Extended Data Fig. 8: 130Xe fluxes over time in successful model realizations. | Nature

Extended Data Fig. 8: 130Xe fluxes over time in successful model realizations.

From: Xenon isotopic constraints on the history of volatile recycling into the mantle

Extended Data Fig. 8

al, Regassing fluxes (ac), degassing fluxes (df), net fluxes (g), 130Xed concentrations (h, i), mass flux (j) and mantle 130Xe concentrations (k, l) are illustrated for an initial mantle 130Xe concentration of 3.2 × 108 atoms per gram (LV = 1%), a convecting mantle reservoir that is 90% of the mass of the whole mantle, and 8 mantle reservoir masses processed over Earth history. Fluxes are reported in moles per year and concentrations are reported in moles per gram. Panels in the left column show results from all successful model realizations (same results as those shown in Figs. 3, 4) and illustrate the 130Xe regassing flux (a), 130Xe degassing flux (d), 130Xe net flux (g) and mass flux over time (j). Panels in the central column show zoomed-in windows with only low-130Xed successful model realizations (light-blue lines), as these largely overlap with each other and are difficult to resolve in the full-scale panels. The right column replicates the central column with semi-logarithmic axes. The regassing 130Xe flux time series (ac) is the product of the downwelling mass flux time series (j; exponentially decreasing with time) and the 130Xed concentration over time (sigmoidally increasing; h, i). Time series for 130Xe regassing fluxes with high present-day 130Xed (darkest-blue lines in a) start near zero owing to near-zero 130Xe concentrations and then rapidly rise as the 130Xed concentration increases faster than the modest decline in mass flux later in Earth history. 130Xe flux time series with low present-day 130Xed (lightest-blue lines in ac) start a protracted, low-magnitude rise relatively early in Earth history. These translate to regassing flux time series that start near zero, rise and then decline with the exponentially decreasing mass flux (b, c). Time series for 130Xe degassing fluxes (df) are the product of the downwelling mass flux time series (j) and the mantle 130Xe concentration over time (k, l), which responds to both degassing and regassing. The net flux over time (g) is the difference between the regassing flux and degassing flux at any given time. The mantle shifts from net degassing to net regassing at some time after 2.5 Gyr ago.

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