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SUMMARY:[online] On Blue Ice: Antarctic Meteorites and Deepening Planetary
  Time - Alexis Rider\, University of Pennsylvania
DTSTART:20200604T140000Z
DTEND:20200604T150000Z
UID:TALK142417@talks.cam.ac.uk
CONTACT:Johanne M. Bruun
DESCRIPTION:During the Antarctic field season of 1969\, a group of Japanes
 e glaciologists stumbled on a unique find—nine meteorite fragments\, fro
 zen and embedded in a patch of ancient blue ice. After geochemical analysi
 s\, the find was revealed to be even more surprising: rather than being pi
 eces of one parent body\, the meteorites were a collection of different ro
 cks of varying terrestrial ages. Hearing of the Antarctic meteorites at a 
 Conference four years later\, geologist William Cassidy immediately suspec
 ted an explanation lay within the ice: slowly spreading from the center of
  the continent\, the Antarctic ice sheet was a "stranding surface" that co
 llected\, subsumed\, and finally revealed meteorites over a vast timeframe
 . Since then\, the Antarctic Search for Meteorites program (ANSMET)—a jo
 int venture between the NSF\, the Smithsonian Institution\, and NASA—has
  scoured patches of blue ice for the rare celestial objects\, collecting a
 s many as 6000 unique fragments in one field season.\n\nThis paper takes u
 p Antarctic meteorites as natural chronometers\, and traces how the space 
 rocks gave glaciologists and meteoriticists a unique temporal tool for und
 erstanding the shape and flow of the Antarctic ice sheet. While meteoritic
 ists were predominantly interested in the meteorites themselves—particul
 arly after waning enthusiasm for moon landings—glaciologists focused on 
 the ice in which they were encased: the preserved meteorites confirmed tha
 t blue ice was some of the oldest frozen matter on the planet\, samples of
  which could be used to reconstruct past climates. This paper proposes tha
 t by treating meteorites and ice as relational timekeepers\, rendered legi
 ble through similar modes of geochemical analysis\, geologists and astroph
 ysicists from the Smithsonian Astrophysical Observatory repositioned blue 
 ice as a scientific tool\, one that could connect the deep time of Antarct
 ic ice to the deeper time of the cosmos.\n
LOCATION:Zoom
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