# What are the natural causes for methane formation?

Natural gas is mostly made of methane ($\ce{CH4}$). Methane can be produced as a result of microbes eating organic matter. But can it also be naturally formed without any assistance from organic matter? Perhaps in conditions such as those found on the early Earth?

• Gasoline is not 'mostly made of methane'. You might have some more informed questions after doing some reading. – kwinkunks Feb 2 '16 at 0:28
• Maybe you're thinking of natural gas. Gasoline, containing things like isooctane, butane, and 3-ethyltoluene, is a much more complex hydrocarbon than methane, which is the most simple of them. – BillDOe Feb 2 '16 at 1:34
• – user5434678 Feb 4 '16 at 10:19
• It is the most common combination of the first and fourth most common elements in universe. And one of the most common compounds in the universe. I know of dozens of ways of making methane abiotically. You really might want to refine your question. – John Dec 19 '16 at 3:00
• So your fundamental answer is yes, and then add a little background to it. Perhaps discuss some that may potentially be considerable sources currently or in likely previous Earth environments, maybe 1 or 2 interesting or funny, and I'd think you'd have a great answer to satisfy this question – JeopardyTempest Dec 19 '16 at 4:45

The 'natural causes' of global methane emissions are, as you indicate, mostly of biological origin. To some extent it depends upon what you regard as 'natural'. There are many and differing estimates of global methane generation, of which I list a summary below. Those in bold you may regard as abiological. Values are in Mega-tonnes per year released to the atmosphere:

Wetlands 217

Fossil Fuels 96

Ruminants 89

Landfill 75

Geological sources 54

Freshwater 40

Biofuels 38

Rice growing 36

Oceans - DMS 20

Termites 11

Wildfires 10

It's a moot point as to whether degradation of dimethyl sulphide (DMS) is biological or not.

• Do you have the source? – farrenthorpe Jan 3 '17 at 2:41
• I can't remember the issue but I jotted the above numbers down from an article in New Scientist, a year or two ago. – Gordon Stanger Jan 4 '17 at 7:31
• You emphasized "oceans" but not "freshwater"? – Spencer Jan 9 '17 at 19:38

Yes

It is one of most common compounds in the universe.

https://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane

Which period of the early earth do you want to know about? the earliest atmosphere likely had less methane than now. http://science.sciencemag.org/content/308/5724/1014 But once life evolved methane rose. http://www.minersoc.org/pages/Archive-MM/Volume_62A/62a-2-751.pdf