(2020) Halogen Heterogeneity in the Icelandic Mantle Source
Waters E, Hartley M, Burgess R, Pawley A, Halldórsson S & Shorttle O
03c: Room 1, Wednesday 24th June 00:06 - 00:09
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Hi Emma, Thanks so much for your presentation! It is a really nice model that you have build. Snæfellsnes is interesting, as it is different from the other active volcanic zones in Iceland. It is not related to an active rifting axis and it is located far from the inferred plume head. Moreover, 3He/4He systematics from Snæfellsnes are spot on MORB (8RA) which could suggest that the high 3He/4He Iceland plume is not contributing to the melts here. That makes me wonder: how do we generate secondary pyroxenites there? Where do we get the boyancy to carry/melt eclogite to form the pyroxenite? Or do you think the pyroxenites are unrelated to recycled crust? Thanks again.
Hi Maja, Thank you for your question. I'm not sure if you were in the session last night or not. We selected Snaefellsnes flank zone as a sample area for exactly the reasons you outlined as one of the main aims of the project overall is to look at any differences in the halogen budget of sources from melts which are both plume-influenced and not plume-influenced. You raise a very valid point on how pyroxenite would come to exist in the flank zone mantle source and this is not something we have given much consideration to at this point in the modelling. Our initial aim with the modelling was to see simply if the trace element signatures could be recreated using this technique. Your suggestion is something we would very much like to consider in the next stages of this work. We hope to have further halogen data once labs reopen (including Br and I) and plan to use ratios of halogen to similarly incompatible trace element pairs to look for any indication of a recycled crustal signature which could be linked to pyroxenite in the Icelandic mantle. If this something you would be interested in discussing more please feel free to contact me as I'd be happy to consider and discuss this further after the conference (firstname.lastname@example.org). Many thanks, Emma
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