REFINING THE NOBLE GAS RECORD OF THE RéUNION MANTLE PLUME SOURCE: IMPLICATIONS ON MANTLE GEOCHEMISTRY
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dc.contributor.author | Hopp J. | |
dc.contributor.author | Trieloff M. | |
dc.date.accessioned | 2023-12-03T03:59:59Z | |
dc.date.available | 2023-12-03T03:59:59Z | |
dc.date.issued | 2005 | |
dc.identifier | https://www.elibrary.ru/item.asp?id=14744134 | |
dc.identifier.citation | Earth and Planetary Science Letters, 2005, 240, 3-4, 573-588 | |
dc.identifier.issn | 0012-821X | |
dc.identifier.uri | https://repository.geologyscience.ru/handle/123456789/42126 | |
dc.description.abstract | We report isotope analyses of helium, neon, argon, and xenon using different extraction techniques such as stepwise dynamic and static crushing, and high-resolution stepwise heating of three mantle xenoliths from Réunion Island. He and Ne isotopic compositions were similar to previously reported Réunion data, yielding a more radiogenic composition when compared to the Hawaiian or Icelandic mantle plume sources. We furthermore observed correlated 129Xe/130Xe and 136Xe/130Xe ratios following the mantle trend with maximum values of 6.93 ± 0.14 and 2.36 ± 0.06, respectively. High-resolution argon analyses resulted in maximum 40Ar/36Ar ratios of 9000–11,000, in agreement with maximum values obtained in previous studies. We observed a well-defined hyperbolic mixing curve between an atmospheric and a mantle component in a diagram of 40Ar/36Ar vs. 20Ne/22Ne. Using a mantle 20Ne/22Ne of 12.5 (Ne–B) a consistent 40Ar/36Ar value of 11,053 ± 220 in sample ILR 84-4 was obtained, whereas extrapolations to a higher mantle 20Ne/22Ne ratio of 13.8 (solar wind) would lead to a much higher 40Ar/36Ar ratio of 75,000, far above observed maximum values. This favours a mantle 20Ne/22Ne of about 12.5 considered to be equivalent to Ne–B. Extrapolated and estimated 40Ar/36Ar ratios of the Réunion, Iceland, Loihi, and MORB mantle sources, respectively, tend to be linearly correlated with air corrected 21Ne/22Ne and show the same systematic sequence of increasing relative contributions in radiogenic isotopes (Iceland–Loihi–Réunion–MORB) as observed for 4He/3He. In general, He–Ne–Ar isotope systematics of the oceanic mantle can be explained by following processes: (i) different degree of mixing between pure radiogenic and pure primordial isotopes generating the MORB and primitive plume (Loihi-type) endmembers; (ii) relatively recent fractionation of He relative to Ne and Ar, in one or both endmembers; (iii) after the primary fractionation event, different degrees of mixing between melts or fluids of MORB and primitive plume affinity generate the variety of observed OIB data, also on a local scale; (iv) very late-stage secondary fractionation during magma ascent and magma degassing leads to further strong variation in He/Ne and He/Ar ratios. | |
dc.subject | noble gas isotope systematics | |
dc.subject | Reunion hotspot | |
dc.subject | mantle plume sources | |
dc.subject | binary mixing scenarios | |
dc.title | REFINING THE NOBLE GAS RECORD OF THE RéUNION MANTLE PLUME SOURCE: IMPLICATIONS ON MANTLE GEOCHEMISTRY | |
dc.type | Статья | |
dc.identifier.doi | 10.1016/j.epsl.2005.09.036 |
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