So, can I assume that it is a natural by product of carbon degradation ?
Entropy
Helium is an element. It is produced by the fusion of Hydrogen inside a star.
I don’t what nuclear fission reactions produce helium, nor the theory about why/how there is helium trapped in the earth’s shell. Now you have my curiosity aroused ;-)
Ahhh ... wiki says ...
Most terrestrial helium present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium), as the alpha particles emitted by such decays consist of helium-4 nuclei. This radiogenic helium is trapped with natural gas in concentrations up to 7% by volume, from which it is extracted commercially by a low-temperature separation process called fractional distillation.