Sulphur-cycle dominated planets

A paper on detecting whether terrestrial planets are dominated by the carbon cycle or the sulphur cycle. Sulphur cycle involves eruption of SO₂ and H₂S, and sulphur removed from the atmosphere as precipitation of sulphites, or photochemical activity. Might be more common on volcanically-active, dry super-earths.

Sulfuric Acid Rain?
What acid rain on Earth is.

Acid rain on Earth, of course, has a lot of water. I wouldn't say that it counts as a Earth-based sulfur cycle, since it is dependent on the water cycle. I think the paper is talking about a cycle that is less dependent on water.

"Dominating cycle" is a tricky one to define.

A planet could have a major amount of one gas, yet have it's properties and chemistry be dominated by a minor component.

F'r instance, Venus has CO2 as it's primary atmospheric component. But it's climate and chemistry appear dominated by it's fascinating sulfur cycle, since the carbon dioxide is sealed in the atmosphere (no carbon cycle).

Check out this abstract on how the sulfur cycle on Venus drives it's climate:
Bullock and Greenspoon Venus Geochemistry: Progress, Prospects, and New Missions (2009) Abstract 2024. "THE ROLE OF SULFUR IN DETECTING RECENT CLIMATE CHANGE ON VENUS."
[BONUS: chemical equations]

(And to make things really messy, the sulfur cycles goes through carbon containing intermediates. I imagine a predominate sulfur dioxide containing planet would likewise use trace carbon containing compounds as intermediates in it's complex chemistry.)

In the case of Venus then, since the atmospheric carbon is not a part of the geochemical cycle, despite being the dominant component, the sulfur cycle on Venus would thus be the only active cycle. Would that not make it the dominant cycle anyway?

Juramike wrote:[BONUS: chemical equations]

Haha you think like I do

Is it possible for a planet to have more than one geochemical cycle? Would Earth's carbon cycle + water cycle constitute an example?

Sirius_Alpha wrote:In the case of Venus then, since the atmospheric carbon is not a part of the geochemical cycle, despite being the dominant component, the sulfur cycle on Venus would thus be the only active cycle. Would that not make it the dominant cycle anyway?

The Venusian sulfur cycle seems to be the dominant cycle. But, it might not necessarily be spectroscopically dominant from a distance.

The point I'm trying to make is that the major stuff we'd see spectroscopically from a distance might not be the player driving the system. The meek might inherit the Earth, so to speak.

I personally think it is very likely that most atmospheric/geochemical systems will have multiple cycles going on at the same time with a lot of cross talk between them.