Ashes to ashes

Fingerprinting volcanic eruptions helps further complete climate puzzles.

Jennifer Pascoe - 24 November 2017

When it comes to understanding the past in order to predict the future, Britta Jensen, new
assistant professor in the Department of Earth and Atmospheric Sciences, takes a keen interest
in the study of volcanic ash, also known as tephrochronology.

This rapidly growing field of science uses the unique geochemical fingerprint of volcanic ashes
spread around the globe by violent eruptions to date and correlate environmental records to
provide a fuller picture of past environmental change.

"In climate change science, we're always looking for a cause and effect," said Jensen. "You
don't necessarily get a complete record of past climate change by just looking at one site. A
volcanic ash acts as a tie-line between different sources of climate information, like ice cores,
peat bogs or lake sediments, each which tells a different part of the story about past climates
and environments. This can help us get a more complete picture of some past climate events."

Jensen explained how uncovering crypto-tephra- -volcanic ash deposits that can't be seen with
the naked eye-has greatly expanded the region that we can use tephrochronology in, and has
shown us that ash from volcanic eruptions can travel much further than we previously thought it
could. The geologist said this has major implications for hazard planning against future impacts
from volcanic eruptions, for example.

"The other reason to study volcanic ash are the stories they tell us about the volcanoes
themselves-- these are geologic records of volcanic eruptions. How often have they erupted? Is
there a pattern to their eruptions? How can this information help us understand how they may
behave in the future? The volcanic ash deposits I study, ones far from the volcanoes, are very
important in supplementing studies closer to or on the volcanoes themselves. They give us a
more complete history of their past behavior, which is incredibly important in understanding the
hazard they represent, and can help us better prepare for the future."

Prior to starting her academic appointment, Jensen completed a stint at the Royal Alberta
Museum (RAM), helping to create new exhibitions for the new museum slated to open in 2018.
Previous to the RAM, and following a PhD with UAlberta Professor Duane Froese, Jensen
completed an NSERC postdoctoral fellowship in Belfast. Jensen said Europe is ahead of North
America in its work in "crypto"tephrochronology, and she's excited to impart that knowledge on
her students here in Canada. Jensen will be teaching the first year Earth and Atmospheric
Sciences field school this spring. Her own fieldwork takes her mostly to the Yukon and Alaska.