Abstract Details
(2020) Planetary and Extrasolar Insights on the Lower Mantle Source of the Hawaiian, and Other Plumes
Putirka K
https://doi.org/10.46427/gold2020.2132
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05h: Room 2, Saturday 27th June 05:51 - 05:54
Keith Putirka
View abstracts at 3 conferences in series
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Submitted by Aaron Pietruszka on Monday 22nd June 23:02
Hi Keith. I have a question about your model. Do your calculations preclude the presence of >20% recycled MORB in the source region of plumes, or is there a way to make it work? Thanks!
Hi Keith. I have a question about your model. Do your calculations preclude the presence of >20% recycled MORB in the source region of plumes, or is there a way to make it work? Thanks!
Submitted by Keith Putirka on Wednesday 24th June 00:09
Hi Aaron - thanks for asking a question. Yes, I think adding 20% MORB is not a problem at all. Let's call that source "Plume Source Mantle" or PSM. A problem arises, though, if we let PSM make up a large fraction of the mantle. If this PSM is only a small fraction of the mantle (say the lower 200 km or whatever you like), then bulk silicate Earth, or BSE is effectively unchanged from what has been proposed by many others, and McDonough and Sun (1995) is as good an estimate as any (recent estimates are effectively the same). But if PSM makes up the entire lower mantle, now BSE starts to look a little odd, compared to estimates of bulk silicate Mars, Moon and Mercury (which on average approach C1 or Sol) as well as the kinds of silicate mantles we would expect from local stars. Such a composition would be distinctly lower in MgO + FeOt, for example. So I would argue that PSM probably just exists in the lowermost mantle.
Hi Aaron - thanks for asking a question. Yes, I think adding 20% MORB is not a problem at all. Let's call that source "Plume Source Mantle" or PSM. A problem arises, though, if we let PSM make up a large fraction of the mantle. If this PSM is only a small fraction of the mantle (say the lower 200 km or whatever you like), then bulk silicate Earth, or BSE is effectively unchanged from what has been proposed by many others, and McDonough and Sun (1995) is as good an estimate as any (recent estimates are effectively the same). But if PSM makes up the entire lower mantle, now BSE starts to look a little odd, compared to estimates of bulk silicate Mars, Moon and Mercury (which on average approach C1 or Sol) as well as the kinds of silicate mantles we would expect from local stars. Such a composition would be distinctly lower in MgO + FeOt, for example. So I would argue that PSM probably just exists in the lowermost mantle.
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