentation led to decreased water depth, slowing the calving rate and allowing for continued advance despite the elevated temperatures.

Pollock will talk about "Portfolios as a Learning and Assessment Tool in an Undergraduate Mineralogy/Petrology Course." Pollock, who joined Wooster's faculty this fall, will explain how portfolios of student work "showcase student mastery of concepts while encouraging them to reflect on the learning process."

Last fall she assigned a portfolio project to 10 geology majors at Dickinson College and provided them with a list of 31 specific learning objectives.

The students were asked to gather evidence and explain how it addressed their mastery of each given concept.

In assessing their experience, most students reported that the portfolio helped them identify and distinguish between concepts they did and did not understand, according to Pollock. Students also reported the process helped them to retain more concepts from the course, and they would likely refer to their portfolios in the future.

Fetters will discuss "Tlingit Legends and Tree Ring Dated Little Ice Age Maximum in Glacier Bay during the Early 18th Century."

Fetters, who co-authored the paper with Wiles, Krivicich, former Wooster faculty member Johannes Koch, and Daniel Lawson of the U.S. Army Cold Regions Research and Engineering Laboratory, Hanover, studied the catastrophic rates of ice expansion in Glacier Bay, Alaska, which forced Tlingit villagers to flee their communities.

In their analysis of the tree-ring calendar dates from the outer rings of logs recovered from the intertidal zones of the southern reaches of the Glacier Bay fjord complex, the authors also pointed out that the tree rings show a period of extreme cold between 1752 and 1754, which may have resulted from the expanding Glacier Bay icefield.

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