DRILLING
Beneath Peru’s largest lake, geologists discover Earth’s
J
ust hours into a weeks-long project to core the sediment of Peru’s Lake Junín for clues to climate history, scientists made an exciting discovery: as some had speculated, this lake wasn’t always a lake. Grace Delgado ’14 was taking samples on the deck of a drilling barge when she noticed a sudden change in the sediment layers. “Look at this. It used to be a peat bog,” she said. “The lake actually dried out.” Indeed, about 55 meters down, the slippery gray clay from a glacial period suddenly gave way to dry, dark brown, decayed plant matter that looked and
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smelled like the packaged peat you’d find at the garden center. Sometime around 100,000 years ago, Lake Junín (hoo-NEEN), high in the remote central Andes, recorded a sudden change from a cold to a warm climate. And chances are this could have been a global event. Last summer, Delgado and Nick Weidhaas ’15 were with an international team of 30 scientists led by Prof. Don Rodbell to extract the first continuous high resolution core of the ancient lake. Funded by the National Science Foundation and the International
Continental Drilling Program, the Lake Junín Project is aimed at furthering our understanding of the Earth’s natural climate cycles over the past one million years. It also has important implications for our climate future. Delgado and Weidhaas are among the dozens of Union students and alumni who have done fieldwork with Rodbell in Peru and other parts of South America. Before this trip, their deepest core of Lake Junín—made with a hand tool—went down only 25 meters, about 50,000 years of deposits. So, nearly every sample that emerged