Constraints on the production of phosphine by Venusian volcanoes

Kavli Affiliate: Sara Seager

| First 5 Authors: William Bains, Oliver Shorttle, Sukrit Ranjan, Paul B. Rimmer, Janusz J. Petkowski

| Summary:

The initial reports of the presence of phosphine in the cloud decks of Venus
has led to the suggestion that volcanism was the source of phosphine, through
volcanic phosphides ejected into the clouds. Here we examine the idea that
mantle plume volcanism, bringing material from the deep mantle to the surface,
could generate observed amounts of phosphine through interaction of explosively
erupted phosphide with sulfuric acid clouds. Direct eruption of deep mantle
phosphide is unphysical, but shallower material could contain traces of
phosphide, and could be erupted to the surface. Explosive eruption that
efficiently transported material to the clouds would require ocean:magma
interactions or subduction of hydrated oceanic crust, neither of which occur on
modern Venus. The transport of erupted material to altitudes coinciding with
the observations of phosphine is consequently very inefficient. Using the model
proposed by Truong and Lunine as a base case, we estimate that an eruption
volume of at least 21,600 km3/year would be required to explain the presence of
1 ppb phosphine in the clouds. This is greater than any historical terrestrial
eruption rate, and would have several detectable consequences for remote and in
situ observations to confirm. More realistic lithospheric mineralogy, volcano
mechanics or atmospheric photochemistry require even more volcanism.

| Search Query: ArXiv Query: search_query=au:”Sara Seager”&id_list=&start=0&max_results=10

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