Abstract Details
(2020) Olivine and Glass Chemistry Record Cycles of Plumbing System Evolution after Summit Collapse at Kīlauea Volcano (HI)
Lynn K, Rose T & Swanson D
https://doi.org/10.46427/gold2020.1670
05c: Plenary Hall, Friday 26th June 00:51 - 00:54
Kendra Lynn
View abstracts at 4 conferences in series
Timothy Rose View all 2 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Donald Swanson View all 3 abstracts at Goldschmidt2020
Timothy Rose View all 2 abstracts at Goldschmidt2020 View abstracts at 2 conferences in series
Donald Swanson View all 3 abstracts at Goldschmidt2020
Listed below are questions that have been submitted by the community that the author will try and cover in their presentation. To submit a question, ensure you are signed in to the website. Authors or session conveners approve questions before they are displayed here.
Submitted by Marc Norman on Monday 22nd June 03:33
Great talk and a compelling story. Just wondering if there might be any trace element or isotopic data that might point toward crustal interaction of the magmas during periods of more significant FC? M. Norman
Hi Marc - thanks for this question. What's interesting is that magma mixing (I think this is what you mean by "crustal interaction of the magmas" in your question?) is always a dominant process at Kilauea, both in effusive+explosive periods and before+after collapse events. In a more detailed version of the olivine Fo figure I use in my talk, many of the eruptions have bimodal populations of Fo contents between the high-Fo and low-Fo end members, showing the deeper primitive component seen following collapse events is almost always mixing with shallower crustal magmas. Over time we end up losing the high-Fo signal and bimodal populations as compositions evolve toward the "steady state" end member I describe. This is also seen in glass minor elements (mixing trends between magma end members). During periods of more significant FC, mixing signals are not as clear because incoming mafic compositions are diluted by the reservoirs I think. I would really love to see isotopic data for the Keanakakoi period compared to the modern historical eruptions, as Pietruszka and Garcia (1999), Pietruszka et al. (2015), and Pietruszka et al. (2018) all point to crustal reservoirs that are long-lived at least on the decadal scale during the modern historical period. I wonder if Aaron is working on this (or would want to?) I hope this answers your question, I'm happy to discuss further.
Great talk and a compelling story. Just wondering if there might be any trace element or isotopic data that might point toward crustal interaction of the magmas during periods of more significant FC? M. Norman
Hi Marc - thanks for this question. What's interesting is that magma mixing (I think this is what you mean by "crustal interaction of the magmas" in your question?) is always a dominant process at Kilauea, both in effusive+explosive periods and before+after collapse events. In a more detailed version of the olivine Fo figure I use in my talk, many of the eruptions have bimodal populations of Fo contents between the high-Fo and low-Fo end members, showing the deeper primitive component seen following collapse events is almost always mixing with shallower crustal magmas. Over time we end up losing the high-Fo signal and bimodal populations as compositions evolve toward the "steady state" end member I describe. This is also seen in glass minor elements (mixing trends between magma end members). During periods of more significant FC, mixing signals are not as clear because incoming mafic compositions are diluted by the reservoirs I think. I would really love to see isotopic data for the Keanakakoi period compared to the modern historical eruptions, as Pietruszka and Garcia (1999), Pietruszka et al. (2015), and Pietruszka et al. (2018) all point to crustal reservoirs that are long-lived at least on the decadal scale during the modern historical period. I wonder if Aaron is working on this (or would want to?) I hope this answers your question, I'm happy to discuss further.
Submitted by Marc Norman on Thursday 25th June 04:53
Hi Kendra - Thanks for your detailed answer. Actually, by 'crustal interaction' I was thinking more in the continental sense of assimilation or addition of non-magmatic (hydrothermal?) components rather than mixing between evolved and primitive magmas. E.g., some early work on O-isotopes in Hawaiian basalts suggested additional of hydrothermally-altered lower crust, either from deeper levels within the volcanic pile or from lithospheric sources. Obviously its a continuum and difficult to disentangle! Perhaps we can catch up later to discuss.
Hi Marc - thanks for clarifying! No, I have not done any work in that area, and I know Mike Garcia has previous work on O-isotopes during the modern historical period. Certainly it would be good to have those data (or examine other proxies) for the older explosive eruptions - a future endeavor!
Hi Kendra - Thanks for your detailed answer. Actually, by 'crustal interaction' I was thinking more in the continental sense of assimilation or addition of non-magmatic (hydrothermal?) components rather than mixing between evolved and primitive magmas. E.g., some early work on O-isotopes in Hawaiian basalts suggested additional of hydrothermally-altered lower crust, either from deeper levels within the volcanic pile or from lithospheric sources. Obviously its a continuum and difficult to disentangle! Perhaps we can catch up later to discuss.
Hi Marc - thanks for clarifying! No, I have not done any work in that area, and I know Mike Garcia has previous work on O-isotopes during the modern historical period. Certainly it would be good to have those data (or examine other proxies) for the older explosive eruptions - a future endeavor!
Submitted by Margaret Hartley on Thursday 25th June 13:24
Hi Kendra. Great talk and a very interesting story. It looks like the erupted glass compositions are highly variable over the Keanakako'i period so I was wondering how you calculated the trends of changing MgO content over time?
Hi Margaret - I chose to show all glass analyses as individual points because (as you point out) there's a lot of variability. The lines drawn are meant to simply highlight the maximum MgO contents we see in erupted products - there is no calculation, and certainly their trends are not as strong as our olivine Fo populations. I highlight max Fo because they suggest (1) that these glasses are sourced from deeper within the crustal reservoir system, (2) have not been evolved significantly by fractional crystallization during prolonged storage, and (3) have not been smeared out by mixing with more evolved compositions (we know mixing is occurring [Lynn et al., 2017 CMP], but it must be incomplete for high-MgO signatures to survive).
Hi Kendra. Great talk and a very interesting story. It looks like the erupted glass compositions are highly variable over the Keanakako'i period so I was wondering how you calculated the trends of changing MgO content over time?
Hi Margaret - I chose to show all glass analyses as individual points because (as you point out) there's a lot of variability. The lines drawn are meant to simply highlight the maximum MgO contents we see in erupted products - there is no calculation, and certainly their trends are not as strong as our olivine Fo populations. I highlight max Fo because they suggest (1) that these glasses are sourced from deeper within the crustal reservoir system, (2) have not been evolved significantly by fractional crystallization during prolonged storage, and (3) have not been smeared out by mixing with more evolved compositions (we know mixing is occurring [Lynn et al., 2017 CMP], but it must be incomplete for high-MgO signatures to survive).
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