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SUMMARY:Isotopes in volcanic emissions: links to Earth’s ancient past an
 d not-so-distant future - Emily Mason (University of Cambridge)
DTSTART:20171009T163000Z
DTEND:20171009T173000Z
UID:TALK86831@talks.cam.ac.uk
CONTACT:Charlie Eardley
DESCRIPTION:The origin of carbon coming from volcanic arc outgassing is a 
 fundamental yet unanswered question. In a newly compiled global data set f
 or carbon and helium isotopes from volcanic arcs we demonstrated that the 
 carbon isotope composition of mean global volcanic gas is considerably hea
 vier than the canonical mid-ocean ridge basalt value of –6.0‰\, sugges
 ting a significant carbonate contribution to global volcanic CO2 emissions
 . The largest volcanic CO2 emitters\, such as Mount Etna\, outgas carbon w
 ith higher δ13C and are often located in mature continental arcs that hav
 e accreted carbonate platforms\, indicating that reworking of crustal lime
 stone is an important source of volcanic carbon. \n\nThe flux of carbon in
 to and out of Earth’s surface environment has implications for Earth’s
  climate and habitability. Our revised value for the global average isotop
 ic composition of volcanic CO2 calls for a re-examination of estimates of 
 fractional organic carbon burial (and therefore the progressive oxygenatio
 n of the planet) over Earth’s history. It also challenges the widely-hel
 d assumption that this value has not changed over geological time. Superco
 ntinent formation and break-up has modulated the make-up of volcanic arcs 
 and thus the isotopic composition of the carbon released throughout Earth
 ’s history. \n\nChanges in isotopic compositions of volcanic gases have 
 also been linked to increases in eruptive activity. With the development o
 f devices that can make in-situ measurements\, the use of isotopes as a fu
 ndamental tool in volcanic monitoring has the potential to improve our pre
 dictive capabilities.
LOCATION:Department of Earth Sciences
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