BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Preliminary results of the 2023 geochemical exploration of volcani
 c volatiles at Deception Island (Antarctica): new inferences on the mantle
  heterogeneity - Antonio Caracausi\, Istituto Nazionale di Geofisica e Vul
 canologia (INGV)\, Palermo\, Italy
DTSTART:20241127T140000Z
DTEND:20241127T150000Z
UID:TALK223120@talks.cam.ac.uk
CONTACT:Adriano Gualandi
DESCRIPTION:Earth’s degassing\, mostly related to magma dynamics and vol
 canic eruptions\, provides the raw material for the formation of the atmos
 phere\, which is essential for life. This fact is not evident in polar reg
 ions where there is still a lack of knowledge about the mantle beneath\, d
 ue to the extreme conditions to work in these areas. In addition\, for the
  mantle studies\, the best samples come from active volcanic areas\, thus 
 increasing the mentioned difficulties related to potential emergencies in 
 case of volcanic crisis.\n\nHere I discuss the preliminary results of a ge
 ochemical survey of the volatiles emitted at Deception Island (DI) active 
 volcano (Bransfield Strait\, Antarctica). In 2023 we explored the gas emis
 sions of the whole island and collected fluids emitted from fumaroles (T u
 p to 104°C) and bubbling in seawater (< 10 m depth) along the Port Foster
  bay shore. We discover that the bubbling gases sampling is strongly condi
 tioned by the tidal waves\, which in turn reduces the time efficiency to f
 inalize the gas collection. This increases the extreme difficulties in exp
 loring and monitor this active volcano.\n\nTwo families of gases are disti
 nguished in terms of chemical composition: CO2 and N2-rich\, respectively.
  The helium (He) isotopic signature is in the range of the MORB mantle val
 ues (8.0±1Ra\; Ra as the ratio in air). We also recognized the presence o
 f an atmospheric component that is higher far from the bay shore. The CCO2
 -He systematics explains the variation of the chemical and isotopic compos
 ition of pristine mantle volatiles due to magma degassing at depth and wat
 er-gas interaction in the shallow layers before reaching surface. Our stud
 y demonstrates that the C/3He and the delta13CCO2 of the mantle source fee
 ding the DI volcanic gases is MORB-type. Furthermore\, the N-isotopes indi
 cate an N-rich-mantle relative to the average MORB mantle.
LOCATION:Wolfson Lecture Theatre
END:VEVENT
END:VCALENDAR