Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8906775 | Earth and Planetary Science Letters | 2018 | 12 Pages |
Abstract
Our estimate of the mantle 3He flux is the first determined independently of oceanographic 3He measurements, and consequently represents a time-integrated flux substantially longer than â¼1000 years. And although at the high end of the range of previous estimates, our estimate does not resolve the long-standing heat-helium paradox. Additionally, our requirement for heterogeneous pre-degassing 3He/22Ne and 3He/36Ar ratios between samples is contrary to conclusions of previous applications of disequilibrium degassing models, which advocated uniform ratios. Furthermore, we find that CO2/Ba ratios are highly variable in MORB samples, but still consistent with an average mantle mass ratio of â¼100. However, estimating pre-degassing CO2 concentrations and the mantle CO2 flux depend strongly on the poorly-constrained carbon diffusivity. Consequently, our demonstration of the prevalence of disequilibrium during mid-ocean ridge degassing, and the potential for disequilibrium in other volcanic settings, highlights the need for better characterization of the physical parameters associated with volcanic degassing.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth and Planetary Sciences (General)
Authors
Jonathan M. Tucker, Sujoy Mukhopadhyay, Helge M. Gonnermann,