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Seminar Series: Britta Jensen, University of Alberta
February 27, 2020 @ 12:00 pm - 1:00 pm
Earth Sciences Seminar Series
February 27, 2020 at 12 PM ES2093
Britta Jensen, University of Alberta
“Extending the reach of volcanic ash: cryptotephra in eastern North America”
Tephrochronology (-stratigraphy) is the use of volcanic ash (tephra) deposits to date and correlate archaeological, paleoenvironmental and geological records. North America has been in the forefront of developing this field, with research focused in the west – near volcanoes. Researchers in Europe had few visible tephras to work with, but circumvented this problem by discovering cryptotephra (tephras not visible to the naked eye). Widely utilized in Europe and in ice core research, cryptotephra studies are in their relative infancy in North America. Until 2012, over 20 years after cryptotephra research was established, only two studies based in North America were published, both from Alaska. For this talk, I am going to explore more recent research that is exploring the potential of cryptotephra in north-eastern North America. This work is unveiling a wealth of deposits, from Michigan to Newfoundland, collectively covering the last ca. 13,500 years. This region appears to be ideally placed to capture tephras from most major arcs in the northern hemisphere – from Kamchatka, Trans-Mexican Volcanic Belt, Wrangells, Cascades, and potentially the Kuriles and Japan. This unique record has unveiled the potential to link paleoenvironmental records from the west Pacific to north Atlantic, and the surprising distances ash can travel. It has also led us to frame new questions beyond the classic applications of tephrochronology, looking at further insights these deposits can provide to fields from volcanology to paleoclimatology.