Evergreen Line 'cores' provide earth scientists with wealth of historical data
As the long-awaited Evergreen SkyTrain Line opens this week, two SFU earth scientists are uncovering a wealth of history about the region from drill cores associated with the line’s tunnel excavation. Lionel Jackson and Brent Ward say the cores are providing a wealth of new detail about the area dating back thousands of years.
“These cores represent an amazing geological archive of the glacial history of the Lower Mainland,” says Ward. Some cores yet to be studied extend below sea level—an earth scientist’s dream, given such material is typically unattainable in an urban area.
Four of several dozen cores are currently stored in Jackson’s garage in Coquitlam, moved there by crane by tunnel contractor SNC Lavalin—for analysis by the pair and one of Jackson’s graduate students.
“At first look, the paleogeography is quite a bit different than what we imagined,” says Jackson, an adjunct professor at SFU and an emeritus at the Geological Survey of Canada. While running a hand over a core, he points to a section of ‘broken’ sediment that was likely caused by the passage of glacial ice.
Jackson has determined that in the recent geologic past there was a deep valley between Burnaby Mountain and central Coquitlam that made them islands in the Salish Sea.
The cores record sediments associated with at least the last glacial cycle, and possibly earlier ones. He is eagerly awaiting radiocarbon analysis that will allow him to resolve the timing of glacial advances.
“To find a place where hundreds of metres of record are available to us is amazing. The cost of getting this sort of data would be astronomical. It will be invaluable for tracing the evolution of this area.”
The researchers hope to access the remaining cores to help complete their research.