RUSSIAN JOURNAL OF EARTH SCIENCES, VOL. 18, ES1003, doi:10.2205/2018ES000614, 2018

Figure 3. Xe isotope in mantle derivates. (a) Isotope composition of Xe from Victoriaquelle gas (Eifel, Germany), presented relative to air Xe: $\delta^i\mathrm{Xe} = 1000 \times \{[(^i\mathrm{Xe}/^{130}\mathrm{Xe)_{SAMPLE}}/^i\mathrm{Xe}/^{130} \mathrm{Xe)_{AIR}}] - 1\}$, parts per mil ($‰$). For comparison a three-component model of mantle Xe is presented, which includes: (1) subducted unfractionated air Xe (84%); (2) carbonaceous chondrite Q-Xe (16%); this mixture is shown by rhombs; (3) radiogenic $^{129}$Xe(I) and fission $^{131-136}$Xe(Pu) isotopes are shown by arrows. Modified after Caracausi et al. [2016]. (b) The radiogenic Xe isotope ratios in mantle rocks and gases, calculated relative to isotope composition of the average carbonaceous chondrite xenon after Parai and Mukhopadhyay [2015] and Caracausi et al. [2016]. These authors considered the different $^{129}$Xe(I)/$^{136}$Xe(Pu) ratios in MORB-source and PLUMR-source materials as indication of different formation and evolution of the respective mantle reservoirs. The interpretation proposed in this contribution takes into account rather different "initial" $^{129}$Xe(I)/$^{136}$Xe(Pu) ratios in the terrestrial regolith and the early crust (Section 2.4) and on this ground envisages some heterogeneity of the PLUME-source reservoir, in accord with data of the U-Th-He isotope systematics (Section 2.5.3).

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Citation: Tolstikhin I. N. (2018), The late Earth's accretion: Processes and materials, Russ. J. Earth Sci., 18, ES1003, doi:10.2205/2018ES000614.

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