JMU students dig into 2.6 million years of Earth’s climate history


by Eric Gorton



Sediment cores drilled from ocean floors tell stories just like pages in a book, stories that include a geologic accounting of Earth’s climate going back millions of years. 

Students in Kristen St. John's upper-level geology courses at James Madison University are learning that story firsthand this semester as they sift through samples from cores drilled from the depths of the Gulf of Mexico and the North Pacific. 

What the students will discover, said St. John, a veteran researcher in the International Ocean Discovery Program, are clues to the climate in two distinct areas of the planet spanning the same geologic time period, from the last ice age — which started about 2.6 million years ago and ended about 11,700 years ago — to the present. Among the artifacts students will uncover are fossils, minerals and grains of various sizes. The way those artifacts change over time through the samples reveals clues to changes in climate. 

St. John, who has gone to sea with teams that dig the cores, hopes to be part of another drilling expedition, perhaps in the Arctic in 2021. “The Arctic is so sensitive to climate change,” she said. “We want a longer and more detailed record of the history.” 

After an initial inspection by researchers on the ship, the cores are stored and made available to researchers from around the world. St. John said having real samples to work with has inspired many of her students to pursue science careers. 

Area residents can get a feel for ocean core research this month by visiting displays and programs showcasing the work of the International Ocean Discovery Program through a pop-up science program, "In Search of Earth's Secrets." 

A partnership between the IODP, JMU, the National Science Foundation and local organizations, the program features six kiosks with hands-on learning activities related to the science performed by St. John and her research colleagues from around the world, and an inflatable ship resembling the JOIDES Resolution, the ship that takes teams of scientists to sea to dig the cores. The kiosks are set up at each branch of Massanutten Regional Library through Sept. 12. All the kiosks and the inflatable ship will be set up at the main branch in downtown Harrisonburg on Saturday, Sept. 14. The complete program will also be set up at Valley Mall on Sept. 15, and at the Lucy F. Simms Continuing Education Center on Nov. 1. 

For more information, contact Eric Gorton at or 540-908-1760.



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Published: Friday, September 6, 2019

Last Updated: Wednesday, November 1, 2023

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