The last time I worked on a story for the Indy about Ed Keller , the UCSB geologist who died in early September, it was the spring of 2019, and he was driving around Santa Barbara, calculating the age of prehistoric debris flows by looking at “neat boulders” — thousands of them. They were still in place, right where they had dropped out of rivers of mud and rock, ages ago.
Ed and his students were measuring the thickness of the oxidized crust or “weathering rind” that had built up on these boulders after they had been scraped clean by the prehistoric flows. Ed said he got so proficient, he could tell at a glance whether their crusts were geologically “young,” of “intermediate age,” or “very old,” that is, one or two inches thick and cracked like the shell of a turtle, signifying a debris flow more than 100,000 years old.
“You’ll never look at boulders the same way!” he said.