December 2nd: Sampling a Cascadia core

A sampled core from the Cascadia Margin

Chris: These two stitched photos show one of the cores from the Cascadia margin Chris has sampled . The plastic sampled boxes have been pushed into the core, then carefully pulled back out with (hopefully) undisturbed sediments inside. A foam plug is put in the hole left behind to stop the remaining core material collapsing on itself.

This section of core is notable because of the clear change in lithology from dark silt and clay to lighter sand and silt at around the 18cm mark. The original core log suggests it is a turbidite deposit. Careful study of many cores has shown that large subduction zone earthquakes appear to trigger submarine landslides that generate turbidites all along the Cascadia margin. Could we be seeing a fingerprint of the 1700 quake?

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